[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

11 files changed, 214 insertions, 2 deletions

diff --git a/clang-tools-extra/clangd/ClangdLSPServer.cpp b/clang-tools-extra/clangd/ClangdLSPServer.cpp
index 19a89353e0f..0384423e151 100644
--- a/clang-tools-extra/clangd/ClangdLSPServer.cpp
+++ b/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);
diff --git a/clang-tools-extra/clangd/ClangdLSPServer.h b/clang-tools-extra/clangd/ClangdLSPServer.h
index 608ff9bf244..656252f868d 100644
--- a/clang-tools-extra/clangd/ClangdLSPServer.h
+++ b/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);
diff --git a/clang-tools-extra/clangd/ClangdServer.cpp b/clang-tools-extra/clangd/ClangdServer.cpp
index 2cf2cb791eb..f5d03252422 100644
--- a/clang-tools-extra/clangd/ClangdServer.cpp
+++ b/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.
+}
diff --git a/clang-tools-extra/clangd/ClangdServer.h b/clang-tools-extra/clangd/ClangdServer.h
index b819264e46a..b42d2d6226d 100644
--- a/clang-tools-extra/clangd/ClangdServer.h
+++ b/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>
diff --git a/clang-tools-extra/clangd/Protocol.cpp b/clang-tools-extra/clangd/Protocol.cpp
index e68add6e4e8..f45e07d17c1 100644
--- a/clang-tools-extra/clangd/Protocol.cpp
+++ b/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) {
diff --git a/clang-tools-extra/clangd/Protocol.h b/clang-tools-extra/clangd/Protocol.h
index 71ab9573a58..a6fcca6a40a 100644
--- a/clang-tools-extra/clangd/Protocol.h
+++ b/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;
diff --git a/clang-tools-extra/clangd/ProtocolHandlers.cpp b/clang-tools-extra/clangd/ProtocolHandlers.cpp
index 544c44c6f23..936c673ebab 100644
--- a/clang-tools-extra/clangd/ProtocolHandlers.cpp
+++ b/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));
 }
diff --git a/clang-tools-extra/clangd/ProtocolHandlers.h b/clang-tools-extra/clangd/ProtocolHandlers.h
index 70796d34bf3..8592e574c8d 100644
--- a/clang-tools-extra/clangd/ProtocolHandlers.h
+++ b/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,
diff --git a/clang-tools-extra/clangd/clients/clangd-vscode/package.json b/clang-tools-extra/clangd/clients/clangd-vscode/package.json
index 729297af172..c048d965d3b 100644
--- a/clang-tools-extra/clangd/clients/clangd-vscode/package.json
+++ b/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."
                 }
             }
         }
diff --git a/clang-tools-extra/clangd/clients/clangd-vscode/src/extension.ts b/clang-tools-extra/clangd/clients/clangd-vscode/src/extension.ts
index c76e0a021ee..f89ddc97ffe 100644
--- a/clang-tools-extra/clangd/clients/clangd-vscode/src/extension.ts
+++ b/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 + '}')
         }
     };
 
diff --git a/clang-tools-extra/test/clangd/did-change-watch-files.test b/clang-tools-extra/test/clangd/did-change-watch-files.test
new file mode 100644
index 00000000000..d9ef6b4c214
--- /dev/null
+++ b/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"}