Implement custom find implementations extension

List all implementation block for traits, structs, and enums.
Fails for traits which are implemented using derive
Listed under wishlist #142

Requires the find-impls branch of https://github.com/jonasbb/rls_vscode

Author: jonasbb

contributing.md

@@ -301,10 +301,29 @@ the RLS.
 
 The RLS uses some custom extensions to the Language Server Protocol.
 
-* `rustDocument/diagnosticsBegin`: notification, no arguments. Sent from the RLS
-  to a client before a build starts and before any diagnostics from a build are sent.
-* `rustDocument/diagnosticsEnd`: notification, no arguments. Sent from the RLS
-  to a client when a build is complete (successfully or not, or even skipped)
-  and all post-build analysis by the RLS is complete.
+#### RLS to LSP Client
+
+These are all sent from the RLS to an LSP client and are only used to improve
+the user experience by showing progress indicators.
+
+* `rustDocument/diagnosticsBegin`: notification, no arguments. Sent before a
+  build starts and before any diagnostics from a build are sent.
+* `rustDocument/diagnosticsEnd`: notification, no arguments. Sent when a build
+  is complete (successfully or not, or even skipped) and all post-build analysis
+  by the RLS is complete.
 * `rustWorkspace/deglob`: message sent from the client to the RLS to initiate a
   deglob refactoring.
+
+#### LSP Client to RLS
+
+The following request is to support Rust specific features.
+
+* `rustDocument/implementations`: request
+  params: [`TextDocumentPositionParams`]
+  result: [`Location`]`[]`
+
+  List all implementation blocks for a trait, struct, or enum denoted by the
+  given text document position.
+
+[`TextDocumentPositionParams`]: (https://github.com/Microsoft/language-server-protocol/blob/master/protocol.md#textdocumentpositionparams)
+[`Location`]: (https://github.com/Microsoft/language-server-protocol/blob/master/protocol.md#location)

src/actions/mod.rs

@@ -253,9 +253,32 @@ impl ActionHandler {
         });
     }
 
+    pub fn find_impls<O: Output>(&self, id: usize, params: TextDocumentPositionParams, out: O) {
+        let t = thread::current();
+        let file_path = parse_file_path!(&params.text_document.uri, "find_impls");
+        let span = self.convert_pos_to_span(file_path, params.position);
+        let type_id = self.analysis.id(&span).expect("Analysis: Getting typeid from span");
+        let analysis = self.analysis.clone();
+
+        let handle = thread::spawn(move || {
+            let result = analysis.find_impls(type_id).map(|spans| {
+                spans.into_iter().map(|x| ls_util::rls_to_location(&x)).collect()
+            });
+            t.unpark();
+            result
+        });
+        thread::park_timeout(Duration::from_millis(::COMPILER_TIMEOUT));
+
+        let result = handle.join();
+        trace!("find_impls: {:?}", result);
+        match result {
+            Ok(Ok(r)) => out.success(id, ResponseData::Locations(r)),
+            _ => out.failure_message(id, ErrorCode::InternalError, "Find Implementations failed to complete successfully"),
+        }
+    }
+
     pub fn on_open<O: Output>(&self, open: DidOpenTextDocumentParams, _out: O) {
         trace!("on_open: {:?}", open.text_document.uri);
-
         let file_path = parse_file_path!(&open.text_document.uri, "on_open");
 
         self.vfs.set_file(&file_path, &open.text_document.text);

src/server.rs

@@ -290,6 +290,7 @@ messages! {
         "textDocument/codeAction" => CodeAction(CodeActionParams);
         "workspace/executeCommand" => ExecuteCommand(ExecuteCommandParams);
         "rustWorkspace/deglob" => Deglob(Location);
+        "rustDocument/implementations" => FindImpls(TextDocumentPositionParams);
     }
     notifications {
         "initialized" => Initialized;
@@ -518,6 +519,7 @@ impl<O: Output> LsService<O> {
                 Deglob(params) => { action: deglob };
                 ExecuteCommand(params) => { action: execute_command };
                 CodeAction(params) => { action: code_action };
+                FindImpls(params) => { action: find_impls };
             }
             notifications {
                 Initialized => {{ self.handler.inited().initialized(self.output.clone()) }};