Merge branch 'main' into n/t2

.github/workflows/release_actions.yml

@@ -6,26 +6,27 @@ jobs:
   discord_release:
     runs-on: ubuntu-latest
     steps:
-    - name: Get release URL
+      - name: Get release URL
-      id: get-release-url
+        id: get-release-url
-      run: |
+        run: |
-        if [ "${{ github.event.release.prerelease }}" == "true" ]; then
+          if [ "${{ github.event.release.prerelease }}" == "true" ]; then
-          URL="https://zed.dev/releases/preview/latest"
+            URL="https://zed.dev/releases/preview/latest"
-        else
+          else
-          URL="https://zed.dev/releases/stable/latest"
+            URL="https://zed.dev/releases/stable/latest"
-        fi
+          fi
-        echo "::set-output name=URL::$URL"
+          echo "::set-output name=URL::$URL"
-    - name: Get content
+      - name: Get content
-      uses: 2428392/gh-truncate-string-action@v1.2.0
+        uses: 2428392/gh-truncate-string-action@v1.3.0
-      id: get-content
+        id: get-content
-      with:
+        with:
-        stringToTruncate: |
+          stringToTruncate: |
-          📣 Zed [${{ github.event.release.tag_name }}](${{ steps.get-release-url.outputs.URL }}) was just released!
+            📣 Zed [${{ github.event.release.tag_name }}](${{ steps.get-release-url.outputs.URL }}) was just released!
 
-          ${{ github.event.release.body }}
+            ${{ github.event.release.body }}
-        maxLength: 2000
+          maxLength: 2000
-    - name: Discord Webhook Action
+          truncationSymbol: "..."
-      uses: tsickert/discord-webhook@v5.3.0
+      - name: Discord Webhook Action
-      with:
+        uses: tsickert/discord-webhook@v5.3.0
-        webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
+        with:
-        content: ${{ steps.get-content.outputs.string }}
+          webhook-url: ${{ secrets.DISCORD_WEBHOOK_URL }}
+          content: ${{ steps.get-content.outputs.string }}

Cargo.lock

@@ -1603,7 +1603,7 @@ dependencies = [
 
 [[package]]
 name = "collab"
-version = "0.27.0"
+version = "0.28.0"
 dependencies = [
  "anyhow",
  "async-trait",

crates/ai/src/test.rs

@@ -153,10 +153,17 @@ impl FakeCompletionProvider {
 
     pub fn send_completion(&self, completion: impl Into<String>) {
         let mut tx = self.last_completion_tx.lock();
-        tx.as_mut().unwrap().try_send(completion.into()).unwrap();
+
+        println!("COMPLETION TX: {:?}", &tx);
+
+        let a = tx.as_mut().unwrap();
+        a.try_send(completion.into()).unwrap();
+
+        // tx.as_mut().unwrap().try_send(completion.into()).unwrap();
     }
 
     pub fn finish_completion(&self) {
+        println!("FINISHING COMPLETION");
         self.last_completion_tx.lock().take().unwrap();
     }
 }
@@ -181,8 +188,10 @@ impl CompletionProvider for FakeCompletionProvider {
         &self,
         _prompt: Box<dyn CompletionRequest>,
     ) -> BoxFuture<'static, anyhow::Result<BoxStream<'static, anyhow::Result<String>>>> {
+        println!("COMPLETING");
         let (tx, rx) = mpsc::channel(1);
         *self.last_completion_tx.lock() = Some(tx);
+        println!("TX: {:?}", *self.last_completion_tx.lock());
         async move { Ok(rx.map(|rx| Ok(rx)).boxed()) }.boxed()
     }
     fn box_clone(&self) -> Box<dyn CompletionProvider> {

crates/ai2/src/auth.rs

@@ -1,4 +1,3 @@
-use async_trait::async_trait;
 use gpui2::AppContext;
 
 #[derive(Clone, Debug)]
@@ -8,10 +7,9 @@ pub enum ProviderCredential {
     NotNeeded,
 }
 
-#[async_trait]
+pub trait CredentialProvider {
-pub trait CredentialProvider: Send + Sync {
     fn has_credentials(&self) -> bool;
-    async fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential;
+    fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential;
-    async fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential);
+    fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential);
-    async fn delete_credentials(&self, cx: &mut AppContext);
+    fn delete_credentials(&self, cx: &mut AppContext);
 }

crates/ai2/src/providers/open_ai/completion.rs

@@ -1,10 +1,9 @@
 use anyhow::{anyhow, Result};
-use async_trait::async_trait;
 use futures::{
     future::BoxFuture, io::BufReader, stream::BoxStream, AsyncBufReadExt, AsyncReadExt, FutureExt,
     Stream, StreamExt,
 };
-use gpui2::{AppContext, Executor};
+use gpui2::{AppContext, BackgroundExecutor};
 use isahc::{http::StatusCode, Request, RequestExt};
 use parking_lot::RwLock;
 use serde::{Deserialize, Serialize};
@@ -105,7 +104,7 @@ pub struct OpenAIResponseStreamEvent {
 
 pub async fn stream_completion(
     credential: ProviderCredential,
-    executor: Arc<Executor>,
+    executor: Arc<BackgroundExecutor>,
     request: Box<dyn CompletionRequest>,
 ) -> Result<impl Stream<Item = Result<OpenAIResponseStreamEvent>>> {
     let api_key = match credential {
@@ -198,11 +197,11 @@ pub async fn stream_completion(
 pub struct OpenAICompletionProvider {
     model: OpenAILanguageModel,
     credential: Arc<RwLock<ProviderCredential>>,
-    executor: Arc<Executor>,
+    executor: Arc<BackgroundExecutor>,
 }
 
 impl OpenAICompletionProvider {
-    pub fn new(model_name: &str, executor: Arc<Executor>) -> Self {
+    pub fn new(model_name: &str, executor: Arc<BackgroundExecutor>) -> Self {
         let model = OpenAILanguageModel::load(model_name);
         let credential = Arc::new(RwLock::new(ProviderCredential::NoCredentials));
         Self {
@@ -213,7 +212,6 @@ impl OpenAICompletionProvider {
     }
 }
 
-#[async_trait]
 impl CredentialProvider for OpenAICompletionProvider {
     fn has_credentials(&self) -> bool {
         match *self.credential.read() {
@@ -221,52 +219,45 @@ impl CredentialProvider for OpenAICompletionProvider {
             _ => false,
         }
     }
-    async fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential {
+
+    fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential {
         let existing_credential = self.credential.read().clone();
-
+        let retrieved_credential = match existing_credential {
-        let retrieved_credential = cx
+            ProviderCredential::Credentials { .. } => existing_credential.clone(),
-            .run_on_main(move |cx| match existing_credential {
+            _ => {
-                ProviderCredential::Credentials { .. } => {
+                if let Some(api_key) = env::var("OPENAI_API_KEY").log_err() {
-                    return existing_credential.clone();
+                    ProviderCredential::Credentials { api_key }
-                }
+                } else if let Some(Some((_, api_key))) =
-                _ => {
+                    cx.read_credentials(OPENAI_API_URL).log_err()
-                    if let Some(api_key) = env::var("OPENAI_API_KEY").log_err() {
+                {
-                        return ProviderCredential::Credentials { api_key };
+                    if let Some(api_key) = String::from_utf8(api_key).log_err() {
-                    }
+                        ProviderCredential::Credentials { api_key }
-
-                    if let Some(Some((_, api_key))) = cx.read_credentials(OPENAI_API_URL).log_err()
-                    {
-                        if let Some(api_key) = String::from_utf8(api_key).log_err() {
-                            return ProviderCredential::Credentials { api_key };
-                        } else {
-                            return ProviderCredential::NoCredentials;
-                        }
                     } else {
-                        return ProviderCredential::NoCredentials;
+                        ProviderCredential::NoCredentials
                     }
+                } else {
+                    ProviderCredential::NoCredentials
                 }
-            })
+            }
-            .await;
+        };
-
         *self.credential.write() = retrieved_credential.clone();
         retrieved_credential
     }
 
-    async fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential) {
+    fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential) {
         *self.credential.write() = credential.clone();
         let credential = credential.clone();
-        cx.run_on_main(move |cx| match credential {
+        match credential {
             ProviderCredential::Credentials { api_key } => {
                 cx.write_credentials(OPENAI_API_URL, "Bearer", api_key.as_bytes())
                     .log_err();
             }
             _ => {}
-        })
+        }
-        .await;
     }
-    async fn delete_credentials(&self, cx: &mut AppContext) {
+
-        cx.run_on_main(move |cx| cx.delete_credentials(OPENAI_API_URL).log_err())
+    fn delete_credentials(&self, cx: &mut AppContext) {
-            .await;
+        cx.delete_credentials(OPENAI_API_URL).log_err();
         *self.credential.write() = ProviderCredential::NoCredentials;
     }
 }

crates/ai2/src/providers/open_ai/embedding.rs

@@ -1,7 +1,7 @@
 use anyhow::{anyhow, Result};
 use async_trait::async_trait;
 use futures::AsyncReadExt;
-use gpui2::Executor;
+use gpui2::BackgroundExecutor;
 use gpui2::{serde_json, AppContext};
 use isahc::http::StatusCode;
 use isahc::prelude::Configurable;
@@ -35,7 +35,7 @@ pub struct OpenAIEmbeddingProvider {
     model: OpenAILanguageModel,
     credential: Arc<RwLock<ProviderCredential>>,
     pub client: Arc<dyn HttpClient>,
-    pub executor: Arc<Executor>,
+    pub executor: Arc<BackgroundExecutor>,
     rate_limit_count_rx: watch::Receiver<Option<Instant>>,
     rate_limit_count_tx: Arc<Mutex<watch::Sender<Option<Instant>>>>,
 }
@@ -66,7 +66,7 @@ struct OpenAIEmbeddingUsage {
 }
 
 impl OpenAIEmbeddingProvider {
-    pub fn new(client: Arc<dyn HttpClient>, executor: Arc<Executor>) -> Self {
+    pub fn new(client: Arc<dyn HttpClient>, executor: Arc<BackgroundExecutor>) -> Self {
         let (rate_limit_count_tx, rate_limit_count_rx) = watch::channel_with(None);
         let rate_limit_count_tx = Arc::new(Mutex::new(rate_limit_count_tx));
 
@@ -146,7 +146,6 @@ impl OpenAIEmbeddingProvider {
     }
 }
 
-#[async_trait]
 impl CredentialProvider for OpenAIEmbeddingProvider {
     fn has_credentials(&self) -> bool {
         match *self.credential.read() {
@@ -154,52 +153,45 @@ impl CredentialProvider for OpenAIEmbeddingProvider {
             _ => false,
         }
     }
-    async fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential {
+    fn retrieve_credentials(&self, cx: &mut AppContext) -> ProviderCredential {
         let existing_credential = self.credential.read().clone();
 
-        let retrieved_credential = cx
+        let retrieved_credential = match existing_credential {
-            .run_on_main(move |cx| match existing_credential {
+            ProviderCredential::Credentials { .. } => existing_credential.clone(),
-                ProviderCredential::Credentials { .. } => {
+            _ => {
-                    return existing_credential.clone();
+                if let Some(api_key) = env::var("OPENAI_API_KEY").log_err() {
-                }
+                    ProviderCredential::Credentials { api_key }
-                _ => {
+                } else if let Some(Some((_, api_key))) =
-                    if let Some(api_key) = env::var("OPENAI_API_KEY").log_err() {
+                    cx.read_credentials(OPENAI_API_URL).log_err()
-                        return ProviderCredential::Credentials { api_key };
+                {
-                    }
+                    if let Some(api_key) = String::from_utf8(api_key).log_err() {
-
+                        ProviderCredential::Credentials { api_key }
-                    if let Some(Some((_, api_key))) = cx.read_credentials(OPENAI_API_URL).log_err()
-                    {
-                        if let Some(api_key) = String::from_utf8(api_key).log_err() {
-                            return ProviderCredential::Credentials { api_key };
-                        } else {
-                            return ProviderCredential::NoCredentials;
-                        }
                     } else {
-                        return ProviderCredential::NoCredentials;
+                        ProviderCredential::NoCredentials
                     }
+                } else {
+                    ProviderCredential::NoCredentials
                 }
-            })
+            }
-            .await;
+        };
 
         *self.credential.write() = retrieved_credential.clone();
         retrieved_credential
     }
 
-    async fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential) {
+    fn save_credentials(&self, cx: &mut AppContext, credential: ProviderCredential) {
         *self.credential.write() = credential.clone();
-        let credential = credential.clone();
+        match credential {
-        cx.run_on_main(move |cx| match credential {
             ProviderCredential::Credentials { api_key } => {
                 cx.write_credentials(OPENAI_API_URL, "Bearer", api_key.as_bytes())
                     .log_err();
             }
             _ => {}
-        })
+        }
-        .await;
     }
-    async fn delete_credentials(&self, cx: &mut AppContext) {
+
-        cx.run_on_main(move |cx| cx.delete_credentials(OPENAI_API_URL).log_err())
+    fn delete_credentials(&self, cx: &mut AppContext) {
-            .await;
+        cx.delete_credentials(OPENAI_API_URL).log_err();
         *self.credential.write() = ProviderCredential::NoCredentials;
     }
 }

crates/ai2/src/test.rs

@@ -100,16 +100,15 @@ impl FakeEmbeddingProvider {
     }
 }
 
-#[async_trait]
 impl CredentialProvider for FakeEmbeddingProvider {
     fn has_credentials(&self) -> bool {
         true
     }
-    async fn retrieve_credentials(&self, _cx: &mut AppContext) -> ProviderCredential {
+    fn retrieve_credentials(&self, _cx: &mut AppContext) -> ProviderCredential {
         ProviderCredential::NotNeeded
     }
-    async fn save_credentials(&self, _cx: &mut AppContext, _credential: ProviderCredential) {}
+    fn save_credentials(&self, _cx: &mut AppContext, _credential: ProviderCredential) {}
-    async fn delete_credentials(&self, _cx: &mut AppContext) {}
+    fn delete_credentials(&self, _cx: &mut AppContext) {}
 }
 
 #[async_trait]
@@ -162,16 +161,15 @@ impl FakeCompletionProvider {
     }
 }
 
-#[async_trait]
 impl CredentialProvider for FakeCompletionProvider {
     fn has_credentials(&self) -> bool {
         true
     }
-    async fn retrieve_credentials(&self, _cx: &mut AppContext) -> ProviderCredential {
+    fn retrieve_credentials(&self, _cx: &mut AppContext) -> ProviderCredential {
         ProviderCredential::NotNeeded
     }
-    async fn save_credentials(&self, _cx: &mut AppContext, _credential: ProviderCredential) {}
+    fn save_credentials(&self, _cx: &mut AppContext, _credential: ProviderCredential) {}
-    async fn delete_credentials(&self, _cx: &mut AppContext) {}
+    fn delete_credentials(&self, _cx: &mut AppContext) {}
 }
 
 impl CompletionProvider for FakeCompletionProvider {

crates/assistant/src/assistant_panel.rs

@@ -142,7 +142,7 @@ pub struct AssistantPanel {
     zoomed: bool,
     has_focus: bool,
     toolbar: ViewHandle<Toolbar>,
-    completion_provider: Box<dyn CompletionProvider>,
+    completion_provider: Arc<dyn CompletionProvider>,
     api_key_editor: Option<ViewHandle<Editor>>,
     languages: Arc<LanguageRegistry>,
     fs: Arc<dyn Fs>,
@@ -204,7 +204,7 @@ impl AssistantPanel {
 
                     let semantic_index = SemanticIndex::global(cx);
                     // Defaulting currently to GPT4, allow for this to be set via config.
-                    let completion_provider = Box::new(OpenAICompletionProvider::new(
+                    let completion_provider = Arc::new(OpenAICompletionProvider::new(
                         "gpt-4",
                         cx.background().clone(),
                     ));
@@ -259,7 +259,13 @@ impl AssistantPanel {
         cx: &mut ViewContext<Workspace>,
     ) {
         let this = if let Some(this) = workspace.panel::<AssistantPanel>(cx) {
-            if this.update(cx, |assistant, _| assistant.has_credentials()) {
+            if this.update(cx, |assistant, cx| {
+                if !assistant.has_credentials() {
+                    assistant.load_credentials(cx);
+                };
+
+                assistant.has_credentials()
+            }) {
                 this
             } else {
                 workspace.focus_panel::<AssistantPanel>(cx);
@@ -320,13 +326,10 @@ impl AssistantPanel {
         };
 
         let inline_assist_id = post_inc(&mut self.next_inline_assist_id);
-        let provider = Arc::new(OpenAICompletionProvider::new(
+        let provider = self.completion_provider.clone();
-            "gpt-4",
-            cx.background().clone(),
-        ));
 
         // Retrieve Credentials Authenticates the Provider
-        // provider.retrieve_credentials(cx);
+        provider.retrieve_credentials(cx);
 
         let codegen = cx.add_model(|cx| {
             Codegen::new(editor.read(cx).buffer().clone(), codegen_kind, provider, cx)
@@ -1439,7 +1442,7 @@ struct Conversation {
     pending_save: Task<Result<()>>,
     path: Option<PathBuf>,
     _subscriptions: Vec<Subscription>,
-    completion_provider: Box<dyn CompletionProvider>,
+    completion_provider: Arc<dyn CompletionProvider>,
 }
 
 impl Entity for Conversation {
@@ -1450,7 +1453,7 @@ impl Conversation {
     fn new(
         language_registry: Arc<LanguageRegistry>,
         cx: &mut ModelContext<Self>,
-        completion_provider: Box<dyn CompletionProvider>,
+        completion_provider: Arc<dyn CompletionProvider>,
     ) -> Self {
         let markdown = language_registry.language_for_name("Markdown");
         let buffer = cx.add_model(|cx| {
@@ -1544,7 +1547,7 @@ impl Conversation {
             None => Some(Uuid::new_v4().to_string()),
         };
         let model = saved_conversation.model;
-        let completion_provider: Box<dyn CompletionProvider> = Box::new(
+        let completion_provider: Arc<dyn CompletionProvider> = Arc::new(
             OpenAICompletionProvider::new(model.full_name(), cx.background().clone()),
         );
         completion_provider.retrieve_credentials(cx);
@@ -2201,7 +2204,7 @@ struct ConversationEditor {
 
 impl ConversationEditor {
     fn new(
-        completion_provider: Box<dyn CompletionProvider>,
+        completion_provider: Arc<dyn CompletionProvider>,
         language_registry: Arc<LanguageRegistry>,
         fs: Arc<dyn Fs>,
         workspace: WeakViewHandle<Workspace>,
@@ -3406,7 +3409,7 @@ mod tests {
         init(cx);
         let registry = Arc::new(LanguageRegistry::test());
 
-        let completion_provider = Box::new(FakeCompletionProvider::new());
+        let completion_provider = Arc::new(FakeCompletionProvider::new());
         let conversation = cx.add_model(|cx| Conversation::new(registry, cx, completion_provider));
         let buffer = conversation.read(cx).buffer.clone();
 
@@ -3535,7 +3538,7 @@ mod tests {
         cx.set_global(SettingsStore::test(cx));
         init(cx);
         let registry = Arc::new(LanguageRegistry::test());
-        let completion_provider = Box::new(FakeCompletionProvider::new());
+        let completion_provider = Arc::new(FakeCompletionProvider::new());
 
         let conversation = cx.add_model(|cx| Conversation::new(registry, cx, completion_provider));
         let buffer = conversation.read(cx).buffer.clone();
@@ -3633,7 +3636,7 @@ mod tests {
         cx.set_global(SettingsStore::test(cx));
         init(cx);
         let registry = Arc::new(LanguageRegistry::test());
-        let completion_provider = Box::new(FakeCompletionProvider::new());
+        let completion_provider = Arc::new(FakeCompletionProvider::new());
         let conversation = cx.add_model(|cx| Conversation::new(registry, cx, completion_provider));
         let buffer = conversation.read(cx).buffer.clone();
 
@@ -3716,7 +3719,7 @@ mod tests {
         cx.set_global(SettingsStore::test(cx));
         init(cx);
         let registry = Arc::new(LanguageRegistry::test());
-        let completion_provider = Box::new(FakeCompletionProvider::new());
+        let completion_provider = Arc::new(FakeCompletionProvider::new());
         let conversation =
             cx.add_model(|cx| Conversation::new(registry.clone(), cx, completion_provider));
         let buffer = conversation.read(cx).buffer.clone();

crates/assistant/src/codegen.rs

@@ -367,6 +367,8 @@ fn strip_invalid_spans_from_codeblock(
 
 #[cfg(test)]
 mod tests {
+    use std::sync::Arc;
+
     use super::*;
     use ai::test::FakeCompletionProvider;
     use futures::stream::{self};
@@ -437,6 +439,7 @@ mod tests {
             let max_len = cmp::min(new_text.len(), 10);
             let len = rng.gen_range(1..=max_len);
             let (chunk, suffix) = new_text.split_at(len);
+            println!("CHUNK: {:?}", &chunk);
             provider.send_completion(chunk);
             new_text = suffix;
             deterministic.run_until_parked();
@@ -569,6 +572,7 @@ mod tests {
             let max_len = cmp::min(new_text.len(), 10);
             let len = rng.gen_range(1..=max_len);
             let (chunk, suffix) = new_text.split_at(len);
+            println!("{:?}", &chunk);
             provider.send_completion(chunk);
             new_text = suffix;
             deterministic.run_until_parked();

crates/audio2/src/audio2.rs

@@ -1,14 +1,13 @@
 use assets::SoundRegistry;
-use futures::{channel::mpsc, StreamExt};
+use gpui2::{AppContext, AssetSource};
-use gpui2::{AppContext, AssetSource, Executor};
 use rodio::{OutputStream, OutputStreamHandle};
 use util::ResultExt;
 
 mod assets;
 
 pub fn init(source: impl AssetSource, cx: &mut AppContext) {
-    cx.set_global(Audio::new(cx.executor()));
     cx.set_global(SoundRegistry::new(source));
+    cx.set_global(Audio::new());
 }
 
 pub enum Sound {
@@ -34,15 +33,18 @@ impl Sound {
 }
 
 pub struct Audio {
-    tx: mpsc::UnboundedSender<Box<dyn FnOnce(&mut AudioState) + Send>>,
-}
-
-struct AudioState {
     _output_stream: Option<OutputStream>,
     output_handle: Option<OutputStreamHandle>,
 }
 
-impl AudioState {
+impl Audio {
+    pub fn new() -> Self {
+        Self {
+            _output_stream: None,
+            output_handle: None,
+        }
+    }
+
     fn ensure_output_exists(&mut self) -> Option<&OutputStreamHandle> {
         if self.output_handle.is_none() {
             let (_output_stream, output_handle) = OutputStream::try_default().log_err().unzip();
@@ -53,59 +55,27 @@ impl AudioState {
         self.output_handle.as_ref()
     }
 
-    fn take(&mut self) {
-        self._output_stream.take();
-        self.output_handle.take();
-    }
-}
-
-impl Audio {
-    pub fn new(executor: &Executor) -> Self {
-        let (tx, mut rx) = mpsc::unbounded::<Box<dyn FnOnce(&mut AudioState) + Send>>();
-        executor
-            .spawn_on_main(|| async move {
-                let mut audio = AudioState {
-                    _output_stream: None,
-                    output_handle: None,
-                };
-
-                while let Some(f) = rx.next().await {
-                    (f)(&mut audio);
-                }
-            })
-            .detach();
-
-        Self { tx }
-    }
-
     pub fn play_sound(sound: Sound, cx: &mut AppContext) {
         if !cx.has_global::<Self>() {
             return;
         }
 
-        let Some(source) = SoundRegistry::global(cx).get(sound.file()).log_err() else {
+        cx.update_global::<Self, _>(|this, cx| {
-            return;
+            let output_handle = this.ensure_output_exists()?;
-        };
+            let source = SoundRegistry::global(cx).get(sound.file()).log_err()?;
-
+            output_handle.play_raw(source).log_err()?;
-        let this = cx.global::<Self>();
+            Some(())
-        this.tx
+        });
-            .unbounded_send(Box::new(move |state| {
-                if let Some(output_handle) = state.ensure_output_exists() {
-                    output_handle.play_raw(source).log_err();
-                }
-            }))
-            .ok();
     }
 
-    pub fn end_call(cx: &AppContext) {
+    pub fn end_call(cx: &mut AppContext) {
         if !cx.has_global::<Self>() {
             return;
         }
 
-        let this = cx.global::<Self>();
+        cx.update_global::<Self, _>(|this, _| {
-
+            this._output_stream.take();
-        this.tx
+            this.output_handle.take();
-            .unbounded_send(Box::new(move |state| state.take()))
+        });
-            .ok();
     }
 }

crates/call2/src/call2.rs

@@ -196,7 +196,7 @@ impl ActiveCall {
                 })
                 .shared();
             self.pending_room_creation = Some(room.clone());
-            cx.executor().spawn(async move {
+            cx.background_executor().spawn(async move {
                 room.await.map_err(|err| anyhow!("{:?}", err))?;
                 anyhow::Ok(())
             })
@@ -230,7 +230,7 @@ impl ActiveCall {
         };
 
         let client = self.client.clone();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             client
                 .request(proto::CancelCall {
                     room_id,

crates/call2/src/room.rs

@@ -134,7 +134,7 @@ impl Room {
                 }
             });
 
-            let _maintain_video_tracks = cx.spawn_on_main({
+            let _maintain_video_tracks = cx.spawn({
                 let room = room.clone();
                 move |this, mut cx| async move {
                     let mut track_video_changes = room.remote_video_track_updates();
@@ -153,7 +153,7 @@ impl Room {
                 }
             });
 
-            let _maintain_audio_tracks = cx.spawn_on_main({
+            let _maintain_audio_tracks = cx.spawn({
                 let room = room.clone();
                 |this, mut cx| async move {
                     let mut track_audio_changes = room.remote_audio_track_updates();
@@ -326,7 +326,7 @@ impl Room {
     fn app_will_quit(&mut self, cx: &mut ModelContext<Self>) -> impl Future<Output = ()> {
         let task = if self.status.is_online() {
             let leave = self.leave_internal(cx);
-            Some(cx.executor().spawn(async move {
+            Some(cx.background_executor().spawn(async move {
                 leave.await.log_err();
             }))
         } else {
@@ -394,7 +394,7 @@ impl Room {
         self.clear_state(cx);
 
         let leave_room = self.client.request(proto::LeaveRoom {});
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             leave_room.await?;
             anyhow::Ok(())
         })
@@ -449,7 +449,8 @@ impl Room {
 
                 // Wait for client to re-establish a connection to the server.
                 {
-                    let mut reconnection_timeout = cx.executor().timer(RECONNECT_TIMEOUT).fuse();
+                    let mut reconnection_timeout =
+                        cx.background_executor().timer(RECONNECT_TIMEOUT).fuse();
                     let client_reconnection = async {
                         let mut remaining_attempts = 3;
                         while remaining_attempts > 0 {
@@ -1195,7 +1196,7 @@ impl Room {
         };
 
         cx.notify();
-        cx.executor().spawn_on_main(move || async move {
+        cx.background_executor().spawn(async move {
             client
                 .request(proto::UpdateParticipantLocation {
                     room_id,
@@ -1300,7 +1301,9 @@ impl Room {
                                 live_kit.room.unpublish_track(publication);
                             } else {
                                 if muted {
-                                    cx.executor().spawn(publication.set_mute(muted)).detach();
+                                    cx.background_executor()
+                                        .spawn(publication.set_mute(muted))
+                                        .detach();
                                 }
                                 live_kit.microphone_track = LocalTrack::Published {
                                     track_publication: publication,
@@ -1343,7 +1346,7 @@ impl Room {
             return Task::ready(Err(anyhow!("live-kit was not initialized")));
         };
 
-        cx.spawn_on_main(move |this, mut cx| async move {
+        cx.spawn(move |this, mut cx| async move {
             let publish_track = async {
                 let displays = displays.await?;
                 let display = displays
@@ -1386,7 +1389,9 @@ impl Room {
                                 live_kit.room.unpublish_track(publication);
                             } else {
                                 if muted {
-                                    cx.executor().spawn(publication.set_mute(muted)).detach();
+                                    cx.background_executor()
+                                        .spawn(publication.set_mute(muted))
+                                        .detach();
                                 }
                                 live_kit.screen_track = LocalTrack::Published {
                                     track_publication: publication,
@@ -1453,14 +1458,11 @@ impl Room {
                     .remote_audio_track_publications(&participant.user.id.to_string())
                 {
                     let deafened = live_kit.deafened;
-                    tasks.push(
+                    tasks.push(cx.foreground_executor().spawn(track.set_enabled(!deafened)));
-                        cx.executor()
-                            .spawn_on_main(move || track.set_enabled(!deafened)),
-                    );
                 }
             }
 
-            Ok(cx.executor().spawn_on_main(|| async {
+            Ok(cx.foreground_executor().spawn(async move {
                 if let Some(mute_task) = mute_task {
                     mute_task.await?;
                 }
@@ -1551,7 +1553,8 @@ impl LiveKitRoom {
                 *muted = should_mute;
                 cx.notify();
                 Ok((
-                    cx.executor().spawn(track_publication.set_mute(*muted)),
+                    cx.background_executor()
+                        .spawn(track_publication.set_mute(*muted)),
                     old_muted,
                 ))
             }

crates/client2/src/client2.rs

@@ -11,7 +11,8 @@ use async_tungstenite::tungstenite::{
     http::{Request, StatusCode},
 };
 use futures::{
-    future::BoxFuture, AsyncReadExt, FutureExt, SinkExt, StreamExt, TryFutureExt as _, TryStreamExt,
+    future::LocalBoxFuture, AsyncReadExt, FutureExt, SinkExt, StreamExt, TryFutureExt as _,
+    TryStreamExt,
 };
 use gpui2::{
     serde_json, AnyModel, AnyWeakModel, AppContext, AsyncAppContext, Model, SemanticVersion, Task,
@@ -240,7 +241,7 @@ struct ClientState {
                     Box<dyn AnyTypedEnvelope>,
                     &Arc<Client>,
                     AsyncAppContext,
-                ) -> BoxFuture<'static, Result<()>>,
+                ) -> LocalBoxFuture<'static, Result<()>>,
         >,
     >,
 }
@@ -310,10 +311,7 @@ pub struct PendingEntitySubscription<T: 'static> {
     consumed: bool,
 }
 
-impl<T> PendingEntitySubscription<T>
+impl<T: 'static> PendingEntitySubscription<T> {
-where
-    T: 'static + Send,
-{
     pub fn set_model(mut self, model: &Model<T>, cx: &mut AsyncAppContext) -> Subscription {
         self.consumed = true;
         let mut state = self.client.state.write();
@@ -341,10 +339,7 @@ where
     }
 }
 
-impl<T> Drop for PendingEntitySubscription<T>
+impl<T: 'static> Drop for PendingEntitySubscription<T> {
-where
-    T: 'static,
-{
     fn drop(&mut self) {
         if !self.consumed {
             let mut state = self.client.state.write();
@@ -505,7 +500,7 @@ impl Client {
                                 },
                                 &cx,
                             );
-                            cx.executor().timer(delay).await;
+                            cx.background_executor().timer(delay).await;
                             delay = delay
                                 .mul_f32(rng.gen_range(1.0..=2.0))
                                 .min(reconnect_interval);
@@ -529,7 +524,7 @@ impl Client {
         remote_id: u64,
     ) -> Result<PendingEntitySubscription<T>>
     where
-        T: 'static + Send,
+        T: 'static,
     {
         let id = (TypeId::of::<T>(), remote_id);
 
@@ -557,9 +552,13 @@ impl Client {
     ) -> Subscription
     where
         M: EnvelopedMessage,
-        E: 'static + Send,
+        E: 'static,
-        H: 'static + Send + Sync + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F,
+        H: 'static
-        F: 'static + Future<Output = Result<()>> + Send,
+            + Sync
+            + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F
+            + Send
+            + Sync,
+        F: 'static + Future<Output = Result<()>>,
     {
         let message_type_id = TypeId::of::<M>();
 
@@ -573,7 +572,7 @@ impl Client {
             Arc::new(move |subscriber, envelope, client, cx| {
                 let subscriber = subscriber.downcast::<E>().unwrap();
                 let envelope = envelope.into_any().downcast::<TypedEnvelope<M>>().unwrap();
-                handler(subscriber, *envelope, client.clone(), cx).boxed()
+                handler(subscriber, *envelope, client.clone(), cx).boxed_local()
             }),
         );
         if prev_handler.is_some() {
@@ -599,9 +598,13 @@ impl Client {
     ) -> Subscription
     where
         M: RequestMessage,
-        E: 'static + Send,
+        E: 'static,
-        H: 'static + Send + Sync + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F,
+        H: 'static
-        F: 'static + Future<Output = Result<M::Response>> + Send,
+            + Sync
+            + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F
+            + Send
+            + Sync,
+        F: 'static + Future<Output = Result<M::Response>>,
     {
         self.add_message_handler(model, move |handle, envelope, this, cx| {
             Self::respond_to_request(
@@ -615,9 +618,9 @@ impl Client {
     pub fn add_model_message_handler<M, E, H, F>(self: &Arc<Self>, handler: H)
     where
         M: EntityMessage,
-        E: 'static + Send,
+        E: 'static,
-        H: 'static + Send + Sync + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F,
+        H: 'static + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F + Send + Sync,
-        F: 'static + Future<Output = Result<()>> + Send,
+        F: 'static + Future<Output = Result<()>>,
     {
         self.add_entity_message_handler::<M, E, _, _>(move |subscriber, message, client, cx| {
             handler(subscriber.downcast::<E>().unwrap(), message, client, cx)
@@ -627,9 +630,9 @@ impl Client {
     fn add_entity_message_handler<M, E, H, F>(self: &Arc<Self>, handler: H)
     where
         M: EntityMessage,
-        E: 'static + Send,
+        E: 'static,
-        H: 'static + Send + Sync + Fn(AnyModel, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F,
+        H: 'static + Fn(AnyModel, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F + Send + Sync,
-        F: 'static + Future<Output = Result<()>> + Send,
+        F: 'static + Future<Output = Result<()>>,
     {
         let model_type_id = TypeId::of::<E>();
         let message_type_id = TypeId::of::<M>();
@@ -655,7 +658,7 @@ impl Client {
             message_type_id,
             Arc::new(move |handle, envelope, client, cx| {
                 let envelope = envelope.into_any().downcast::<TypedEnvelope<M>>().unwrap();
-                handler(handle, *envelope, client.clone(), cx).boxed()
+                handler(handle, *envelope, client.clone(), cx).boxed_local()
             }),
         );
         if prev_handler.is_some() {
@@ -666,9 +669,9 @@ impl Client {
     pub fn add_model_request_handler<M, E, H, F>(self: &Arc<Self>, handler: H)
     where
         M: EntityMessage + RequestMessage,
-        E: 'static + Send,
+        E: 'static,
-        H: 'static + Send + Sync + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F,
+        H: 'static + Fn(Model<E>, TypedEnvelope<M>, Arc<Self>, AsyncAppContext) -> F + Send + Sync,
-        F: 'static + Future<Output = Result<M::Response>> + Send,
+        F: 'static + Future<Output = Result<M::Response>>,
     {
         self.add_model_message_handler(move |entity, envelope, client, cx| {
             Self::respond_to_request::<M, _>(
@@ -705,7 +708,7 @@ impl Client {
         read_credentials_from_keychain(cx).await.is_some()
     }
 
-    #[async_recursion]
+    #[async_recursion(?Send)]
     pub async fn authenticate_and_connect(
         self: &Arc<Self>,
         try_keychain: bool,
@@ -763,7 +766,8 @@ impl Client {
             self.set_status(Status::Reconnecting, cx);
         }
 
-        let mut timeout = futures::FutureExt::fuse(cx.executor().timer(CONNECTION_TIMEOUT));
+        let mut timeout =
+            futures::FutureExt::fuse(cx.background_executor().timer(CONNECTION_TIMEOUT));
         futures::select_biased! {
             connection = self.establish_connection(&credentials, cx).fuse() => {
                 match connection {
@@ -814,7 +818,7 @@ impl Client {
         conn: Connection,
         cx: &AsyncAppContext,
     ) -> Result<()> {
-        let executor = cx.executor();
+        let executor = cx.background_executor();
         log::info!("add connection to peer");
         let (connection_id, handle_io, mut incoming) = self.peer.add_connection(conn, {
             let executor = executor.clone();
@@ -978,7 +982,7 @@ impl Client {
             .header("x-zed-protocol-version", rpc2::PROTOCOL_VERSION);
 
         let http = self.http.clone();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let mut rpc_url = Self::get_rpc_url(http, use_preview_server).await?;
             let rpc_host = rpc_url
                 .host_str()
@@ -1049,7 +1053,7 @@ impl Client {
                 write!(&mut url, "&impersonate={}", impersonate_login).unwrap();
             }
 
-            cx.run_on_main(move |cx| cx.open_url(&url))?.await;
+            cx.update(|cx| cx.open_url(&url))?;
 
             // Receive the HTTP request from the user's browser. Retrieve the user id and encrypted
             // access token from the query params.
@@ -1100,7 +1104,7 @@ impl Client {
             let access_token = private_key
                 .decrypt_string(&access_token)
                 .context("failed to decrypt access token")?;
-            cx.run_on_main(|cx| cx.activate(true))?.await;
+            cx.update(|cx| cx.activate(true))?;
 
             Ok(Credentials {
                 user_id: user_id.parse()?,
@@ -1292,7 +1296,7 @@ impl Client {
                 sender_id,
                 type_name
             );
-            cx.spawn_on_main(move |_| async move {
+            cx.spawn(move |_| async move {
                     match future.await {
                         Ok(()) => {
                             log::debug!(
@@ -1331,9 +1335,8 @@ async fn read_credentials_from_keychain(cx: &AsyncAppContext) -> Option<Credenti
     }
 
     let (user_id, access_token) = cx
-        .run_on_main(|cx| cx.read_credentials(&ZED_SERVER_URL).log_err().flatten())
+        .update(|cx| cx.read_credentials(&ZED_SERVER_URL).log_err().flatten())
-        .ok()?
+        .ok()??;
-        .await?;
 
     Some(Credentials {
         user_id: user_id.parse().ok()?,
@@ -1345,19 +1348,17 @@ async fn write_credentials_to_keychain(
     credentials: Credentials,
     cx: &AsyncAppContext,
 ) -> Result<()> {
-    cx.run_on_main(move |cx| {
+    cx.update(move |cx| {
         cx.write_credentials(
             &ZED_SERVER_URL,
             &credentials.user_id.to_string(),
             credentials.access_token.as_bytes(),
         )
     })?
-    .await
 }
 
 async fn delete_credentials_from_keychain(cx: &AsyncAppContext) -> Result<()> {
-    cx.run_on_main(move |cx| cx.delete_credentials(&ZED_SERVER_URL))?
+    cx.update(move |cx| cx.delete_credentials(&ZED_SERVER_URL))?
-        .await
 }
 
 const WORKTREE_URL_PREFIX: &str = "zed://worktrees/";
@@ -1382,7 +1383,7 @@ mod tests {
     use super::*;
     use crate::test::FakeServer;
 
-    use gpui2::{Context, Executor, TestAppContext};
+    use gpui2::{BackgroundExecutor, Context, TestAppContext};
     use parking_lot::Mutex;
     use std::future;
     use util::http::FakeHttpClient;
@@ -1422,14 +1423,14 @@ mod tests {
     }
 
     #[gpui2::test(iterations = 10)]
-    async fn test_connection_timeout(executor: Executor, cx: &mut TestAppContext) {
+    async fn test_connection_timeout(executor: BackgroundExecutor, cx: &mut TestAppContext) {
         let user_id = 5;
         let client = cx.update(|cx| Client::new(FakeHttpClient::with_404_response(), cx));
         let mut status = client.status();
 
         // Time out when client tries to connect.
         client.override_authenticate(move |cx| {
-            cx.executor().spawn(async move {
+            cx.background_executor().spawn(async move {
                 Ok(Credentials {
                     user_id,
                     access_token: "token".into(),
@@ -1437,7 +1438,7 @@ mod tests {
             })
         });
         client.override_establish_connection(|_, cx| {
-            cx.executor().spawn(async move {
+            cx.background_executor().spawn(async move {
                 future::pending::<()>().await;
                 unreachable!()
             })
@@ -1471,7 +1472,7 @@ mod tests {
         // Time out when re-establishing the connection.
         server.allow_connections();
         client.override_establish_connection(|_, cx| {
-            cx.executor().spawn(async move {
+            cx.background_executor().spawn(async move {
                 future::pending::<()>().await;
                 unreachable!()
             })
@@ -1490,7 +1491,10 @@ mod tests {
     }
 
     #[gpui2::test(iterations = 10)]
-    async fn test_authenticating_more_than_once(cx: &mut TestAppContext, executor: Executor) {
+    async fn test_authenticating_more_than_once(
+        cx: &mut TestAppContext,
+        executor: BackgroundExecutor,
+    ) {
         let auth_count = Arc::new(Mutex::new(0));
         let dropped_auth_count = Arc::new(Mutex::new(0));
         let client = cx.update(|cx| Client::new(FakeHttpClient::with_404_response(), cx));
@@ -1500,7 +1504,7 @@ mod tests {
             move |cx| {
                 let auth_count = auth_count.clone();
                 let dropped_auth_count = dropped_auth_count.clone();
-                cx.executor().spawn(async move {
+                cx.background_executor().spawn(async move {
                     *auth_count.lock() += 1;
                     let _drop = util::defer(move || *dropped_auth_count.lock() += 1);
                     future::pending::<()>().await;

crates/client2/src/telemetry.rs

@@ -1,5 +1,5 @@
 use crate::{TelemetrySettings, ZED_SECRET_CLIENT_TOKEN, ZED_SERVER_URL};
-use gpui2::{serde_json, AppContext, AppMetadata, Executor, Task};
+use gpui2::{serde_json, AppContext, AppMetadata, BackgroundExecutor, Task};
 use lazy_static::lazy_static;
 use parking_lot::Mutex;
 use serde::Serialize;
@@ -14,7 +14,7 @@ use util::{channel::ReleaseChannel, TryFutureExt};
 
 pub struct Telemetry {
     http_client: Arc<dyn HttpClient>,
-    executor: Executor,
+    executor: BackgroundExecutor,
     state: Mutex<TelemetryState>,
 }
 
@@ -123,7 +123,7 @@ impl Telemetry {
         // TODO: Replace all hardware stuff with nested SystemSpecs json
         let this = Arc::new(Self {
             http_client: client,
-            executor: cx.executor().clone(),
+            executor: cx.background_executor().clone(),
             state: Mutex::new(TelemetryState {
                 app_metadata: cx.app_metadata(),
                 architecture: env::consts::ARCH,

crates/client2/src/test.rs

@@ -1,7 +1,7 @@
 use crate::{Client, Connection, Credentials, EstablishConnectionError, UserStore};
 use anyhow::{anyhow, Result};
 use futures::{stream::BoxStream, StreamExt};
-use gpui2::{Context, Executor, Model, TestAppContext};
+use gpui2::{BackgroundExecutor, Context, Model, TestAppContext};
 use parking_lot::Mutex;
 use rpc2::{
     proto::{self, GetPrivateUserInfo, GetPrivateUserInfoResponse},
@@ -14,7 +14,7 @@ pub struct FakeServer {
     peer: Arc<Peer>,
     state: Arc<Mutex<FakeServerState>>,
     user_id: u64,
-    executor: Executor,
+    executor: BackgroundExecutor,
 }
 
 #[derive(Default)]
@@ -79,10 +79,10 @@ impl FakeServer {
                         }
 
                         let (client_conn, server_conn, _) =
-                            Connection::in_memory(cx.executor().clone());
+                            Connection::in_memory(cx.background_executor().clone());
                         let (connection_id, io, incoming) =
-                            peer.add_test_connection(server_conn, cx.executor().clone());
+                            peer.add_test_connection(server_conn, cx.background_executor().clone());
-                        cx.executor().spawn(io).detach();
+                        cx.background_executor().spawn(io).detach();
                         {
                             let mut state = state.lock();
                             state.connection_id = Some(connection_id);

crates/collab/Cargo.toml

@@ -3,7 +3,7 @@ authors = ["Nathan Sobo <nathan@zed.dev>"]
 default-run = "collab"
 edition = "2021"
 name = "collab"
-version = "0.27.0"
+version = "0.28.0"
 publish = false
 
 [[bin]]

crates/copilot2/src/copilot2.rs

@@ -208,7 +208,7 @@ impl RegisteredBuffer {
                 let new_snapshot = buffer.update(&mut cx, |buffer, _| buffer.snapshot()).ok()?;
 
                 let content_changes = cx
-                    .executor()
+                    .background_executor()
                     .spawn({
                         let new_snapshot = new_snapshot.clone();
                         async move {
@@ -535,7 +535,7 @@ impl Copilot {
                 }
             };
 
-            cx.executor()
+            cx.background_executor()
                 .spawn(task.map_err(|err| anyhow!("{:?}", err)))
         } else {
             // If we're downloading, wait until download is finished
@@ -549,7 +549,7 @@ impl Copilot {
         self.update_sign_in_status(request::SignInStatus::NotSignedIn, cx);
         if let CopilotServer::Running(RunningCopilotServer { lsp: server, .. }) = &self.server {
             let server = server.clone();
-            cx.executor().spawn(async move {
+            cx.background_executor().spawn(async move {
                 server
                     .request::<request::SignOut>(request::SignOutParams {})
                     .await?;
@@ -579,7 +579,7 @@ impl Copilot {
 
         cx.notify();
 
-        cx.executor().spawn(start_task)
+        cx.background_executor().spawn(start_task)
     }
 
     pub fn language_server(&self) -> Option<(&LanguageServerName, &Arc<LanguageServer>)> {
@@ -760,7 +760,7 @@ impl Copilot {
                 .request::<request::NotifyAccepted>(request::NotifyAcceptedParams {
                     uuid: completion.uuid.clone(),
                 });
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             request.await?;
             Ok(())
         })
@@ -784,7 +784,7 @@ impl Copilot {
                         .map(|completion| completion.uuid.clone())
                         .collect(),
                 });
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             request.await?;
             Ok(())
         })
@@ -827,7 +827,7 @@ impl Copilot {
             .map(|file| file.path().to_path_buf())
             .unwrap_or_default();
 
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let (version, snapshot) = snapshot.await?;
             let result = lsp
                 .request::<R>(request::GetCompletionsParams {

crates/db2/src/db2.rs

@@ -185,7 +185,7 @@ pub fn write_and_log<F>(cx: &mut AppContext, db_write: impl FnOnce() -> F + Send
 where
     F: Future<Output = anyhow::Result<()>> + Send,
 {
-    cx.executor()
+    cx.background_executor()
         .spawn(async move { db_write().await.log_err() })
         .detach()
 }

crates/feature_flags2/src/feature_flags2.rs

@@ -28,7 +28,7 @@ pub trait FeatureFlagViewExt<V: 'static> {
         F: Fn(bool, &mut V, &mut ViewContext<V>) + Send + Sync + 'static;
 }
 
-impl<V> FeatureFlagViewExt<V> for ViewContext<'_, '_, V>
+impl<V> FeatureFlagViewExt<V> for ViewContext<'_, V>
 where
     V: 'static + Send + Sync,
 {

crates/fs2/src/fs2.rs

@@ -288,7 +288,7 @@ impl Fs for RealFs {
 pub struct FakeFs {
     // Use an unfair lock to ensure tests are deterministic.
     state: Mutex<FakeFsState>,
-    executor: gpui2::Executor,
+    executor: gpui2::BackgroundExecutor,
 }
 
 #[cfg(any(test, feature = "test-support"))]
@@ -434,7 +434,7 @@ lazy_static::lazy_static! {
 
 #[cfg(any(test, feature = "test-support"))]
 impl FakeFs {
-    pub fn new(executor: gpui2::Executor) -> Arc<Self> {
+    pub fn new(executor: gpui2::BackgroundExecutor) -> Arc<Self> {
         Arc::new(Self {
             executor,
             state: Mutex::new(FakeFsState {
@@ -1222,11 +1222,11 @@ pub fn copy_recursive<'a>(
 #[cfg(test)]
 mod tests {
     use super::*;
-    use gpui2::Executor;
+    use gpui2::BackgroundExecutor;
     use serde_json::json;
 
     #[gpui2::test]
-    async fn test_fake_fs(executor: Executor) {
+    async fn test_fake_fs(executor: BackgroundExecutor) {
         let fs = FakeFs::new(executor.clone());
         fs.insert_tree(
             "/root",

crates/fuzzy2/src/paths.rs

@@ -1,4 +1,4 @@
-use gpui2::Executor;
+use gpui2::BackgroundExecutor;
 use std::{
     borrow::Cow,
     cmp::{self, Ordering},
@@ -134,7 +134,7 @@ pub async fn match_path_sets<'a, Set: PathMatchCandidateSet<'a>>(
     smart_case: bool,
     max_results: usize,
     cancel_flag: &AtomicBool,
-    executor: Executor,
+    executor: BackgroundExecutor,
 ) -> Vec<PathMatch> {
     let path_count: usize = candidate_sets.iter().map(|s| s.len()).sum();
     if path_count == 0 {

crates/fuzzy2/src/strings.rs

@@ -2,7 +2,7 @@ use crate::{
     matcher::{Match, MatchCandidate, Matcher},
     CharBag,
 };
-use gpui2::Executor;
+use gpui2::BackgroundExecutor;
 use std::{
     borrow::Cow,
     cmp::{self, Ordering},
@@ -83,7 +83,7 @@ pub async fn match_strings(
     smart_case: bool,
     max_results: usize,
     cancel_flag: &AtomicBool,
-    executor: Executor,
+    executor: BackgroundExecutor,
 ) -> Vec<StringMatch> {
     if candidates.is_empty() || max_results == 0 {
         return Default::default();

crates/gpui2/src/action.rs

@@ -4,7 +4,7 @@ use collections::{HashMap, HashSet};
 use serde::Deserialize;
 use std::any::{type_name, Any};
 
-pub trait Action: Any + Send {
+pub trait Action: 'static {
     fn qualified_name() -> SharedString
     where
         Self: Sized;
@@ -19,7 +19,7 @@ pub trait Action: Any + Send {
 
 impl<A> Action for A
 where
-    A: for<'a> Deserialize<'a> + PartialEq + Any + Send + Clone + Default,
+    A: for<'a> Deserialize<'a> + PartialEq + Clone + Default + 'static,
 {
     fn qualified_name() -> SharedString {
         type_name::<A>().into()

crates/gpui2/src/app.rs

@@ -13,30 +13,32 @@ use smallvec::SmallVec;
 pub use test_context::*;
 
 use crate::{
-    current_platform, image_cache::ImageCache, Action, AnyBox, AnyView, AppMetadata, AssetSource,
+    current_platform, image_cache::ImageCache, Action, AnyBox, AnyView, AnyWindowHandle,
-    ClipboardItem, Context, DispatchPhase, DisplayId, Executor, FocusEvent, FocusHandle, FocusId,
+    AppMetadata, AssetSource, BackgroundExecutor, ClipboardItem, Context, DispatchPhase, DisplayId,
-    KeyBinding, Keymap, LayoutId, MainThread, MainThreadOnly, Pixels, Platform, Point, Render,
+    Entity, FocusEvent, FocusHandle, FocusId, ForegroundExecutor, KeyBinding, Keymap, LayoutId,
-    SharedString, SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement,
+    PathPromptOptions, Pixels, Platform, PlatformDisplay, Point, Render, SharedString,
-    TextSystem, View, Window, WindowContext, WindowHandle, WindowId,
+    SubscriberSet, Subscription, SvgRenderer, Task, TextStyle, TextStyleRefinement, TextSystem,
+    View, Window, WindowContext, WindowHandle, WindowId,
 };
 use anyhow::{anyhow, Result};
 use collections::{HashMap, HashSet, VecDeque};
-use futures::{future::BoxFuture, Future};
+use futures::{channel::oneshot, future::LocalBoxFuture, Future};
 use parking_lot::Mutex;
 use slotmap::SlotMap;
 use std::{
     any::{type_name, Any, TypeId},
-    borrow::Borrow,
+    cell::RefCell,
     marker::PhantomData,
     mem,
     ops::{Deref, DerefMut},
-    path::PathBuf,
+    path::{Path, PathBuf},
-    sync::{atomic::Ordering::SeqCst, Arc, Weak},
+    rc::{Rc, Weak},
+    sync::{atomic::Ordering::SeqCst, Arc},
     time::Duration,
 };
 use util::http::{self, HttpClient};
 
-pub struct App(Arc<Mutex<AppContext>>);
+pub struct App(Rc<RefCell<AppContext>>);
 
 /// Represents an application before it is fully launched. Once your app is
 /// configured, you'll start the app with `App::run`.
@@ -54,13 +56,12 @@ impl App {
     /// app is fully launched.
     pub fn run<F>(self, on_finish_launching: F)
     where
-        F: 'static + FnOnce(&mut MainThread<AppContext>),
+        F: 'static + FnOnce(&mut AppContext),
     {
         let this = self.0.clone();
-        let platform = self.0.lock().platform.clone();
+        let platform = self.0.borrow().platform.clone();
-        platform.borrow_on_main_thread().run(Box::new(move || {
+        platform.run(Box::new(move || {
-            let cx = &mut *this.lock();
+            let cx = &mut *this.borrow_mut();
-            let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
             on_finish_launching(cx);
         }));
     }
@@ -71,16 +72,12 @@ impl App {
     where
         F: 'static + FnMut(Vec<String>, &mut AppContext),
     {
-        let this = Arc::downgrade(&self.0);
+        let this = Rc::downgrade(&self.0);
-        self.0
+        self.0.borrow().platform.on_open_urls(Box::new(move |urls| {
-            .lock()
+            if let Some(app) = this.upgrade() {
-            .platform
+                callback(urls, &mut *app.borrow_mut());
-            .borrow_on_main_thread()
+            }
-            .on_open_urls(Box::new(move |urls| {
+        }));
-                if let Some(app) = this.upgrade() {
-                    callback(urls, &mut app.lock());
-                }
-            }));
         self
     }
 
@@ -88,49 +85,50 @@ impl App {
     where
         F: 'static + FnMut(&mut AppContext),
     {
-        let this = Arc::downgrade(&self.0);
+        let this = Rc::downgrade(&self.0);
-        self.0
+        self.0.borrow_mut().platform.on_reopen(Box::new(move || {
-            .lock()
+            if let Some(app) = this.upgrade() {
-            .platform
+                callback(&mut app.borrow_mut());
-            .borrow_on_main_thread()
+            }
-            .on_reopen(Box::new(move || {
+        }));
-                if let Some(app) = this.upgrade() {
-                    callback(&mut app.lock());
-                }
-            }));
         self
     }
 
     pub fn metadata(&self) -> AppMetadata {
-        self.0.lock().app_metadata.clone()
+        self.0.borrow().app_metadata.clone()
     }
 
-    pub fn executor(&self) -> Executor {
+    pub fn background_executor(&self) -> BackgroundExecutor {
-        self.0.lock().executor.clone()
+        self.0.borrow().background_executor.clone()
+    }
+
+    pub fn foreground_executor(&self) -> ForegroundExecutor {
+        self.0.borrow().foreground_executor.clone()
     }
 
     pub fn text_system(&self) -> Arc<TextSystem> {
-        self.0.lock().text_system.clone()
+        self.0.borrow().text_system.clone()
     }
 }
 
 type ActionBuilder = fn(json: Option<serde_json::Value>) -> anyhow::Result<Box<dyn Action>>;
-type FrameCallback = Box<dyn FnOnce(&mut WindowContext) + Send>;
+type FrameCallback = Box<dyn FnOnce(&mut WindowContext)>;
-type Handler = Box<dyn FnMut(&mut AppContext) -> bool + Send + 'static>;
+type Handler = Box<dyn FnMut(&mut AppContext) -> bool + 'static>;
-type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + Send + 'static>;
+type Listener = Box<dyn FnMut(&dyn Any, &mut AppContext) -> bool + 'static>;
-type QuitHandler = Box<dyn FnMut(&mut AppContext) -> BoxFuture<'static, ()> + Send + 'static>;
+type QuitHandler = Box<dyn FnOnce(&mut AppContext) -> LocalBoxFuture<'static, ()> + 'static>;
-type ReleaseListener = Box<dyn FnMut(&mut dyn Any, &mut AppContext) + Send + 'static>;
+type ReleaseListener = Box<dyn FnOnce(&mut dyn Any, &mut AppContext) + 'static>;
 
 pub struct AppContext {
-    this: Weak<Mutex<AppContext>>,
+    this: Weak<RefCell<AppContext>>,
-    pub(crate) platform: MainThreadOnly<dyn Platform>,
+    pub(crate) platform: Rc<dyn Platform>,
     app_metadata: AppMetadata,
     text_system: Arc<TextSystem>,
     flushing_effects: bool,
     pending_updates: usize,
     pub(crate) active_drag: Option<AnyDrag>,
     pub(crate) next_frame_callbacks: HashMap<DisplayId, Vec<FrameCallback>>,
-    pub(crate) executor: Executor,
+    pub(crate) background_executor: BackgroundExecutor,
+    pub(crate) foreground_executor: ForegroundExecutor,
     pub(crate) svg_renderer: SvgRenderer,
     asset_source: Arc<dyn AssetSource>,
     pub(crate) image_cache: ImageCache,
@@ -140,7 +138,7 @@ pub struct AppContext {
     pub(crate) windows: SlotMap<WindowId, Option<Window>>,
     pub(crate) keymap: Arc<Mutex<Keymap>>,
     pub(crate) global_action_listeners:
-        HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self) + Send>>>,
+        HashMap<TypeId, Vec<Box<dyn Fn(&dyn Action, DispatchPhase, &mut Self)>>>,
     action_builders: HashMap<SharedString, ActionBuilder>,
     pending_effects: VecDeque<Effect>,
     pub(crate) pending_notifications: HashSet<EntityId>,
@@ -156,11 +154,12 @@ pub struct AppContext {
 
 impl AppContext {
     pub(crate) fn new(
-        platform: Arc<dyn Platform>,
+        platform: Rc<dyn Platform>,
         asset_source: Arc<dyn AssetSource>,
         http_client: Arc<dyn HttpClient>,
-    ) -> Arc<Mutex<Self>> {
+    ) -> Rc<RefCell<Self>> {
-        let executor = platform.executor();
+        let executor = platform.background_executor();
+        let foreground_executor = platform.foreground_executor();
         assert!(
             executor.is_main_thread(),
             "must construct App on main thread"
@@ -175,16 +174,17 @@ impl AppContext {
             app_version: platform.app_version().ok(),
         };
 
-        Arc::new_cyclic(|this| {
+        Rc::new_cyclic(|this| {
-            Mutex::new(AppContext {
+            RefCell::new(AppContext {
                 this: this.clone(),
                 text_system,
-                platform: MainThreadOnly::new(platform, executor.clone()),
+                platform,
                 app_metadata,
                 flushing_effects: false,
                 pending_updates: 0,
                 next_frame_callbacks: Default::default(),
-                executor,
+                background_executor: executor,
+                foreground_executor,
                 svg_renderer: SvgRenderer::new(asset_source.clone()),
                 asset_source,
                 image_cache: ImageCache::new(http_client),
@@ -215,17 +215,16 @@ impl AppContext {
     pub fn quit(&mut self) {
         let mut futures = Vec::new();
 
-        self.quit_observers.clone().retain(&(), |observer| {
+        for observer in self.quit_observers.remove(&()) {
             futures.push(observer(self));
-            true
+        }
-        });
 
         self.windows.clear();
         self.flush_effects();
 
         let futures = futures::future::join_all(futures);
         if self
-            .executor
+            .background_executor
             .block_with_timeout(Duration::from_millis(100), futures)
             .is_err()
         {
@@ -244,7 +243,6 @@ impl AppContext {
     pub fn refresh(&mut self) {
         self.pending_effects.push_back(Effect::Refresh);
     }
-
     pub(crate) fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
         self.pending_updates += 1;
         let result = update(self);
@@ -257,44 +255,91 @@ impl AppContext {
         result
     }
 
-    pub(crate) fn read_window<R>(
+    pub fn windows(&self) -> Vec<AnyWindowHandle> {
-        &mut self,
+        self.windows
-        id: WindowId,
+            .values()
-        read: impl FnOnce(&WindowContext) -> R,
+            .filter_map(|window| Some(window.as_ref()?.handle.clone()))
-    ) -> Result<R> {
+            .collect()
-        let window = self
-            .windows
-            .get(id)
-            .ok_or_else(|| anyhow!("window not found"))?
-            .as_ref()
-            .unwrap();
-        Ok(read(&WindowContext::immutable(self, &window)))
     }
 
-    pub(crate) fn update_window<R>(
+    /// Opens a new window with the given option and the root view returned by the given function.
+    /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
+    /// functionality.
+    pub fn open_window<V: Render>(
         &mut self,
-        id: WindowId,
+        options: crate::WindowOptions,
-        update: impl FnOnce(&mut WindowContext) -> R,
+        build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
-    ) -> Result<R> {
+    ) -> WindowHandle<V> {
         self.update(|cx| {
-            let mut window = cx
+            let id = cx.windows.insert(None);
-                .windows
+            let handle = WindowHandle::new(id);
-                .get_mut(id)
+            let mut window = Window::new(handle.into(), options, cx);
-                .ok_or_else(|| anyhow!("window not found"))?
+            let root_view = build_root_view(&mut WindowContext::new(cx, &mut window));
-                .take()
+            window.root_view.replace(root_view.into());
-                .unwrap();
+            cx.windows.get_mut(id).unwrap().replace(window);
-
+            handle
-            let result = update(&mut WindowContext::mutable(cx, &mut window));
-
-            cx.windows
-                .get_mut(id)
-                .ok_or_else(|| anyhow!("window not found"))?
-                .replace(window);
-
-            Ok(result)
         })
     }
 
+    /// Instructs the platform to activate the application by bringing it to the foreground.
+    pub fn activate(&self, ignoring_other_apps: bool) {
+        self.platform.activate(ignoring_other_apps);
+    }
+
+    /// Returns the list of currently active displays.
+    pub fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
+        self.platform.displays()
+    }
+
+    /// Writes data to the platform clipboard.
+    pub fn write_to_clipboard(&self, item: ClipboardItem) {
+        self.platform.write_to_clipboard(item)
+    }
+
+    /// Reads data from the platform clipboard.
+    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
+        self.platform.read_from_clipboard()
+    }
+
+    /// Writes credentials to the platform keychain.
+    pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
+        self.platform.write_credentials(url, username, password)
+    }
+
+    /// Reads credentials from the platform keychain.
+    pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
+        self.platform.read_credentials(url)
+    }
+
+    /// Deletes credentials from the platform keychain.
+    pub fn delete_credentials(&self, url: &str) -> Result<()> {
+        self.platform.delete_credentials(url)
+    }
+
+    /// Directs the platform's default browser to open the given URL.
+    pub fn open_url(&self, url: &str) {
+        self.platform.open_url(url);
+    }
+
+    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
+        self.platform.path_for_auxiliary_executable(name)
+    }
+
+    pub fn prompt_for_paths(
+        &self,
+        options: PathPromptOptions,
+    ) -> oneshot::Receiver<Option<Vec<PathBuf>>> {
+        self.platform.prompt_for_paths(options)
+    }
+
+    pub fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>> {
+        self.platform.prompt_for_new_path(directory)
+    }
+
+    pub fn reveal_path(&self, path: &Path) {
+        self.platform.reveal_path(path)
+    }
+
     pub(crate) fn push_effect(&mut self, effect: Effect) {
         match &effect {
             Effect::Notify { emitter } => {
@@ -326,8 +371,11 @@ impl AppContext {
                         self.apply_notify_effect(emitter);
                     }
                     Effect::Emit { emitter, event } => self.apply_emit_effect(emitter, event),
-                    Effect::FocusChanged { window_id, focused } => {
+                    Effect::FocusChanged {
-                        self.apply_focus_changed_effect(window_id, focused);
+                        window_handle,
+                        focused,
+                    } => {
+                        self.apply_focus_changed_effect(window_handle, focused);
                     }
                     Effect::Refresh => {
                         self.apply_refresh_effect();
@@ -347,18 +395,18 @@ impl AppContext {
         let dirty_window_ids = self
             .windows
             .iter()
-            .filter_map(|(window_id, window)| {
+            .filter_map(|(_, window)| {
                 let window = window.as_ref().unwrap();
                 if window.dirty {
-                    Some(window_id)
+                    Some(window.handle.clone())
                 } else {
                     None
                 }
             })
             .collect::<SmallVec<[_; 8]>>();
 
-        for dirty_window_id in dirty_window_ids {
+        for dirty_window_handle in dirty_window_ids {
-            self.update_window(dirty_window_id, |cx| cx.draw()).unwrap();
+            dirty_window_handle.update(self, |_, cx| cx.draw()).unwrap();
         }
     }
 
@@ -375,7 +423,7 @@ impl AppContext {
             for (entity_id, mut entity) in dropped {
                 self.observers.remove(&entity_id);
                 self.event_listeners.remove(&entity_id);
-                for mut release_callback in self.release_listeners.remove(&entity_id) {
+                for release_callback in self.release_listeners.remove(&entity_id) {
                     release_callback(entity.as_mut(), self);
                 }
             }
@@ -386,27 +434,27 @@ impl AppContext {
     /// For now, we simply blur the window if this happens, but we may want to support invoking
     /// a window blur handler to restore focus to some logical element.
     fn release_dropped_focus_handles(&mut self) {
-        let window_ids = self.windows.keys().collect::<SmallVec<[_; 8]>>();
+        for window_handle in self.windows() {
-        for window_id in window_ids {
+            window_handle
-            self.update_window(window_id, |cx| {
+                .update(self, |_, cx| {
-                let mut blur_window = false;
+                    let mut blur_window = false;
-                let focus = cx.window.focus;
+                    let focus = cx.window.focus;
-                cx.window.focus_handles.write().retain(|handle_id, count| {
+                    cx.window.focus_handles.write().retain(|handle_id, count| {
-                    if count.load(SeqCst) == 0 {
+                        if count.load(SeqCst) == 0 {
-                        if focus == Some(handle_id) {
+                            if focus == Some(handle_id) {
-                            blur_window = true;
+                                blur_window = true;
+                            }
+                            false
+                        } else {
+                            true
                         }
-                        false
+                    });
-                    } else {
-                        true
-                    }
-                });
 
-                if blur_window {
+                    if blur_window {
-                    cx.blur();
+                        cx.blur();
-                }
+                    }
-            })
+                })
-            .unwrap();
+                .unwrap();
         }
     }
 
@@ -423,30 +471,35 @@ impl AppContext {
             .retain(&emitter, |handler| handler(event.as_ref(), self));
     }
 
-    fn apply_focus_changed_effect(&mut self, window_id: WindowId, focused: Option<FocusId>) {
+    fn apply_focus_changed_effect(
-        self.update_window(window_id, |cx| {
+        &mut self,
-            if cx.window.focus == focused {
+        window_handle: AnyWindowHandle,
-                let mut listeners = mem::take(&mut cx.window.focus_listeners);
+        focused: Option<FocusId>,
-                let focused =
+    ) {
-                    focused.map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
+        window_handle
-                let blurred = cx
+            .update(self, |_, cx| {
-                    .window
+                if cx.window.focus == focused {
-                    .last_blur
+                    let mut listeners = mem::take(&mut cx.window.focus_listeners);
-                    .take()
+                    let focused = focused
-                    .unwrap()
+                        .map(|id| FocusHandle::for_id(id, &cx.window.focus_handles).unwrap());
-                    .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
+                    let blurred = cx
-                if focused.is_some() || blurred.is_some() {
+                        .window
-                    let event = FocusEvent { focused, blurred };
+                        .last_blur
-                    for listener in &listeners {
+                        .take()
-                        listener(&event, cx);
+                        .unwrap()
+                        .and_then(|id| FocusHandle::for_id(id, &cx.window.focus_handles));
+                    if focused.is_some() || blurred.is_some() {
+                        let event = FocusEvent { focused, blurred };
+                        for listener in &listeners {
+                            listener(&event, cx);
+                        }
                     }
-                }
 
-                listeners.extend(cx.window.focus_listeners.drain(..));
+                    listeners.extend(cx.window.focus_listeners.drain(..));
-                cx.window.focus_listeners = listeners;
+                    cx.window.focus_listeners = listeners;
-            }
+                }
-        })
+            })
-        .ok();
+            .ok();
     }
 
     fn apply_refresh_effect(&mut self) {
@@ -464,7 +517,7 @@ impl AppContext {
             .retain(&type_id, |observer| observer(self));
     }
 
-    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + Send + 'static>) {
+    fn apply_defer_effect(&mut self, callback: Box<dyn FnOnce(&mut Self) + 'static>) {
         callback(self);
     }
 
@@ -473,72 +526,34 @@ impl AppContext {
     pub fn to_async(&self) -> AsyncAppContext {
         AsyncAppContext {
             app: unsafe { mem::transmute(self.this.clone()) },
-            executor: self.executor.clone(),
+            background_executor: self.background_executor.clone(),
+            foreground_executor: self.foreground_executor.clone(),
         }
     }
 
     /// Obtains a reference to the executor, which can be used to spawn futures.
-    pub fn executor(&self) -> &Executor {
+    pub fn background_executor(&self) -> &BackgroundExecutor {
-        &self.executor
+        &self.background_executor
     }
 
-    /// Runs the given closure on the main thread, where interaction with the platform
+    /// Obtains a reference to the executor, which can be used to spawn futures.
-    /// is possible. The given closure will be invoked with a `MainThread<AppContext>`, which
+    pub fn foreground_executor(&self) -> &ForegroundExecutor {
-    /// has platform-specific methods that aren't present on `AppContext`.
+        &self.foreground_executor
-    pub fn run_on_main<R>(
-        &mut self,
-        f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
-    ) -> Task<R>
-    where
-        R: Send + 'static,
-    {
-        if self.executor.is_main_thread() {
-            Task::ready(f(unsafe {
-                mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(self)
-            }))
-        } else {
-            let this = self.this.upgrade().unwrap();
-            self.executor.run_on_main(move || {
-                let cx = &mut *this.lock();
-                cx.update(|cx| f(unsafe { mem::transmute::<&mut Self, &mut MainThread<Self>>(cx) }))
-            })
-        }
-    }
-
-    /// Spawns the future returned by the given function on the main thread, where interaction with
-    /// the platform is possible. The given closure will be invoked with a `MainThread<AsyncAppContext>`,
-    /// which has platform-specific methods that aren't present on `AsyncAppContext`. The future will be
-    /// polled exclusively on the main thread.
-    // todo!("I think we need somehow to prevent the MainThread<AsyncAppContext> from implementing Send")
-    pub fn spawn_on_main<F, R>(
-        &self,
-        f: impl FnOnce(MainThread<AsyncAppContext>) -> F + Send + 'static,
-    ) -> Task<R>
-    where
-        F: Future<Output = R> + 'static,
-        R: Send + 'static,
-    {
-        let cx = self.to_async();
-        self.executor.spawn_on_main(move || f(MainThread(cx)))
     }
 
     /// Spawns the future returned by the given function on the thread pool. The closure will be invoked
     /// with AsyncAppContext, which allows the application state to be accessed across await points.
-    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
     where
-        Fut: Future<Output = R> + Send + 'static,
+        Fut: Future<Output = R> + 'static,
-        R: Send + 'static,
+        R: 'static,
     {
-        let cx = self.to_async();
+        self.foreground_executor.spawn(f(self.to_async()))
-        self.executor.spawn(async move {
-            let future = f(cx);
-            future.await
-        })
     }
 
     /// Schedules the given function to be run at the end of the current effect cycle, allowing entities
     /// that are currently on the stack to be returned to the app.
-    pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static + Send) {
+    pub fn defer(&mut self, f: impl FnOnce(&mut AppContext) + 'static) {
         self.push_effect(Effect::Defer {
             callback: Box::new(f),
         });
@@ -597,7 +612,7 @@ impl AppContext {
 
     /// Access the global of the given type mutably. A default value is assigned if a global of this type has not
     /// yet been assigned.
-    pub fn default_global<G: 'static + Default + Send>(&mut self) -> &mut G {
+    pub fn default_global<G: 'static + Default>(&mut self) -> &mut G {
         let global_type = TypeId::of::<G>();
         self.push_effect(Effect::NotifyGlobalObservers { global_type });
         self.globals_by_type
@@ -608,7 +623,7 @@ impl AppContext {
     }
 
     /// Set the value of the global of the given type.
-    pub fn set_global<G: Any + Send>(&mut self, global: G) {
+    pub fn set_global<G: Any>(&mut self, global: G) {
         let global_type = TypeId::of::<G>();
         self.push_effect(Effect::NotifyGlobalObservers { global_type });
         self.globals_by_type.insert(global_type, Box::new(global));
@@ -626,7 +641,7 @@ impl AppContext {
     /// Register a callback to be invoked when a global of the given type is updated.
     pub fn observe_global<G: 'static>(
         &mut self,
-        mut f: impl FnMut(&mut Self) + Send + 'static,
+        mut f: impl FnMut(&mut Self) + 'static,
     ) -> Subscription {
         self.global_observers.insert(
             TypeId::of::<G>(),
@@ -658,6 +673,24 @@ impl AppContext {
         self.globals_by_type.insert(global_type, lease.global);
     }
 
+    pub fn observe_release<E, T>(
+        &mut self,
+        handle: &E,
+        on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
+    ) -> Subscription
+    where
+        E: Entity<T>,
+        T: 'static,
+    {
+        self.release_listeners.insert(
+            handle.entity_id(),
+            Box::new(move |entity, cx| {
+                let entity = entity.downcast_mut().expect("invalid entity type");
+                on_release(entity, cx)
+            }),
+        )
+    }
+
     pub(crate) fn push_text_style(&mut self, text_style: TextStyleRefinement) {
         self.text_style_stack.push(text_style);
     }
@@ -673,7 +706,7 @@ impl AppContext {
     }
 
     /// Register a global listener for actions invoked via the keyboard.
-    pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + Send + 'static) {
+    pub fn on_action<A: Action>(&mut self, listener: impl Fn(&A, &mut Self) + 'static) {
         self.global_action_listeners
             .entry(TypeId::of::<A>())
             .or_default()
@@ -711,19 +744,18 @@ impl AppContext {
 }
 
 impl Context for AppContext {
-    type ModelContext<'a, T> = ModelContext<'a, T>;
     type Result<T> = T;
 
     /// Build an entity that is owned by the application. The given function will be invoked with
     /// a `ModelContext` and must return an object representing the entity. A `Model` will be returned
     /// which can be used to access the entity in a context.
-    fn build_model<T: 'static + Send>(
+    fn build_model<T: 'static>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
+        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
     ) -> Model<T> {
         self.update(|cx| {
             let slot = cx.entities.reserve();
-            let entity = build_model(&mut ModelContext::mutable(cx, slot.downgrade()));
+            let entity = build_model(&mut ModelContext::new(cx, slot.downgrade()));
             cx.entities.insert(slot, entity)
         })
     }
@@ -733,117 +765,36 @@ impl Context for AppContext {
     fn update_model<T: 'static, R>(
         &mut self,
         model: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> R {
         self.update(|cx| {
             let mut entity = cx.entities.lease(model);
-            let result = update(
+            let result = update(&mut entity, &mut ModelContext::new(cx, model.downgrade()));
-                &mut entity,
-                &mut ModelContext::mutable(cx, model.downgrade()),
-            );
             cx.entities.end_lease(entity);
             result
         })
     }
-}
 
-impl<C> MainThread<C>
+    fn update_window<T, F>(&mut self, handle: AnyWindowHandle, update: F) -> Result<T>
-where
+    where
-    C: Borrow<AppContext>,
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
-{
+    {
-    pub(crate) fn platform(&self) -> &dyn Platform {
-        self.0.borrow().platform.borrow_on_main_thread()
-    }
-
-    /// Instructs the platform to activate the application by bringing it to the foreground.
-    pub fn activate(&self, ignoring_other_apps: bool) {
-        self.platform().activate(ignoring_other_apps);
-    }
-
-    /// Writes data to the platform clipboard.
-    pub fn write_to_clipboard(&self, item: ClipboardItem) {
-        self.platform().write_to_clipboard(item)
-    }
-
-    /// Reads data from the platform clipboard.
-    pub fn read_from_clipboard(&self) -> Option<ClipboardItem> {
-        self.platform().read_from_clipboard()
-    }
-
-    /// Writes credentials to the platform keychain.
-    pub fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Result<()> {
-        self.platform().write_credentials(url, username, password)
-    }
-
-    /// Reads credentials from the platform keychain.
-    pub fn read_credentials(&self, url: &str) -> Result<Option<(String, Vec<u8>)>> {
-        self.platform().read_credentials(url)
-    }
-
-    /// Deletes credentials from the platform keychain.
-    pub fn delete_credentials(&self, url: &str) -> Result<()> {
-        self.platform().delete_credentials(url)
-    }
-
-    /// Directs the platform's default browser to open the given URL.
-    pub fn open_url(&self, url: &str) {
-        self.platform().open_url(url);
-    }
-
-    pub fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
-        self.platform().path_for_auxiliary_executable(name)
-    }
-}
-
-impl MainThread<AppContext> {
-    fn update<R>(&mut self, update: impl FnOnce(&mut Self) -> R) -> R {
-        self.0.update(|cx| {
-            update(unsafe {
-                std::mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx)
-            })
-        })
-    }
-
-    pub(crate) fn update_window<R>(
-        &mut self,
-        id: WindowId,
-        update: impl FnOnce(&mut MainThread<WindowContext>) -> R,
-    ) -> Result<R> {
-        self.0.update_window(id, |cx| {
-            update(unsafe {
-                std::mem::transmute::<&mut WindowContext, &mut MainThread<WindowContext>>(cx)
-            })
-        })
-    }
-
-    /// Opens a new window with the given option and the root view returned by the given function.
-    /// The function is invoked with a `WindowContext`, which can be used to interact with window-specific
-    /// functionality.
-    pub fn open_window<V: Render>(
-        &mut self,
-        options: crate::WindowOptions,
-        build_root_view: impl FnOnce(&mut WindowContext) -> View<V> + Send + 'static,
-    ) -> WindowHandle<V> {
         self.update(|cx| {
-            let id = cx.windows.insert(None);
+            let mut window = cx
-            let handle = WindowHandle::new(id);
+                .windows
-            let mut window = Window::new(handle.into(), options, cx);
+                .get_mut(handle.id)
-            let root_view = build_root_view(&mut WindowContext::mutable(cx, &mut window));
+                .ok_or_else(|| anyhow!("window not found"))?
-            window.root_view.replace(root_view.into());
+                .take()
-            cx.windows.get_mut(id).unwrap().replace(window);
+                .unwrap();
-            handle
-        })
-    }
 
-    /// Update the global of the given type with a closure. Unlike `global_mut`, this method provides
+            let root_view = window.root_view.clone().unwrap();
-    /// your closure with mutable access to the `MainThread<AppContext>` and the global simultaneously.
+            let result = update(root_view, &mut WindowContext::new(cx, &mut window));
-    pub fn update_global<G: 'static + Send, R>(
+            cx.windows
-        &mut self,
+                .get_mut(handle.id)
-        update: impl FnOnce(&mut G, &mut MainThread<AppContext>) -> R,
+                .ok_or_else(|| anyhow!("window not found"))?
-    ) -> R {
+                .replace(window);
-        self.0.update_global(|global, cx| {
+
-            let cx = unsafe { mem::transmute::<&mut AppContext, &mut MainThread<AppContext>>(cx) };
+            Ok(result)
-            update(global, cx)
         })
     }
 }
@@ -855,10 +806,10 @@ pub(crate) enum Effect {
     },
     Emit {
         emitter: EntityId,
-        event: Box<dyn Any + Send + 'static>,
+        event: Box<dyn Any>,
     },
     FocusChanged {
-        window_id: WindowId,
+        window_handle: AnyWindowHandle,
         focused: Option<FocusId>,
     },
     Refresh,
@@ -866,7 +817,7 @@ pub(crate) enum Effect {
         global_type: TypeId,
     },
     Defer {
-        callback: Box<dyn FnOnce(&mut AppContext) + Send + 'static>,
+        callback: Box<dyn FnOnce(&mut AppContext) + 'static>,
     },
 }
 
@@ -905,15 +856,3 @@ pub(crate) struct AnyDrag {
     pub view: AnyView,
     pub cursor_offset: Point<Pixels>,
 }
-
-#[cfg(test)]
-mod tests {
-    use super::AppContext;
-
-    #[test]
-    fn test_app_context_send_sync() {
-        // This will not compile if `AppContext` does not implement `Send`
-        fn assert_send<T: Send>() {}
-        assert_send::<AppContext>();
-    }
-}

crates/gpui2/src/app/async_context.rs

@@ -1,48 +1,57 @@
 use crate::{
-    AnyWindowHandle, AppContext, Context, Executor, MainThread, Model, ModelContext, Result, Task,
+    AnyView, AnyWindowHandle, AppContext, BackgroundExecutor, Context, ForegroundExecutor, Model,
-    WindowContext,
+    ModelContext, Render, Result, Task, View, ViewContext, VisualContext, WindowContext,
+    WindowHandle,
 };
-use anyhow::anyhow;
+use anyhow::{anyhow, Context as _};
 use derive_more::{Deref, DerefMut};
-use parking_lot::Mutex;
+use std::{cell::RefCell, future::Future, rc::Weak};
-use std::{future::Future, sync::Weak};
 
 #[derive(Clone)]
 pub struct AsyncAppContext {
-    pub(crate) app: Weak<Mutex<AppContext>>,
+    pub(crate) app: Weak<RefCell<AppContext>>,
-    pub(crate) executor: Executor,
+    pub(crate) background_executor: BackgroundExecutor,
+    pub(crate) foreground_executor: ForegroundExecutor,
 }
 
 impl Context for AsyncAppContext {
-    type ModelContext<'a, T> = ModelContext<'a, T>;
     type Result<T> = Result<T>;
 
     fn build_model<T: 'static>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
+        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
     ) -> Self::Result<Model<T>>
     where
-        T: 'static + Send,
+        T: 'static,
     {
         let app = self
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let mut lock = app.lock(); // Need this to compile
+        let mut app = app.borrow_mut();
-        Ok(lock.build_model(build_model))
+        Ok(app.build_model(build_model))
     }
 
     fn update_model<T: 'static, R>(
         &mut self,
         handle: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> Self::Result<R> {
         let app = self
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let mut lock = app.lock(); // Need this to compile
+        let mut app = app.borrow_mut();
-        Ok(lock.update_model(handle, update))
+        Ok(app.update_model(handle, update))
+    }
+
+    fn update_window<T, F>(&mut self, window: AnyWindowHandle, f: F) -> Result<T>
+    where
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
+    {
+        let app = self.app.upgrade().context("app was released")?;
+        let mut lock = app.borrow_mut();
+        lock.update_window(window, f)
     }
 }
 
@@ -52,13 +61,17 @@ impl AsyncAppContext {
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let mut lock = app.lock(); // Need this to compile
+        let mut lock = app.borrow_mut();
         lock.refresh();
         Ok(())
     }
 
-    pub fn executor(&self) -> &Executor {
+    pub fn background_executor(&self) -> &BackgroundExecutor {
-        &self.executor
+        &self.background_executor
+    }
+
+    pub fn foreground_executor(&self) -> &ForegroundExecutor {
+        &self.foreground_executor
     }
 
     pub fn update<R>(&self, f: impl FnOnce(&mut AppContext) -> R) -> Result<R> {
@@ -66,70 +79,32 @@ impl AsyncAppContext {
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let mut lock = app.lock();
+        let mut lock = app.borrow_mut();
         Ok(f(&mut *lock))
     }
 
-    pub fn read_window<R>(
+    pub fn open_window<V>(
         &self,
-        handle: AnyWindowHandle,
+        options: crate::WindowOptions,
-        update: impl FnOnce(&WindowContext) -> R,
+        build_root_view: impl FnOnce(&mut WindowContext) -> View<V>,
-    ) -> Result<R> {
+    ) -> Result<WindowHandle<V>>
-        let app = self
-            .app
-            .upgrade()
-            .ok_or_else(|| anyhow!("app was released"))?;
-        let mut app_context = app.lock();
-        app_context.read_window(handle.id, update)
-    }
-
-    pub fn update_window<R>(
-        &self,
-        handle: AnyWindowHandle,
-        update: impl FnOnce(&mut WindowContext) -> R,
-    ) -> Result<R> {
-        let app = self
-            .app
-            .upgrade()
-            .ok_or_else(|| anyhow!("app was released"))?;
-        let mut app_context = app.lock();
-        app_context.update_window(handle.id, update)
-    }
-
-    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
     where
-        Fut: Future<Output = R> + Send + 'static,
+        V: Render,
-        R: Send + 'static,
     {
-        let this = self.clone();
+        let app = self
-        self.executor.spawn(async move { f(this).await })
+            .app
+            .upgrade()
+            .ok_or_else(|| anyhow!("app was released"))?;
+        let mut lock = app.borrow_mut();
+        Ok(lock.open_window(options, build_root_view))
     }
 
-    pub fn spawn_on_main<Fut, R>(
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
-        &self,
-        f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static,
-    ) -> Task<R>
     where
         Fut: Future<Output = R> + 'static,
-        R: Send + 'static,
+        R: 'static,
     {
-        let this = self.clone();
+        self.foreground_executor.spawn(f(self.clone()))
-        self.executor.spawn_on_main(|| f(this))
-    }
-
-    pub fn run_on_main<R>(
-        &self,
-        f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
-    ) -> Result<Task<R>>
-    where
-        R: Send + 'static,
-    {
-        let app = self
-            .app
-            .upgrade()
-            .ok_or_else(|| anyhow!("app was released"))?;
-        let mut app_context = app.lock();
-        Ok(app_context.run_on_main(f))
     }
 
     pub fn has_global<G: 'static>(&self) -> Result<bool> {
@@ -137,8 +112,8 @@ impl AsyncAppContext {
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let lock = app.lock(); // Need this to compile
+        let app = app.borrow_mut();
-        Ok(lock.has_global::<G>())
+        Ok(app.has_global::<G>())
     }
 
     pub fn read_global<G: 'static, R>(&self, read: impl FnOnce(&G, &AppContext) -> R) -> Result<R> {
@@ -146,8 +121,8 @@ impl AsyncAppContext {
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let lock = app.lock(); // Need this to compile
+        let app = app.borrow_mut(); // Need this to compile
-        Ok(read(lock.global(), &lock))
+        Ok(read(app.global(), &app))
     }
 
     pub fn try_read_global<G: 'static, R>(
@@ -155,8 +130,8 @@ impl AsyncAppContext {
         read: impl FnOnce(&G, &AppContext) -> R,
     ) -> Option<R> {
         let app = self.app.upgrade()?;
-        let lock = app.lock(); // Need this to compile
+        let app = app.borrow_mut();
-        Some(read(lock.try_global()?, &lock))
+        Some(read(app.try_global()?, &app))
     }
 
     pub fn update_global<G: 'static, R>(
@@ -167,8 +142,8 @@ impl AsyncAppContext {
             .app
             .upgrade()
             .ok_or_else(|| anyhow!("app was released"))?;
-        let mut lock = app.lock(); // Need this to compile
+        let mut app = app.borrow_mut();
-        Ok(lock.update_global(update))
+        Ok(app.update_global(update))
     }
 }
 
@@ -185,22 +160,22 @@ impl AsyncWindowContext {
         Self { app, window }
     }
 
-    pub fn update<R>(&self, update: impl FnOnce(&mut WindowContext) -> R) -> Result<R> {
+    pub fn update<R>(
+        &mut self,
+        update: impl FnOnce(AnyView, &mut WindowContext) -> R,
+    ) -> Result<R> {
         self.app.update_window(self.window, update)
     }
 
-    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut WindowContext) + Send + 'static) {
+    pub fn on_next_frame(&mut self, f: impl FnOnce(&mut WindowContext) + 'static) {
-        self.app
+        self.window.update(self, |_, cx| cx.on_next_frame(f)).ok();
-            .update_window(self.window, |cx| cx.on_next_frame(f))
-            .ok();
     }
 
     pub fn read_global<G: 'static, R>(
-        &self,
+        &mut self,
         read: impl FnOnce(&G, &WindowContext) -> R,
     ) -> Result<R> {
-        self.app
+        self.window.update(self, |_, cx| read(cx.global(), cx))
-            .read_window(self.window, |cx| read(cx.global(), cx))
     }
 
     pub fn update_global<G, R>(
@@ -210,43 +185,78 @@ impl AsyncWindowContext {
     where
         G: 'static,
     {
-        self.app
+        self.window.update(self, |_, cx| cx.update_global(update))
-            .update_window(self.window, |cx| cx.update_global(update))
+    }
+
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncWindowContext) -> Fut) -> Task<R>
+    where
+        Fut: Future<Output = R> + 'static,
+        R: 'static,
+    {
+        self.foreground_executor.spawn(f(self.clone()))
     }
 }
 
 impl Context for AsyncWindowContext {
-    type ModelContext<'a, T> = ModelContext<'a, T>;
     type Result<T> = Result<T>;
 
     fn build_model<T>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
+        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
     ) -> Result<Model<T>>
     where
-        T: 'static + Send,
+        T: 'static,
     {
-        self.app
+        self.window
-            .update_window(self.window, |cx| cx.build_model(build_model))
+            .update(self, |_, cx| cx.build_model(build_model))
     }
 
     fn update_model<T: 'static, R>(
         &mut self,
         handle: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> Result<R> {
-        self.app
+        self.window
-            .update_window(self.window, |cx| cx.update_model(handle, update))
+            .update(self, |_, cx| cx.update_model(handle, update))
+    }
+
+    fn update_window<T, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<T>
+    where
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
+    {
+        self.app.update_window(window, update)
     }
 }
 
-#[cfg(test)]
+impl VisualContext for AsyncWindowContext {
-mod tests {
+    fn build_view<V>(
-    use super::*;
+        &mut self,
+        build_view_state: impl FnOnce(&mut ViewContext<'_, V>) -> V,
+    ) -> Self::Result<View<V>>
+    where
+        V: 'static,
+    {
+        self.window
+            .update(self, |_, cx| cx.build_view(build_view_state))
+    }
 
-    #[test]
+    fn update_view<V: 'static, R>(
-    fn test_async_app_context_send_sync() {
+        &mut self,
-        fn assert_send_sync<T: Send + Sync>() {}
+        view: &View<V>,
-        assert_send_sync::<AsyncAppContext>();
+        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
+    ) -> Self::Result<R> {
+        self.window
+            .update(self, |_, cx| cx.update_view(view, update))
+    }
+
+    fn replace_root_view<V>(
+        &mut self,
+        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
+    ) -> Self::Result<View<V>>
+    where
+        V: Render,
+    {
+        self.window
+            .update(self, |_, cx| cx.replace_root_view(build_view))
     }
 }

crates/gpui2/src/app/entity_map.rs

@@ -1,4 +1,4 @@
-use crate::{private::Sealed, AnyBox, AppContext, Context, Entity};
+use crate::{private::Sealed, AnyBox, AppContext, Context, Entity, ModelContext};
 use anyhow::{anyhow, Result};
 use derive_more::{Deref, DerefMut};
 use parking_lot::{RwLock, RwLockUpgradableReadGuard};
@@ -59,7 +59,7 @@ impl EntityMap {
     /// Insert an entity into a slot obtained by calling `reserve`.
     pub fn insert<T>(&mut self, slot: Slot<T>, entity: T) -> Model<T>
     where
-        T: 'static + Send,
+        T: 'static,
     {
         let model = slot.0;
         self.entities.insert(model.entity_id, Box::new(entity));
@@ -169,6 +169,10 @@ impl AnyModel {
         self.entity_id
     }
 
+    pub fn entity_type(&self) -> TypeId {
+        self.entity_type
+    }
+
     pub fn downgrade(&self) -> AnyWeakModel {
         AnyWeakModel {
             entity_id: self.entity_id,
@@ -329,7 +333,7 @@ impl<T: 'static> Model<T> {
     pub fn update<C, R>(
         &self,
         cx: &mut C,
-        update: impl FnOnce(&mut T, &mut C::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> C::Result<R>
     where
         C: Context,
@@ -475,7 +479,7 @@ impl<T: 'static> WeakModel<T> {
     pub fn update<C, R>(
         &self,
         cx: &mut C,
-        update: impl FnOnce(&mut T, &mut C::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> Result<R>
     where
         C: Context,

crates/gpui2/src/app/model_context.rs

@@ -1,7 +1,8 @@
 use crate::{
-    AppContext, AsyncAppContext, Context, Effect, Entity, EntityId, EventEmitter, MainThread,
+    AnyView, AnyWindowHandle, AppContext, AsyncAppContext, Context, Effect, Entity, EntityId,
-    Model, Reference, Subscription, Task, WeakModel,
+    EventEmitter, Model, Subscription, Task, WeakModel, WindowContext,
 };
+use anyhow::Result;
 use derive_more::{Deref, DerefMut};
 use futures::FutureExt;
 use std::{
@@ -14,16 +15,13 @@ use std::{
 pub struct ModelContext<'a, T> {
     #[deref]
     #[deref_mut]
-    app: Reference<'a, AppContext>,
+    app: &'a mut AppContext,
     model_state: WeakModel<T>,
 }
 
 impl<'a, T: 'static> ModelContext<'a, T> {
-    pub(crate) fn mutable(app: &'a mut AppContext, model_state: WeakModel<T>) -> Self {
+    pub(crate) fn new(app: &'a mut AppContext, model_state: WeakModel<T>) -> Self {
-        Self {
+        Self { app, model_state }
-            app: Reference::Mutable(app),
-            model_state,
-        }
     }
 
     pub fn entity_id(&self) -> EntityId {
@@ -40,15 +38,15 @@ impl<'a, T: 'static> ModelContext<'a, T> {
         self.model_state.clone()
     }
 
-    pub fn observe<T2, E>(
+    pub fn observe<W, E>(
         &mut self,
         entity: &E,
-        mut on_notify: impl FnMut(&mut T, E, &mut ModelContext<'_, T>) + Send + 'static,
+        mut on_notify: impl FnMut(&mut T, E, &mut ModelContext<'_, T>) + 'static,
     ) -> Subscription
     where
-        T: 'static + Send,
+        T: 'static,
-        T2: 'static,
+        W: 'static,
-        E: Entity<T2>,
+        E: Entity<W>,
     {
         let this = self.weak_model();
         let entity_id = entity.entity_id();
@@ -69,10 +67,10 @@ impl<'a, T: 'static> ModelContext<'a, T> {
     pub fn subscribe<T2, E>(
         &mut self,
         entity: &E,
-        mut on_event: impl FnMut(&mut T, E, &T2::Event, &mut ModelContext<'_, T>) + Send + 'static,
+        mut on_event: impl FnMut(&mut T, E, &T2::Event, &mut ModelContext<'_, T>) + 'static,
     ) -> Subscription
     where
-        T: 'static + Send,
+        T: 'static,
         T2: 'static + EventEmitter,
         E: Entity<T2>,
     {
@@ -95,7 +93,7 @@ impl<'a, T: 'static> ModelContext<'a, T> {
 
     pub fn on_release(
         &mut self,
-        mut on_release: impl FnMut(&mut T, &mut AppContext) + Send + 'static,
+        on_release: impl FnOnce(&mut T, &mut AppContext) + 'static,
     ) -> Subscription
     where
         T: 'static,
@@ -112,10 +110,10 @@ impl<'a, T: 'static> ModelContext<'a, T> {
     pub fn observe_release<T2, E>(
         &mut self,
         entity: &E,
-        mut on_release: impl FnMut(&mut T, &mut T2, &mut ModelContext<'_, T>) + Send + 'static,
+        on_release: impl FnOnce(&mut T, &mut T2, &mut ModelContext<'_, T>) + 'static,
     ) -> Subscription
     where
-        T: Any + Send,
+        T: Any,
         T2: 'static,
         E: Entity<T2>,
     {
@@ -134,10 +132,10 @@ impl<'a, T: 'static> ModelContext<'a, T> {
 
     pub fn observe_global<G: 'static>(
         &mut self,
-        mut f: impl FnMut(&mut T, &mut ModelContext<'_, T>) + Send + 'static,
+        mut f: impl FnMut(&mut T, &mut ModelContext<'_, T>) + 'static,
     ) -> Subscription
     where
-        T: 'static + Send,
+        T: 'static,
     {
         let handle = self.weak_model();
         self.global_observers.insert(
@@ -148,11 +146,11 @@ impl<'a, T: 'static> ModelContext<'a, T> {
 
     pub fn on_app_quit<Fut>(
         &mut self,
-        mut on_quit: impl FnMut(&mut T, &mut ModelContext<T>) -> Fut + Send + 'static,
+        mut on_quit: impl FnMut(&mut T, &mut ModelContext<T>) -> Fut + 'static,
     ) -> Subscription
     where
-        Fut: 'static + Future<Output = ()> + Send,
+        Fut: 'static + Future<Output = ()>,
-        T: 'static + Send,
+        T: 'static,
     {
         let handle = self.weak_model();
         self.app.quit_observers.insert(
@@ -164,7 +162,7 @@ impl<'a, T: 'static> ModelContext<'a, T> {
                         future.await;
                     }
                 }
-                .boxed()
+                .boxed_local()
             }),
         )
     }
@@ -183,7 +181,7 @@ impl<'a, T: 'static> ModelContext<'a, T> {
 
     pub fn update_global<G, R>(&mut self, f: impl FnOnce(&mut G, &mut Self) -> R) -> R
     where
-        G: 'static + Send,
+        G: 'static,
     {
         let mut global = self.app.lease_global::<G>();
         let result = f(&mut global, self);
@@ -191,36 +189,20 @@ impl<'a, T: 'static> ModelContext<'a, T> {
         result
     }
 
-    pub fn spawn<Fut, R>(
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(WeakModel<T>, AsyncAppContext) -> Fut) -> Task<R>
-        &self,
-        f: impl FnOnce(WeakModel<T>, AsyncAppContext) -> Fut + Send + 'static,
-    ) -> Task<R>
     where
         T: 'static,
-        Fut: Future<Output = R> + Send + 'static,
+        Fut: Future<Output = R> + 'static,
-        R: Send + 'static,
+        R: 'static,
     {
         let this = self.weak_model();
         self.app.spawn(|cx| f(this, cx))
     }
-
-    pub fn spawn_on_main<Fut, R>(
-        &self,
-        f: impl FnOnce(WeakModel<T>, MainThread<AsyncAppContext>) -> Fut + Send + 'static,
-    ) -> Task<R>
-    where
-        Fut: Future<Output = R> + 'static,
-        R: Send + 'static,
-    {
-        let this = self.weak_model();
-        self.app.spawn_on_main(|cx| f(this, cx))
-    }
 }
 
 impl<'a, T> ModelContext<'a, T>
 where
     T: EventEmitter,
-    T::Event: Send,
 {
     pub fn emit(&mut self, event: T::Event) {
         self.app.pending_effects.push_back(Effect::Emit {
@@ -231,26 +213,29 @@ where
 }
 
 impl<'a, T> Context for ModelContext<'a, T> {
-    type ModelContext<'b, U> = ModelContext<'b, U>;
     type Result<U> = U;
 
-    fn build_model<U>(
+    fn build_model<U: 'static>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, U>) -> U,
+        build_model: impl FnOnce(&mut ModelContext<'_, U>) -> U,
-    ) -> Model<U>
+    ) -> Model<U> {
-    where
-        U: 'static + Send,
-    {
         self.app.build_model(build_model)
     }
 
     fn update_model<U: 'static, R>(
         &mut self,
         handle: &Model<U>,
-        update: impl FnOnce(&mut U, &mut Self::ModelContext<'_, U>) -> R,
+        update: impl FnOnce(&mut U, &mut ModelContext<'_, U>) -> R,
     ) -> R {
         self.app.update_model(handle, update)
     }
+
+    fn update_window<R, F>(&mut self, window: AnyWindowHandle, update: F) -> Result<R>
+    where
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> R,
+    {
+        self.app.update_window(window, update)
+    }
 }
 
 impl<T> Borrow<AppContext> for ModelContext<'_, T> {

crates/gpui2/src/app/test_context.rs

@@ -1,138 +1,115 @@
 use crate::{
-    AnyWindowHandle, AppContext, AsyncAppContext, Context, EventEmitter, Executor, MainThread,
+    AnyView, AnyWindowHandle, AppContext, AsyncAppContext, BackgroundExecutor, Context,
-    Model, ModelContext, Result, Task, TestDispatcher, TestPlatform, WindowContext,
+    EventEmitter, ForegroundExecutor, Model, ModelContext, Result, Task, TestDispatcher,
+    TestPlatform, WindowContext,
 };
-use futures::SinkExt;
+use anyhow::{anyhow, bail};
-use parking_lot::Mutex;
+use futures::{Stream, StreamExt};
-use std::{future::Future, sync::Arc};
+use std::{cell::RefCell, future::Future, rc::Rc, sync::Arc, time::Duration};
 
 #[derive(Clone)]
 pub struct TestAppContext {
-    pub app: Arc<Mutex<AppContext>>,
+    pub app: Rc<RefCell<AppContext>>,
-    pub executor: Executor,
+    pub background_executor: BackgroundExecutor,
+    pub foreground_executor: ForegroundExecutor,
 }
 
 impl Context for TestAppContext {
-    type ModelContext<'a, T> = ModelContext<'a, T>;
     type Result<T> = T;
 
     fn build_model<T: 'static>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
+        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
     ) -> Self::Result<Model<T>>
     where
-        T: 'static + Send,
+        T: 'static,
     {
-        let mut lock = self.app.lock();
+        let mut app = self.app.borrow_mut();
-        lock.build_model(build_model)
+        app.build_model(build_model)
     }
 
     fn update_model<T: 'static, R>(
         &mut self,
         handle: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
     ) -> Self::Result<R> {
-        let mut lock = self.app.lock();
+        let mut app = self.app.borrow_mut();
-        lock.update_model(handle, update)
+        app.update_model(handle, update)
+    }
+
+    fn update_window<T, F>(&mut self, window: AnyWindowHandle, f: F) -> Result<T>
+    where
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T,
+    {
+        let mut lock = self.app.borrow_mut();
+        lock.update_window(window, f)
     }
 }
 
 impl TestAppContext {
     pub fn new(dispatcher: TestDispatcher) -> Self {
-        let executor = Executor::new(Arc::new(dispatcher));
+        let dispatcher = Arc::new(dispatcher);
-        let platform = Arc::new(TestPlatform::new(executor.clone()));
+        let background_executor = BackgroundExecutor::new(dispatcher.clone());
+        let foreground_executor = ForegroundExecutor::new(dispatcher);
+        let platform = Rc::new(TestPlatform::new(
+            background_executor.clone(),
+            foreground_executor.clone(),
+        ));
         let asset_source = Arc::new(());
         let http_client = util::http::FakeHttpClient::with_404_response();
         Self {
             app: AppContext::new(platform, asset_source, http_client),
-            executor,
+            background_executor,
+            foreground_executor,
         }
     }
 
     pub fn quit(&self) {
-        self.app.lock().quit();
+        self.app.borrow_mut().quit();
     }
 
     pub fn refresh(&mut self) -> Result<()> {
-        let mut lock = self.app.lock();
+        let mut app = self.app.borrow_mut();
-        lock.refresh();
+        app.refresh();
         Ok(())
     }
 
-    pub fn executor(&self) -> &Executor {
+    pub fn executor(&self) -> &BackgroundExecutor {
-        &self.executor
+        &self.background_executor
+    }
+
+    pub fn foreground_executor(&self) -> &ForegroundExecutor {
+        &self.foreground_executor
     }
 
     pub fn update<R>(&self, f: impl FnOnce(&mut AppContext) -> R) -> R {
-        let mut cx = self.app.lock();
+        let mut cx = self.app.borrow_mut();
         cx.update(f)
     }
 
-    pub fn read_window<R>(
+    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut) -> Task<R>
-        &self,
-        handle: AnyWindowHandle,
-        read: impl FnOnce(&WindowContext) -> R,
-    ) -> R {
-        let mut app_context = self.app.lock();
-        app_context.read_window(handle.id, read).unwrap()
-    }
-
-    pub fn update_window<R>(
-        &self,
-        handle: AnyWindowHandle,
-        update: impl FnOnce(&mut WindowContext) -> R,
-    ) -> R {
-        let mut app = self.app.lock();
-        app.update_window(handle.id, update).unwrap()
-    }
-
-    pub fn spawn<Fut, R>(&self, f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static) -> Task<R>
-    where
-        Fut: Future<Output = R> + Send + 'static,
-        R: Send + 'static,
-    {
-        let cx = self.to_async();
-        self.executor.spawn(async move { f(cx).await })
-    }
-
-    pub fn spawn_on_main<Fut, R>(
-        &self,
-        f: impl FnOnce(AsyncAppContext) -> Fut + Send + 'static,
-    ) -> Task<R>
     where
         Fut: Future<Output = R> + 'static,
-        R: Send + 'static,
+        R: 'static,
     {
-        let cx = self.to_async();
+        self.foreground_executor.spawn(f(self.to_async()))
-        self.executor.spawn_on_main(|| f(cx))
-    }
-
-    pub fn run_on_main<R>(
-        &self,
-        f: impl FnOnce(&mut MainThread<AppContext>) -> R + Send + 'static,
-    ) -> Task<R>
-    where
-        R: Send + 'static,
-    {
-        let mut app_context = self.app.lock();
-        app_context.run_on_main(f)
     }
 
     pub fn has_global<G: 'static>(&self) -> bool {
-        let lock = self.app.lock();
+        let app = self.app.borrow();
-        lock.has_global::<G>()
+        app.has_global::<G>()
     }
 
     pub fn read_global<G: 'static, R>(&self, read: impl FnOnce(&G, &AppContext) -> R) -> R {
-        let lock = self.app.lock();
+        let app = self.app.borrow();
-        read(lock.global(), &lock)
+        read(app.global(), &app)
     }
 
     pub fn try_read_global<G: 'static, R>(
         &self,
         read: impl FnOnce(&G, &AppContext) -> R,
     ) -> Option<R> {
-        let lock = self.app.lock();
+        let lock = self.app.borrow();
         Some(read(lock.try_global()?, &lock))
     }
 
@@ -140,32 +117,75 @@ impl TestAppContext {
         &mut self,
         update: impl FnOnce(&mut G, &mut AppContext) -> R,
     ) -> R {
-        let mut lock = self.app.lock();
+        let mut lock = self.app.borrow_mut();
         lock.update_global(update)
     }
 
     pub fn to_async(&self) -> AsyncAppContext {
         AsyncAppContext {
-            app: Arc::downgrade(&self.app),
+            app: Rc::downgrade(&self.app),
-            executor: self.executor.clone(),
+            background_executor: self.background_executor.clone(),
+            foreground_executor: self.foreground_executor.clone(),
         }
     }
 
-    pub fn subscribe<T: 'static + EventEmitter + Send>(
+    pub fn notifications<T: 'static>(&mut self, entity: &Model<T>) -> impl Stream<Item = ()> {
+        let (tx, rx) = futures::channel::mpsc::unbounded();
+
+        entity.update(self, move |_, cx: &mut ModelContext<T>| {
+            cx.observe(entity, {
+                let tx = tx.clone();
+                move |_, _, _| {
+                    let _ = tx.unbounded_send(());
+                }
+            })
+            .detach();
+
+            cx.on_release(move |_, _| tx.close_channel()).detach();
+        });
+
+        rx
+    }
+
+    pub fn events<T: 'static + EventEmitter>(
         &mut self,
         entity: &Model<T>,
     ) -> futures::channel::mpsc::UnboundedReceiver<T::Event>
     where
-        T::Event: 'static + Send + Clone,
+        T::Event: 'static + Clone,
     {
-        let (mut tx, rx) = futures::channel::mpsc::unbounded();
+        let (tx, rx) = futures::channel::mpsc::unbounded();
         entity
             .update(self, |_, cx: &mut ModelContext<T>| {
-                cx.subscribe(entity, move |_, _, event, cx| {
+                cx.subscribe(entity, move |_model, _handle, event, _cx| {
-                    cx.executor().block(tx.send(event.clone())).unwrap();
+                    let _ = tx.unbounded_send(event.clone());
                 })
             })
             .detach();
         rx
     }
+
+    pub async fn condition<T: 'static>(
+        &mut self,
+        model: &Model<T>,
+        mut predicate: impl FnMut(&mut T, &mut ModelContext<T>) -> bool,
+    ) {
+        let timer = self.executor().timer(Duration::from_secs(3));
+        let mut notifications = self.notifications(model);
+
+        use futures::FutureExt as _;
+        use smol::future::FutureExt as _;
+
+        async {
+            while notifications.next().await.is_some() {
+                if model.update(self, &mut predicate) {
+                    return Ok(());
+                }
+            }
+            bail!("model dropped")
+        }
+        .race(timer.map(|_| Err(anyhow!("condition timed out"))))
+        .await
+        .unwrap();
+    }
 }

crates/gpui2/src/element.rs

@@ -4,7 +4,7 @@ pub(crate) use smallvec::SmallVec;
 use std::{any::Any, mem};
 
 pub trait Element<V: 'static> {
-    type ElementState: 'static + Send;
+    type ElementState: 'static;
 
     fn id(&self) -> Option<ElementId>;
 
@@ -97,7 +97,7 @@ impl<V, E: Element<V>> RenderedElement<V, E> {
 impl<V, E> ElementObject<V> for RenderedElement<V, E>
 where
     E: Element<V>,
-    E::ElementState: 'static + Send,
+    E::ElementState: 'static,
 {
     fn initialize(&mut self, view_state: &mut V, cx: &mut ViewContext<V>) {
         let frame_state = if let Some(id) = self.element.id() {
@@ -170,16 +170,14 @@ where
     }
 }
 
-pub struct AnyElement<V>(Box<dyn ElementObject<V> + Send>);
+pub struct AnyElement<V>(Box<dyn ElementObject<V>>);
-
-unsafe impl<V> Send for AnyElement<V> {}
 
 impl<V> AnyElement<V> {
     pub fn new<E>(element: E) -> Self
     where
         V: 'static,
-        E: 'static + Element<V> + Send,
+        E: 'static + Element<V>,
-        E::ElementState: Any + Send,
+        E::ElementState: Any,
     {
         AnyElement(Box::new(RenderedElement::new(element)))
     }
@@ -220,8 +218,8 @@ impl<V> Component<V> for AnyElement<V> {
 impl<V, E, F> Element<V> for Option<F>
 where
     V: 'static,
-    E: 'static + Component<V> + Send,
+    E: 'static + Component<V>,
-    F: FnOnce(&mut V, &mut ViewContext<'_, '_, V>) -> E + Send + 'static,
+    F: FnOnce(&mut V, &mut ViewContext<'_, V>) -> E + 'static,
 {
     type ElementState = AnyElement<V>;
 
@@ -264,8 +262,8 @@ where
 impl<V, E, F> Component<V> for Option<F>
 where
     V: 'static,
-    E: 'static + Component<V> + Send,
+    E: 'static + Component<V>,
-    F: FnOnce(&mut V, &mut ViewContext<'_, '_, V>) -> E + Send + 'static,
+    F: FnOnce(&mut V, &mut ViewContext<'_, V>) -> E + 'static,
 {
     fn render(self) -> AnyElement<V> {
         AnyElement::new(self)
@@ -275,8 +273,8 @@ where
 impl<V, E, F> Component<V> for F
 where
     V: 'static,
-    E: 'static + Component<V> + Send,
+    E: 'static + Component<V>,
-    F: FnOnce(&mut V, &mut ViewContext<'_, '_, V>) -> E + Send + 'static,
+    F: FnOnce(&mut V, &mut ViewContext<'_, V>) -> E + 'static,
 {
     fn render(self) -> AnyElement<V> {
         AnyElement::new(Some(self))

crates/gpui2/src/elements/div.rs

@@ -305,7 +305,6 @@ where
 
 impl<V, I, F> Component<V> for Div<V, I, F>
 where
-    // V: Any + Send + Sync,
     I: ElementInteraction<V>,
     F: ElementFocus<V>,
 {

crates/gpui2/src/elements/text.rs

@@ -44,9 +44,6 @@ pub struct Text<V> {
     state_type: PhantomData<V>,
 }
 
-unsafe impl<V> Send for Text<V> {}
-unsafe impl<V> Sync for Text<V> {}
-
 impl<V: 'static> Component<V> for Text<V> {
     fn render(self) -> AnyElement<V> {
         AnyElement::new(self)

crates/gpui2/src/executor.rs

@@ -6,6 +6,7 @@ use std::{
     marker::PhantomData,
     mem,
     pin::Pin,
+    rc::Rc,
     sync::{
         atomic::{AtomicBool, Ordering::SeqCst},
         Arc,
@@ -17,10 +18,16 @@ use util::TryFutureExt;
 use waker_fn::waker_fn;
 
 #[derive(Clone)]
-pub struct Executor {
+pub struct BackgroundExecutor {
     dispatcher: Arc<dyn PlatformDispatcher>,
 }
 
+#[derive(Clone)]
+pub struct ForegroundExecutor {
+    dispatcher: Arc<dyn PlatformDispatcher>,
+    not_send: PhantomData<Rc<()>>,
+}
+
 #[must_use]
 pub enum Task<T> {
     Ready(Option<T>),
@@ -46,7 +53,7 @@ where
     E: 'static + Send + Debug,
 {
     pub fn detach_and_log_err(self, cx: &mut AppContext) {
-        cx.executor().spawn(self.log_err()).detach();
+        cx.background_executor().spawn(self.log_err()).detach();
     }
 }
 
@@ -61,7 +68,7 @@ impl<T> Future for Task<T> {
     }
 }
 
-impl Executor {
+impl BackgroundExecutor {
     pub fn new(dispatcher: Arc<dyn PlatformDispatcher>) -> Self {
         Self { dispatcher }
     }
@@ -79,72 +86,30 @@ impl Executor {
         Task::Spawned(task)
     }
 
-    /// Enqueues the given closure to run on the application's event loop.
+    #[cfg(any(test, feature = "test-support"))]
-    /// Returns the result asynchronously.
+    pub fn block_test<R>(&self, future: impl Future<Output = R>) -> R {
-    pub fn run_on_main<F, R>(&self, func: F) -> Task<R>
+        self.block_internal(false, future)
-    where
-        F: FnOnce() -> R + Send + 'static,
-        R: Send + 'static,
-    {
-        if self.dispatcher.is_main_thread() {
-            Task::ready(func())
-        } else {
-            self.spawn_on_main(move || async move { func() })
-        }
-    }
-
-    /// Enqueues the given closure to be run on the application's event loop. The
-    /// closure returns a future which will be run to completion on the main thread.
-    pub fn spawn_on_main<F, R>(&self, func: impl FnOnce() -> F + Send + 'static) -> Task<R>
-    where
-        F: Future<Output = R> + 'static,
-        R: Send + 'static,
-    {
-        let (runnable, task) = async_task::spawn(
-            {
-                let this = self.clone();
-                async move {
-                    let task = this.spawn_on_main_local(func());
-                    task.await
-                }
-            },
-            {
-                let dispatcher = self.dispatcher.clone();
-                move |runnable| dispatcher.dispatch_on_main_thread(runnable)
-            },
-        );
-        runnable.schedule();
-        Task::Spawned(task)
-    }
-
-    /// Enqueues the given closure to be run on the application's event loop. Must
-    /// be called on the main thread.
-    pub fn spawn_on_main_local<R>(&self, future: impl Future<Output = R> + 'static) -> Task<R>
-    where
-        R: 'static,
-    {
-        assert!(
-            self.dispatcher.is_main_thread(),
-            "must be called on main thread"
-        );
-
-        let dispatcher = self.dispatcher.clone();
-        let (runnable, task) = async_task::spawn_local(future, move |runnable| {
-            dispatcher.dispatch_on_main_thread(runnable)
-        });
-        runnable.schedule();
-        Task::Spawned(task)
     }
 
     pub fn block<R>(&self, future: impl Future<Output = R>) -> R {
-        pin_mut!(future);
+        self.block_internal(true, future)
-        let (parker, unparker) = parking::pair();
+    }
-        let awoken = Arc::new(AtomicBool::new(false));
-        let awoken2 = awoken.clone();
 
-        let waker = waker_fn(move || {
+    pub(crate) fn block_internal<R>(
-            awoken2.store(true, SeqCst);
+        &self,
-            unparker.unpark();
+        background_only: bool,
+        future: impl Future<Output = R>,
+    ) -> R {
+        pin_mut!(future);
+        let unparker = self.dispatcher.unparker();
+        let awoken = Arc::new(AtomicBool::new(false));
+
+        let waker = waker_fn({
+            let awoken = awoken.clone();
+            move || {
+                awoken.store(true, SeqCst);
+                unparker.unpark();
+            }
         });
         let mut cx = std::task::Context::from_waker(&waker);
 
@@ -152,7 +117,7 @@ impl Executor {
             match future.as_mut().poll(&mut cx) {
                 Poll::Ready(result) => return result,
                 Poll::Pending => {
-                    if !self.dispatcher.poll() {
+                    if !self.dispatcher.poll(background_only) {
                         if awoken.swap(false, SeqCst) {
                             continue;
                         }
@@ -168,7 +133,8 @@ impl Executor {
                                 panic!("parked with nothing left to run\n{:?}", backtrace_message)
                             }
                         }
-                        parker.park();
+
+                        self.dispatcher.park();
                     }
                 }
             }
@@ -234,7 +200,7 @@ impl Executor {
 
     #[cfg(any(test, feature = "test-support"))]
     pub fn simulate_random_delay(&self) -> impl Future<Output = ()> {
-        self.spawn(self.dispatcher.as_test().unwrap().simulate_random_delay())
+        self.dispatcher.as_test().unwrap().simulate_random_delay()
     }
 
     #[cfg(any(test, feature = "test-support"))]
@@ -261,8 +227,31 @@ impl Executor {
     }
 }
 
+impl ForegroundExecutor {
+    pub fn new(dispatcher: Arc<dyn PlatformDispatcher>) -> Self {
+        Self {
+            dispatcher,
+            not_send: PhantomData,
+        }
+    }
+
+    /// Enqueues the given closure to be run on any thread. The closure returns
+    /// a future which will be run to completion on any available thread.
+    pub fn spawn<R>(&self, future: impl Future<Output = R> + 'static) -> Task<R>
+    where
+        R: 'static,
+    {
+        let dispatcher = self.dispatcher.clone();
+        let (runnable, task) = async_task::spawn_local(future, move |runnable| {
+            dispatcher.dispatch_on_main_thread(runnable)
+        });
+        runnable.schedule();
+        Task::Spawned(task)
+    }
+}
+
 pub struct Scope<'a> {
-    executor: Executor,
+    executor: BackgroundExecutor,
     futures: Vec<Pin<Box<dyn Future<Output = ()> + Send + 'static>>>,
     tx: Option<mpsc::Sender<()>>,
     rx: mpsc::Receiver<()>,
@@ -270,7 +259,7 @@ pub struct Scope<'a> {
 }
 
 impl<'a> Scope<'a> {
-    fn new(executor: Executor) -> Self {
+    fn new(executor: BackgroundExecutor) -> Self {
         let (tx, rx) = mpsc::channel(1);
         Self {
             executor,

crates/gpui2/src/focusable.rs

@@ -8,7 +8,7 @@ use smallvec::SmallVec;
 pub type FocusListeners<V> = SmallVec<[FocusListener<V>; 2]>;
 
 pub type FocusListener<V> =
-    Box<dyn Fn(&mut V, &FocusHandle, &FocusEvent, &mut ViewContext<V>) + Send + 'static>;
+    Box<dyn Fn(&mut V, &FocusHandle, &FocusEvent, &mut ViewContext<V>) + 'static>;
 
 pub trait Focusable<V: 'static>: Element<V> {
     fn focus_listeners(&mut self) -> &mut FocusListeners<V>;
@@ -42,7 +42,7 @@ pub trait Focusable<V: 'static>: Element<V> {
 
     fn on_focus(
         mut self,
-        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -58,7 +58,7 @@ pub trait Focusable<V: 'static>: Element<V> {
 
     fn on_blur(
         mut self,
-        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -74,7 +74,7 @@ pub trait Focusable<V: 'static>: Element<V> {
 
     fn on_focus_in(
         mut self,
-        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -99,7 +99,7 @@ pub trait Focusable<V: 'static>: Element<V> {
 
     fn on_focus_out(
         mut self,
-        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &FocusEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -122,7 +122,7 @@ pub trait Focusable<V: 'static>: Element<V> {
     }
 }
 
-pub trait ElementFocus<V: 'static>: 'static + Send {
+pub trait ElementFocus<V: 'static>: 'static {
     fn as_focusable(&self) -> Option<&FocusEnabled<V>>;
     fn as_focusable_mut(&mut self) -> Option<&mut FocusEnabled<V>>;
 

crates/gpui2/src/geometry.rs

@@ -931,6 +931,18 @@ impl From<f64> for GlobalPixels {
     }
 }
 
+impl sqlez::bindable::StaticColumnCount for GlobalPixels {}
+
+impl sqlez::bindable::Bind for GlobalPixels {
+    fn bind(
+        &self,
+        statement: &sqlez::statement::Statement,
+        start_index: i32,
+    ) -> anyhow::Result<i32> {
+        self.0.bind(statement, start_index)
+    }
+}
+
 #[derive(Clone, Copy, Default, Add, Sub, Mul, Div, Neg)]
 pub struct Rems(f32);
 

crates/gpui2/src/gpui2.rs

@@ -68,51 +68,56 @@ use derive_more::{Deref, DerefMut};
 use std::{
     any::{Any, TypeId},
     borrow::{Borrow, BorrowMut},
-    mem,
-    ops::{Deref, DerefMut},
-    sync::Arc,
 };
 use taffy::TaffyLayoutEngine;
 
-type AnyBox = Box<dyn Any + Send>;
+type AnyBox = Box<dyn Any>;
 
 pub trait Context {
-    type ModelContext<'a, T>;
     type Result<T>;
 
-    fn build_model<T>(
+    fn build_model<T: 'static>(
         &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
+        build_model: impl FnOnce(&mut ModelContext<'_, T>) -> T,
-    ) -> Self::Result<Model<T>>
+    ) -> Self::Result<Model<T>>;
-    where
-        T: 'static + Send;
 
-    fn update_model<T: 'static, R>(
+    fn update_model<T, R>(
         &mut self,
         handle: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
+        update: impl FnOnce(&mut T, &mut ModelContext<'_, T>) -> R,
-    ) -> Self::Result<R>;
+    ) -> Self::Result<R>
+    where
+        T: 'static;
+
+    fn update_window<T, F>(&mut self, window: AnyWindowHandle, f: F) -> Result<T>
+    where
+        F: FnOnce(AnyView, &mut WindowContext<'_>) -> T;
 }
 
 pub trait VisualContext: Context {
-    type ViewContext<'a, 'w, V>;
-
     fn build_view<V>(
         &mut self,
-        build_view_state: impl FnOnce(&mut Self::ViewContext<'_, '_, V>) -> V,
+        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
     ) -> Self::Result<View<V>>
     where
-        V: 'static + Send;
+        V: 'static;
 
     fn update_view<V: 'static, R>(
         &mut self,
         view: &View<V>,
-        update: impl FnOnce(&mut V, &mut Self::ViewContext<'_, '_, V>) -> R,
+        update: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
     ) -> Self::Result<R>;
+
+    fn replace_root_view<V>(
+        &mut self,
+        build_view: impl FnOnce(&mut ViewContext<'_, V>) -> V,
+    ) -> Self::Result<View<V>>
+    where
+        V: Render;
 }
 
 pub trait Entity<T>: Sealed {
-    type Weak: 'static + Send;
+    type Weak: 'static;
 
     fn entity_id(&self) -> EntityId;
     fn downgrade(&self) -> Self::Weak;
@@ -127,106 +132,12 @@ pub enum GlobalKey {
     Type(TypeId),
 }
 
-#[repr(transparent)]
-pub struct MainThread<T>(T);
-
-impl<T> Deref for MainThread<T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl<T> DerefMut for MainThread<T> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.0
-    }
-}
-
-impl<C: Context> Context for MainThread<C> {
-    type ModelContext<'a, T> = MainThread<C::ModelContext<'a, T>>;
-    type Result<T> = C::Result<T>;
-
-    fn build_model<T>(
-        &mut self,
-        build_model: impl FnOnce(&mut Self::ModelContext<'_, T>) -> T,
-    ) -> Self::Result<Model<T>>
-    where
-        T: 'static + Send,
-    {
-        self.0.build_model(|cx| {
-            let cx = unsafe {
-                mem::transmute::<
-                    &mut C::ModelContext<'_, T>,
-                    &mut MainThread<C::ModelContext<'_, T>>,
-                >(cx)
-            };
-            build_model(cx)
-        })
-    }
-
-    fn update_model<T: 'static, R>(
-        &mut self,
-        handle: &Model<T>,
-        update: impl FnOnce(&mut T, &mut Self::ModelContext<'_, T>) -> R,
-    ) -> Self::Result<R> {
-        self.0.update_model(handle, |entity, cx| {
-            let cx = unsafe {
-                mem::transmute::<
-                    &mut C::ModelContext<'_, T>,
-                    &mut MainThread<C::ModelContext<'_, T>>,
-                >(cx)
-            };
-            update(entity, cx)
-        })
-    }
-}
-
-impl<C: VisualContext> VisualContext for MainThread<C> {
-    type ViewContext<'a, 'w, V> = MainThread<C::ViewContext<'a, 'w, V>>;
-
-    fn build_view<V>(
-        &mut self,
-        build_view_state: impl FnOnce(&mut Self::ViewContext<'_, '_, V>) -> V,
-    ) -> Self::Result<View<V>>
-    where
-        V: 'static + Send,
-    {
-        self.0.build_view(|cx| {
-            let cx = unsafe {
-                mem::transmute::<
-                    &mut C::ViewContext<'_, '_, V>,
-                    &mut MainThread<C::ViewContext<'_, '_, V>>,
-                >(cx)
-            };
-            build_view_state(cx)
-        })
-    }
-
-    fn update_view<V: 'static, R>(
-        &mut self,
-        view: &View<V>,
-        update: impl FnOnce(&mut V, &mut Self::ViewContext<'_, '_, V>) -> R,
-    ) -> Self::Result<R> {
-        self.0.update_view(view, |view_state, cx| {
-            let cx = unsafe {
-                mem::transmute::<
-                    &mut C::ViewContext<'_, '_, V>,
-                    &mut MainThread<C::ViewContext<'_, '_, V>>,
-                >(cx)
-            };
-            update(view_state, cx)
-        })
-    }
-}
-
 pub trait BorrowAppContext {
     fn with_text_style<F, R>(&mut self, style: TextStyleRefinement, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R;
 
-    fn set_global<T: Send + 'static>(&mut self, global: T);
+    fn set_global<T: 'static>(&mut self, global: T);
 }
 
 impl<C> BorrowAppContext for C
@@ -243,7 +154,7 @@ where
         result
     }
 
-    fn set_global<G: 'static + Send>(&mut self, global: G) {
+    fn set_global<G: 'static>(&mut self, global: G) {
         self.borrow_mut().set_global(global)
     }
 }
@@ -306,59 +217,3 @@ impl<T: Into<ArcCow<'static, str>>> From<T> for SharedString {
         Self(value.into())
     }
 }
-
-pub enum Reference<'a, T> {
-    Immutable(&'a T),
-    Mutable(&'a mut T),
-}
-
-impl<'a, T> Deref for Reference<'a, T> {
-    type Target = T;
-
-    fn deref(&self) -> &Self::Target {
-        match self {
-            Reference::Immutable(target) => target,
-            Reference::Mutable(target) => target,
-        }
-    }
-}
-
-impl<'a, T> DerefMut for Reference<'a, T> {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        match self {
-            Reference::Immutable(_) => {
-                panic!("cannot mutably deref an immutable reference. this is a bug in GPUI.");
-            }
-            Reference::Mutable(target) => target,
-        }
-    }
-}
-
-pub(crate) struct MainThreadOnly<T: ?Sized> {
-    executor: Executor,
-    value: Arc<T>,
-}
-
-impl<T: ?Sized> Clone for MainThreadOnly<T> {
-    fn clone(&self) -> Self {
-        Self {
-            executor: self.executor.clone(),
-            value: self.value.clone(),
-        }
-    }
-}
-
-/// Allows a value to be accessed only on the main thread, allowing a non-`Send` type
-/// to become `Send`.
-impl<T: 'static + ?Sized> MainThreadOnly<T> {
-    pub(crate) fn new(value: Arc<T>, executor: Executor) -> Self {
-        Self { executor, value }
-    }
-
-    pub(crate) fn borrow_on_main_thread(&self) -> &T {
-        assert!(self.executor.is_main_thread());
-        &self.value
-    }
-}
-
-unsafe impl<T: ?Sized> Send for MainThreadOnly<T> {}

crates/gpui2/src/interactive.rs

@@ -50,7 +50,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
     fn on_mouse_down(
         mut self,
         button: MouseButton,
-        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -71,7 +71,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
     fn on_mouse_up(
         mut self,
         button: MouseButton,
-        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -92,7 +92,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
     fn on_mouse_down_out(
         mut self,
         button: MouseButton,
-        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &MouseDownEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -113,7 +113,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
     fn on_mouse_up_out(
         mut self,
         button: MouseButton,
-        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &MouseUpEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -133,7 +133,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
 
     fn on_mouse_move(
         mut self,
-        handler: impl Fn(&mut V, &MouseMoveEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &MouseMoveEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -150,7 +150,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
 
     fn on_scroll_wheel(
         mut self,
-        handler: impl Fn(&mut V, &ScrollWheelEvent, &mut ViewContext<V>) + Send + 'static,
+        handler: impl Fn(&mut V, &ScrollWheelEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -178,7 +178,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
 
     fn on_action<A: 'static>(
         mut self,
-        listener: impl Fn(&mut V, &A, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &A, DispatchPhase, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -196,7 +196,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
 
     fn on_key_down(
         mut self,
-        listener: impl Fn(&mut V, &KeyDownEvent, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &KeyDownEvent, DispatchPhase, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -214,7 +214,7 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
 
     fn on_key_up(
         mut self,
-        listener: impl Fn(&mut V, &KeyUpEvent, DispatchPhase, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &KeyUpEvent, DispatchPhase, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -258,9 +258,9 @@ pub trait StatelessInteractive<V: 'static>: Element<V> {
         self
     }
 
-    fn on_drop<W: 'static + Send>(
+    fn on_drop<W: 'static>(
         mut self,
-        listener: impl Fn(&mut V, View<W>, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, View<W>, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -303,7 +303,7 @@ pub trait StatefulInteractive<V: 'static>: StatelessInteractive<V> {
 
     fn on_click(
         mut self,
-        listener: impl Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + Send + 'static,
+        listener: impl Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + 'static,
     ) -> Self
     where
         Self: Sized,
@@ -316,11 +316,11 @@ pub trait StatefulInteractive<V: 'static>: StatelessInteractive<V> {
 
     fn on_drag<W>(
         mut self,
-        listener: impl Fn(&mut V, &mut ViewContext<V>) -> View<W> + Send + 'static,
+        listener: impl Fn(&mut V, &mut ViewContext<V>) -> View<W> + 'static,
     ) -> Self
     where
         Self: Sized,
-        W: 'static + Send + Render,
+        W: 'static + Render,
     {
         debug_assert!(
             self.stateful_interaction().drag_listener.is_none(),
@@ -335,7 +335,7 @@ pub trait StatefulInteractive<V: 'static>: StatelessInteractive<V> {
     }
 }
 
-pub trait ElementInteraction<V: 'static>: 'static + Send {
+pub trait ElementInteraction<V: 'static>: 'static {
     fn as_stateless(&self) -> &StatelessInteraction<V>;
     fn as_stateless_mut(&mut self) -> &mut StatelessInteraction<V>;
     fn as_stateful(&self) -> Option<&StatefulInteraction<V>>;
@@ -672,7 +672,7 @@ impl<V> From<ElementId> for StatefulInteraction<V> {
     }
 }
 
-type DropListener<V> = dyn Fn(&mut V, AnyView, &mut ViewContext<V>) + 'static + Send;
+type DropListener<V> = dyn Fn(&mut V, AnyView, &mut ViewContext<V>) + 'static;
 
 pub struct StatelessInteraction<V> {
     pub dispatch_context: DispatchContext,
@@ -1077,32 +1077,25 @@ pub struct FocusEvent {
 }
 
 pub type MouseDownListener<V> = Box<
-    dyn Fn(&mut V, &MouseDownEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
+    dyn Fn(&mut V, &MouseDownEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
-        + Send
-        + 'static,
 >;
 pub type MouseUpListener<V> = Box<
-    dyn Fn(&mut V, &MouseUpEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
+    dyn Fn(&mut V, &MouseUpEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
-        + Send
-        + 'static,
 >;
 
 pub type MouseMoveListener<V> = Box<
-    dyn Fn(&mut V, &MouseMoveEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
+    dyn Fn(&mut V, &MouseMoveEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>) + 'static,
-        + Send
-        + 'static,
 >;
 
 pub type ScrollWheelListener<V> = Box<
     dyn Fn(&mut V, &ScrollWheelEvent, &Bounds<Pixels>, DispatchPhase, &mut ViewContext<V>)
-        + Send
         + 'static,
 >;
 
-pub type ClickListener<V> = Box<dyn Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + Send + 'static>;
+pub type ClickListener<V> = Box<dyn Fn(&mut V, &ClickEvent, &mut ViewContext<V>) + 'static>;
 
 pub(crate) type DragListener<V> =
-    Box<dyn Fn(&mut V, Point<Pixels>, &mut ViewContext<V>) -> AnyDrag + Send + 'static>;
+    Box<dyn Fn(&mut V, Point<Pixels>, &mut ViewContext<V>) -> AnyDrag + 'static>;
 
 pub type KeyListener<V> = Box<
     dyn Fn(
@@ -1112,6 +1105,5 @@ pub type KeyListener<V> = Box<
             DispatchPhase,
             &mut ViewContext<V>,
         ) -> Option<Box<dyn Action>>
-        + Send
         + 'static,
 >;

crates/gpui2/src/platform.rs

@@ -5,15 +5,19 @@ mod mac;
 mod test;
 
 use crate::{
-    AnyWindowHandle, Bounds, DevicePixels, Executor, Font, FontId, FontMetrics, FontRun,
+    point, size, AnyWindowHandle, BackgroundExecutor, Bounds, DevicePixels, Font, FontId,
-    GlobalPixels, GlyphId, InputEvent, LineLayout, Pixels, Point, RenderGlyphParams,
+    FontMetrics, FontRun, ForegroundExecutor, GlobalPixels, GlyphId, InputEvent, LineLayout,
-    RenderImageParams, RenderSvgParams, Result, Scene, SharedString, Size,
+    Pixels, Point, RenderGlyphParams, RenderImageParams, RenderSvgParams, Result, Scene,
+    SharedString, Size,
 };
-use anyhow::anyhow;
+use anyhow::{anyhow, bail};
 use async_task::Runnable;
 use futures::channel::oneshot;
+use parking::Unparker;
 use seahash::SeaHasher;
 use serde::{Deserialize, Serialize};
+use sqlez::bindable::{Bind, Column, StaticColumnCount};
+use sqlez::statement::Statement;
 use std::borrow::Cow;
 use std::hash::{Hash, Hasher};
 use std::time::Duration;
@@ -26,6 +30,7 @@ use std::{
     str::FromStr,
     sync::Arc,
 };
+use uuid::Uuid;
 
 pub use keystroke::*;
 #[cfg(target_os = "macos")]
@@ -35,12 +40,13 @@ pub use test::*;
 pub use time::UtcOffset;
 
 #[cfg(target_os = "macos")]
-pub(crate) fn current_platform() -> Arc<dyn Platform> {
+pub(crate) fn current_platform() -> Rc<dyn Platform> {
-    Arc::new(MacPlatform::new())
+    Rc::new(MacPlatform::new())
 }
 
 pub(crate) trait Platform: 'static {
-    fn executor(&self) -> Executor;
+    fn background_executor(&self) -> BackgroundExecutor;
+    fn foreground_executor(&self) -> ForegroundExecutor;
     fn text_system(&self) -> Arc<dyn PlatformTextSystem>;
 
     fn run(&self, on_finish_launching: Box<dyn 'static + FnOnce()>);
@@ -104,6 +110,9 @@ pub(crate) trait Platform: 'static {
 
 pub trait PlatformDisplay: Send + Sync + Debug {
     fn id(&self) -> DisplayId;
+    /// Returns a stable identifier for this display that can be persisted and used
+    /// across system restarts.
+    fn uuid(&self) -> Result<Uuid>;
     fn as_any(&self) -> &dyn Any;
     fn bounds(&self) -> Bounds<GlobalPixels>;
 }
@@ -129,12 +138,7 @@ pub(crate) trait PlatformWindow {
     fn mouse_position(&self) -> Point<Pixels>;
     fn as_any_mut(&mut self) -> &mut dyn Any;
     fn set_input_handler(&mut self, input_handler: Box<dyn PlatformInputHandler>);
-    fn prompt(
+    fn prompt(&self, level: PromptLevel, msg: &str, answers: &[&str]) -> oneshot::Receiver<usize>;
-        &self,
-        level: WindowPromptLevel,
-        msg: &str,
-        answers: &[&str],
-    ) -> oneshot::Receiver<usize>;
     fn activate(&self);
     fn set_title(&mut self, title: &str);
     fn set_edited(&mut self, edited: bool);
@@ -161,7 +165,9 @@ pub trait PlatformDispatcher: Send + Sync {
     fn dispatch(&self, runnable: Runnable);
     fn dispatch_on_main_thread(&self, runnable: Runnable);
     fn dispatch_after(&self, duration: Duration, runnable: Runnable);
-    fn poll(&self) -> bool;
+    fn poll(&self, background_only: bool) -> bool;
+    fn park(&self);
+    fn unparker(&self) -> Unparker;
 
     #[cfg(any(test, feature = "test-support"))]
     fn as_test(&self) -> Option<&TestDispatcher> {
@@ -368,6 +374,67 @@ pub enum WindowBounds {
     Fixed(Bounds<GlobalPixels>),
 }
 
+impl StaticColumnCount for WindowBounds {
+    fn column_count() -> usize {
+        5
+    }
+}
+
+impl Bind for WindowBounds {
+    fn bind(&self, statement: &Statement, start_index: i32) -> Result<i32> {
+        let (region, next_index) = match self {
+            WindowBounds::Fullscreen => {
+                let next_index = statement.bind(&"Fullscreen", start_index)?;
+                (None, next_index)
+            }
+            WindowBounds::Maximized => {
+                let next_index = statement.bind(&"Maximized", start_index)?;
+                (None, next_index)
+            }
+            WindowBounds::Fixed(region) => {
+                let next_index = statement.bind(&"Fixed", start_index)?;
+                (Some(*region), next_index)
+            }
+        };
+
+        statement.bind(
+            &region.map(|region| {
+                (
+                    region.origin.x,
+                    region.origin.y,
+                    region.size.width,
+                    region.size.height,
+                )
+            }),
+            next_index,
+        )
+    }
+}
+
+impl Column for WindowBounds {
+    fn column(statement: &mut Statement, start_index: i32) -> Result<(Self, i32)> {
+        let (window_state, next_index) = String::column(statement, start_index)?;
+        let bounds = match window_state.as_str() {
+            "Fullscreen" => WindowBounds::Fullscreen,
+            "Maximized" => WindowBounds::Maximized,
+            "Fixed" => {
+                let ((x, y, width, height), _) = Column::column(statement, next_index)?;
+                let x: f64 = x;
+                let y: f64 = y;
+                let width: f64 = width;
+                let height: f64 = height;
+                WindowBounds::Fixed(Bounds {
+                    origin: point(x.into(), y.into()),
+                    size: size(width.into(), height.into()),
+                })
+            }
+            _ => bail!("Window State did not have a valid string"),
+        };
+
+        Ok((bounds, next_index + 4))
+    }
+}
+
 #[derive(Copy, Clone, Debug)]
 pub enum WindowAppearance {
     Light,
@@ -382,14 +449,6 @@ impl Default for WindowAppearance {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Default)]
-pub enum WindowPromptLevel {
-    #[default]
-    Info,
-    Warning,
-    Critical,
-}
-
 #[derive(Copy, Clone, Debug)]
 pub struct PathPromptOptions {
     pub files: bool,

crates/gpui2/src/platform/mac/dispatcher.rs

@@ -9,8 +9,11 @@ use objc::{
     runtime::{BOOL, YES},
     sel, sel_impl,
 };
+use parking::{Parker, Unparker};
+use parking_lot::Mutex;
 use std::{
     ffi::c_void,
+    sync::Arc,
     time::{Duration, SystemTime},
 };
 
@@ -20,7 +23,17 @@ pub fn dispatch_get_main_queue() -> dispatch_queue_t {
     unsafe { &_dispatch_main_q as *const _ as dispatch_queue_t }
 }
 
-pub struct MacDispatcher;
+pub struct MacDispatcher {
+    parker: Arc<Mutex<Parker>>,
+}
+
+impl MacDispatcher {
+    pub fn new() -> Self {
+        MacDispatcher {
+            parker: Arc::new(Mutex::new(Parker::new())),
+        }
+    }
+}
 
 impl PlatformDispatcher for MacDispatcher {
     fn is_main_thread(&self) -> bool {
@@ -68,33 +81,20 @@ impl PlatformDispatcher for MacDispatcher {
         }
     }
 
-    fn poll(&self) -> bool {
+    fn poll(&self, _background_only: bool) -> bool {
         false
     }
+
+    fn park(&self) {
+        self.parker.lock().park()
+    }
+
+    fn unparker(&self) -> Unparker {
+        self.parker.lock().unparker()
+    }
 }
 
 extern "C" fn trampoline(runnable: *mut c_void) {
     let task = unsafe { Runnable::from_raw(runnable as *mut ()) };
     task.run();
 }
-
-// #include <dispatch/dispatch.h>
-
-// int main(void) {
-
-//     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
-//         // Do some lengthy background work here...
-//         printf("Background Work\n");
-
-//         dispatch_async(dispatch_get_main_queue(), ^{
-//             // Once done, update your UI on the main queue here.
-//             printf("UI Updated\n");
-
-//         });
-//     });
-
-//     sleep(3);  // prevent the program from terminating immediately
-
-//     return 0;
-// }
-// ```

crates/gpui2/src/platform/mac/display.rs

@@ -1,9 +1,12 @@
 use crate::{point, size, Bounds, DisplayId, GlobalPixels, PlatformDisplay};
+use anyhow::Result;
+use core_foundation::uuid::{CFUUIDGetUUIDBytes, CFUUIDRef};
 use core_graphics::{
     display::{CGDirectDisplayID, CGDisplayBounds, CGGetActiveDisplayList},
     geometry::{CGPoint, CGRect, CGSize},
 };
 use std::any::Any;
+use uuid::Uuid;
 
 #[derive(Debug)]
 pub struct MacDisplay(pub(crate) CGDirectDisplayID);
@@ -11,17 +14,23 @@ pub struct MacDisplay(pub(crate) CGDirectDisplayID);
 unsafe impl Send for MacDisplay {}
 
 impl MacDisplay {
-    /// Get the screen with the given UUID.
+    /// Get the screen with the given [DisplayId].
     pub fn find_by_id(id: DisplayId) -> Option<Self> {
         Self::all().find(|screen| screen.id() == id)
     }
 
+    /// Get the screen with the given persistent [Uuid].
+    pub fn find_by_uuid(uuid: Uuid) -> Option<Self> {
+        Self::all().find(|screen| screen.uuid().ok() == Some(uuid))
+    }
+
     /// Get the primary screen - the one with the menu bar, and whose bottom left
     /// corner is at the origin of the AppKit coordinate system.
     pub fn primary() -> Self {
         Self::all().next().unwrap()
     }
 
+    /// Obtains an iterator over all currently active system displays.
     pub fn all() -> impl Iterator<Item = Self> {
         unsafe {
             let mut display_count: u32 = 0;
@@ -40,6 +49,11 @@ impl MacDisplay {
     }
 }
 
+#[link(name = "ApplicationServices", kind = "framework")]
+extern "C" {
+    pub fn CGDisplayCreateUUIDFromDisplayID(display: CGDirectDisplayID) -> CFUUIDRef;
+}
+
 /// Convert the given rectangle from CoreGraphics' native coordinate space to GPUI's coordinate space.
 ///
 /// CoreGraphics' coordinate space has its origin at the bottom left of the primary screen,
@@ -88,6 +102,34 @@ impl PlatformDisplay for MacDisplay {
         DisplayId(self.0)
     }
 
+    fn uuid(&self) -> Result<Uuid> {
+        let cfuuid = unsafe { CGDisplayCreateUUIDFromDisplayID(self.0 as CGDirectDisplayID) };
+        anyhow::ensure!(
+            !cfuuid.is_null(),
+            "AppKit returned a null from CGDisplayCreateUUIDFromDisplayID"
+        );
+
+        let bytes = unsafe { CFUUIDGetUUIDBytes(cfuuid) };
+        Ok(Uuid::from_bytes([
+            bytes.byte0,
+            bytes.byte1,
+            bytes.byte2,
+            bytes.byte3,
+            bytes.byte4,
+            bytes.byte5,
+            bytes.byte6,
+            bytes.byte7,
+            bytes.byte8,
+            bytes.byte9,
+            bytes.byte10,
+            bytes.byte11,
+            bytes.byte12,
+            bytes.byte13,
+            bytes.byte14,
+            bytes.byte15,
+        ]))
+    }
+
     fn as_any(&self) -> &dyn Any {
         self
     }

crates/gpui2/src/platform/mac/platform.rs

@@ -1,9 +1,9 @@
 use super::BoolExt;
 use crate::{
-    AnyWindowHandle, ClipboardItem, CursorStyle, DisplayId, Executor, InputEvent, MacDispatcher,
+    AnyWindowHandle, BackgroundExecutor, ClipboardItem, CursorStyle, DisplayId, ForegroundExecutor,
-    MacDisplay, MacDisplayLinker, MacTextSystem, MacWindow, PathPromptOptions, Platform,
+    InputEvent, MacDispatcher, MacDisplay, MacDisplayLinker, MacTextSystem, MacWindow,
-    PlatformDisplay, PlatformTextSystem, PlatformWindow, Result, SemanticVersion, VideoTimestamp,
+    PathPromptOptions, Platform, PlatformDisplay, PlatformTextSystem, PlatformWindow, Result,
-    WindowOptions,
+    SemanticVersion, VideoTimestamp, WindowOptions,
 };
 use anyhow::anyhow;
 use block::ConcreteBlock;
@@ -143,7 +143,8 @@ unsafe fn build_classes() {
 pub struct MacPlatform(Mutex<MacPlatformState>);
 
 pub struct MacPlatformState {
-    executor: Executor,
+    background_executor: BackgroundExecutor,
+    foreground_executor: ForegroundExecutor,
     text_system: Arc<MacTextSystem>,
     display_linker: MacDisplayLinker,
     pasteboard: id,
@@ -164,8 +165,10 @@ pub struct MacPlatformState {
 
 impl MacPlatform {
     pub fn new() -> Self {
+        let dispatcher = Arc::new(MacDispatcher::new());
         Self(Mutex::new(MacPlatformState {
-            executor: Executor::new(Arc::new(MacDispatcher)),
+            background_executor: BackgroundExecutor::new(dispatcher.clone()),
+            foreground_executor: ForegroundExecutor::new(dispatcher),
             text_system: Arc::new(MacTextSystem::new()),
             display_linker: MacDisplayLinker::new(),
             pasteboard: unsafe { NSPasteboard::generalPasteboard(nil) },
@@ -345,8 +348,12 @@ impl MacPlatform {
 }
 
 impl Platform for MacPlatform {
-    fn executor(&self) -> Executor {
+    fn background_executor(&self) -> BackgroundExecutor {
-        self.0.lock().executor.clone()
+        self.0.lock().background_executor.clone()
+    }
+
+    fn foreground_executor(&self) -> crate::ForegroundExecutor {
+        self.0.lock().foreground_executor.clone()
     }
 
     fn text_system(&self) -> Arc<dyn PlatformTextSystem> {
@@ -457,6 +464,10 @@ impl Platform for MacPlatform {
         }
     }
 
+    // fn add_status_item(&self, _handle: AnyWindowHandle) -> Box<dyn platform::Window> {
+    //     Box::new(StatusItem::add(self.fonts()))
+    // }
+
     fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>> {
         MacDisplay::all()
             .into_iter()
@@ -464,10 +475,6 @@ impl Platform for MacPlatform {
             .collect()
     }
 
-    // fn add_status_item(&self, _handle: AnyWindowHandle) -> Box<dyn platform::Window> {
-    //     Box::new(StatusItem::add(self.fonts()))
-    // }
-
     fn display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>> {
         MacDisplay::find_by_id(id).map(|screen| Rc::new(screen) as Rc<_>)
     }
@@ -481,7 +488,7 @@ impl Platform for MacPlatform {
         handle: AnyWindowHandle,
         options: WindowOptions,
     ) -> Box<dyn PlatformWindow> {
-        Box::new(MacWindow::open(handle, options, self.executor()))
+        Box::new(MacWindow::open(handle, options, self.foreground_executor()))
     }
 
     fn set_display_link_output_callback(
@@ -589,8 +596,8 @@ impl Platform for MacPlatform {
             let path = path.to_path_buf();
             self.0
                 .lock()
-                .executor
+                .background_executor
-                .spawn_on_main_local(async move {
+                .spawn(async move {
                     let full_path = ns_string(path.to_str().unwrap_or(""));
                     let root_full_path = ns_string("");
                     let workspace: id = msg_send![class!(NSWorkspace), sharedWorkspace];
@@ -674,23 +681,6 @@ impl Platform for MacPlatform {
         }
     }
 
-    fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
-        unsafe {
-            let bundle: id = NSBundle::mainBundle();
-            if bundle.is_null() {
-                Err(anyhow!("app is not running inside a bundle"))
-            } else {
-                let name = ns_string(name);
-                let url: id = msg_send![bundle, URLForAuxiliaryExecutable: name];
-                if url.is_null() {
-                    Err(anyhow!("resource not found"))
-                } else {
-                    ns_url_to_path(url)
-                }
-            }
-        }
-    }
-
     // fn on_menu_command(&self, callback: Box<dyn FnMut(&dyn Action)>) {
     //     self.0.lock().menu_command = Some(callback);
     // }
@@ -717,6 +707,23 @@ impl Platform for MacPlatform {
     //     }
     // }
 
+    fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf> {
+        unsafe {
+            let bundle: id = NSBundle::mainBundle();
+            if bundle.is_null() {
+                Err(anyhow!("app is not running inside a bundle"))
+            } else {
+                let name = ns_string(name);
+                let url: id = msg_send![bundle, URLForAuxiliaryExecutable: name];
+                if url.is_null() {
+                    Err(anyhow!("resource not found"))
+                } else {
+                    ns_url_to_path(url)
+                }
+            }
+        }
+    }
+
     fn set_cursor_style(&self, style: CursorStyle) {
         unsafe {
             let new_cursor: id = match style {

crates/gpui2/src/platform/mac/window.rs

@@ -1,10 +1,10 @@
 use super::{display_bounds_from_native, ns_string, MacDisplay, MetalRenderer, NSRange};
 use crate::{
-    display_bounds_to_native, point, px, size, AnyWindowHandle, Bounds, Executor, ExternalPaths,
+    display_bounds_to_native, point, px, size, AnyWindowHandle, Bounds, ExternalPaths,
-    FileDropEvent, GlobalPixels, InputEvent, KeyDownEvent, Keystroke, Modifiers,
+    FileDropEvent, ForegroundExecutor, GlobalPixels, InputEvent, KeyDownEvent, Keystroke,
-    ModifiersChangedEvent, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Pixels,
+    Modifiers, ModifiersChangedEvent, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
-    PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point, Scene, Size,
+    Pixels, PlatformAtlas, PlatformDisplay, PlatformInputHandler, PlatformWindow, Point,
-    Timer, WindowAppearance, WindowBounds, WindowKind, WindowOptions, WindowPromptLevel,
+    PromptLevel, Scene, Size, Timer, WindowAppearance, WindowBounds, WindowKind, WindowOptions,
 };
 use block::ConcreteBlock;
 use cocoa::{
@@ -315,7 +315,7 @@ struct InsertText {
 
 struct MacWindowState {
     handle: AnyWindowHandle,
-    executor: Executor,
+    executor: ForegroundExecutor,
     native_window: id,
     renderer: MetalRenderer,
     scene_to_render: Option<Scene>,
@@ -451,7 +451,11 @@ unsafe impl Send for MacWindowState {}
 pub struct MacWindow(Arc<Mutex<MacWindowState>>);
 
 impl MacWindow {
-    pub fn open(handle: AnyWindowHandle, options: WindowOptions, executor: Executor) -> Self {
+    pub fn open(
+        handle: AnyWindowHandle,
+        options: WindowOptions,
+        executor: ForegroundExecutor,
+    ) -> Self {
         unsafe {
             let pool = NSAutoreleasePool::new(nil);
 
@@ -674,13 +678,10 @@ impl MacWindow {
 
 impl Drop for MacWindow {
     fn drop(&mut self) {
-        let this = self.0.clone();
+        let native_window = self.0.lock().native_window;
-        let executor = self.0.lock().executor.clone();
+        unsafe {
-        executor
+            native_window.close();
-            .run_on_main(move || unsafe {
+        }
-                this.lock().native_window.close();
-            })
-            .detach();
     }
 }
 
@@ -741,12 +742,7 @@ impl PlatformWindow for MacWindow {
         self.0.as_ref().lock().input_handler = Some(input_handler);
     }
 
-    fn prompt(
+    fn prompt(&self, level: PromptLevel, msg: &str, answers: &[&str]) -> oneshot::Receiver<usize> {
-        &self,
-        level: WindowPromptLevel,
-        msg: &str,
-        answers: &[&str],
-    ) -> oneshot::Receiver<usize> {
         // macOs applies overrides to modal window buttons after they are added.
         // Two most important for this logic are:
         // * Buttons with "Cancel" title will be displayed as the last buttons in the modal
@@ -776,9 +772,9 @@ impl PlatformWindow for MacWindow {
             let alert: id = msg_send![class!(NSAlert), alloc];
             let alert: id = msg_send![alert, init];
             let alert_style = match level {
-                WindowPromptLevel::Info => 1,
+                PromptLevel::Info => 1,
-                WindowPromptLevel::Warning => 0,
+                PromptLevel::Warning => 0,
-                WindowPromptLevel::Critical => 2,
+                PromptLevel::Critical => 2,
             };
             let _: () = msg_send![alert, setAlertStyle: alert_style];
             let _: () = msg_send![alert, setMessageText: ns_string(msg)];
@@ -807,7 +803,7 @@ impl PlatformWindow for MacWindow {
             let native_window = self.0.lock().native_window;
             let executor = self.0.lock().executor.clone();
             executor
-                .spawn_on_main_local(async move {
+                .spawn(async move {
                     let _: () = msg_send![
                         alert,
                         beginSheetModalForWindow: native_window
@@ -824,7 +820,7 @@ impl PlatformWindow for MacWindow {
         let window = self.0.lock().native_window;
         let executor = self.0.lock().executor.clone();
         executor
-            .spawn_on_main_local(async move {
+            .spawn(async move {
                 unsafe {
                     let _: () = msg_send![window, makeKeyAndOrderFront: nil];
                 }
@@ -872,25 +868,17 @@ impl PlatformWindow for MacWindow {
     fn zoom(&self) {
         let this = self.0.lock();
         let window = this.native_window;
-        this.executor
+        unsafe {
-            .spawn_on_main_local(async move {
+            window.zoom_(nil);
-                unsafe {
+        }
-                    window.zoom_(nil);
-                }
-            })
-            .detach();
     }
 
     fn toggle_full_screen(&self) {
         let this = self.0.lock();
         let window = this.native_window;
-        this.executor
+        unsafe {
-            .spawn_on_main_local(async move {
+            window.toggleFullScreen_(nil);
-                unsafe {
+        }
-                    window.toggleFullScreen_(nil);
-                }
-            })
-            .detach();
     }
 
     fn on_input(&self, callback: Box<dyn FnMut(InputEvent) -> bool>) {
@@ -1189,7 +1177,7 @@ extern "C" fn handle_view_event(this: &Object, _: Sel, native_event: id) {
                 lock.synthetic_drag_counter += 1;
                 let executor = lock.executor.clone();
                 executor
-                    .spawn_on_main_local(synthetic_drag(
+                    .spawn(synthetic_drag(
                         weak_window_state,
                         lock.synthetic_drag_counter,
                         event.clone(),
@@ -1317,7 +1305,7 @@ extern "C" fn window_did_change_key_status(this: &Object, selector: Sel, _: id)
     let executor = lock.executor.clone();
     drop(lock);
     executor
-        .spawn_on_main_local(async move {
+        .spawn(async move {
             let mut lock = window_state.as_ref().lock();
             if let Some(mut callback) = lock.activate_callback.take() {
                 drop(lock);

crates/gpui2/src/platform/test/dispatcher.rs

@@ -2,6 +2,7 @@ use crate::PlatformDispatcher;
 use async_task::Runnable;
 use backtrace::Backtrace;
 use collections::{HashMap, VecDeque};
+use parking::{Parker, Unparker};
 use parking_lot::Mutex;
 use rand::prelude::*;
 use std::{
@@ -19,6 +20,8 @@ struct TestDispatcherId(usize);
 pub struct TestDispatcher {
     id: TestDispatcherId,
     state: Arc<Mutex<TestDispatcherState>>,
+    parker: Arc<Mutex<Parker>>,
+    unparker: Unparker,
 }
 
 struct TestDispatcherState {
@@ -35,6 +38,7 @@ struct TestDispatcherState {
 
 impl TestDispatcher {
     pub fn new(random: StdRng) -> Self {
+        let (parker, unparker) = parking::pair();
         let state = TestDispatcherState {
             random,
             foreground: HashMap::default(),
@@ -50,6 +54,8 @@ impl TestDispatcher {
         TestDispatcher {
             id: TestDispatcherId(0),
             state: Arc::new(Mutex::new(state)),
+            parker: Arc::new(Mutex::new(parker)),
+            unparker,
         }
     }
 
@@ -96,7 +102,7 @@ impl TestDispatcher {
     }
 
     pub fn run_until_parked(&self) {
-        while self.poll() {}
+        while self.poll(false) {}
     }
 
     pub fn parking_allowed(&self) -> bool {
@@ -129,6 +135,8 @@ impl Clone for TestDispatcher {
         Self {
             id: TestDispatcherId(id),
             state: self.state.clone(),
+            parker: self.parker.clone(),
+            unparker: self.unparker.clone(),
         }
     }
 }
@@ -140,6 +148,7 @@ impl PlatformDispatcher for TestDispatcher {
 
     fn dispatch(&self, runnable: Runnable) {
         self.state.lock().background.push(runnable);
+        self.unparker.unpark();
     }
 
     fn dispatch_on_main_thread(&self, runnable: Runnable) {
@@ -149,6 +158,7 @@ impl PlatformDispatcher for TestDispatcher {
             .entry(self.id)
             .or_default()
             .push_back(runnable);
+        self.unparker.unpark();
     }
 
     fn dispatch_after(&self, duration: std::time::Duration, runnable: Runnable) {
@@ -160,7 +170,7 @@ impl PlatformDispatcher for TestDispatcher {
         state.delayed.insert(ix, (next_time, runnable));
     }
 
-    fn poll(&self) -> bool {
+    fn poll(&self, background_only: bool) -> bool {
         let mut state = self.state.lock();
 
         while let Some((deadline, _)) = state.delayed.first() {
@@ -171,11 +181,15 @@ impl PlatformDispatcher for TestDispatcher {
             state.background.push(runnable);
         }
 
-        let foreground_len: usize = state
+        let foreground_len: usize = if background_only {
-            .foreground
+            0
-            .values()
+        } else {
-            .map(|runnables| runnables.len())
+            state
-            .sum();
+                .foreground
+                .values()
+                .map(|runnables| runnables.len())
+                .sum()
+        };
         let background_len = state.background.len();
 
         if foreground_len == 0 && background_len == 0 {
@@ -211,62 +225,15 @@ impl PlatformDispatcher for TestDispatcher {
         true
     }
 
+    fn park(&self) {
+        self.parker.lock().park();
+    }
+
+    fn unparker(&self) -> Unparker {
+        self.unparker.clone()
+    }
+
     fn as_test(&self) -> Option<&TestDispatcher> {
         Some(self)
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::Executor;
-    use std::sync::Arc;
-
-    #[test]
-    fn test_dispatch() {
-        let dispatcher = TestDispatcher::new(StdRng::seed_from_u64(0));
-        let executor = Executor::new(Arc::new(dispatcher));
-
-        let result = executor.block(async { executor.run_on_main(|| 1).await });
-        assert_eq!(result, 1);
-
-        let result = executor.block({
-            let executor = executor.clone();
-            async move {
-                executor
-                    .spawn_on_main({
-                        let executor = executor.clone();
-                        assert!(executor.is_main_thread());
-                        || async move {
-                            assert!(executor.is_main_thread());
-                            let result = executor
-                                .spawn({
-                                    let executor = executor.clone();
-                                    async move {
-                                        assert!(!executor.is_main_thread());
-
-                                        let result = executor
-                                            .spawn_on_main({
-                                                let executor = executor.clone();
-                                                || async move {
-                                                    assert!(executor.is_main_thread());
-                                                    2
-                                                }
-                                            })
-                                            .await;
-
-                                        assert!(!executor.is_main_thread());
-                                        result
-                                    }
-                                })
-                                .await;
-                            assert!(executor.is_main_thread());
-                            result
-                        }
-                    })
-                    .await
-            }
-        });
-        assert_eq!(result, 2);
-    }
-}

crates/gpui2/src/platform/test/platform.rs

@@ -1,21 +1,29 @@
-use crate::{DisplayId, Executor, Platform, PlatformTextSystem};
+use crate::{BackgroundExecutor, DisplayId, ForegroundExecutor, Platform, PlatformTextSystem};
 use anyhow::{anyhow, Result};
 use std::sync::Arc;
 
 pub struct TestPlatform {
-    executor: Executor,
+    background_executor: BackgroundExecutor,
+    foreground_executor: ForegroundExecutor,
 }
 
 impl TestPlatform {
-    pub fn new(executor: Executor) -> Self {
+    pub fn new(executor: BackgroundExecutor, foreground_executor: ForegroundExecutor) -> Self {
-        TestPlatform { executor }
+        TestPlatform {
+            background_executor: executor,
+            foreground_executor,
+        }
     }
 }
 
 // todo!("implement out what our tests needed in GPUI 1")
 impl Platform for TestPlatform {
-    fn executor(&self) -> Executor {
+    fn background_executor(&self) -> BackgroundExecutor {
-        self.executor.clone()
+        self.background_executor.clone()
+    }
+
+    fn foreground_executor(&self) -> ForegroundExecutor {
+        self.foreground_executor.clone()
     }
 
     fn text_system(&self) -> Arc<dyn PlatformTextSystem> {

crates/gpui2/src/subscription.rs

@@ -21,8 +21,8 @@ struct SubscriberSetState<EmitterKey, Callback> {
 
 impl<EmitterKey, Callback> SubscriberSet<EmitterKey, Callback>
 where
-    EmitterKey: 'static + Send + Ord + Clone + Debug,
+    EmitterKey: 'static + Ord + Clone + Debug,
-    Callback: 'static + Send,
+    Callback: 'static,
 {
     pub fn new() -> Self {
         Self(Arc::new(Mutex::new(SubscriberSetState {
@@ -96,7 +96,7 @@ where
 
 #[must_use]
 pub struct Subscription {
-    unsubscribe: Option<Box<dyn FnOnce() + Send + 'static>>,
+    unsubscribe: Option<Box<dyn FnOnce() + 'static>>,
 }
 
 impl Subscription {

crates/gpui2/src/view.rs

@@ -1,13 +1,16 @@
 use crate::{
     private::Sealed, AnyBox, AnyElement, AnyModel, AnyWeakModel, AppContext, AvailableSpace,
-    BorrowWindow, Bounds, Component, Element, ElementId, Entity, EntityId, LayoutId, Model, Pixels,
+    BorrowWindow, Bounds, Component, Element, ElementId, Entity, EntityId, Flatten, LayoutId,
-    Size, ViewContext, VisualContext, WeakModel, WindowContext,
+    Model, Pixels, Size, ViewContext, VisualContext, WeakModel, WindowContext,
 };
 use anyhow::{Context, Result};
-use std::{any::TypeId, marker::PhantomData};
+use std::{
+    any::{Any, TypeId},
+    hash::{Hash, Hasher},
+};
 
 pub trait Render: 'static + Sized {
-    type Element: Element<Self> + 'static + Send;
+    type Element: Element<Self> + 'static;
 
     fn render(&mut self, cx: &mut ViewContext<Self>) -> Self::Element;
 }
@@ -49,7 +52,7 @@ impl<V: 'static> View<V> {
     pub fn update<C, R>(
         &self,
         cx: &mut C,
-        f: impl FnOnce(&mut V, &mut C::ViewContext<'_, '_, V>) -> R,
+        f: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
     ) -> C::Result<R>
     where
         C: VisualContext,
@@ -70,55 +73,23 @@ impl<V> Clone for View<V> {
     }
 }
 
-impl<V: Render, ParentViewState: 'static> Component<ParentViewState> for View<V> {
+impl<V> Hash for View<V> {
-    fn render(self) -> AnyElement<ParentViewState> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
-        AnyElement::new(EraseViewState {
+        self.model.hash(state);
-            view: self,
-            parent_view_state_type: PhantomData,
-        })
     }
 }
 
-impl<V> Element<()> for View<V>
+impl<V> PartialEq for View<V> {
-where
+    fn eq(&self, other: &Self) -> bool {
-    V: Render,
+        self.model == other.model
-{
-    type ElementState = AnyElement<V>;
-
-    fn id(&self) -> Option<crate::ElementId> {
-        Some(ElementId::View(self.model.entity_id))
     }
+}
 
-    fn initialize(
+impl<V> Eq for View<V> {}
-        &mut self,
-        _: &mut (),
-        _: Option<Self::ElementState>,
-        cx: &mut ViewContext<()>,
-    ) -> Self::ElementState {
-        self.update(cx, |state, cx| {
-            let mut any_element = AnyElement::new(state.render(cx));
-            any_element.initialize(state, cx);
-            any_element
-        })
-    }
 
-    fn layout(
+impl<V: Render, ParentViewState: 'static> Component<ParentViewState> for View<V> {
-        &mut self,
+    fn render(self) -> AnyElement<ParentViewState> {
-        _: &mut (),
+        AnyElement::new(AnyView::from(self))
-        element: &mut Self::ElementState,
-        cx: &mut ViewContext<()>,
-    ) -> LayoutId {
-        self.update(cx, |state, cx| element.layout(state, cx))
-    }
-
-    fn paint(
-        &mut self,
-        _: Bounds<Pixels>,
-        _: &mut (),
-        element: &mut Self::ElementState,
-        cx: &mut ViewContext<()>,
-    ) {
-        self.update(cx, |state, cx| element.paint(state, cx))
     }
 }
 
@@ -127,17 +98,25 @@ pub struct WeakView<V> {
 }
 
 impl<V: 'static> WeakView<V> {
+    pub fn entity_id(&self) -> EntityId {
+        self.model.entity_id
+    }
+
     pub fn upgrade(&self) -> Option<View<V>> {
         Entity::upgrade_from(self)
     }
 
-    pub fn update<R>(
+    pub fn update<C, R>(
         &self,
-        cx: &mut WindowContext,
+        cx: &mut C,
-        f: impl FnOnce(&mut V, &mut ViewContext<V>) -> R,
+        f: impl FnOnce(&mut V, &mut ViewContext<'_, V>) -> R,
-    ) -> Result<R> {
+    ) -> Result<R>
+    where
+        C: VisualContext,
+        Result<C::Result<R>>: Flatten<R>,
+    {
         let view = self.upgrade().context("error upgrading view")?;
-        Ok(view.update(cx, f))
+        Ok(view.update(cx, f)).flatten()
     }
 }
 
@@ -149,115 +128,19 @@ impl<V> Clone for WeakView<V> {
     }
 }
 
-struct EraseViewState<V, ParentV> {
+impl<V> Hash for WeakView<V> {
-    view: View<V>,
+    fn hash<H: Hasher>(&self, state: &mut H) {
-    parent_view_state_type: PhantomData<ParentV>,
+        self.model.hash(state);
-}
-
-unsafe impl<V, ParentV> Send for EraseViewState<V, ParentV> {}
-
-impl<V: Render, ParentV: 'static> Component<ParentV> for EraseViewState<V, ParentV> {
-    fn render(self) -> AnyElement<ParentV> {
-        AnyElement::new(self)
     }
 }
 
-impl<V: Render, ParentV: 'static> Element<ParentV> for EraseViewState<V, ParentV> {
+impl<V> PartialEq for WeakView<V> {
-    type ElementState = AnyBox;
+    fn eq(&self, other: &Self) -> bool {
-
+        self.model == other.model
-    fn id(&self) -> Option<crate::ElementId> {
-        Element::id(&self.view)
-    }
-
-    fn initialize(
-        &mut self,
-        _: &mut ParentV,
-        _: Option<Self::ElementState>,
-        cx: &mut ViewContext<ParentV>,
-    ) -> Self::ElementState {
-        ViewObject::initialize(&mut self.view, cx)
-    }
-
-    fn layout(
-        &mut self,
-        _: &mut ParentV,
-        element: &mut Self::ElementState,
-        cx: &mut ViewContext<ParentV>,
-    ) -> LayoutId {
-        ViewObject::layout(&mut self.view, element, cx)
-    }
-
-    fn paint(
-        &mut self,
-        bounds: Bounds<Pixels>,
-        _: &mut ParentV,
-        element: &mut Self::ElementState,
-        cx: &mut ViewContext<ParentV>,
-    ) {
-        ViewObject::paint(&mut self.view, bounds, element, cx)
     }
 }
 
-trait ViewObject: Send + Sync {
+impl<V> Eq for WeakView<V> {}
-    fn entity_type(&self) -> TypeId;
-    fn entity_id(&self) -> EntityId;
-    fn model(&self) -> AnyModel;
-    fn initialize(&self, cx: &mut WindowContext) -> AnyBox;
-    fn layout(&self, element: &mut AnyBox, cx: &mut WindowContext) -> LayoutId;
-    fn paint(&self, bounds: Bounds<Pixels>, element: &mut AnyBox, cx: &mut WindowContext);
-    fn debug(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result;
-}
-
-impl<V> ViewObject for View<V>
-where
-    V: Render,
-{
-    fn entity_type(&self) -> TypeId {
-        TypeId::of::<V>()
-    }
-
-    fn entity_id(&self) -> EntityId {
-        Entity::entity_id(self)
-    }
-
-    fn model(&self) -> AnyModel {
-        self.model.clone().into_any()
-    }
-
-    fn initialize(&self, cx: &mut WindowContext) -> AnyBox {
-        cx.with_element_id(ViewObject::entity_id(self), |_global_id, cx| {
-            self.update(cx, |state, cx| {
-                let mut any_element = Box::new(AnyElement::new(state.render(cx)));
-                any_element.initialize(state, cx);
-                any_element
-            })
-        })
-    }
-
-    fn layout(&self, element: &mut AnyBox, cx: &mut WindowContext) -> LayoutId {
-        cx.with_element_id(ViewObject::entity_id(self), |_global_id, cx| {
-            self.update(cx, |state, cx| {
-                let element = element.downcast_mut::<AnyElement<V>>().unwrap();
-                element.layout(state, cx)
-            })
-        })
-    }
-
-    fn paint(&self, _: Bounds<Pixels>, element: &mut AnyBox, cx: &mut WindowContext) {
-        cx.with_element_id(ViewObject::entity_id(self), |_global_id, cx| {
-            self.update(cx, |state, cx| {
-                let element = element.downcast_mut::<AnyElement<V>>().unwrap();
-                element.paint(state, cx);
-            });
-        });
-    }
-
-    fn debug(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_struct(&format!("AnyView<{}>", std::any::type_name::<V>()))
-            .field("entity_id", &ViewObject::entity_id(self).as_u64())
-            .finish()
-    }
-}
 
 #[derive(Clone, Debug)]
 pub struct AnyView {
@@ -289,7 +172,7 @@ impl AnyView {
         }
     }
 
-    pub(crate) fn entity_type(&self) -> TypeId {
+    pub fn entity_type(&self) -> TypeId {
         self.model.entity_type
     }
 
@@ -343,7 +226,7 @@ impl<V: Render> From<View<V>> for AnyView {
 }
 
 impl<ParentViewState: 'static> Element<ParentViewState> for AnyView {
-    type ElementState = AnyBox;
+    type ElementState = Box<dyn Any>;
 
     fn id(&self) -> Option<ElementId> {
         Some(self.model.entity_id.into())

crates/gpui2_macros/src/derive_component.rs

@@ -30,7 +30,7 @@ pub fn derive_component(input: TokenStream) -> TokenStream {
     let expanded = quote! {
         impl #impl_generics gpui2::Component<#view_type> for #name #ty_generics #where_clause {
             fn render(self) -> gpui2::AnyElement<#view_type> {
-                (move |view_state: &mut #view_type, cx: &mut gpui2::ViewContext<'_, '_, #view_type>| self.render(view_state, cx))
+                (move |view_state: &mut #view_type, cx: &mut gpui2::ViewContext<'_, #view_type>| self.render(view_state, cx))
                     .render()
             }
         }

crates/gpui2_macros/src/test.rs

@@ -89,9 +89,9 @@ pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
                             inner_fn_args.extend(quote!(rand::SeedableRng::seed_from_u64(_seed),));
                             continue;
                         }
-                        Some("Executor") => {
+                        Some("BackgroundExecutor") => {
-                            inner_fn_args.extend(quote!(gpui2::Executor::new(
+                            inner_fn_args.extend(quote!(gpui2::BackgroundExecutor::new(
-                                std::sync::Arc::new(dispatcher.clone())
+                                std::sync::Arc::new(dispatcher.clone()),
                             ),));
                             continue;
                         }
@@ -134,9 +134,9 @@ pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
                     #num_iterations as u64,
                     #max_retries,
                     &mut |dispatcher, _seed| {
-                        let executor = gpui2::Executor::new(std::sync::Arc::new(dispatcher.clone()));
+                        let executor = gpui2::BackgroundExecutor::new(std::sync::Arc::new(dispatcher.clone()));
                         #cx_vars
-                        executor.block(#inner_fn_name(#inner_fn_args));
+                        executor.block_test(#inner_fn_name(#inner_fn_args));
                         #cx_teardowns
                     },
                     #on_failure_fn_name,
@@ -170,7 +170,7 @@ pub fn test(args: TokenStream, function: TokenStream) -> TokenStream {
                                     let mut #cx_varname = gpui2::TestAppContext::new(
                                        dispatcher.clone()
                                     );
-                                    let mut #cx_varname_lock = #cx_varname.app.lock();
+                                    let mut #cx_varname_lock = #cx_varname.app.borrow_mut();
                                 ));
                                 inner_fn_args.extend(quote!(&mut #cx_varname_lock,));
                                 cx_teardowns.extend(quote!(

crates/install_cli2/src/install_cli2.rs

@@ -7,9 +7,7 @@ use util::ResultExt;
 // actions!(cli, [Install]);
 
 pub async fn install_cli(cx: &AsyncAppContext) -> Result<()> {
-    let cli_path = cx
+    let cli_path = cx.update(|cx| cx.path_for_auxiliary_executable("cli"))??;
-        .run_on_main(|cx| cx.path_for_auxiliary_executable("cli"))?
-        .await?;
     let link_path = Path::new("/usr/local/bin/zed");
     let bin_dir_path = link_path.parent().unwrap();
 

crates/journal2/src/journal2.rs

@@ -77,7 +77,7 @@ pub fn new_journal_entry(_: Arc<AppState>, cx: &mut AppContext) {
     let now = now.time();
     let _entry_heading = heading_entry(now, &settings.hour_format);
 
-    let _create_entry = cx.executor().spawn(async move {
+    let _create_entry = cx.background_executor().spawn(async move {
         std::fs::create_dir_all(month_dir)?;
         OpenOptions::new()
             .create(true)

crates/language2/src/buffer.rs

@@ -434,7 +434,7 @@ impl Buffer {
         ));
 
         let text_operations = self.text.operations().clone();
-        cx.spawn(|_| async move {
+        cx.background_executor().spawn(async move {
             let since = since.unwrap_or_default();
             operations.extend(
                 text_operations
@@ -652,7 +652,7 @@ impl Buffer {
 
                     if !self.is_dirty() {
                         let reload = self.reload(cx).log_err().map(drop);
-                        task = cx.executor().spawn(reload);
+                        task = cx.background_executor().spawn(reload);
                     }
                 }
             }
@@ -684,7 +684,7 @@ impl Buffer {
         let snapshot = self.snapshot();
 
         let mut diff = self.git_diff.clone();
-        let diff = cx.executor().spawn(async move {
+        let diff = cx.background_executor().spawn(async move {
             diff.update(&diff_base, &snapshot).await;
             diff
         });
@@ -793,7 +793,7 @@ impl Buffer {
         let mut syntax_snapshot = syntax_map.snapshot();
         drop(syntax_map);
 
-        let parse_task = cx.executor().spawn({
+        let parse_task = cx.background_executor().spawn({
             let language = language.clone();
             let language_registry = language_registry.clone();
             async move {
@@ -803,7 +803,7 @@ impl Buffer {
         });
 
         match cx
-            .executor()
+            .background_executor()
             .block_with_timeout(self.sync_parse_timeout, parse_task)
         {
             Ok(new_syntax_snapshot) => {
@@ -866,9 +866,9 @@ impl Buffer {
 
     fn request_autoindent(&mut self, cx: &mut ModelContext<Self>) {
         if let Some(indent_sizes) = self.compute_autoindents() {
-            let indent_sizes = cx.executor().spawn(indent_sizes);
+            let indent_sizes = cx.background_executor().spawn(indent_sizes);
             match cx
-                .executor()
+                .background_executor()
                 .block_with_timeout(Duration::from_micros(500), indent_sizes)
             {
                 Ok(indent_sizes) => self.apply_autoindents(indent_sizes, cx),
@@ -1117,7 +1117,7 @@ impl Buffer {
     pub fn diff(&self, mut new_text: String, cx: &AppContext) -> Task<Diff> {
         let old_text = self.as_rope().clone();
         let base_version = self.version();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let old_text = old_text.to_string();
             let line_ending = LineEnding::detect(&new_text);
             LineEnding::normalize(&mut new_text);
@@ -1155,7 +1155,7 @@ impl Buffer {
         let old_text = self.as_rope().clone();
         let line_ending = self.line_ending();
         let base_version = self.version();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let ranges = trailing_whitespace_ranges(&old_text);
             let empty = Arc::<str>::from("");
             Diff {

crates/language2/src/buffer_tests.rs

@@ -559,7 +559,7 @@ async fn test_outline(cx: &mut gpui2::TestAppContext) {
         cx: &'a gpui2::TestAppContext,
     ) -> Vec<(&'a str, Vec<usize>)> {
         let matches = cx
-            .update(|cx| outline.search(query, cx.executor().clone()))
+            .update(|cx| outline.search(query, cx.background_executor().clone()))
             .await;
         matches
             .into_iter()
@@ -1879,7 +1879,7 @@ fn test_serialization(cx: &mut gpui2::AppContext) {
 
     let state = buffer1.read(cx).to_proto();
     let ops = cx
-        .executor()
+        .background_executor()
         .block(buffer1.read(cx).serialize_ops(None, cx));
     let buffer2 = cx.build_model(|cx| {
         let mut buffer = Buffer::from_proto(1, state, None).unwrap();
@@ -1921,7 +1921,7 @@ fn test_random_collaboration(cx: &mut AppContext, mut rng: StdRng) {
         let buffer = cx.build_model(|cx| {
             let state = base_buffer.read(cx).to_proto();
             let ops = cx
-                .executor()
+                .background_executor()
                 .block(base_buffer.read(cx).serialize_ops(None, cx));
             let mut buffer = Buffer::from_proto(i as ReplicaId, state, None).unwrap();
             buffer
@@ -1943,6 +1943,7 @@ fn test_random_collaboration(cx: &mut AppContext, mut rng: StdRng) {
             .detach();
             buffer
         });
+
         buffers.push(buffer);
         replica_ids.push(i as ReplicaId);
         network.lock().add_peer(i as ReplicaId);
@@ -2025,7 +2026,9 @@ fn test_random_collaboration(cx: &mut AppContext, mut rng: StdRng) {
             }
             50..=59 if replica_ids.len() < max_peers => {
                 let old_buffer_state = buffer.read(cx).to_proto();
-                let old_buffer_ops = cx.executor().block(buffer.read(cx).serialize_ops(None, cx));
+                let old_buffer_ops = cx
+                    .background_executor()
+                    .block(buffer.read(cx).serialize_ops(None, cx));
                 let new_replica_id = (0..=replica_ids.len() as ReplicaId)
                     .filter(|replica_id| *replica_id != buffer.read(cx).replica_id())
                     .choose(&mut rng)

crates/language2/src/language2.rs

@@ -17,7 +17,7 @@ use futures::{
     future::{BoxFuture, Shared},
     FutureExt, TryFutureExt as _,
 };
-use gpui2::{AppContext, AsyncAppContext, Executor, Task};
+use gpui2::{AppContext, AsyncAppContext, BackgroundExecutor, Task};
 pub use highlight_map::HighlightMap;
 use lazy_static::lazy_static;
 use lsp2::{CodeActionKind, LanguageServerBinary};
@@ -631,7 +631,7 @@ pub struct LanguageRegistry {
     lsp_binary_paths: Mutex<
         HashMap<LanguageServerName, Shared<Task<Result<LanguageServerBinary, Arc<anyhow::Error>>>>>,
     >,
-    executor: Option<Executor>,
+    executor: Option<BackgroundExecutor>,
     lsp_binary_status_tx: LspBinaryStatusSender,
 }
 
@@ -680,7 +680,7 @@ impl LanguageRegistry {
         Self::new(Task::ready(()))
     }
 
-    pub fn set_executor(&mut self, executor: Executor) {
+    pub fn set_executor(&mut self, executor: BackgroundExecutor) {
         self.executor = Some(executor);
     }
 
@@ -916,7 +916,7 @@ impl LanguageRegistry {
                 }
 
                 let servers_tx = servers_tx.clone();
-                cx.executor()
+                cx.background_executor()
                     .spawn(async move {
                         if fake_server
                             .try_receive_notification::<lsp2::notification::Initialized>()

crates/language2/src/outline.rs

@@ -1,5 +1,5 @@
 use fuzzy2::{StringMatch, StringMatchCandidate};
-use gpui2::{Executor, HighlightStyle};
+use gpui2::{BackgroundExecutor, HighlightStyle};
 use std::ops::Range;
 
 #[derive(Debug)]
@@ -57,7 +57,7 @@ impl<T> Outline<T> {
         }
     }
 
-    pub async fn search(&self, query: &str, executor: Executor) -> Vec<StringMatch> {
+    pub async fn search(&self, query: &str, executor: BackgroundExecutor) -> Vec<StringMatch> {
         let query = query.trim_start();
         let is_path_query = query.contains(' ');
         let smart_case = query.chars().any(|c| c.is_uppercase());

crates/live_kit_client2/examples/test_app.rs

@@ -42,7 +42,7 @@ fn main() {
         let live_kit_key = std::env::var("LIVE_KIT_KEY").unwrap_or("devkey".into());
         let live_kit_secret = std::env::var("LIVE_KIT_SECRET").unwrap_or("secret".into());
 
-        cx.spawn_on_main(|cx| async move {
+        cx.spawn(|cx| async move {
             let user_a_token = token::create(
                 &live_kit_key,
                 &live_kit_secret,
@@ -104,7 +104,7 @@ fn main() {
             }
 
             println!("Pausing for 5 seconds to test audio, make some noise!");
-            let timer = cx.executor().timer(Duration::from_secs(5));
+            let timer = cx.background_executor().timer(Duration::from_secs(5));
             timer.await;
             let remote_audio_track = room_b
                 .remote_audio_tracks("test-participant-1")

crates/live_kit_client2/src/test.rs

@@ -2,7 +2,7 @@ use anyhow::{anyhow, Context, Result};
 use async_trait::async_trait;
 use collections::{BTreeMap, HashMap};
 use futures::Stream;
-use gpui2::Executor;
+use gpui2::BackgroundExecutor;
 use live_kit_server::token;
 use media::core_video::CVImageBuffer;
 use parking_lot::Mutex;
@@ -16,7 +16,7 @@ pub struct TestServer {
     pub api_key: String,
     pub secret_key: String,
     rooms: Mutex<HashMap<String, TestServerRoom>>,
-    executor: Arc<Executor>,
+    executor: Arc<BackgroundExecutor>,
 }
 
 impl TestServer {
@@ -24,7 +24,7 @@ impl TestServer {
         url: String,
         api_key: String,
         secret_key: String,
-        executor: Arc<Executor>,
+        executor: Arc<BackgroundExecutor>,
     ) -> Result<Arc<TestServer>> {
         let mut servers = SERVERS.lock();
         if servers.contains_key(&url) {

crates/lsp2/src/lsp2.rs

@@ -5,7 +5,7 @@ pub use lsp_types::*;
 use anyhow::{anyhow, Context, Result};
 use collections::HashMap;
 use futures::{channel::oneshot, io::BufWriter, AsyncRead, AsyncWrite, FutureExt};
-use gpui2::{AsyncAppContext, Executor, Task};
+use gpui2::{AsyncAppContext, BackgroundExecutor, Task};
 use parking_lot::Mutex;
 use postage::{barrier, prelude::Stream};
 use serde::{de::DeserializeOwned, Deserialize, Serialize};
@@ -62,7 +62,7 @@ pub struct LanguageServer {
     notification_handlers: Arc<Mutex<HashMap<&'static str, NotificationHandler>>>,
     response_handlers: Arc<Mutex<Option<HashMap<usize, ResponseHandler>>>>,
     io_handlers: Arc<Mutex<HashMap<usize, IoHandler>>>,
-    executor: Executor,
+    executor: BackgroundExecutor,
     #[allow(clippy::type_complexity)]
     io_tasks: Mutex<Option<(Task<Option<()>>, Task<Option<()>>)>>,
     output_done_rx: Mutex<Option<barrier::Receiver>>,
@@ -248,7 +248,7 @@ impl LanguageServer {
             let (stdout, stderr) = futures::join!(stdout_input_task, stderr_input_task);
             stdout.or(stderr)
         });
-        let output_task = cx.executor().spawn({
+        let output_task = cx.background_executor().spawn({
             Self::handle_output(
                 stdin,
                 outbound_rx,
@@ -269,7 +269,7 @@ impl LanguageServer {
             code_action_kinds,
             next_id: Default::default(),
             outbound_tx,
-            executor: cx.executor().clone(),
+            executor: cx.background_executor().clone(),
             io_tasks: Mutex::new(Some((input_task, output_task))),
             output_done_rx: Mutex::new(Some(output_done_rx)),
             root_path: root_path.to_path_buf(),
@@ -595,8 +595,8 @@ impl LanguageServer {
     where
         T: request::Request,
         T::Params: 'static + Send,
-        F: 'static + Send + FnMut(T::Params, AsyncAppContext) -> Fut,
+        F: 'static + FnMut(T::Params, AsyncAppContext) -> Fut + Send,
-        Fut: 'static + Future<Output = Result<T::Result>> + Send,
+        Fut: 'static + Future<Output = Result<T::Result>>,
     {
         self.on_custom_request(T::METHOD, f)
     }
@@ -629,7 +629,7 @@ impl LanguageServer {
     #[must_use]
     pub fn on_custom_notification<Params, F>(&self, method: &'static str, mut f: F) -> Subscription
     where
-        F: 'static + Send + FnMut(Params, AsyncAppContext),
+        F: 'static + FnMut(Params, AsyncAppContext) + Send,
         Params: DeserializeOwned,
     {
         let prev_handler = self.notification_handlers.lock().insert(
@@ -657,8 +657,8 @@ impl LanguageServer {
         mut f: F,
     ) -> Subscription
     where
-        F: 'static + Send + FnMut(Params, AsyncAppContext) -> Fut,
+        F: 'static + FnMut(Params, AsyncAppContext) -> Fut + Send,
-        Fut: 'static + Future<Output = Result<Res>> + Send,
+        Fut: 'static + Future<Output = Result<Res>>,
         Params: DeserializeOwned + Send + 'static,
         Res: Serialize,
     {
@@ -670,10 +670,10 @@ impl LanguageServer {
                     match serde_json::from_str(params) {
                         Ok(params) => {
                             let response = f(params, cx.clone());
-                            cx.executor()
+                            cx.foreground_executor()
-                                .spawn_on_main({
+                                .spawn({
                                     let outbound_tx = outbound_tx.clone();
-                                    move || async move {
+                                    async move {
                                         let response = match response.await {
                                             Ok(result) => Response {
                                                 jsonrpc: JSON_RPC_VERSION,
@@ -769,7 +769,7 @@ impl LanguageServer {
         next_id: &AtomicUsize,
         response_handlers: &Mutex<Option<HashMap<usize, ResponseHandler>>>,
         outbound_tx: &channel::Sender<String>,
-        executor: &Executor,
+        executor: &BackgroundExecutor,
         params: T::Params,
     ) -> impl 'static + Future<Output = anyhow::Result<T::Result>>
     where
@@ -1047,8 +1047,9 @@ impl FakeLanguageServer {
             .on_request::<T, _, _>(move |params, cx| {
                 let result = handler(params, cx.clone());
                 let responded_tx = responded_tx.clone();
+                let executor = cx.background_executor().clone();
                 async move {
-                    cx.executor().simulate_random_delay().await;
+                    executor.simulate_random_delay().await;
                     let result = result.await;
                     responded_tx.unbounded_send(()).ok();
                     result

crates/multi_buffer2/src/multi_buffer2.rs

@@ -878,7 +878,7 @@ impl MultiBuffer {
         cx.spawn(move |this, mut cx| async move {
             let mut excerpt_ranges = Vec::new();
             let mut range_counts = Vec::new();
-            cx.executor()
+            cx.background_executor()
                 .scoped(|scope| {
                     scope.spawn(async {
                         let (ranges, counts) =
@@ -4177,7 +4177,7 @@ mod tests {
         let guest_buffer = cx.build_model(|cx| {
             let state = host_buffer.read(cx).to_proto();
             let ops = cx
-                .executor()
+                .background_executor()
                 .block(host_buffer.read(cx).serialize_ops(None, cx));
             let mut buffer = Buffer::from_proto(1, state, None).unwrap();
             buffer

crates/prettier2/src/prettier2.rs

@@ -143,7 +143,7 @@ impl Prettier {
     ) -> anyhow::Result<Self> {
         use lsp2::LanguageServerBinary;
 
-        let executor = cx.executor().clone();
+        let executor = cx.background_executor().clone();
         anyhow::ensure!(
             prettier_dir.is_dir(),
             "Prettier dir {prettier_dir:?} is not a directory"

crates/project2/src/lsp_command.rs

@@ -32,7 +32,7 @@ pub fn lsp_formatting_options(tab_size: u32) -> lsp2::FormattingOptions {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 pub(crate) trait LspCommand: 'static + Sized + Send {
     type Response: 'static + Default + Send;
     type LspRequest: 'static + Send + lsp2::request::Request;
@@ -148,7 +148,7 @@ impl From<lsp2::FormattingOptions> for FormattingOptions {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for PrepareRename {
     type Response = Option<Range<Anchor>>;
     type LspRequest = lsp2::request::PrepareRenameRequest;
@@ -279,7 +279,7 @@ impl LspCommand for PrepareRename {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for PerformRename {
     type Response = ProjectTransaction;
     type LspRequest = lsp2::request::Rename;
@@ -398,7 +398,7 @@ impl LspCommand for PerformRename {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetDefinition {
     type Response = Vec<LocationLink>;
     type LspRequest = lsp2::request::GotoDefinition;
@@ -491,7 +491,7 @@ impl LspCommand for GetDefinition {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetTypeDefinition {
     type Response = Vec<LocationLink>;
     type LspRequest = lsp2::request::GotoTypeDefinition;
@@ -783,7 +783,7 @@ fn location_links_to_proto(
         .collect()
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetReferences {
     type Response = Vec<Location>;
     type LspRequest = lsp2::request::References;
@@ -945,7 +945,7 @@ impl LspCommand for GetReferences {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetDocumentHighlights {
     type Response = Vec<DocumentHighlight>;
     type LspRequest = lsp2::request::DocumentHighlightRequest;
@@ -1096,7 +1096,7 @@ impl LspCommand for GetDocumentHighlights {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetHover {
     type Response = Option<Hover>;
     type LspRequest = lsp2::request::HoverRequest;
@@ -1314,7 +1314,7 @@ impl LspCommand for GetHover {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetCompletions {
     type Response = Vec<Completion>;
     type LspRequest = lsp2::request::Completion;
@@ -1545,7 +1545,7 @@ impl LspCommand for GetCompletions {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for GetCodeActions {
     type Response = Vec<CodeAction>;
     type LspRequest = lsp2::request::CodeActionRequest;
@@ -1684,7 +1684,7 @@ impl LspCommand for GetCodeActions {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for OnTypeFormatting {
     type Response = Option<Transaction>;
     type LspRequest = lsp2::request::OnTypeFormatting;
@@ -2192,7 +2192,7 @@ impl InlayHints {
     }
 }
 
-#[async_trait]
+#[async_trait(?Send)]
 impl LspCommand for InlayHints {
     type Response = Vec<InlayHint>;
     type LspRequest = lsp2::InlayHintRequest;

crates/project2/src/project2.rs

@@ -26,8 +26,8 @@ use futures::{
 };
 use globset::{Glob, GlobSet, GlobSetBuilder};
 use gpui2::{
-    AnyModel, AppContext, AsyncAppContext, Context, Entity, EventEmitter, Executor, Model,
+    AnyModel, AppContext, AsyncAppContext, BackgroundExecutor, Context, Entity, EventEmitter,
-    ModelContext, Task, WeakModel,
+    Model, ModelContext, Task, WeakModel,
 };
 use itertools::Itertools;
 use language2::{
@@ -207,7 +207,7 @@ impl DelayedDebounced {
 
         let previous_task = self.task.take();
         self.task = Some(cx.spawn(move |project, mut cx| async move {
-            let mut timer = cx.executor().timer(delay).fuse();
+            let mut timer = cx.background_executor().timer(delay).fuse();
             if let Some(previous_task) = previous_task {
                 previous_task.await;
             }
@@ -1453,7 +1453,7 @@ impl Project {
                             };
                             if client.send(initial_state).log_err().is_some() {
                                 let client = client.clone();
-                                cx.executor()
+                                cx.background_executor()
                                     .spawn(async move {
                                         let mut chunks = split_operations(operations).peekable();
                                         while let Some(chunk) = chunks.next() {
@@ -1758,7 +1758,7 @@ impl Project {
             }
         };
 
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             wait_for_loading_buffer(loading_watch)
                 .await
                 .map_err(|error| anyhow!("{}", error))
@@ -2436,7 +2436,7 @@ impl Project {
                                 Duration::from_secs(1);
 
                             let task = cx.spawn(move |this, mut cx| async move {
-                                cx.executor().timer(DISK_BASED_DIAGNOSTICS_DEBOUNCE).await;
+                                cx.background_executor().timer(DISK_BASED_DIAGNOSTICS_DEBOUNCE).await;
                                 if let Some(this) = this.upgrade() {
                                     this.update(&mut cx, |this, cx| {
                                         this.disk_based_diagnostics_finished(
@@ -3477,7 +3477,7 @@ impl Project {
             });
 
             const PROCESS_TIMEOUT: Duration = Duration::from_secs(5);
-            let mut timeout = cx.executor().timer(PROCESS_TIMEOUT).fuse();
+            let mut timeout = cx.background_executor().timer(PROCESS_TIMEOUT).fuse();
 
             let mut errored = false;
             if let Some(mut process) = process {
@@ -5593,7 +5593,7 @@ impl Project {
             })
             .collect::<Vec<_>>();
 
-        let background = cx.executor().clone();
+        let background = cx.background_executor().clone();
         let path_count: usize = snapshots.iter().map(|s| s.visible_file_count()).sum();
         if path_count == 0 {
             let (_, rx) = smol::channel::bounded(1024);
@@ -5616,11 +5616,11 @@ impl Project {
                 }
             })
             .collect();
-        cx.executor()
+        cx.background_executor()
             .spawn(Self::background_search(
                 unnamed_files,
                 opened_buffers,
-                cx.executor().clone(),
+                cx.background_executor().clone(),
                 self.fs.clone(),
                 workers,
                 query.clone(),
@@ -5631,9 +5631,9 @@ impl Project {
             .detach();
 
         let (buffers, buffers_rx) = Self::sort_candidates_and_open_buffers(matching_paths_rx, cx);
-        let background = cx.executor().clone();
+        let background = cx.background_executor().clone();
         let (result_tx, result_rx) = smol::channel::bounded(1024);
-        cx.executor()
+        cx.background_executor()
             .spawn(async move {
                 let Ok(buffers) = buffers.await else {
                     return;
@@ -5741,7 +5741,7 @@ impl Project {
     async fn background_search(
         unnamed_buffers: Vec<Model<Buffer>>,
         opened_buffers: HashMap<Arc<Path>, (Model<Buffer>, BufferSnapshot)>,
-        executor: Executor,
+        executor: BackgroundExecutor,
         fs: Arc<dyn Fs>,
         workers: usize,
         query: SearchQuery,
@@ -5993,7 +5993,7 @@ impl Project {
             Task::ready(Ok((tree, relative_path)))
         } else {
             let worktree = self.create_local_worktree(abs_path, visible, cx);
-            cx.executor()
+            cx.background_executor()
                 .spawn(async move { Ok((worktree.await?, PathBuf::new())) })
         }
     }
@@ -6064,7 +6064,7 @@ impl Project {
                 .shared()
             })
             .clone();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             match task.await {
                 Ok(worktree) => Ok(worktree),
                 Err(err) => Err(anyhow!("{}", err)),
@@ -6376,7 +6376,7 @@ impl Project {
             let snapshot =
                 worktree_handle.update(&mut cx, |tree, _| tree.as_local().unwrap().snapshot())?;
             let diff_bases_by_buffer = cx
-                .executor()
+                .background_executor()
                 .spawn(async move {
                     future_buffers
                         .into_iter()
@@ -6519,7 +6519,7 @@ impl Project {
                 })
                 .collect::<Vec<_>>();
 
-            cx.executor()
+            cx.background_executor()
                 .spawn(async move {
                     for task_result in future::join_all(prettiers_to_reload.into_iter().map(|(worktree_id, prettier_path, prettier_task)| {
                         async move {
@@ -7358,7 +7358,7 @@ impl Project {
                         })
                         .log_err();
 
-                    cx.executor()
+                    cx.background_executor()
                         .spawn(
                             async move {
                                 let operations = operations.await;
@@ -7960,7 +7960,7 @@ impl Project {
                         if let Some(buffer) = this.buffer_for_id(buffer_id) {
                             let operations =
                                 buffer.read(cx).serialize_ops(Some(remote_version), cx);
-                            cx.executor().spawn(async move {
+                            cx.background_executor().spawn(async move {
                                 let operations = operations.await;
                                 for chunk in split_operations(operations) {
                                     client
@@ -7983,7 +7983,7 @@ impl Project {
             // Any incomplete buffers have open requests waiting. Request that the host sends
             // creates these buffers for us again to unblock any waiting futures.
             for id in incomplete_buffer_ids {
-                cx.executor()
+                cx.background_executor()
                     .spawn(client.request(proto::OpenBufferById { project_id, id }))
                     .detach();
             }
@@ -8198,7 +8198,7 @@ impl Project {
         cx: &mut ModelContext<Self>,
     ) -> Task<Result<Vec<(Range<Anchor>, String)>>> {
         let snapshot = self.buffer_snapshot_for_lsp_version(buffer, server_id, version, cx);
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let snapshot = snapshot?;
             let mut lsp_edits = lsp_edits
                 .into_iter()
@@ -8438,7 +8438,7 @@ impl Project {
             let fs = self.fs.clone();
             cx.spawn(move |this, mut cx| async move {
                 let prettier_dir = match cx
-                    .executor()
+                    .background_executor()
                     .spawn(Prettier::locate(
                         worktree_path.zip(buffer_path).map(
                             |(worktree_root_path, starting_path)| LocateStart {
@@ -8649,7 +8649,7 @@ impl Project {
             .get(&(worktree, default_prettier_dir.to_path_buf()))
             .cloned();
         let fs = Arc::clone(&self.fs);
-        cx.spawn_on_main(move |this, mut cx| async move {
+        cx.spawn(move |this, mut cx| async move {
             if let Some(previous_installation_process) = previous_installation_process {
                 previous_installation_process.await;
             }

crates/project2/src/worktree.rs

@@ -17,12 +17,13 @@ use futures::{
     },
     select_biased,
     task::Poll,
-    FutureExt, Stream, StreamExt,
+    FutureExt as _, Stream, StreamExt,
 };
 use fuzzy2::CharBag;
 use git::{DOT_GIT, GITIGNORE};
 use gpui2::{
-    AppContext, AsyncAppContext, Context, EventEmitter, Executor, Model, ModelContext, Task,
+    AppContext, AsyncAppContext, BackgroundExecutor, Context, EventEmitter, Model, ModelContext,
+    Task,
 };
 use language2::{
     proto::{
@@ -296,6 +297,7 @@ impl Worktree {
         // After determining whether the root entry is a file or a directory, populate the
         // snapshot's "root name", which will be used for the purpose of fuzzy matching.
         let abs_path = path.into();
+
         let metadata = fs
             .metadata(&abs_path)
             .await
@@ -364,10 +366,10 @@ impl Worktree {
             })
             .detach();
 
-            let background_scanner_task = cx.executor().spawn({
+            let background_scanner_task = cx.background_executor().spawn({
                 let fs = fs.clone();
                 let snapshot = snapshot.clone();
-                let background = cx.executor().clone();
+                let background = cx.background_executor().clone();
                 async move {
                     let events = fs.watch(&abs_path, Duration::from_millis(100)).await;
                     BackgroundScanner::new(
@@ -428,7 +430,7 @@ impl Worktree {
             let background_snapshot = Arc::new(Mutex::new(snapshot.clone()));
             let (mut snapshot_updated_tx, mut snapshot_updated_rx) = watch::channel();
 
-            cx.executor()
+            cx.background_executor()
                 .spawn({
                     let background_snapshot = background_snapshot.clone();
                     async move {
@@ -600,7 +602,7 @@ impl LocalWorktree {
                 .update(&mut cx, |t, cx| t.as_local().unwrap().load(&path, cx))?
                 .await?;
             let text_buffer = cx
-                .executor()
+                .background_executor()
                 .spawn(async move { text::Buffer::new(0, id, contents) })
                 .await;
             cx.build_model(|_| Buffer::build(text_buffer, diff_base, Some(Arc::new(file))))
@@ -888,7 +890,7 @@ impl LocalWorktree {
                 if let Some(repo) = snapshot.git_repositories.get(&*repo.work_directory) {
                     let repo = repo.repo_ptr.clone();
                     index_task = Some(
-                        cx.executor()
+                        cx.background_executor()
                             .spawn(async move { repo.lock().load_index_text(&repo_path) }),
                     );
                 }
@@ -1007,7 +1009,7 @@ impl LocalWorktree {
         let lowest_ancestor = self.lowest_ancestor(&path);
         let abs_path = self.absolutize(&path);
         let fs = self.fs.clone();
-        let write = cx.executor().spawn(async move {
+        let write = cx.background_executor().spawn(async move {
             if is_dir {
                 fs.create_dir(&abs_path).await
             } else {
@@ -1057,7 +1059,7 @@ impl LocalWorktree {
         let abs_path = self.absolutize(&path);
         let fs = self.fs.clone();
         let write = cx
-            .executor()
+            .background_executor()
             .spawn(async move { fs.save(&abs_path, &text, line_ending).await });
 
         cx.spawn(|this, mut cx| async move {
@@ -1078,7 +1080,7 @@ impl LocalWorktree {
         let abs_path = self.absolutize(&entry.path);
         let fs = self.fs.clone();
 
-        let delete = cx.executor().spawn(async move {
+        let delete = cx.background_executor().spawn(async move {
             if entry.is_file() {
                 fs.remove_file(&abs_path, Default::default()).await?;
             } else {
@@ -1118,7 +1120,7 @@ impl LocalWorktree {
         let abs_old_path = self.absolutize(&old_path);
         let abs_new_path = self.absolutize(&new_path);
         let fs = self.fs.clone();
-        let rename = cx.executor().spawn(async move {
+        let rename = cx.background_executor().spawn(async move {
             fs.rename(&abs_old_path, &abs_new_path, Default::default())
                 .await
         });
@@ -1145,7 +1147,7 @@ impl LocalWorktree {
         let abs_old_path = self.absolutize(&old_path);
         let abs_new_path = self.absolutize(&new_path);
         let fs = self.fs.clone();
-        let copy = cx.executor().spawn(async move {
+        let copy = cx.background_executor().spawn(async move {
             copy_recursive(
                 fs.as_ref(),
                 &abs_old_path,
@@ -1173,7 +1175,7 @@ impl LocalWorktree {
     ) -> Option<Task<Result<()>>> {
         let path = self.entry_for_id(entry_id)?.path.clone();
         let mut refresh = self.refresh_entries_for_paths(vec![path]);
-        Some(cx.executor().spawn(async move {
+        Some(cx.background_executor().spawn(async move {
             refresh.next().await;
             Ok(())
         }))
@@ -1247,7 +1249,7 @@ impl LocalWorktree {
             .ok();
 
         let worktree_id = cx.entity_id().as_u64();
-        let _maintain_remote_snapshot = cx.executor().spawn(async move {
+        let _maintain_remote_snapshot = cx.background_executor().spawn(async move {
             let mut is_first = true;
             while let Some((snapshot, entry_changes, repo_changes)) = snapshots_rx.next().await {
                 let update;
@@ -1305,7 +1307,7 @@ impl LocalWorktree {
         let rx = self.observe_updates(project_id, cx, move |update| {
             client.request(update).map(|result| result.is_ok())
         });
-        cx.executor()
+        cx.background_executor()
             .spawn(async move { rx.await.map_err(|_| anyhow!("share ended")) })
     }
 
@@ -2671,7 +2673,8 @@ impl language2::LocalFile for File {
         let worktree = self.worktree.read(cx).as_local().unwrap();
         let abs_path = worktree.absolutize(&self.path);
         let fs = worktree.fs.clone();
-        cx.executor().spawn(async move { fs.load(&abs_path).await })
+        cx.background_executor()
+            .spawn(async move { fs.load(&abs_path).await })
     }
 
     fn buffer_reloaded(
@@ -3012,7 +3015,7 @@ struct BackgroundScanner {
     state: Mutex<BackgroundScannerState>,
     fs: Arc<dyn Fs>,
     status_updates_tx: UnboundedSender<ScanState>,
-    executor: Executor,
+    executor: BackgroundExecutor,
     scan_requests_rx: channel::Receiver<ScanRequest>,
     path_prefixes_to_scan_rx: channel::Receiver<Arc<Path>>,
     next_entry_id: Arc<AtomicUsize>,
@@ -3032,7 +3035,7 @@ impl BackgroundScanner {
         next_entry_id: Arc<AtomicUsize>,
         fs: Arc<dyn Fs>,
         status_updates_tx: UnboundedSender<ScanState>,
-        executor: Executor,
+        executor: BackgroundExecutor,
         scan_requests_rx: channel::Receiver<ScanRequest>,
         path_prefixes_to_scan_rx: channel::Receiver<Arc<Path>>,
     ) -> Self {
@@ -4050,7 +4053,8 @@ impl WorktreeModelHandle for Model<Worktree> {
         &self,
         cx: &'a mut gpui2::TestAppContext,
     ) -> futures::future::LocalBoxFuture<'a, ()> {
-        let filename = "fs-event-sentinel";
+        let file_name = "fs-event-sentinel";
+
         let tree = self.clone();
         let (fs, root_path) = self.update(cx, |tree, _| {
             let tree = tree.as_local().unwrap();
@@ -4058,17 +4062,18 @@ impl WorktreeModelHandle for Model<Worktree> {
         });
 
         async move {
-            fs.create_file(&root_path.join(filename), Default::default())
+            fs.create_file(&root_path.join(file_name), Default::default())
                 .await
                 .unwrap();
-            cx.executor().run_until_parked();
-            assert!(tree.update(cx, |tree, _| tree.entry_for_path(filename).is_some()));
 
-            fs.remove_file(&root_path.join(filename), Default::default())
+            cx.condition(&tree, |tree, _| tree.entry_for_path(file_name).is_some())
+                .await;
+
+            fs.remove_file(&root_path.join(file_name), Default::default())
                 .await
                 .unwrap();
-            cx.executor().run_until_parked();
+            cx.condition(&tree, |tree, _| tree.entry_for_path(file_name).is_none())
-            assert!(tree.update(cx, |tree, _| tree.entry_for_path(filename).is_none()));
+                .await;
 
             cx.update(|cx| tree.read(cx).as_local().unwrap().scan_complete())
                 .await;

crates/rpc2/src/conn.rs

@@ -34,7 +34,7 @@ impl Connection {
 
     #[cfg(any(test, feature = "test-support"))]
     pub fn in_memory(
-        executor: gpui2::Executor,
+        executor: gpui2::BackgroundExecutor,
     ) -> (Self, Self, std::sync::Arc<std::sync::atomic::AtomicBool>) {
         use std::sync::{
             atomic::{AtomicBool, Ordering::SeqCst},
@@ -53,7 +53,7 @@ impl Connection {
         #[allow(clippy::type_complexity)]
         fn channel(
             killed: Arc<AtomicBool>,
-            executor: gpui2::Executor,
+            executor: gpui2::BackgroundExecutor,
         ) -> (
             Box<dyn Send + Unpin + futures::Sink<WebSocketMessage, Error = anyhow::Error>>,
             Box<dyn Send + Unpin + futures::Stream<Item = Result<WebSocketMessage, anyhow::Error>>>,

crates/rpc2/src/peer.rs

@@ -342,7 +342,7 @@ impl Peer {
     pub fn add_test_connection(
         self: &Arc<Self>,
         connection: Connection,
-        executor: gpui2::Executor,
+        executor: gpui2::BackgroundExecutor,
     ) -> (
         ConnectionId,
         impl Future<Output = anyhow::Result<()>> + Send,
@@ -559,7 +559,6 @@ mod tests {
     use async_tungstenite::tungstenite::Message as WebSocketMessage;
     use gpui2::TestAppContext;
 
-    #[ctor::ctor]
     fn init_logger() {
         if std::env::var("RUST_LOG").is_ok() {
             env_logger::init();
@@ -568,6 +567,8 @@ mod tests {
 
     #[gpui2::test(iterations = 50)]
     async fn test_request_response(cx: &mut TestAppContext) {
+        init_logger();
+
         let executor = cx.executor();
 
         // create 2 clients connected to 1 server

crates/settings2/src/settings_file.rs

@@ -2,7 +2,7 @@ use crate::{settings_store::SettingsStore, Settings};
 use anyhow::Result;
 use fs2::Fs;
 use futures::{channel::mpsc, StreamExt};
-use gpui2::{AppContext, Executor};
+use gpui2::{AppContext, BackgroundExecutor};
 use std::{io::ErrorKind, path::PathBuf, str, sync::Arc, time::Duration};
 use util::{paths, ResultExt};
 
@@ -28,7 +28,7 @@ pub fn test_settings() -> String {
 }
 
 pub fn watch_config_file(
-    executor: &Executor,
+    executor: &BackgroundExecutor,
     fs: Arc<dyn Fs>,
     path: PathBuf,
 ) -> mpsc::UnboundedReceiver<String> {
@@ -63,7 +63,10 @@ pub fn handle_settings_file_changes(
     mut user_settings_file_rx: mpsc::UnboundedReceiver<String>,
     cx: &mut AppContext,
 ) {
-    let user_settings_content = cx.executor().block(user_settings_file_rx.next()).unwrap();
+    let user_settings_content = cx
+        .background_executor()
+        .block(user_settings_file_rx.next())
+        .unwrap();
     cx.update_global(|store: &mut SettingsStore, cx| {
         store
             .set_user_settings(&user_settings_content, cx)

crates/sqlez/src/thread_safe_connection.rs

@@ -336,13 +336,13 @@ mod test {
                         FOREIGN KEY(dock_pane) REFERENCES panes(pane_id),
                         FOREIGN KEY(active_pane) REFERENCES panes(pane_id)
                     ) STRICT;
-                    
+
                     CREATE TABLE panes(
                         pane_id INTEGER PRIMARY KEY,
                         workspace_id INTEGER NOT NULL,
                         active INTEGER NOT NULL, -- Boolean
-                        FOREIGN KEY(workspace_id) REFERENCES workspaces(workspace_id) 
+                        FOREIGN KEY(workspace_id) REFERENCES workspaces(workspace_id)
-                            ON DELETE CASCADE 
+                            ON DELETE CASCADE
                             ON UPDATE CASCADE
                     ) STRICT;
                 "]

crates/terminal2/src/terminal2.rs

@@ -51,8 +51,8 @@ use thiserror::Error;
 
 use gpui2::{
     px, AnyWindowHandle, AppContext, Bounds, ClipboardItem, EventEmitter, Hsla, Keystroke,
-    MainThread, ModelContext, Modifiers, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent,
+    ModelContext, Modifiers, MouseButton, MouseDownEvent, MouseMoveEvent, MouseUpEvent, Pixels,
-    Pixels, Point, ScrollWheelEvent, Size, Task, TouchPhase,
+    Point, ScrollWheelEvent, Size, Task, TouchPhase,
 };
 
 use crate::mappings::{colors::to_alac_rgb, keys::to_esc_str};
@@ -403,7 +403,7 @@ impl TerminalBuilder {
 
     pub fn subscribe(mut self, cx: &mut ModelContext<Terminal>) -> Terminal {
         //Event loop
-        cx.spawn_on_main(|this, mut cx| async move {
+        cx.spawn(|this, mut cx| async move {
             use futures::StreamExt;
 
             while let Some(event) = self.events_rx.next().await {
@@ -414,7 +414,10 @@ impl TerminalBuilder {
 
                 'outer: loop {
                     let mut events = vec![];
-                    let mut timer = cx.executor().timer(Duration::from_millis(4)).fuse();
+                    let mut timer = cx
+                        .background_executor()
+                        .timer(Duration::from_millis(4))
+                        .fuse();
                     let mut wakeup = false;
                     loop {
                         futures::select_biased! {
@@ -551,7 +554,7 @@ pub struct Terminal {
 }
 
 impl Terminal {
-    fn process_event(&mut self, event: &AlacTermEvent, cx: &mut MainThread<ModelContext<Self>>) {
+    fn process_event(&mut self, event: &AlacTermEvent, cx: &mut ModelContext<Self>) {
         match event {
             AlacTermEvent::Title(title) => {
                 self.breadcrumb_text = title.to_string();
@@ -708,8 +711,7 @@ impl Terminal {
 
             InternalEvent::Copy => {
                 if let Some(txt) = term.selection_to_string() {
-                    cx.run_on_main(|cx| cx.write_to_clipboard(ClipboardItem::new(txt)))
+                    cx.write_to_clipboard(ClipboardItem::new(txt))
-                        .detach();
                 }
             }
             InternalEvent::ScrollToAlacPoint(point) => {
@@ -982,7 +984,7 @@ impl Terminal {
             term.lock_unfair() //It's been too long, force block
         } else if let None = self.sync_task {
             //Skip this frame
-            let delay = cx.executor().timer(Duration::from_millis(16));
+            let delay = cx.background_executor().timer(Duration::from_millis(16));
             self.sync_task = Some(cx.spawn(|weak_handle, mut cx| async move {
                 delay.await;
                 if let Some(handle) = weak_handle.upgrade() {
@@ -1189,7 +1191,7 @@ impl Terminal {
         &mut self,
         e: &MouseUpEvent,
         origin: Point<Pixels>,
-        cx: &mut MainThread<ModelContext<Self>>,
+        cx: &mut ModelContext<Self>,
     ) {
         let setting = TerminalSettings::get_global(cx);
 
@@ -1300,7 +1302,7 @@ impl Terminal {
         cx: &mut ModelContext<Self>,
     ) -> Task<Vec<RangeInclusive<AlacPoint>>> {
         let term = self.term.clone();
-        cx.executor().spawn(async move {
+        cx.background_executor().spawn(async move {
             let term = term.lock();
 
             all_search_matches(&term, &searcher).collect()

crates/ui2/src/components/panes.rs

@@ -51,7 +51,7 @@ impl<V: 'static> Pane<V> {
                     .id("drag-target")
                     .drag_over::<ExternalPaths>(|d| d.bg(red()))
                     .on_drop(|_, files: View<ExternalPaths>, cx| {
-                        dbg!("dropped files!", files.read(cx));
+                        eprintln!("dropped files! {:?}", files.read(cx));
                     })
                     .absolute()
                     .inset_0(),

crates/ui2/src/components/tab.rs

@@ -129,7 +129,7 @@ impl Tab {
             .on_drag(move |_view, cx| cx.build_view(|cx| drag_state.clone()))
             .drag_over::<TabDragState>(|d| d.bg(cx.theme().colors().element_drop_target))
             .on_drop(|_view, state: View<TabDragState>, cx| {
-                dbg!(state.read(cx));
+                eprintln!("{:?}", state.read(cx));
             })
             .px_2()
             .py_0p5()

crates/zed2/src/main.rs

@@ -62,20 +62,26 @@ fn main() {
     log::info!("========== starting zed ==========");
     let app = App::production(Arc::new(Assets));
 
-    let installation_id = app.executor().block(installation_id()).ok();
+    let installation_id = app.background_executor().block(installation_id()).ok();
     let session_id = Uuid::new_v4().to_string();
     init_panic_hook(&app, installation_id.clone(), session_id.clone());
 
     let fs = Arc::new(RealFs);
-    let user_settings_file_rx =
+    let user_settings_file_rx = watch_config_file(
-        watch_config_file(&app.executor(), fs.clone(), paths::SETTINGS.clone());
+        &app.background_executor(),
-    let _user_keymap_file_rx =
+        fs.clone(),
-        watch_config_file(&app.executor(), fs.clone(), paths::KEYMAP.clone());
+        paths::SETTINGS.clone(),
+    );
+    let _user_keymap_file_rx = watch_config_file(
+        &app.background_executor(),
+        fs.clone(),
+        paths::KEYMAP.clone(),
+    );
 
     let login_shell_env_loaded = if stdout_is_a_pty() {
         Task::ready(())
     } else {
-        app.executor().spawn(async {
+        app.background_executor().spawn(async {
             load_login_shell_environment().await.log_err();
         })
     };
@@ -111,7 +117,7 @@ fn main() {
         let client = client2::Client::new(http.clone(), cx);
         let mut languages = LanguageRegistry::new(login_shell_env_loaded);
         let copilot_language_server_id = languages.next_language_server_id();
-        languages.set_executor(cx.executor().clone());
+        languages.set_executor(cx.background_executor().clone());
         languages.set_language_server_download_dir(paths::LANGUAGES_DIR.clone());
         let languages = Arc::new(languages);
         let node_runtime = RealNodeRuntime::new(http.clone());
@@ -508,7 +514,7 @@ fn init_panic_hook(app: &App, installation_id: Option<String>, session_id: Strin
 fn upload_previous_panics(http: Arc<dyn HttpClient>, cx: &mut AppContext) {
     let telemetry_settings = *client2::TelemetrySettings::get_global(cx);
 
-    cx.executor()
+    cx.background_executor()
         .spawn(async move {
             let panic_report_url = format!("{}/api/panic", &*client2::ZED_SERVER_URL);
             let mut children = smol::fs::read_dir(&*paths::LOGS_DIR).await?;
@@ -638,7 +644,7 @@ fn load_embedded_fonts(cx: &AppContext) {
     let asset_source = cx.asset_source();
     let font_paths = asset_source.list("fonts").unwrap();
     let embedded_fonts = Mutex::new(Vec::new());
-    let executor = cx.executor();
+    let executor = cx.background_executor();
 
     executor.block(executor.scoped(|scope| {
         for font_path in &font_paths {