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/*
* Copyright (c) 2013 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.
*/
#include "webrtc/modules/audio_device/android/low_latency_event.h"
#include <assert.h>
#define HANDLE_EINTR(x) ({ \
typeof(x) eintr_wrapper_result; \
do { \
eintr_wrapper_result = (x); \
} while (eintr_wrapper_result == -1 && errno == EINTR); \
eintr_wrapper_result; \
})
#define IGNORE_EINTR(x) ({ \
typeof(x) eintr_wrapper_result; \
do { \
eintr_wrapper_result = (x); \
if (eintr_wrapper_result == -1 && errno == EINTR) { \
eintr_wrapper_result = 0; \
} \
} while (0); \
eintr_wrapper_result; \
})
namespace webrtc {
const LowLatencyEvent::Handle LowLatencyEvent::kInvalidHandle = -1;
const int LowLatencyEvent::kReadHandle = 0;
const int LowLatencyEvent::kWriteHandle = 1;
LowLatencyEvent::LowLatencyEvent() {
handles_[kReadHandle] = kInvalidHandle;
handles_[kWriteHandle] = kInvalidHandle;
}
LowLatencyEvent::~LowLatencyEvent() {
Stop();
}
bool LowLatencyEvent::Start() {
assert(handles_[kReadHandle] == kInvalidHandle);
assert(handles_[kWriteHandle] == kInvalidHandle);
return socketpair(AF_UNIX, SOCK_STREAM, 0, handles_) == 0;
}
bool LowLatencyEvent::Stop() {
bool ret = Close(&handles_[kReadHandle]) && Close(&handles_[kWriteHandle]);
handles_[kReadHandle] = kInvalidHandle;
handles_[kWriteHandle] = kInvalidHandle;
return ret;
}
void LowLatencyEvent::SignalEvent(int event_id, int event_msg) {
WriteFd(event_id, event_msg);
}
void LowLatencyEvent::WaitOnEvent(int* event_id, int* event_msg) {
ReadFd(event_id, event_msg);
}
bool LowLatencyEvent::Close(Handle* handle) {
if (*handle == kInvalidHandle) {
return false;
}
int retval = IGNORE_EINTR(close(*handle));
*handle = kInvalidHandle;
return retval == 0;
}
void LowLatencyEvent::WriteFd(int message_id, int message) {
char buffer[sizeof(message_id) + sizeof(message)];
size_t bytes = sizeof(buffer);
memcpy(buffer, &message_id, sizeof(message_id));
memcpy(&buffer[sizeof(message_id)], &message, sizeof(message));
ssize_t bytes_written = HANDLE_EINTR(write(handles_[kWriteHandle], buffer,
bytes));
if (bytes_written != static_cast<ssize_t>(bytes)) {
assert(false);
}
}
void LowLatencyEvent::ReadFd(int* message_id, int* message) {
char buffer[sizeof(message_id) + sizeof(message)];
size_t bytes = sizeof(buffer);
ssize_t bytes_read = HANDLE_EINTR(read(handles_[kReadHandle], buffer, bytes));
if (bytes_read == 0) {
*message_id = 0;
*message = 0;
return;
} else if (bytes_read == static_cast<ssize_t>(bytes)) {
memcpy(message_id, buffer, sizeof(*message_id));
memcpy(message, &buffer[sizeof(*message_id)], sizeof(*message));
} else {
assert(false);
}
}
} // namespace webrtc
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