Create WorkerThread, an abstraction to perform some work on an interval.

util/thread/worker_thread_test.cc

+// Copyright 2015 The Crashpad Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "util/thread/worker_thread.h"
+
+#include "gtest/gtest.h"
+#include "util/misc/clock.h"
+#include "util/synchronization/semaphore.h"
+
+namespace crashpad {
+namespace test {
+namespace {
+
+const uint64_t kNanosecondsPerSecond = 1E9;
+
+class WorkDelegate : public WorkerThread::Delegate {
+ public:
+  WorkDelegate() {}
+  ~WorkDelegate() {}
+
+  void DoWork(const WorkerThread* thread) override {
+    if (++work_count_ == waiting_for_count_)
+      semaphore_.Signal();
+  }
+
+  //! \brief Suspends the calling thread until the DoWork() has been called
+  //!     the specified number of times.
+  void WaitForWorkCount(int times) {
+    waiting_for_count_ = times;
+    semaphore_.Wait();
+  }
+
+  int work_count() const { return work_count_; }
+
+ private:
+  Semaphore semaphore_{0};
+  int work_count_ = 0;
+  int waiting_for_count_ = -1;
+
+  DISALLOW_COPY_AND_ASSIGN(WorkDelegate);
+};
+
+TEST(WorkerThread, DoWork) {
+  WorkDelegate delegate;
+  WorkerThread thread(0.05, &delegate);
+
+  uint64_t start = ClockMonotonicNanoseconds();
+  thread.Start(0);
+  EXPECT_TRUE(thread.is_running());
+
+  delegate.WaitForWorkCount(2);
+  thread.Stop();
+  EXPECT_FALSE(thread.is_running());
+
+  EXPECT_GE(1 * kNanosecondsPerSecond, ClockMonotonicNanoseconds() - start);
+}
+
+TEST(WorkerThread, StopBeforeDoWork) {
+  WorkDelegate delegate;
+  WorkerThread thread(1, &delegate);
+
+  thread.Start(15);
+  thread.Stop();
+
+  EXPECT_EQ(0, delegate.work_count());
+}
+
+TEST(WorkerThread, Restart) {
+  WorkDelegate delegate;
+  WorkerThread thread(0.05, &delegate);
+
+  thread.Start(0);
+  EXPECT_TRUE(thread.is_running());
+
+  delegate.WaitForWorkCount(1);
+  thread.Stop();
+  ASSERT_FALSE(thread.is_running());
+
+  thread.Start(0);
+  delegate.WaitForWorkCount(2);
+  thread.Stop();
+  ASSERT_FALSE(thread.is_running());
+}
+
+TEST(WorkerThread, DoWorkNow) {
+  WorkDelegate delegate;
+  WorkerThread thread(100, &delegate);
+
+  thread.Start(0);
+  EXPECT_TRUE(thread.is_running());
+
+  uint64_t start = ClockMonotonicNanoseconds();
+
+  delegate.WaitForWorkCount(1);
+  EXPECT_EQ(1, delegate.work_count());
+
+  thread.DoWorkNow();
+  delegate.WaitForWorkCount(2);
+  thread.Stop();
+  EXPECT_EQ(2, delegate.work_count());
+
+  EXPECT_GE(100 * kNanosecondsPerSecond, ClockMonotonicNanoseconds() - start);
+}
+
+TEST(WorkerThread, DoWorkNowAtStart) {
+  WorkDelegate delegate;
+  WorkerThread thread(100, &delegate);
+
+  uint64_t start = ClockMonotonicNanoseconds();
+
+  thread.Start(100);
+  EXPECT_TRUE(thread.is_running());
+
+  thread.DoWorkNow();
+  delegate.WaitForWorkCount(1);
+  EXPECT_EQ(1, delegate.work_count());
+
+  EXPECT_GE(100 * kNanosecondsPerSecond, ClockMonotonicNanoseconds() - start);
+
+  thread.Stop();
+  EXPECT_FALSE(thread.is_running());
+}
+
+}  // namespace
+}  // namespace test
+}  // namespace crashpad