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/*
* Copyright 2019 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 "rtc_base/synchronization/sequence_checker.h"
#if defined(WEBRTC_MAC)
#include <dispatch/dispatch.h>
#endif
#include "rtc_base/strings/string_builder.h"
namespace webrtc {
namespace {
// On Mac, returns the label of the current dispatch queue; elsewhere, return
// null.
const void* GetSystemQueueRef() {
#if defined(WEBRTC_MAC)
return dispatch_queue_get_label(DISPATCH_CURRENT_QUEUE_LABEL);
#else
return nullptr;
#endif
}
} // namespace
std::string ExpectationToString(const webrtc::SequenceChecker* checker) {
#if RTC_DCHECK_IS_ON
return checker->ExpectationToString();
#endif
return std::string();
}
SequenceCheckerImpl::SequenceCheckerImpl()
: attached_(true),
valid_thread_(rtc::CurrentThreadRef()),
valid_queue_(TaskQueueBase::Current()),
valid_system_queue_(GetSystemQueueRef()) {}
SequenceCheckerImpl::~SequenceCheckerImpl() = default;
bool SequenceCheckerImpl::IsCurrent() const {
const TaskQueueBase* const current_queue = TaskQueueBase::Current();
const rtc::PlatformThreadRef current_thread = rtc::CurrentThreadRef();
const void* const current_system_queue = GetSystemQueueRef();
MutexLock scoped_lock(&lock_);
if (!attached_) { // Previously detached.
attached_ = true;
valid_thread_ = current_thread;
valid_queue_ = current_queue;
valid_system_queue_ = current_system_queue;
return true;
}
if (valid_queue_ || current_queue) {
return valid_queue_ == current_queue;
}
if (valid_system_queue_ && valid_system_queue_ == current_system_queue) {
return true;
}
return rtc::IsThreadRefEqual(valid_thread_, current_thread);
}
void SequenceCheckerImpl::Detach() {
MutexLock scoped_lock(&lock_);
attached_ = false;
// We don't need to touch the other members here, they will be
// reset on the next call to IsCurrent().
}
#if RTC_DCHECK_IS_ON
std::string SequenceCheckerImpl::ExpectationToString() const {
const TaskQueueBase* const current_queue = TaskQueueBase::Current();
const rtc::PlatformThreadRef current_thread = rtc::CurrentThreadRef();
const void* const current_system_queue = GetSystemQueueRef();
MutexLock scoped_lock(&lock_);
if (!attached_)
return "Checker currently not attached.";
// The format of the string is meant to compliment the one we have inside of
// FatalLog() (checks.cc). Example:
//
// # Expected: TQ: 0x0 SysQ: 0x7fff69541330 Thread: 0x11dcf6dc0
// # Actual: TQ: 0x7fa8f0604190 SysQ: 0x7fa8f0604a30 Thread: 0x700006f1a000
// TaskQueue doesn't match
rtc::StringBuilder message;
message.AppendFormat(
"# Expected: TQ: %p SysQ: %p Thread: %p\n"
"# Actual: TQ: %p SysQ: %p Thread: %p\n",
valid_queue_, valid_system_queue_,
reinterpret_cast<const void*>(valid_thread_), current_queue,
current_system_queue, reinterpret_cast<const void*>(current_thread));
if ((valid_queue_ || current_queue) && valid_queue_ != current_queue) {
message << "TaskQueue doesn't match\n";
} else if (valid_system_queue_ &&
valid_system_queue_ != current_system_queue) {
message << "System queue doesn't match\n";
} else if (!rtc::IsThreadRefEqual(valid_thread_, current_thread)) {
message << "Threads don't match\n";
}
return message.Release();
}
#endif // RTC_DCHECK_IS_ON
} // namespace webrtc
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