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/*
* Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef WEBRTC_TEST_SINGLE_THREADED_TASK_QUEUE_H_
#define WEBRTC_TEST_SINGLE_THREADED_TASK_QUEUE_H_
#include <functional>
#include <list>
#include <memory>
#include "webrtc/rtc_base/criticalsection.h"
#include "webrtc/rtc_base/event.h"
#include "webrtc/rtc_base/platform_thread.h"
#include "webrtc/rtc_base/thread_checker.h"
namespace webrtc {
namespace test {
// This class gives capabilities similar to rtc::TaskQueue, but ensures
// everything happens on the same thread. This is intended to make the
// threading model of unit-tests (specifically end-to-end tests) more closely
// resemble that of real WebRTC, thereby allowing us to replace some critical
// sections by thread-checkers.
// This task is NOT tuned for performance, but rather for simplicity.
class SingleThreadedTaskQueueForTesting {
public:
using Task = std::function<void()>;
using TaskId = size_t;
explicit SingleThreadedTaskQueueForTesting(const char* name);
~SingleThreadedTaskQueueForTesting();
// Sends one task to the task-queue, and returns a handle by which the
// task can be cancelled.
// This mimics the behavior of TaskQueue, but only for lambdas, rather than
// for both lambdas and QueuedTask objects.
TaskId PostTask(Task task);
// Same as PostTask(), but ensures that the task will not begin execution
// less than |delay_ms| milliseconds after being posted; an upper bound
// is not provided.
TaskId PostDelayedTask(Task task, int64_t delay_ms);
// Send one task to the queue. The function does not return until the task
// has finished executing. No support for canceling the task.
void SendTask(Task task);
// Given an identifier to the task, attempts to eject it from the queue.
// Returns true if the task was found and cancelled. Failure possible
// only for invalid task IDs, or for tasks which have already been executed.
bool CancelTask(TaskId task_id);
private:
struct QueuedTask {
QueuedTask(TaskId task_id, int64_t earliest_execution_time, Task task);
~QueuedTask();
TaskId task_id;
int64_t earliest_execution_time;
Task task;
};
static void Run(void* obj);
void RunLoop();
rtc::CriticalSection cs_;
std::list<std::unique_ptr<QueuedTask>> tasks_ RTC_GUARDED_BY(cs_);
rtc::ThreadChecker owner_thread_checker_;
rtc::PlatformThread thread_;
bool running_ RTC_GUARDED_BY(cs_);
TaskId next_task_id_;
// The task-queue will sleep when not executing a task. Wake up occurs when:
// * Upon destruction, to make sure that the |thead_| terminates, so that it
// may be joined. [Event will be set.]
// * New task added. Because we optimize for simplicity rahter than for
// performance (this class is a testing facility only), waking up occurs
// when we get a new task even if it is scheduled with a delay. The RunLoop
// is in charge of sending itself back to sleep if the next task is only
// to be executed at a later time. [Event will be set.]
// * When the next task in the queue is a delayed-task, and the time for
// its execution has come. [Event will time-out.]
rtc::Event wake_up_;
};
} // namespace test
} // namespace webrtc
#endif // WEBRTC_TEST_SINGLE_THREADED_TASK_QUEUE_H_