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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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.
*/
#ifndef ANDROID_HIDL_TASK_RUNNER_H
#define ANDROID_HIDL_TASK_RUNNER_H
#include <memory>
#include <thread>
namespace android {
namespace hardware {
namespace details {
using Task = std::function<void(void)>;
template <typename T>
struct SynchronizedQueue;
/*
* A background infinite loop that runs the Tasks push()'ed.
* Equivalent to a simple single-threaded Looper.
*/
class TaskRunner {
public:
/* Create an empty task runner. Nothing will be done until start() is called. */
TaskRunner();
/*
* Notify the background thread to terminate and return immediately.
* Tasks in the queue will continue to be done sequentially in background
* until all tasks are finished.
*/
~TaskRunner();
/*
* Sets the queue limit. Fails the push operation once the limit is reached.
* This function is named start for legacy reasons and to maintain ABI
* stability, but the underlying thread running tasks isn't started until
* the first task is pushed.
*/
void start(size_t limit);
/*
* Add a task. Return true if successful, false if
* the queue's size exceeds limit or t doesn't contain a callable target.
*/
bool push(const Task &t);
private:
std::shared_ptr<SynchronizedQueue<Task>> mQueue;
};
} // namespace details
} // namespace hardware
} // namespace android
#endif // ANDROID_HIDL_TASK_RUNNER_H