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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.
#include "content/browser/renderer_host/media/audio_sync_reader.h"
#include <algorithm>
#include "base/process_util.h"
#include "base/shared_memory.h"
#include "base/threading/platform_thread.h"
#include "media/audio/audio_buffers_state.h"
#include "media/audio/audio_util.h"
const int kMinIntervalBetweenReadCallsInMs = 10;
AudioSyncReader::AudioSyncReader(base::SharedMemory* shared_memory)
: shared_memory_(shared_memory) {
}
AudioSyncReader::~AudioSyncReader() {
}
bool AudioSyncReader::DataReady() {
return !media::IsUnknownDataSize(
shared_memory_,
media::PacketSizeSizeInBytes(shared_memory_->created_size()));
}
// media::AudioOutputController::SyncReader implementations.
void AudioSyncReader::UpdatePendingBytes(uint32 bytes) {
if (bytes != static_cast<uint32>(media::AudioOutputController::kPauseMark)) {
// Store unknown length of data into buffer, so we later
// can find out if data became available.
media::SetUnknownDataSize(
shared_memory_,
media::PacketSizeSizeInBytes(shared_memory_->created_size()));
}
base::AutoLock auto_lock(lock_);
if (socket_.get()) {
socket_->Send(&bytes, sizeof(bytes));
}
}
uint32 AudioSyncReader::Read(void* data, uint32 size) {
uint32 max_size = media::PacketSizeSizeInBytes(
shared_memory_->created_size());
#if defined(OS_WIN)
// HACK: yield if reader is called too often.
// Problem is lack of synchronization between host and renderer. We cannot be
// sure if renderer already filled the buffer, and due to all the plugins we
// cannot change the API, so we yield if previous call was too recent.
// Optimization: if renderer is "new" one that writes length of data we can
// stop yielding the moment length is written -- not ideal solution,
// but better than nothing.
while (!DataReady() &&
((base::Time::Now() - previous_call_time_).InMilliseconds() <
kMinIntervalBetweenReadCallsInMs)) {
base::PlatformThread::YieldCurrentThread();
}
previous_call_time_ = base::Time::Now();
#endif
uint32 read_size = std::min(media::GetActualDataSizeInBytes(shared_memory_,
max_size),
size);
// Get the data from the buffer.
memcpy(data, shared_memory_->memory(), read_size);
// If amount read was less than requested, then zero out the remainder.
if (read_size < size)
memset(static_cast<char*>(data) + read_size, 0, size - read_size);
// Zero out the entire buffer.
memset(shared_memory_->memory(), 0, max_size);
// Store unknown length of data into buffer, in case renderer does not store
// the length itself. It also helps in decision if we need to yield.
media::SetUnknownDataSize(shared_memory_, max_size);
return read_size;
}
void AudioSyncReader::Close() {
base::AutoLock auto_lock(lock_);
if (socket_.get()) {
socket_->Close();
socket_.reset(NULL);
}
}
bool AudioSyncReader::Init() {
socket_.reset(new base::SyncSocket());
foreign_socket_.reset(new base::SyncSocket());
return base::SyncSocket::CreatePair(socket_.get(), foreign_socket_.get());
}
#if defined(OS_WIN)
bool AudioSyncReader::PrepareForeignSocketHandle(
base::ProcessHandle process_handle,
base::SyncSocket::Handle* foreign_handle) {
::DuplicateHandle(GetCurrentProcess(), foreign_socket_->handle(),
process_handle, foreign_handle,
0, FALSE, DUPLICATE_SAME_ACCESS);
if (*foreign_handle != 0)
return true;
return false;
}
#else
bool AudioSyncReader::PrepareForeignSocketHandle(
base::ProcessHandle process_handle,
base::FileDescriptor* foreign_handle) {
foreign_handle->fd = foreign_socket_->handle();
foreign_handle->auto_close = false;
if (foreign_handle->fd != -1)
return true;
return false;
}
#endif
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