[clangd] Handle exit notification (proper shutdown)

Summary:
This changes the onShutdown handler to do essentially nothing (for now), and
instead exits the runloop when we receive the exit notification from the client.

Some clients may wait on the reply from the shutdown request before sending an
exit notification. If we exit the runloop already in the shutdown request, a
client might block forever.

This also gives us the opportunity to do any global cleanups and/or
serializations of PCH preambles to disk, but I've left that out for now.

See the LSP protocol documentation for details.

Reviewers: malaperle, krasimir, bkramer, sammccall, ilya-biryukov

Reviewed By: malaperle, sammccall, ilya-biryukov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D38939

llvm-svn: 316564

clang-tools-extra/clangd/ClangdLSPServer.cpp

@@ -56,9 +56,13 @@ void ClangdLSPServer::onInitialize(Ctx C, InitializeParams &Params) {
 }
 
 void ClangdLSPServer::onShutdown(Ctx C, ShutdownParams &Params) {
-  IsDone = true;
+  // Do essentially nothing, just say we're ready to exit.
+  ShutdownRequestReceived = true;
+  C.reply("null");
 }
 
+void ClangdLSPServer::onExit(Ctx C, ExitParams &Params) { IsDone = true; }
+
 void ClangdLSPServer::onDocumentDidOpen(Ctx C,
                                         DidOpenTextDocumentParams &Params) {
   if (Params.metadata && !Params.metadata->extraFlags.empty())
@@ -197,7 +201,7 @@ ClangdLSPServer::ClangdLSPServer(JSONOutput &Out, unsigned AsyncThreadsCount,
                  /*EnableSnippetsAndCodePatterns=*/SnippetCompletions),
              /*Logger=*/Out, ResourceDir) {}
 
-void ClangdLSPServer::run(std::istream &In) {
+bool ClangdLSPServer::run(std::istream &In) {
   assert(!IsDone && "Run was called before");
 
   // Set up JSONRPCDispatcher.
@@ -213,6 +217,8 @@ void ClangdLSPServer::run(std::istream &In) {
   // Make sure IsDone is set to true after this method exits to ensure assertion
   // at the start of the method fires if it's ever executed again.
   IsDone = true;
+
+  return ShutdownRequestReceived;
 }
 
 std::vector<clang::tooling::Replacement>

clang-tools-extra/clangd/ClangdLSPServer.h

@@ -39,7 +39,9 @@ class ClangdLSPServer : private DiagnosticsConsumer, private ProtocolCallbacks {
   /// opened in binary mode. Output will be written using Out variable passed to
   /// class constructor. This method must not be executed more than once for
   /// each instance of ClangdLSPServer.
-  void run(std::istream &In);
+  ///
+  /// \return Wether we received a 'shutdown' request before an 'exit' request
+  bool run(std::istream &In);
 
 private:
   // Implement DiagnosticsConsumer.
@@ -50,6 +52,7 @@ class ClangdLSPServer : private DiagnosticsConsumer, private ProtocolCallbacks {
   // Implement ProtocolCallbacks.
   void onInitialize(Ctx C, InitializeParams &Params) override;
   void onShutdown(Ctx C, ShutdownParams &Params) override;
+  void onExit(Ctx C, ExitParams &Params) override;
   void onDocumentDidOpen(Ctx C, DidOpenTextDocumentParams &Params) override;
   void onDocumentDidChange(Ctx C, DidChangeTextDocumentParams &Params) override;
   void onDocumentDidClose(Ctx C, DidCloseTextDocumentParams &Params) override;
@@ -79,6 +82,10 @@ class ClangdLSPServer : private DiagnosticsConsumer, private ProtocolCallbacks {
   JSONOutput &Out;
   /// Used to indicate that the 'shutdown' request was received from the
   /// Language Server client.
+  bool ShutdownRequestReceived = false;
+
+  /// Used to indicate that the 'exit' notification was received from the
+  /// Language Server client.
   /// It's used to break out of the LSP parsing loop.
   bool IsDone = false;
 

clang-tools-extra/clangd/Protocol.h

@@ -173,6 +173,7 @@ struct NoParams {
   }
 };
 using ShutdownParams = NoParams;
+using ExitParams = NoParams;
 
 struct InitializeParams {
   /// The process Id of the parent process that started

clang-tools-extra/clangd/ProtocolHandlers.cpp

@@ -52,6 +52,7 @@ void clangd::registerCallbackHandlers(JSONRPCDispatcher &Dispatcher,
 
   Register("initialize", &ProtocolCallbacks::onInitialize);
   Register("shutdown", &ProtocolCallbacks::onShutdown);
+  Register("exit", &ProtocolCallbacks::onExit);
   Register("textDocument/didOpen", &ProtocolCallbacks::onDocumentDidOpen);
   Register("textDocument/didClose", &ProtocolCallbacks::onDocumentDidClose);
   Register("textDocument/didChange", &ProtocolCallbacks::onDocumentDidChange);

clang-tools-extra/clangd/ProtocolHandlers.h

@@ -34,6 +34,7 @@ class ProtocolCallbacks {
 
   virtual void onInitialize(Ctx C, InitializeParams &Params) = 0;
   virtual void onShutdown(Ctx C, ShutdownParams &Params) = 0;
+  virtual void onExit(Ctx C, ExitParams &Params) = 0;
   virtual void onDocumentDidOpen(Ctx C, DidOpenTextDocumentParams &Params) = 0;
   virtual void onDocumentDidChange(Ctx C,
                                    DidChangeTextDocumentParams &Params) = 0;

clang-tools-extra/clangd/tool/ClangdMain.cpp

@@ -114,5 +114,7 @@ int main(int argc, char *argv[]) {
   /// Initialize and run ClangdLSPServer.
   ClangdLSPServer LSPServer(Out, WorkerThreadsCount, EnableSnippets,
                             ResourceDirRef, CompileCommandsDirPath);
-  LSPServer.run(std::cin);
+
+  constexpr int NoShutdownRequestErrorCode = 1;
+  return LSPServer.run(std::cin) ? 0 : NoShutdownRequestErrorCode;
 }

clang-tools-extra/test/clangd/authority-less-uri.test

@@ -30,3 +30,7 @@ Content-Length: 172
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/completion-priorities.test

@@ -34,3 +34,7 @@ Content-Length: 151
 Content-Length: 58
 
 {"jsonrpc":"2.0","id":4,"method":"shutdown","params":null}
+# CHECK: {"jsonrpc":"2.0","id":4,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/completion-qualifiers.test

@@ -16,3 +16,7 @@ Content-Length: 151
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":4,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":4,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/completion-snippet.test

@@ -52,3 +52,7 @@ Content-Length: 148
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":4,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":4,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/completion.test

@@ -52,3 +52,7 @@ Content-Length: 148
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":4,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":4,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/definitions.test

@@ -166,3 +166,7 @@ Content-Length: 148
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/diagnostics-preamble.test

@@ -13,3 +13,7 @@ Content-Length: 206
 Content-Length: 58
 
 {"jsonrpc":"2.0","id":2,"method":"shutdown","params":null}
+# CHECK: {"jsonrpc":"2.0","id":2,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/diagnostics.test

@@ -15,3 +15,7 @@ Content-Length: 152
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":5,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":5,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

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

@@ -59,3 +59,6 @@ Content-Length: 86
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/extra-flags.test

@@ -18,5 +18,9 @@ Content-Length: 175
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":5,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":5,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}
 
 

clang-tools-extra/test/clangd/fixits.test

@@ -26,3 +26,7 @@ Content-Length: 771
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/formatting.test

@@ -65,3 +65,7 @@ Content-Length: 204
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":6,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":6,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/initialize-params-invalid.test

@@ -20,3 +20,7 @@ Content-Length: 142
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/initialize-params.test

@@ -20,3 +20,7 @@ Content-Length: 143
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/input-mirror.test

@@ -152,3 +152,7 @@ Content-Length: 148
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":3,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":3,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/protocol.test

@@ -1,8 +1,10 @@
-# RUN: clangd -run-synchronously < %s | FileCheck %s
-# RUN: clangd -run-synchronously < %s 2>&1 | FileCheck -check-prefix=STDERR %s
+# RUN: not clangd -run-synchronously < %s | FileCheck %s
+# RUN: not clangd -run-synchronously < %s 2>&1 | FileCheck -check-prefix=STDERR %s
 # vim: fileformat=dos
 # It is absolutely vital that this file has CRLF line endings.
 #
+# Note that we invert the test because we intent to let clangd exit prematurely.
+#
 # Test protocol parsing
 Content-Length: 125
 Content-Type: application/vscode-jsonrpc; charset-utf-8

clang-tools-extra/test/clangd/shutdown-with-exit.test

@@ -0,0 +1,9 @@
+# RUN: clangd -run-synchronously < %s
+# vim: fileformat=dos
+# It is absolutely vital that this file has CRLF line endings.
+Content-Length: 44
+
+{"jsonrpc":"2.0","id":3,"method":"shutdown"}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/shutdown-without-exit.test

@@ -0,0 +1,6 @@
+# RUN: not clangd -run-synchronously < %s
+# vim: fileformat=dos
+# It is absolutely vital that this file has CRLF line endings.
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/signature-help.test

@@ -40,3 +40,7 @@ Content-Length: 151
 Content-Length: 49
 
 {"jsonrpc":"2.0","id":100000,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":100000,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}

clang-tools-extra/test/clangd/unsupported-method.test

@@ -17,3 +17,7 @@ Content-Length: 92
 Content-Length: 44
 
 {"jsonrpc":"2.0","id":2,"method":"shutdown"}
+# CHECK: {"jsonrpc":"2.0","id":2,"result":null}
+Content-Length: 33
+
+{"jsonrpc":"2.0":"method":"exit"}