git: Implement a basic repository selector (#23419)

This PR adds a rough-and-ready picker for selecting which of the
project's repositories the git panel should display.

Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Nate <nate@zed.dev>

crates/project/src/project.rs

@@ -22,6 +22,7 @@ mod project_tests;
 mod direnv;
 mod environment;
 pub use environment::EnvironmentErrorMessage;
+use git::RepositoryHandle;
 pub mod search_history;
 mod yarn;
 
@@ -691,7 +692,8 @@ impl Project {
                 )
             });
 
-            let git_state = Some(cx.new_model(|cx| GitState::new(languages.clone(), cx)));
+            let git_state =
+                Some(cx.new_model(|cx| GitState::new(&worktree_store, languages.clone(), cx)));
 
             cx.subscribe(&lsp_store, Self::on_lsp_store_event).detach();
 
@@ -2324,6 +2326,18 @@ impl Project {
             }
             WorktreeStoreEvent::WorktreeOrderChanged => cx.emit(Event::WorktreeOrderChanged),
             WorktreeStoreEvent::WorktreeUpdateSent(_) => {}
+            WorktreeStoreEvent::WorktreeUpdatedEntries(worktree_id, changes) => {
+                self.client()
+                    .telemetry()
+                    .report_discovered_project_events(*worktree_id, changes);
+                cx.emit(Event::WorktreeUpdatedEntries(*worktree_id, changes.clone()))
+            }
+            WorktreeStoreEvent::WorktreeUpdatedGitRepositories(worktree_id) => {
+                cx.emit(Event::WorktreeUpdatedGitRepositories(*worktree_id))
+            }
+            WorktreeStoreEvent::WorktreeDeletedEntry(worktree_id, id) => {
+                cx.emit(Event::DeletedEntry(*worktree_id, *id))
+            }
         }
     }
 
@@ -2335,27 +2349,6 @@ impl Project {
             }
         }
         cx.observe(worktree, |_, _, cx| cx.notify()).detach();
-        cx.subscribe(worktree, |project, worktree, event, cx| {
-            let worktree_id = worktree.update(cx, |worktree, _| worktree.id());
-            match event {
-                worktree::Event::UpdatedEntries(changes) => {
-                    cx.emit(Event::WorktreeUpdatedEntries(
-                        worktree.read(cx).id(),
-                        changes.clone(),
-                    ));
-
-                    project
-                        .client()
-                        .telemetry()
-                        .report_discovered_project_events(worktree_id, changes);
-                }
-                worktree::Event::UpdatedGitRepositories(_) => {
-                    cx.emit(Event::WorktreeUpdatedGitRepositories(worktree_id));
-                }
-                worktree::Event::DeletedEntry(id) => cx.emit(Event::DeletedEntry(worktree_id, *id)),
-            }
-        })
-        .detach();
         cx.notify();
     }
 
@@ -4169,6 +4162,17 @@ impl Project {
     pub fn git_state(&self) -> Option<&Model<GitState>> {
         self.git_state.as_ref()
     }
+
+    pub fn active_repository(&self, cx: &AppContext) -> Option<RepositoryHandle> {
+        self.git_state()
+            .and_then(|git_state| git_state.read(cx).active_repository())
+    }
+
+    pub fn all_repositories(&self, cx: &AppContext) -> Vec<RepositoryHandle> {
+        self.git_state()
+            .map(|git_state| git_state.read(cx).all_repositories())
+            .unwrap_or_default()
+    }
 }
 
 fn deserialize_code_actions(code_actions: &HashMap<String, bool>) -> Vec<lsp::CodeActionKind> {