[clangd] Handle workspace/didChangeWatchedFiles

Summary:
The client can send notifications when it detects watched files have
changed. This patch adds the protocol handling for this type of notification.
For now, the notification will be passed down to the ClangdServer, but it will
not be acted upon. However, this will become useful for the indexer to react
to file changes.
The events could also potentially be used to invalidate other caches
(compilation database, etc).

This change also updates the VSCode extension so that it sends the events.

Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>

Reviewers: ilya-biryukov, Nebiroth

Subscribers: ilya-biryukov

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D38422

llvm-svn: 314693

clang-tools-extra/clangd/ClangdLSPServer.cpp

@@ -73,6 +73,10 @@ void ClangdLSPServer::onDocumentDidChange(DidChangeTextDocumentParams Params,
                      Params.contentChanges[0].text);
 }
 
+void ClangdLSPServer::onFileEvent(const DidChangeWatchedFilesParams &Params) {
+  Server.onFileEvent(Params);
+}
+
 void ClangdLSPServer::onDocumentDidClose(DidCloseTextDocumentParams Params,
                                          JSONOutput &Out) {
   Server.removeDocument(Params.textDocument.uri.file);

clang-tools-extra/clangd/ClangdLSPServer.h

@@ -71,6 +71,7 @@ private:
                         JSONOutput &Out) override;
   void onSwitchSourceHeader(TextDocumentIdentifier Params, StringRef ID,
                             JSONOutput &Out) override;
+  void onFileEvent(const DidChangeWatchedFilesParams &Params) override;
 
   std::vector<clang::tooling::Replacement>
   getFixIts(StringRef File, const clangd::Diagnostic &D);

clang-tools-extra/clangd/ClangdServer.cpp

@@ -424,3 +424,8 @@ ClangdServer::scheduleCancelRebuild(std::shared_ptr<CppFile> Resources) {
                            std::move(DeferredCancel));
   return DoneFuture;
 }
+
+void ClangdServer::onFileEvent(const DidChangeWatchedFilesParams &Params) {
+  // FIXME: Do nothing for now. This will be used for indexing and potentially
+  // invalidating other caches.
+}

clang-tools-extra/clangd/ClangdServer.h

@@ -268,6 +268,8 @@ public:
   /// Waits until all requests to worker thread are finished and dumps AST for
   /// \p File. \p File must be in the list of added documents.
   std::string dumpAST(PathRef File);
+  /// Called when an event occurs for a watched file in the workspace.
+  void onFileEvent(const DidChangeWatchedFilesParams &Params);
 
 private:
   std::future<void>

clang-tools-extra/clangd/Protocol.cpp

@@ -447,6 +447,84 @@ DidChangeTextDocumentParams::parse(llvm::yaml::MappingNode *Params,
   return Result;
 }
 
+llvm::Optional<FileEvent> FileEvent::parse(llvm::yaml::MappingNode *Params,
+                                           clangd::Logger &Logger) {
+  llvm::Optional<FileEvent> Result = FileEvent();
+  for (auto &NextKeyValue : *Params) {
+    // We have to consume the whole MappingNode because it doesn't support
+    // skipping and we want to be able to parse further valid events.
+    if (!Result)
+      continue;
+
+    auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
+    if (!KeyString) {
+      Result.reset();
+      continue;
+    }
+
+    llvm::SmallString<10> KeyStorage;
+    StringRef KeyValue = KeyString->getValue(KeyStorage);
+    auto *Value =
+        dyn_cast_or_null<llvm::yaml::ScalarNode>(NextKeyValue.getValue());
+    if (!Value) {
+      Result.reset();
+      continue;
+    }
+    llvm::SmallString<10> Storage;
+    if (KeyValue == "uri") {
+      Result->uri = URI::parse(Value);
+    } else if (KeyValue == "type") {
+      long long Val;
+      if (llvm::getAsSignedInteger(Value->getValue(Storage), 0, Val)) {
+        Result.reset();
+        continue;
+      }
+      Result->type = static_cast<FileChangeType>(Val);
+      if (Result->type < FileChangeType::Created ||
+          Result->type > FileChangeType::Deleted)
+        Result.reset();
+    } else {
+      logIgnoredField(KeyValue, Logger);
+    }
+  }
+  return Result;
+}
+
+llvm::Optional<DidChangeWatchedFilesParams>
+DidChangeWatchedFilesParams::parse(llvm::yaml::MappingNode *Params,
+                                   clangd::Logger &Logger) {
+  DidChangeWatchedFilesParams Result;
+  for (auto &NextKeyValue : *Params) {
+    auto *KeyString = dyn_cast<llvm::yaml::ScalarNode>(NextKeyValue.getKey());
+    if (!KeyString)
+      return llvm::None;
+
+    llvm::SmallString<10> KeyStorage;
+    StringRef KeyValue = KeyString->getValue(KeyStorage);
+    auto *Value = NextKeyValue.getValue();
+
+    llvm::SmallString<10> Storage;
+    if (KeyValue == "changes") {
+      auto *Seq = dyn_cast<llvm::yaml::SequenceNode>(Value);
+      if (!Seq)
+        return llvm::None;
+      for (auto &Item : *Seq) {
+        auto *I = dyn_cast<llvm::yaml::MappingNode>(&Item);
+        if (!I)
+          return llvm::None;
+        auto Parsed = FileEvent::parse(I, Logger);
+        if (Parsed)
+          Result.changes.push_back(std::move(*Parsed));
+        else
+          Logger.log("Failed to decode a FileEvent.\n");
+      }
+    } else {
+      logIgnoredField(KeyValue, Logger);
+    }
+  }
+  return Result;
+}
+
 llvm::Optional<TextDocumentContentChangeEvent>
 TextDocumentContentChangeEvent::parse(llvm::yaml::MappingNode *Params,
                                       clangd::Logger &Logger) {

clang-tools-extra/clangd/Protocol.h

@@ -237,6 +237,33 @@ struct DidChangeTextDocumentParams {
   parse(llvm::yaml::MappingNode *Params, clangd::Logger &Logger);
 };
 
+enum class FileChangeType {
+  /// The file got created.
+  Created = 1,
+  /// The file got changed.
+  Changed = 2,
+  /// The file got deleted.
+  Deleted = 3
+};
+
+struct FileEvent {
+  /// The file's URI.
+  URI uri;
+  /// The change type.
+  FileChangeType type;
+
+  static llvm::Optional<FileEvent> parse(llvm::yaml::MappingNode *Params,
+                                         clangd::Logger &Logger);
+};
+
+struct DidChangeWatchedFilesParams {
+  /// The actual file events.
+  std::vector<FileEvent> changes;
+
+  static llvm::Optional<DidChangeWatchedFilesParams>
+  parse(llvm::yaml::MappingNode *Params, clangd::Logger &Logger);
+};
+
 struct FormattingOptions {
   /// Size of a tab in spaces.
   int tabSize;

clang-tools-extra/clangd/ProtocolHandlers.cpp

@@ -226,6 +226,25 @@ private:
   ProtocolCallbacks &Callbacks;
 };
 
+struct WorkspaceDidChangeWatchedFilesHandler : Handler {
+  WorkspaceDidChangeWatchedFilesHandler(JSONOutput &Output,
+                                        ProtocolCallbacks &Callbacks)
+      : Handler(Output), Callbacks(Callbacks) {}
+
+  void handleNotification(llvm::yaml::MappingNode *Params) {
+    auto DCWFP = DidChangeWatchedFilesParams::parse(Params, Output);
+    if (!DCWFP) {
+      Output.log("Failed to decode DidChangeWatchedFilesParams.\n");
+      return;
+    }
+
+    Callbacks.onFileEvent(*DCWFP);
+  }
+
+private:
+  ProtocolCallbacks &Callbacks;
+};
+
 } // namespace
 
 void clangd::registerCallbackHandlers(JSONRPCDispatcher &Dispatcher,
@@ -264,5 +283,8 @@ void clangd::registerCallbackHandlers(JSONRPCDispatcher &Dispatcher,
       llvm::make_unique<GotoDefinitionHandler>(Out, Callbacks));
   Dispatcher.registerHandler(
       "textDocument/switchSourceHeader",
-      llvm::make_unique<SwitchSourceHeaderHandler>(Out, Callbacks));    
+      llvm::make_unique<SwitchSourceHeaderHandler>(Out, Callbacks));
+  Dispatcher.registerHandler(
+      "workspace/didChangeWatchedFiles",
+      llvm::make_unique<WorkspaceDidChangeWatchedFilesHandler>(Out, Callbacks));
 }

clang-tools-extra/clangd/ProtocolHandlers.h

@@ -51,6 +51,7 @@ public:
                                 JSONOutput &Out) = 0;
   virtual void onSwitchSourceHeader(TextDocumentIdentifier Params, StringRef ID,
                                     JSONOutput &Out) = 0;
+  virtual void onFileEvent(const DidChangeWatchedFilesParams &Params) = 0;
 };
 
 void registerCallbackHandlers(JSONRPCDispatcher &Dispatcher, JSONOutput &Out,

clang-tools-extra/clangd/clients/clangd-vscode/package.json

@@ -51,6 +51,11 @@
                         "type": "string"
                     },
                     "description": "Arguments for clangd server"
+                },
+                "clangd.syncFileEvents": {
+                    "type": "boolean",
+                    "default": true,
+                    "description": "Whether or not to send file events to clangd (File created, changed or deleted). This can be disabled for performance consideration."
                 }
             }
         }

clang-tools-extra/clangd/clients/clangd-vscode/src/extension.ts

@@ -18,18 +18,24 @@ function getConfig<T>(option: string, defaultValue?: any) : T {
 export function activate(context: vscode.ExtensionContext) {
     const clangdPath = getConfig<string>('path');
     const clangdArgs = getConfig<string[]>('arguments');
+    const syncFileEvents = getConfig<boolean>('syncFileEvents', true);
 
     const serverOptions: vscodelc.ServerOptions = { command: clangdPath, args: clangdArgs };
 
+    const cppFileExtensions: string[] = ['cpp', 'c', 'cc', 'cxx', 'c++', 'm', 'mm', 'h', 'hh', 'hpp', 'hxx', 'inc'];
+    const cppFileExtensionsPattern = cppFileExtensions.join();
     const clientOptions: vscodelc.LanguageClientOptions = {
         // Register the server for C/C++ files
-        documentSelector: ['c', 'cc', 'cpp', 'h', 'hh', 'hpp'],
+        documentSelector: cppFileExtensions,
         uriConverters: {
             // FIXME: by default the URI sent over the protocol will be percent encoded (see rfc3986#section-2.1)
             //        the "workaround" below disables temporarily the encoding until decoding
             //        is implemented properly in clangd
             code2Protocol: (uri: vscode.Uri) : string => uri.toString(true),
             protocol2Code: (uri: string) : vscode.Uri => vscode.Uri.parse(uri)
+        },
+        synchronize: !syncFileEvents ? undefined : {
+            fileEvents: vscode.workspace.createFileSystemWatcher('**/*.{' + cppFileExtensionsPattern + '}')
         }
     };
 

clang-tools-extra/test/clangd/did-change-watch-files.test

@@ -0,0 +1,61 @@
+# RUN: clangd -run-synchronously < %s 2>&1 | FileCheck -check-prefix=STDERR %s
+# It is absolutely vital that this file has CRLF line endings.
+#
+# Test initialize request parameters with rootUri
+Content-Length: 143
+
+{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootUri":"file:///path/to/workspace","capabilities":{},"trace":"off"}}
+# CHECK: Content-Length: 466
+# CHECK: {"jsonrpc":"2.0","id":0,"result":{"capabilities":{
+# CHECK:   "textDocumentSync": 1,
+# CHECK:   "documentFormattingProvider": true,
+# CHECK:   "documentRangeFormattingProvider": true,
+# CHECK:   "documentOnTypeFormattingProvider": {"firstTriggerCharacter":"}","moreTriggerCharacter":[]},
+# CHECK:   "codeActionProvider": true,
+# CHECK:   "completionProvider": {"resolveProvider": false, "triggerCharacters": [".",">",":"]},
+# CHECK:   "definitionProvider": true
+# CHECK: }}}
+#
+#Normal case
+Content-Length: 217
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[{"uri":"file:///path/to/file.cpp","type":1},{"uri":"file:///path/to/file2.cpp","type":2},{"uri":"file:///path/to/file3.cpp","type":3}]}}
+
+# Wrong event type, integer
+Content-Length: 173
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[{"uri":"file:///path/to/file2.cpp","type":0},{"uri":"file:///path/to/file3.cpp","type":4}]}}
+# STDERR: Failed to decode a FileEvent.
+# Wrong event type, string
+Content-Length: 132
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[{"uri":"file:///path/to/file2.cpp","type":"foo"}]}}
+# STDERR: Failed to decode a FileEvent.
+#Custom event field
+Content-Length: 143
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[{"uri":"file:///path/to/file2.cpp","type":1,"custom":"foo"}]}}
+# STDERR: Failed to decode a FileEvent.
+#Event field with object
+Content-Length: 140
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[{"uri":"file:///path/to/file2.cpp","type":{"foo":"bar"}}]}}
+# STDERR: Failed to decode a FileEvent.
+# Changes field with sequence but no object
+Content-Length: 86
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":[""]}}
+# STDERR: Failed to decode DidChangeWatchedFilesParams.
+# Changes field with no sequence
+Content-Length: 84
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"changes":""}}
+# STDERR: Failed to decode DidChangeWatchedFilesParams.
+# Custom field
+Content-Length: 86
+
+{"jsonrpc":"2.0","method":"workspace/didChangeWatchedFiles","params":{"custom":"foo"}}
+# STDERR: Ignored unknown field "custom"
+Content-Length: 44
+
+{"jsonrpc":"2.0","id":3,"method":"shutdown"}