chore: Move component_preview into zed (#30480)

This improves our build times by ~0.2s

Closes #ISSUE

Release Notes:

- N/A

crates/zed/src/main.rs

@@ -658,7 +658,7 @@ fn main() {
 
         let app_state = app_state.clone();
 
-        component_preview::init(app_state.clone(), cx);
+        crate::zed::component_preview::init(app_state.clone(), cx);
 
         cx.spawn(async move |cx| {
             while let Some(urls) = open_rx.next().await {

crates/zed/src/zed.rs

@@ -1,4 +1,5 @@
 mod app_menus;
+pub mod component_preview;
 pub mod inline_completion_registry;
 #[cfg(target_os = "macos")]
 pub(crate) mod mac_only_instance;

crates/zed/src/zed/component_preview/persistence.rs

@@ -0,0 +1,50 @@
+use anyhow::Result;
+use db::{define_connection, query, sqlez::statement::Statement, sqlez_macros::sql};
+use workspace::{ItemId, WorkspaceDb, WorkspaceId};
+
+define_connection! {
+    pub static ref COMPONENT_PREVIEW_DB: ComponentPreviewDb<WorkspaceDb> =
+        &[sql!(
+            CREATE TABLE component_previews (
+                workspace_id INTEGER,
+                item_id INTEGER UNIQUE,
+                active_page_id TEXT,
+                PRIMARY KEY(workspace_id, item_id),
+                FOREIGN KEY(workspace_id) REFERENCES workspaces(workspace_id)
+                ON DELETE CASCADE
+            ) STRICT;
+        )];
+}
+
+impl ComponentPreviewDb {
+    pub async fn save_active_page(
+        &self,
+        item_id: ItemId,
+        workspace_id: WorkspaceId,
+        active_page_id: String,
+    ) -> Result<()> {
+        log::debug!(
+            "Saving active page: item_id={item_id:?}, workspace_id={workspace_id:?}, active_page_id={active_page_id}"
+        );
+        let query = "INSERT INTO component_previews(item_id, workspace_id, active_page_id)
+            VALUES (?1, ?2, ?3)
+            ON CONFLICT DO UPDATE SET
+                active_page_id = ?3";
+        self.write(move |conn| {
+            let mut statement = Statement::prepare(conn, query)?;
+            let mut next_index = statement.bind(&item_id, 1)?;
+            next_index = statement.bind(&workspace_id, next_index)?;
+            statement.bind(&active_page_id, next_index)?;
+            statement.exec()
+        })
+        .await
+    }
+
+    query! {
+        pub fn get_active_page(item_id: ItemId, workspace_id: WorkspaceId) -> Result<Option<String>> {
+            SELECT active_page_id
+            FROM component_previews
+            WHERE item_id = ? AND workspace_id = ?
+        }
+    }
+}

crates/zed/src/zed/component_preview/preview_support.rs

@@ -0,0 +1 @@
+pub mod active_thread;

crates/zed/src/zed/component_preview/preview_support/active_thread.rs

@@ -0,0 +1,101 @@
+use agent::{ActiveThread, ContextStore, MessageSegment, TextThreadStore, ThreadStore};
+use anyhow::{Result, anyhow};
+use assistant_tool::ToolWorkingSet;
+use gpui::{AppContext, AsyncApp, Entity, Task, WeakEntity};
+use indoc::indoc;
+use languages::LanguageRegistry;
+use project::Project;
+use prompt_store::PromptBuilder;
+use std::sync::Arc;
+use ui::{App, Window};
+use workspace::Workspace;
+
+pub fn load_preview_thread_store(
+    workspace: WeakEntity<Workspace>,
+    project: Entity<Project>,
+    cx: &mut AsyncApp,
+) -> Task<Result<Entity<ThreadStore>>> {
+    workspace
+        .update(cx, |_, cx| {
+            ThreadStore::load(
+                project.clone(),
+                cx.new(|_| ToolWorkingSet::default()),
+                None,
+                Arc::new(PromptBuilder::new(None).unwrap()),
+                cx,
+            )
+        })
+        .unwrap_or(Task::ready(Err(anyhow!("workspace dropped"))))
+}
+
+pub fn load_preview_text_thread_store(
+    workspace: WeakEntity<Workspace>,
+    project: Entity<Project>,
+    cx: &mut AsyncApp,
+) -> Task<Result<Entity<TextThreadStore>>> {
+    workspace
+        .update(cx, |_, cx| {
+            TextThreadStore::new(
+                project.clone(),
+                Arc::new(PromptBuilder::new(None).unwrap()),
+                Default::default(),
+                cx,
+            )
+        })
+        .unwrap_or(Task::ready(Err(anyhow!("workspace dropped"))))
+}
+
+pub fn static_active_thread(
+    workspace: WeakEntity<Workspace>,
+    project: Entity<Project>,
+    language_registry: Arc<LanguageRegistry>,
+    thread_store: Entity<ThreadStore>,
+    text_thread_store: Entity<TextThreadStore>,
+    window: &mut Window,
+    cx: &mut App,
+) -> Entity<ActiveThread> {
+    let context_store =
+        cx.new(|_| ContextStore::new(project.downgrade(), Some(thread_store.downgrade())));
+
+    let thread = thread_store.update(cx, |thread_store, cx| thread_store.create_thread(cx));
+    thread.update(cx, |thread, cx| {
+        thread.insert_assistant_message(vec![
+            MessageSegment::Text(indoc! {"
+                I'll help you fix the lifetime error in your `cx.spawn` call. When working with async operations in GPUI, there are specific patterns to follow for proper lifetime management.
+
+                Let's look at what's happening in your code:
+
+                ---
+
+                Let's check the current state of the active_thread.rs file to understand what might have changed:
+
+                ---
+
+                Looking at the implementation of `load_preview_thread_store` and understanding GPUI's async patterns, here's the issue:
+
+                1. `load_preview_thread_store` returns a `Task<anyhow::Result<Entity<ThreadStore>>>`, which means it's already a task.
+                2. When you call this function inside another `spawn` call, you're nesting tasks incorrectly.
+
+                Here's the correct way to implement this:
+
+                ---
+
+                The problem is in how you're setting up the async closure and trying to reference variables like `window` and `language_registry` that aren't accessible in that scope.
+
+                Here's how to fix it:
+            "}.to_string()),
+        ], cx);
+    });
+    cx.new(|cx| {
+        ActiveThread::new(
+            thread,
+            thread_store,
+            text_thread_store,
+            context_store,
+            language_registry,
+            workspace.clone(),
+            window,
+            cx,
+        )
+    })
+}