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// Copyright (c) 2012 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.
#ifndef SERVICES_AUDIO_SYNC_READER_H_
#define SERVICES_AUDIO_SYNC_READER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <string>
#include "base/callback.h"
#include "base/compiler_specific.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/process/process.h"
#include "base/sync_socket.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "media/base/audio_bus.h"
#include "media/base/audio_latency.h"
#include "services/audio/output_controller.h"
#if defined(OS_POSIX)
#include "base/file_descriptor_posix.h"
#endif
namespace audio {
// An OutputController::SyncReader implementation using SyncSocket. This is used
// by OutputController to provide a low latency data source for transmitting
// audio packets between the Audio Service process and the process where the
// mojo client runs.
class SyncReader : public OutputController::SyncReader {
public:
// Constructor: Creates and maps shared memory; and initializes a SyncSocket
// pipe, assigning the client handle to |foreign_socket|. The caller must
// confirm IsValid() returns true before any other methods are called.
SyncReader(base::RepeatingCallback<void(const std::string&)> log_callback,
const media::AudioParameters& params,
base::CancelableSyncSocket* foreign_socket);
SyncReader(const SyncReader&) = delete;
SyncReader& operator=(const SyncReader&) = delete;
~SyncReader() override;
// Returns true if the SyncReader initialized successfully, and
// TakeSharedMemoryRegion() will return a valid region.
bool IsValid() const;
// Transfers shared memory region ownership to a caller. It shouldn't be
// called more than once.
base::UnsafeSharedMemoryRegion TakeSharedMemoryRegion();
void set_max_wait_timeout_for_test(base::TimeDelta time) {
maximum_wait_time_ = time;
}
// OutputController::SyncReader implementation.
void RequestMoreData(base::TimeDelta delay,
base::TimeTicks delay_timestamp,
int prior_frames_skipped) override;
void Read(media::AudioBus* dest) override;
void Close() override;
private:
// Blocks until data is ready for reading or a timeout expires. Returns false
// if an error or timeout occurs.
bool WaitUntilDataIsReady();
const base::RepeatingCallback<void(const std::string&)> log_callback_;
base::UnsafeSharedMemoryRegion shared_memory_region_;
base::WritableSharedMemoryMapping shared_memory_mapping_;
const media::AudioLatency::LatencyType latency_tag_;
// Mutes all incoming samples. This is used to prevent audible sound
// during automated testing.
const bool mute_audio_for_testing_;
// Denotes that the most recent socket error has been logged. Used to avoid
// log spam.
bool had_socket_error_;
// Socket for transmitting audio data.
base::CancelableSyncSocket socket_;
const uint32_t output_bus_buffer_size_;
// Shared memory wrapper used for transferring audio data to Read() callers.
std::unique_ptr<media::AudioBus> output_bus_;
// Track the number of times the renderer missed its real-time deadline and
// report a UMA stat during destruction.
size_t renderer_callback_count_;
size_t renderer_missed_callback_count_;
size_t trailing_renderer_missed_callback_count_;
// The maximum amount of time to wait for data from the renderer. Calculated
// from the parameters given at construction.
base::TimeDelta maximum_wait_time_;
// The index of the audio buffer we're expecting to be sent from the renderer;
// used to block with timeout for audio data.
uint32_t buffer_index_;
};
} // namespace audio
#endif // SERVICES_AUDIO_SYNC_READER_H_
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