project: Track manifest locations per unique manifest locator (#27194)

This pull request paves way for exposing manifest tracking to
extensions.
- Project tree was renamed to manifest tree to better reflect it's
intent (and avoid confusion).
- Language server adapters now provide a name of their *manifest
locator*. If multiple language servers refer to the same locator, the
locating code will run just once for a given path.

Release Notes:

- N/A *or* Added/Fixed/Improved ...

---------

Co-authored-by: Anthony <anthony@zed.dev>

crates/languages/src/lib.rs

@@ -2,6 +2,7 @@ use anyhow::Context as _;
 use gpui::{App, UpdateGlobal};
 use json::json_task_context;
 use node_runtime::NodeRuntime;
+use rust::CargoManifestProvider;
 use rust_embed::RustEmbed;
 use settings::SettingsStore;
 use smol::stream::StreamExt;
@@ -301,6 +302,7 @@ pub fn init(languages: Arc<LanguageRegistry>, node: NodeRuntime, cx: &mut App) {
         anyhow::Ok(())
     })
     .detach();
+    project::ManifestProviders::global(cx).register(Arc::from(CargoManifestProvider));
 }
 
 #[derive(Default)]

crates/languages/src/rust.rs

@@ -3,7 +3,7 @@ use async_compression::futures::bufread::GzipDecoder;
 use async_trait::async_trait;
 use collections::HashMap;
 use futures::{io::BufReader, StreamExt};
-use gpui::{App, AsyncApp, Task};
+use gpui::{App, AsyncApp, SharedString, Task};
 use http_client::github::AssetKind;
 use http_client::github::{latest_github_release, GitHubLspBinaryVersion};
 pub use language::*;
@@ -68,20 +68,23 @@ impl RustLspAdapter {
     }
 }
 
-#[async_trait(?Send)]
-impl LspAdapter for RustLspAdapter {
-    fn name(&self) -> LanguageServerName {
-        Self::SERVER_NAME.clone()
+pub(crate) struct CargoManifestProvider;
+
+impl ManifestProvider for CargoManifestProvider {
+    fn name(&self) -> ManifestName {
+        SharedString::new_static("Cargo.toml").into()
     }
 
-    fn find_project_root(
+    fn search(
         &self,
-        path: &Path,
-        ancestor_depth: usize,
-        delegate: &Arc<dyn LspAdapterDelegate>,
+        ManifestQuery {
+            path,
+            depth,
+            delegate,
+        }: ManifestQuery,
     ) -> Option<Arc<Path>> {
         let mut outermost_cargo_toml = None;
-        for path in path.ancestors().take(ancestor_depth) {
+        for path in path.ancestors().take(depth) {
             let p = path.join("Cargo.toml");
             if delegate.exists(&p, Some(false)) {
                 outermost_cargo_toml = Some(Arc::from(path));
@@ -90,6 +93,17 @@ impl LspAdapter for RustLspAdapter {
 
         outermost_cargo_toml
     }
+}
+
+#[async_trait(?Send)]
+impl LspAdapter for RustLspAdapter {
+    fn name(&self) -> LanguageServerName {
+        Self::SERVER_NAME.clone()
+    }
+
+    fn manifest_name(&self) -> Option<ManifestName> {
+        Some(SharedString::new_static("Cargo.toml").into())
+    }
 
     async fn check_if_user_installed(
         &self,