kadircet updated this revision to Diff 161428.
kadircet marked 2 inline comments as done.
kadircet added a comment.
- Check cancellation earlier && Fix normalization difference between string and
integer request ids.
Repository:
rCTE Clang Tools Extra
https://reviews.llvm.org/D50502
Files:
clangd/CMakeLists.txt
clangd/Cancellation.cpp
clangd/Cancellation.h
clangd/ClangdLSPServer.cpp
clangd/ClangdLSPServer.h
clangd/ClangdServer.cpp
clangd/ClangdServer.h
clangd/JSONRPCDispatcher.cpp
clangd/JSONRPCDispatcher.h
clangd/Protocol.cpp
clangd/Protocol.h
clangd/ProtocolHandlers.cpp
clangd/ProtocolHandlers.h
unittests/clangd/CMakeLists.txt
unittests/clangd/CancellationTests.cpp
Index: unittests/clangd/CancellationTests.cpp
===================================================================
--- /dev/null
+++ unittests/clangd/CancellationTests.cpp
@@ -0,0 +1,79 @@
+#include "Cancellation.h"
+#include "Context.h"
+#include "Threading.h"
+#include "llvm/Support/Error.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include <atomic>
+#include <memory>
+#include <thread>
+
+namespace clang {
+namespace clangd {
+namespace {
+
+TEST(CancellationTest, CancellationTest) {
+ TaskHandle TH = TaskHandle::create();
+ WithContext ContextWithCancellation(
+ setCurrentCancellationToken(TH.createCancellationToken()));
+ EXPECT_FALSE(isCancelled());
+ TH.cancel();
+ EXPECT_TRUE(isCancelled());
+}
+
+TEST(CancellationTest, TaskHandleTestHandleDiesContextLives) {
+ llvm::Optional<WithContext> ContextWithCancellation;
+ {
+ auto CancellableTaskHandle = TaskHandle::create();
+ ContextWithCancellation.emplace(setCurrentCancellationToken(
+ CancellableTaskHandle.createCancellationToken()));
+ EXPECT_FALSE(isCancelled());
+ CancellableTaskHandle.cancel();
+ EXPECT_TRUE(isCancelled());
+ }
+ EXPECT_TRUE(isCancelled());
+}
+
+TEST(CancellationTest, TaskHandleContextDiesHandleLives) {
+ auto CancellableTaskHandle = TaskHandle::create();
+ {
+ WithContext ContextWithCancellation(setCurrentCancellationToken(
+ CancellableTaskHandle.createCancellationToken()));
+ EXPECT_FALSE(isCancelled());
+ CancellableTaskHandle.cancel();
+ EXPECT_TRUE(isCancelled());
+ }
+ // Still should be able to cancel without any problems.
+ CancellableTaskHandle.cancel();
+}
+
+TEST(CancellationTest, CancellationToken) {
+ auto CancellableTaskHandle = TaskHandle::create();
+ WithContext ContextWithCancellation(setCurrentCancellationToken(
+ CancellableTaskHandle.createCancellationToken()));
+ const auto &CT = getCurrentCancellationToken();
+ EXPECT_FALSE(CT);
+ CancellableTaskHandle.cancel();
+ EXPECT_TRUE(CT);
+}
+
+TEST(CancellationTest, AsynCancellationTest) {
+ std::atomic<bool> HasCancelled(false);
+ Notification Cancelled;
+ auto TaskToBeCancelled = [&](CancellationToken CT) {
+ WithContext ContextGuard(setCurrentCancellationToken(std::move(CT)));
+ Cancelled.wait();
+ HasCancelled = isCancelled();
+ };
+ TaskHandle TH = TaskHandle::create();
+ std::thread AsyncTask(TaskToBeCancelled, TH.createCancellationToken());
+ TH.cancel();
+ Cancelled.notify();
+ AsyncTask.join();
+
+ EXPECT_TRUE(HasCancelled);
+}
+
+} // namespace
+} // namespace clangd
+} // namespace clang
Index: unittests/clangd/CMakeLists.txt
===================================================================
--- unittests/clangd/CMakeLists.txt
+++ unittests/clangd/CMakeLists.txt
@@ -10,6 +10,7 @@
add_extra_unittest(ClangdTests
Annotations.cpp
+ CancellationTests.cpp
ClangdTests.cpp
ClangdUnitTests.cpp
CodeCompleteTests.cpp
Index: clangd/ProtocolHandlers.h
===================================================================
--- clangd/ProtocolHandlers.h
+++ clangd/ProtocolHandlers.h
@@ -55,6 +55,7 @@
virtual void onDocumentHighlight(TextDocumentPositionParams &Params) = 0;
virtual void onHover(TextDocumentPositionParams &Params) = 0;
virtual void onChangeConfiguration(DidChangeConfigurationParams &Params) = 0;
+ virtual void onCancelRequest(CancelParams &Params) = 0;
};
void registerCallbackHandlers(JSONRPCDispatcher &Dispatcher,
Index: clangd/ProtocolHandlers.cpp
===================================================================
--- clangd/ProtocolHandlers.cpp
+++ clangd/ProtocolHandlers.cpp
@@ -75,4 +75,5 @@
Register("workspace/didChangeConfiguration",
&ProtocolCallbacks::onChangeConfiguration);
Register("workspace/symbol", &ProtocolCallbacks::onWorkspaceSymbol);
+ Register("$/cancelRequest", &ProtocolCallbacks::onCancelRequest);
}
Index: clangd/Protocol.h
===================================================================
--- clangd/Protocol.h
+++ clangd/Protocol.h
@@ -867,6 +867,16 @@
llvm::json::Value toJSON(const DocumentHighlight &DH);
llvm::raw_ostream &operator<<(llvm::raw_ostream &, const DocumentHighlight &);
+struct CancelParams {
+ /// The request id to cancel.
+ /// This can be either a number or string, if it is a number simply print it
+ /// out and always use a string.
+ std::string ID;
+};
+llvm::json::Value toJSON(const CancelParams &);
+llvm::raw_ostream &operator<<(llvm::raw_ostream &, const CancelParams &);
+bool fromJSON(const llvm::json::Value &, CancelParams &);
+
} // namespace clangd
} // namespace clang
Index: clangd/Protocol.cpp
===================================================================
--- clangd/Protocol.cpp
+++ clangd/Protocol.cpp
@@ -615,5 +615,30 @@
O.map("compilationDatabaseChanges", CCPC.compilationDatabaseChanges);
}
+json::Value toJSON(const CancelParams &CP) {
+ return json::Object{{"id", CP.ID}};
+}
+
+llvm::raw_ostream &operator<<(llvm::raw_ostream &O, const CancelParams &CP) {
+ O << toJSON(CP);
+ return O;
+}
+
+bool fromJSON(const json::Value &Params, CancelParams &CP) {
+ json::ObjectMapper O(Params);
+ if (!O)
+ return false;
+ // ID is either a number or a string, check for both.
+ if (O.map("id", CP.ID))
+ return true;
+
+ int64_t id_number;
+ if (O.map("id", id_number)) {
+ CP.ID = utostr(id_number);
+ return true;
+ }
+ return false;
+}
+
} // namespace clangd
} // namespace clang
Index: clangd/JSONRPCDispatcher.h
===================================================================
--- clangd/JSONRPCDispatcher.h
+++ clangd/JSONRPCDispatcher.h
@@ -64,6 +64,13 @@
/// Sends an error response to the client, and logs it.
/// Current context must derive from JSONRPCDispatcher::Handler.
void replyError(ErrorCode Code, const llvm::StringRef &Message);
+/// Implements ErrorCode and message extraction from a given llvm::Error. It
+/// fetches the related message from error's message method. If error doesn't
+/// match any known errors, uses ErrorCode::InvalidParams for the error.
+void replyError(llvm::Error E);
+/// Returns the request-id of the current request. Should not be used directly
+/// for replying to requests, use the above mentioned methods for that case.
+const llvm::json::Value *getRequestId();
/// Sends a request to the client.
/// Current context must derive from JSONRPCDispatcher::Handler.
void call(llvm::StringRef Method, llvm::json::Value &&Params);
@@ -110,7 +117,6 @@
void runLanguageServerLoop(std::FILE *In, JSONOutput &Out,
JSONStreamStyle InputStyle,
JSONRPCDispatcher &Dispatcher, bool &IsDone);
-
} // namespace clangd
} // namespace clang
Index: clangd/JSONRPCDispatcher.cpp
===================================================================
--- clangd/JSONRPCDispatcher.cpp
+++ clangd/JSONRPCDispatcher.cpp
@@ -8,6 +8,7 @@
//===----------------------------------------------------------------------===//
#include "JSONRPCDispatcher.h"
+#include "Cancellation.h"
#include "ProtocolHandlers.h"
#include "Trace.h"
#include "llvm/ADT/SmallString.h"
@@ -93,7 +94,7 @@
}
void clangd::reply(json::Value &&Result) {
- auto ID = Context::current().get(RequestID);
+ auto ID = getRequestId();
if (!ID) {
elog("Attempted to reply to a notification!");
return;
@@ -116,7 +117,7 @@
{"message", Message.str()}};
});
- if (auto ID = Context::current().get(RequestID)) {
+ if (auto ID = getRequestId()) {
log("--> reply({0}) error: {1}", *ID, Message);
Context::current()
.getExisting(RequestOut)
@@ -129,6 +130,16 @@
}
}
+void clangd::replyError(Error E) {
+ handleAllErrors(std::move(E),
+ [](const CancelledError &TCE) {
+ replyError(ErrorCode::RequestCancelled, TCE.message());
+ },
+ [](const ErrorInfoBase &EIB) {
+ replyError(ErrorCode::InvalidParams, EIB.message());
+ });
+}
+
void clangd::call(StringRef Method, json::Value &&Params) {
RequestSpan::attach([&](json::Object &Args) {
Args["Call"] = json::Object{{"method", Method.str()}, {"params", Params}};
@@ -366,3 +377,7 @@
}
}
}
+
+const json::Value *clangd::getRequestId() {
+ return Context::current().get(RequestID);
+}
Index: clangd/ClangdServer.h
===================================================================
--- clangd/ClangdServer.h
+++ clangd/ClangdServer.h
@@ -10,6 +10,7 @@
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_CLANGDSERVER_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CLANGDSERVER_H
+#include "Cancellation.h"
#include "ClangdUnit.h"
#include "CodeComplete.h"
#include "FSProvider.h"
@@ -122,9 +123,9 @@
/// while returned future is not yet ready.
/// A version of `codeComplete` that runs \p Callback on the processing thread
/// when codeComplete results become available.
- void codeComplete(PathRef File, Position Pos,
- const clangd::CodeCompleteOptions &Opts,
- Callback<CodeCompleteResult> CB);
+ TaskHandle codeComplete(PathRef File, Position Pos,
+ const clangd::CodeCompleteOptions &Opts,
+ Callback<CodeCompleteResult> CB);
/// Provide signature help for \p File at \p Pos. This method should only be
/// called for tracked files.
Index: clangd/ClangdServer.cpp
===================================================================
--- clangd/ClangdServer.cpp
+++ clangd/ClangdServer.cpp
@@ -8,6 +8,7 @@
//===-------------------------------------------------------------------===//
#include "ClangdServer.h"
+#include "Cancellation.h"
#include "CodeComplete.h"
#include "FindSymbols.h"
#include "Headers.h"
@@ -140,20 +141,26 @@
WorkScheduler.remove(File);
}
-void ClangdServer::codeComplete(PathRef File, Position Pos,
- const clangd::CodeCompleteOptions &Opts,
- Callback<CodeCompleteResult> CB) {
+TaskHandle ClangdServer::codeComplete(PathRef File, Position Pos,
+ const clangd::CodeCompleteOptions &Opts,
+ Callback<CodeCompleteResult> CB) {
// Copy completion options for passing them to async task handler.
auto CodeCompleteOpts = Opts;
if (!CodeCompleteOpts.Index) // Respect overridden index.
CodeCompleteOpts.Index = Index;
+ auto TH = TaskHandle::create();
+ WithContext ContextWithCancellation(
+ setCurrentCancellationToken(TH.createCancellationToken()));
// Copy PCHs to avoid accessing this->PCHs concurrently
std::shared_ptr<PCHContainerOperations> PCHs = this->PCHs;
auto FS = FSProvider.getFileSystem();
auto Task = [PCHs, Pos, FS,
CodeCompleteOpts](Path File, Callback<CodeCompleteResult> CB,
llvm::Expected<InputsAndPreamble> IP) {
+ if (isCancelled())
+ return CB(llvm::make_error<CancelledError>());
+
if (!IP)
return CB(IP.takeError());
@@ -170,6 +177,7 @@
WorkScheduler.runWithPreamble("CodeComplete", File,
Bind(Task, File.str(), std::move(CB)));
+ return TH;
}
void ClangdServer::signatureHelp(PathRef File, Position Pos,
Index: clangd/ClangdLSPServer.h
===================================================================
--- clangd/ClangdLSPServer.h
+++ clangd/ClangdLSPServer.h
@@ -75,6 +75,7 @@
void onRename(RenameParams &Parames) override;
void onHover(TextDocumentPositionParams &Params) override;
void onChangeConfiguration(DidChangeConfigurationParams &Params) override;
+ void onCancelRequest(CancelParams &Params) override;
std::vector<Fix> getFixes(StringRef File, const clangd::Diagnostic &D);
@@ -167,8 +168,20 @@
// the worker thread that may otherwise run an async callback on partially
// destructed instance of ClangdLSPServer.
ClangdServer Server;
-};
+ // Holds task handles for running requets. Key of the map is a serialized
+ // request id.
+ llvm::StringMap<TaskHandle> TaskHandles;
+ std::mutex TaskHandlesMutex;
+
+ // Following two functions are for managing TaskHandles map. They store or
+ // remove a task handle for the request-id stored in current Context.
+ // FIXME(kadircet): Wrap the following two functions in a RAII object to make
+ // sure these do not get misused. The object might be stored in the Context of
+ // the thread or moved around until a reply is generated for the request.
+ void CleanupTaskHandle();
+ void StoreTaskHandle(TaskHandle TH);
+};
} // namespace clangd
} // namespace clang
Index: clangd/ClangdLSPServer.cpp
===================================================================
--- clangd/ClangdLSPServer.cpp
+++ clangd/ClangdLSPServer.cpp
@@ -8,10 +8,12 @@
//===----------------------------------------------------------------------===//
#include "ClangdLSPServer.h"
+#include "Cancellation.h"
#include "Diagnostics.h"
#include "JSONRPCDispatcher.h"
#include "SourceCode.h"
#include "URI.h"
+#include "llvm/ADT/ScopeExit.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/Path.h"
@@ -69,6 +71,11 @@
return Defaults;
}
+std::string NormalizeRequestID(const json::Value &ID) {
+ CancelParams CP;
+ fromJSON(json::Object{{"id", ID}}, CP);
+ return CP.ID;
+}
} // namespace
void ClangdLSPServer::onInitialize(InitializeParams &Params) {
@@ -337,17 +344,20 @@
}
void ClangdLSPServer::onCompletion(TextDocumentPositionParams &Params) {
- Server.codeComplete(Params.textDocument.uri.file(), Params.position, CCOpts,
- [this](llvm::Expected<CodeCompleteResult> List) {
- if (!List)
- return replyError(ErrorCode::InvalidParams,
- llvm::toString(List.takeError()));
- CompletionList LSPList;
- LSPList.isIncomplete = List->HasMore;
- for (const auto &R : List->Completions)
- LSPList.items.push_back(R.render(CCOpts));
- reply(std::move(LSPList));
- });
+ TaskHandle TH = Server.codeComplete(
+ Params.textDocument.uri.file(), Params.position, CCOpts,
+ [this](llvm::Expected<CodeCompleteResult> List) {
+ auto _ = llvm::make_scope_exit([this]() { CleanupTaskHandle(); });
+
+ if (!List)
+ return replyError(List.takeError());
+ CompletionList LSPList;
+ LSPList.isIncomplete = List->HasMore;
+ for (const auto &R : List->Completions)
+ LSPList.items.push_back(R.render(CCOpts));
+ return reply(std::move(LSPList));
+ });
+ StoreTaskHandle(std::move(TH));
}
void ClangdLSPServer::onSignatureHelp(TextDocumentPositionParams &Params) {
@@ -362,14 +372,14 @@
}
void ClangdLSPServer::onGoToDefinition(TextDocumentPositionParams &Params) {
- Server.findDefinitions(
- Params.textDocument.uri.file(), Params.position,
- [](llvm::Expected<std::vector<Location>> Items) {
- if (!Items)
- return replyError(ErrorCode::InvalidParams,
- llvm::toString(Items.takeError()));
- reply(json::Array(*Items));
- });
+ Server.findDefinitions(Params.textDocument.uri.file(), Params.position,
+ [](llvm::Expected<std::vector<Location>> Items) {
+ if (!Items)
+ return replyError(
+ ErrorCode::InvalidParams,
+ llvm::toString(Items.takeError()));
+ reply(json::Array(*Items));
+ });
}
void ClangdLSPServer::onSwitchSourceHeader(TextDocumentIdentifier &Params) {
@@ -604,3 +614,31 @@
return *CachingCDB;
return *CDB;
}
+
+void ClangdLSPServer::onCancelRequest(CancelParams &Params) {
+ std::lock_guard<std::mutex> Lock(TaskHandlesMutex);
+ const auto &it = TaskHandles.find(Params.ID);
+ if (it != TaskHandles.end()) {
+ it->second.cancel();
+ TaskHandles.erase(it);
+ }
+}
+
+void ClangdLSPServer::CleanupTaskHandle() {
+ const json::Value *ID = getRequestId();
+ if (!ID)
+ return;
+ std::string NormalizedID = NormalizeRequestID(*ID);
+ std::lock_guard<std::mutex> Lock(TaskHandlesMutex);
+ TaskHandles.erase(NormalizedID);
+}
+
+void ClangdLSPServer::StoreTaskHandle(TaskHandle TH) {
+ const json::Value *ID = getRequestId();
+ if (!ID)
+ return;
+ std::string NormalizedID = NormalizeRequestID(*ID);
+ std::lock_guard<std::mutex> Lock(TaskHandlesMutex);
+ if (!TaskHandles.insert({NormalizedID, std::move(TH)}).second)
+ elog("Insertion of TaskHandle for request: {0} failed.", NormalizedID);
+}
Index: clangd/Cancellation.h
===================================================================
--- /dev/null
+++ clangd/Cancellation.h
@@ -0,0 +1,154 @@
+//===--- Cancellation.h -------------------------------------------*-C++-*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// Cancellation mechanism for async tasks. Roughly all the clients of this code
+// can be classified into three categories:
+// 1. The code that creates and schedules async tasks, e.g. TUScheduler.
+// 2. The callers of the async method that can cancel some of the running tasks,
+// e.g. `ClangdLSPServer`
+// 3. The code running inside the async task itself, i.e. code completion or
+// find definition implementation that run clang, etc.
+//
+// For (1), the guideline is to accept a callback for the result of async
+// operation and return a `TaskHandle` to allow cancelling the request.
+//
+// TaskHandle someAsyncMethod(Task T,
+// function<void(llvm::Expected<ResultType>)> Callback) {
+// // Make sure TaskHandler is created before starting the thread. Otherwise
+// // CancellationToken might not get copied into thread.
+// auto TH = TaskHandle::create();
+// auto run = [](TaskHandle TH){
+// WithContext ContextWithCancellationToken(std::move(TH));
+// Callback(T());
+// }
+// // Start run() in a new thread. You should bind TH.clone() to run since
+// // TaskHandle doesn't allow implicit copies.
+// return TH;
+// }
+//
+// The callers of async methods (2) can issue cancellations and should be
+// prepared to handle `TaskCancelledError` result:
+//
+// void Caller() {
+// // You should store this handle if you wanna cancel the task later on.
+// TaskHandle TH = someAsyncMethod(Task, [](llvm::Expected<ResultType> R) {
+// if(/*check for task cancellation error*/)
+// // Handle the error
+// // Do other things on R.
+// });
+// // To cancel the task:
+// sleep(5);
+// TH.cancel();
+// }
+//
+// The worker code itself (3) should check for cancellations using
+// `CancellationToken` that can be retrieved via
+// `CancellationToken::isCancelled()`.
+//
+// llvm::Expected<ResultType> Task() {
+// // You can either store the read only token by calling hasCancelled once
+// // and just use the variable everytime you want to check for cancellation,
+// // or call hasCancelled everytime. The former is more efficient if you are
+// // going to have multiple checks.
+// const auto CT = CancellationHandler::hasCancelled();
+// // DO SMTHNG...
+// if(CT) {
+// // Task has been cancelled, lets get out.
+// return llvm::makeError<CancelledError>();
+// }
+// // DO SOME MORE THING...
+// if(CT) {
+// // Task has been cancelled, lets get out.
+// return llvm::makeError<CancelledError>();
+// }
+// return ResultType(...);
+// }
+// If the operation was cancelled before task could run to completion, it should
+// propagate the TaskCancelledError as a result.
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_CANCELLATION_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_CANCELLATION_H
+
+#include "Context.h"
+#include "llvm/Support/Error.h"
+#include <atomic>
+#include <memory>
+#include <system_error>
+
+namespace clang {
+namespace clangd {
+
+/// Enables async tasks to check for cancellation signal, contains a read only
+/// token cached from context. Tokens for the currently running task can be
+/// obtained via clangd::getCurrentCancellationToken. It is thread-safe,
+/// multiple threads can check for cancellation on the same token.
+///
+/// If cancellation checks are rare, one could use the isCancelled() helper in
+/// the namespace to simplify the code. However, if cancellation checks are
+/// frequent, the guideline is first obtain the CancellationToken for the
+/// currently running task with getCurrentCancellationToken() and do cancel
+/// checks using it to avoid extra lookups in the Context.
+class CancellationToken {
+public:
+ bool isCancelled() const { return Token ? Token->load() : false; }
+ friend class TaskHandle;
+ operator bool() const { return isCancelled(); }
+
+ CancellationToken(const CancellationToken &) = delete;
+ CancellationToken &operator=(const CancellationToken &) = delete;
+ CancellationToken(CancellationToken &&) = default;
+ CancellationToken &operator=(CancellationToken &&) = default;
+
+private:
+ CancellationToken(const std::shared_ptr<const std::atomic<bool>> Token)
+ : Token(Token) {}
+
+ std::shared_ptr<const std::atomic<bool>> Token;
+};
+
+/// Enables signalling a cancellation on an async task. It is thread-safe to
+/// trigger cancellation from multiple threads or create cancellation tokens.
+class TaskHandle {
+public:
+ void cancel();
+ static TaskHandle create();
+ CancellationToken createCancellationToken() const;
+
+ TaskHandle(const TaskHandle &) = delete;
+ TaskHandle &operator=(const TaskHandle &) = delete;
+ TaskHandle(TaskHandle &&) = default;
+ TaskHandle &operator=(TaskHandle &&) = default;
+
+private:
+ TaskHandle() : CT(std::make_shared<std::atomic<bool>>()) {}
+ TaskHandle(std::shared_ptr<std::atomic<bool>> CT) : CT(std::move(CT)) {}
+ std::shared_ptr<std::atomic<bool>> CT;
+};
+
+const CancellationToken &getCurrentCancellationToken();
+LLVM_NODISCARD Context setCurrentCancellationToken(CancellationToken TH);
+inline bool isCancelled() {
+ return getCurrentCancellationToken().isCancelled();
+}
+
+class CancelledError : public llvm::ErrorInfo<CancelledError> {
+public:
+ static char ID;
+
+ void log(llvm::raw_ostream &OS) const override {
+ OS << "Task was cancelled.";
+ }
+ std::error_code convertToErrorCode() const override {
+ return std::make_error_code(std::errc::operation_canceled);
+ }
+};
+
+} // namespace clangd
+} // namespace clang
+
+#endif
Index: clangd/Cancellation.cpp
===================================================================
--- /dev/null
+++ clangd/Cancellation.cpp
@@ -0,0 +1,39 @@
+//===--- Cancellation.cpp -----------------------------------------*-C++-*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Cancellation.h"
+#include <atomic>
+
+namespace clang {
+namespace clangd {
+
+namespace {
+static Key<CancellationToken> CancellationTokenKey;
+} // namespace
+
+char CancelledError::ID = 0;
+
+const CancellationToken &getCurrentCancellationToken() {
+ return Context::current().getExisting(CancellationTokenKey);
+}
+
+Context setCurrentCancellationToken(CancellationToken CT) {
+ return Context::current().derive(CancellationTokenKey, std::move(CT));
+}
+
+void TaskHandle::cancel() { *CT = true; }
+
+TaskHandle TaskHandle::create() { return TaskHandle(); }
+
+CancellationToken TaskHandle::createCancellationToken() const {
+ return CancellationToken(CT);
+}
+
+} // namespace clangd
+} // namespace clang
Index: clangd/CMakeLists.txt
===================================================================
--- clangd/CMakeLists.txt
+++ clangd/CMakeLists.txt
@@ -9,6 +9,7 @@
add_clang_library(clangDaemon
AST.cpp
+ Cancellation.cpp
ClangdLSPServer.cpp
ClangdServer.cpp
ClangdUnit.cpp
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