SSH Remoting: Add the ability to resolve file paths on the remote host (#18250)

Release Notes:

- N/A

crates/remote_server/src/headless_project.rs

@@ -108,6 +108,7 @@ impl HeadlessProject {
         session.subscribe_to_entity(SSH_PROJECT_ID, &settings_observer);
 
         client.add_request_handler(cx.weak_model(), Self::handle_list_remote_directory);
+        client.add_request_handler(cx.weak_model(), Self::handle_check_file_exists);
 
         client.add_model_request_handler(Self::handle_add_worktree);
         client.add_model_request_handler(Self::handle_open_buffer_by_path);
@@ -298,4 +299,20 @@ impl HeadlessProject {
         }
         Ok(proto::ListRemoteDirectoryResponse { entries })
     }
+
+    pub async fn handle_check_file_exists(
+        this: Model<Self>,
+        envelope: TypedEnvelope<proto::CheckFileExists>,
+        cx: AsyncAppContext,
+    ) -> Result<proto::CheckFileExistsResponse> {
+        let fs = cx.read_model(&this, |this, _| this.fs.clone())?;
+        let expanded = shellexpand::tilde(&envelope.payload.path).to_string();
+
+        let exists = fs.is_file(&PathBuf::from(expanded.clone())).await;
+
+        Ok(proto::CheckFileExistsResponse {
+            exists,
+            path: expanded,
+        })
+    }
 }

crates/remote_server/src/remote_editing_tests.rs

@@ -12,7 +12,7 @@ use lsp::{CompletionContext, CompletionResponse, CompletionTriggerKind};
 use node_runtime::NodeRuntime;
 use project::{
     search::{SearchQuery, SearchResult},
-    Project,
+    Project, ProjectPath,
 };
 use remote::SshSession;
 use serde_json::json;
@@ -440,6 +440,49 @@ async fn test_remote_lsp(cx: &mut TestAppContext, server_cx: &mut TestAppContext
     })
 }
 
+#[gpui::test]
+async fn test_remote_resolve_file_path(cx: &mut TestAppContext, server_cx: &mut TestAppContext) {
+    let (project, _headless, _fs) = init_test(cx, server_cx).await;
+    let (worktree, _) = project
+        .update(cx, |project, cx| {
+            project.find_or_create_worktree("/code/project1", true, cx)
+        })
+        .await
+        .unwrap();
+
+    let worktree_id = cx.update(|cx| worktree.read(cx).id());
+
+    let buffer = project
+        .update(cx, |project, cx| {
+            project.open_buffer((worktree_id, Path::new("src/lib.rs")), cx)
+        })
+        .await
+        .unwrap();
+
+    let path = project
+        .update(cx, |project, cx| {
+            project.resolve_existing_file_path("/code/project1/README.md", &buffer, cx)
+        })
+        .await
+        .unwrap();
+    assert_eq!(
+        path.abs_path().unwrap().to_string_lossy(),
+        "/code/project1/README.md"
+    );
+
+    let path = project
+        .update(cx, |project, cx| {
+            project.resolve_existing_file_path("../README.md", &buffer, cx)
+        })
+        .await
+        .unwrap();
+
+    assert_eq!(
+        path.project_path().unwrap().clone(),
+        ProjectPath::from((worktree_id, "README.md"))
+    );
+}
+
 fn init_logger() {
     if std::env::var("RUST_LOG").is_ok() {
         env_logger::try_init().ok();