Add language toolchains (#19576)

This PR adds support for selecting toolchains for a given language (e.g.
Rust toolchains or Python virtual environments) with support for SSH
projects provided out of the box. For Python we piggy-back off of
[PET](https://github.com/microsoft/python-environment-tools), a library
maintained by Microsoft.
Closes #16421
Closes #7646

Release Notes:

- Added toolchain selector to the status bar (with initial support for
Python virtual environments)

crates/project/src/project.rs

@@ -11,6 +11,7 @@ pub mod search;
 mod task_inventory;
 pub mod task_store;
 pub mod terminals;
+pub mod toolchain_store;
 pub mod worktree_store;
 
 #[cfg(test)]
@@ -44,8 +45,8 @@ use itertools::Itertools;
 use language::{
     language_settings::InlayHintKind, proto::split_operations, Buffer, BufferEvent,
     CachedLspAdapter, Capability, CodeLabel, DiagnosticEntry, Documentation, File as _, Language,
-    LanguageRegistry, LanguageServerName, PointUtf16, ToOffset, ToPointUtf16, Transaction,
-    Unclipped,
+    LanguageName, LanguageRegistry, LanguageServerName, PointUtf16, ToOffset, ToPointUtf16,
+    Toolchain, ToolchainList, Transaction, Unclipped,
 };
 use lsp::{
     CompletionContext, CompletionItemKind, DocumentHighlightKind, LanguageServer, LanguageServerId,
@@ -101,7 +102,7 @@ pub use lsp_store::{
     LanguageServerStatus, LanguageServerToQuery, LspStore, LspStoreEvent,
     SERVER_PROGRESS_THROTTLE_TIMEOUT,
 };
-
+pub use toolchain_store::ToolchainStore;
 const MAX_PROJECT_SEARCH_HISTORY_SIZE: usize = 500;
 const MAX_SEARCH_RESULT_FILES: usize = 5_000;
 const MAX_SEARCH_RESULT_RANGES: usize = 10_000;
@@ -158,6 +159,7 @@ pub struct Project {
     snippets: Model<SnippetProvider>,
     environment: Model<ProjectEnvironment>,
     settings_observer: Model<SettingsObserver>,
+    toolchain_store: Option<Model<ToolchainStore>>,
 }
 
 #[derive(Default)]
@@ -579,6 +581,7 @@ impl Project {
         LspStore::init(&client);
         SettingsObserver::init(&client);
         TaskStore::init(Some(&client));
+        ToolchainStore::init(&client);
     }
 
     pub fn local(
@@ -635,12 +638,15 @@ impl Project {
             });
             cx.subscribe(&settings_observer, Self::on_settings_observer_event)
                 .detach();
-
+            let toolchain_store = cx.new_model(|cx| {
+                ToolchainStore::local(languages.clone(), worktree_store.clone(), cx)
+            });
             let lsp_store = cx.new_model(|cx| {
                 LspStore::new_local(
                     buffer_store.clone(),
                     worktree_store.clone(),
                     prettier_store.clone(),
+                    toolchain_store.clone(),
                     environment.clone(),
                     languages.clone(),
                     client.http_client(),
@@ -681,6 +687,8 @@ impl Project {
 
                 search_included_history: Self::new_search_history(),
                 search_excluded_history: Self::new_search_history(),
+
+                toolchain_store: Some(toolchain_store),
             }
         })
     }
@@ -737,10 +745,14 @@ impl Project {
                 .detach();
 
             let environment = ProjectEnvironment::new(&worktree_store, None, cx);
+            let toolchain_store = Some(cx.new_model(|cx| {
+                ToolchainStore::remote(SSH_PROJECT_ID, ssh.read(cx).proto_client(), cx)
+            }));
             let lsp_store = cx.new_model(|cx| {
                 LspStore::new_remote(
                     buffer_store.clone(),
                     worktree_store.clone(),
+                    toolchain_store.clone(),
                     languages.clone(),
                     ssh_proto.clone(),
                     SSH_PROJECT_ID,
@@ -798,6 +810,8 @@ impl Project {
 
                 search_included_history: Self::new_search_history(),
                 search_excluded_history: Self::new_search_history(),
+
+                toolchain_store,
             };
 
             let ssh = ssh.read(cx);
@@ -818,6 +832,7 @@ impl Project {
             LspStore::init(&ssh_proto);
             SettingsObserver::init(&ssh_proto);
             TaskStore::init(Some(&ssh_proto));
+            ToolchainStore::init(&ssh_proto);
 
             this
         })
@@ -905,6 +920,7 @@ impl Project {
             let mut lsp_store = LspStore::new_remote(
                 buffer_store.clone(),
                 worktree_store.clone(),
+                None,
                 languages.clone(),
                 client.clone().into(),
                 remote_id,
@@ -993,6 +1009,7 @@ impl Project {
                 search_excluded_history: Self::new_search_history(),
                 environment: ProjectEnvironment::new(&worktree_store, None, cx),
                 remotely_created_models: Arc::new(Mutex::new(RemotelyCreatedModels::default())),
+                toolchain_store: None,
             };
             this.set_role(role, cx);
             for worktree in worktrees {
@@ -2346,6 +2363,46 @@ impl Project {
             .map_err(|e| anyhow!(e))
     }
 
+    pub fn available_toolchains(
+        &self,
+        worktree_id: WorktreeId,
+        language_name: LanguageName,
+        cx: &AppContext,
+    ) -> Task<Option<ToolchainList>> {
+        if let Some(toolchain_store) = self.toolchain_store.as_ref() {
+            toolchain_store
+                .read(cx)
+                .list_toolchains(worktree_id, language_name, cx)
+        } else {
+            Task::ready(None)
+        }
+    }
+    pub fn activate_toolchain(
+        &self,
+        worktree_id: WorktreeId,
+        toolchain: Toolchain,
+        cx: &mut AppContext,
+    ) -> Task<Option<()>> {
+        let Some(toolchain_store) = self.toolchain_store.clone() else {
+            return Task::ready(None);
+        };
+        toolchain_store.update(cx, |this, cx| {
+            this.activate_toolchain(worktree_id, toolchain, cx)
+        })
+    }
+    pub fn active_toolchain(
+        &self,
+        worktree_id: WorktreeId,
+        language_name: LanguageName,
+        cx: &AppContext,
+    ) -> Task<Option<Toolchain>> {
+        let Some(toolchain_store) = self.toolchain_store.clone() else {
+            return Task::ready(None);
+        };
+        toolchain_store
+            .read(cx)
+            .active_toolchain(worktree_id, language_name, cx)
+    }
     pub fn language_server_statuses<'a>(
         &'a self,
         cx: &'a AppContext,