Repo created

TMessagesProj/jni/voip/webrtc/base/one_shot_event.cc

@@ -0,0 +1,111 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/one_shot_event.h"
+
+#include <stddef.h>
+
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/single_thread_task_runner.h"
+#include "base/task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "base/time/time.h"
+
+namespace base {
+
+struct OneShotEvent::TaskInfo {
+  TaskInfo() {}
+  TaskInfo(const Location& from_here,
+           const scoped_refptr<SingleThreadTaskRunner>& runner,
+           OnceClosure task,
+           const TimeDelta& delay)
+      : from_here(from_here),
+        runner(runner),
+        task(std::move(task)),
+        delay(delay) {
+    CHECK(runner.get());  // Detect mistakes with a decent stack frame.
+  }
+  TaskInfo(TaskInfo&&) = default;
+
+  Location from_here;
+  scoped_refptr<SingleThreadTaskRunner> runner;
+  OnceClosure task;
+  TimeDelta delay;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TaskInfo);
+};
+
+OneShotEvent::OneShotEvent() : signaled_(false) {
+  // It's acceptable to construct the OneShotEvent on one thread, but
+  // immediately move it to another thread.
+  thread_checker_.DetachFromThread();
+}
+OneShotEvent::OneShotEvent(bool signaled) : signaled_(signaled) {
+  thread_checker_.DetachFromThread();
+}
+OneShotEvent::~OneShotEvent() {}
+
+void OneShotEvent::Post(const Location& from_here, OnceClosure task) const {
+  PostImpl(from_here, std::move(task), ThreadTaskRunnerHandle::Get(),
+           TimeDelta());
+}
+
+void OneShotEvent::Post(
+    const Location& from_here,
+    OnceClosure task,
+    const scoped_refptr<SingleThreadTaskRunner>& runner) const {
+  PostImpl(from_here, std::move(task), runner, TimeDelta());
+}
+
+void OneShotEvent::PostDelayed(const Location& from_here,
+                               OnceClosure task,
+                               const TimeDelta& delay) const {
+  PostImpl(from_here, std::move(task), ThreadTaskRunnerHandle::Get(), delay);
+}
+
+void OneShotEvent::Signal() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  CHECK(!signaled_) << "Only call Signal once.";
+
+  signaled_ = true;
+  // After this point, a call to Post() from one of the queued tasks
+  // could proceed immediately, but the fact that this object is
+  // single-threaded prevents that from being relevant.
+
+  // Move tasks to a temporary to ensure no new ones are added.
+  std::vector<TaskInfo> moved_tasks;
+  std::swap(moved_tasks, tasks_);
+
+  // We could randomize tasks in debug mode in order to check that
+  // the order doesn't matter...
+  for (TaskInfo& task : moved_tasks) {
+    if (task.delay.is_zero())
+      task.runner->PostTask(task.from_here, std::move(task.task));
+    else
+      task.runner->PostDelayedTask(task.from_here, std::move(task.task),
+                                   task.delay);
+  }
+  DCHECK(tasks_.empty()) << "No new tasks should be added during task running!";
+}
+
+void OneShotEvent::PostImpl(const Location& from_here,
+                            OnceClosure task,
+                            const scoped_refptr<SingleThreadTaskRunner>& runner,
+                            const TimeDelta& delay) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (is_signaled()) {
+    if (delay.is_zero())
+      runner->PostTask(from_here, std::move(task));
+    else
+      runner->PostDelayedTask(from_here, std::move(task), delay);
+  } else {
+    tasks_.emplace_back(from_here, runner, std::move(task), delay);
+  }
+}
+
+}  // namespace base