[clangd] Initial cancellation mechanism for LSP requests.

Reviewers: ilya-biryukov, ioeric, hokein

Reviewed By: ilya-biryukov

Subscribers: mgorny, ioeric, MaskRay, jkorous, arphaman, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D50502

llvm-svn: 340607

1 files changed, 74 insertions, 0 deletions

diff --git a/clang-tools-extra/unittests/clangd/CancellationTests.cpp b/clang-tools-extra/unittests/clangd/CancellationTests.cpp
new file mode 100644
index 00000000000..7afd1086ac7
--- /dev/null
+++ b/clang-tools-extra/unittests/clangd/CancellationTests.cpp
@@ -0,0 +1,74 @@
+#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 = Task::createHandle();
+  WithContext ContextWithCancellation(setCurrentTask(TH));
+  EXPECT_FALSE(isCancelled());
+  TH->cancel();
+  EXPECT_TRUE(isCancelled());
+}
+
+TEST(CancellationTest, TaskTestHandleDiesContextLives) {
+  llvm::Optional<WithContext> ContextWithCancellation;
+  {
+    TaskHandle TH = Task::createHandle();
+    ContextWithCancellation.emplace(setCurrentTask(TH));
+    EXPECT_FALSE(isCancelled());
+    TH->cancel();
+    EXPECT_TRUE(isCancelled());
+  }
+  EXPECT_TRUE(isCancelled());
+}
+
+TEST(CancellationTest, TaskContextDiesHandleLives) {
+  TaskHandle TH = Task::createHandle();
+  {
+    WithContext ContextWithCancellation(setCurrentTask(TH));
+    EXPECT_FALSE(isCancelled());
+    TH->cancel();
+    EXPECT_TRUE(isCancelled());
+  }
+  // Still should be able to cancel without any problems.
+  TH->cancel();
+}
+
+TEST(CancellationTest, CancellationToken) {
+  TaskHandle TH = Task::createHandle();
+  WithContext ContextWithCancellation(setCurrentTask(TH));
+  const auto &CT = getCurrentTask();
+  EXPECT_FALSE(CT.isCancelled());
+  TH->cancel();
+  EXPECT_TRUE(CT.isCancelled());
+}
+
+TEST(CancellationTest, AsynCancellationTest) {
+  std::atomic<bool> HasCancelled(false);
+  Notification Cancelled;
+  auto TaskToBeCancelled = [&](ConstTaskHandle CT) {
+    WithContext ContextGuard(setCurrentTask(std::move(CT)));
+    Cancelled.wait();
+    HasCancelled = isCancelled();
+  };
+  TaskHandle TH = Task::createHandle();
+  std::thread AsyncTask(TaskToBeCancelled, TH);
+  TH->cancel();
+  Cancelled.notify();
+  AsyncTask.join();
+
+  EXPECT_TRUE(HasCancelled);
+}
+} // namespace
+} // namespace clangd
+} // namespace clang