73 lines
2.5 KiB
C++
73 lines
2.5 KiB
C++
/*
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* Copyright (C) 2020 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_MEDIA_SAMPLE_QUEUE_H
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#define ANDROID_MEDIA_SAMPLE_QUEUE_H
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#include <media/MediaSample.h>
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#include <utils/Mutex.h>
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#include <memory>
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#include <mutex>
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#include <queue>
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namespace android {
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/**
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* MediaSampleQueue asynchronously connects a producer and a consumer of media samples.
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* Media samples flows through the queue in FIFO order. If the queue is empty the consumer will be
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* blocked until a new media sample is added or until the producer aborts the queue operation.
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*/
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class MediaSampleQueue {
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public:
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/**
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* Enqueues a media sample at the end of the queue and notifies potentially waiting consumers.
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* If the queue has previously been aborted this method does nothing.
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* @param sample The media sample to enqueue.
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* @return True if the queue has been aborted.
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*/
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bool enqueue(const std::shared_ptr<MediaSample>& sample);
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/**
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* Removes the next media sample from the queue and returns it. If the queue has previously been
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* aborted this method returns null. Note that this method will block while the queue is empty.
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* @param[out] sample The next media sample in the queue.
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* @return True if the queue has been aborted.
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*/
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bool dequeue(std::shared_ptr<MediaSample>* sample /* nonnull */);
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/**
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* Checks if the queue currently holds any media samples.
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* @return True if the queue is empty or has been aborted. False otherwise.
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*/
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bool isEmpty();
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/**
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* Aborts the queue operation. This clears the queue and notifies waiting consumers. After the
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* has been aborted it is not possible to enqueue more samples, and dequeue will return null.
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*/
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void abort();
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private:
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std::queue<std::shared_ptr<MediaSample>> mSampleQueue GUARDED_BY(mMutex);
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std::mutex mMutex;
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std::condition_variable mCondition;
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bool mAborted GUARDED_BY(mMutex) = false;
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};
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} // namespace android
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#endif // ANDROID_MEDIA_SAMPLE_QUEUE_H
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