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/*
* Copyright (c) 2015 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/platform_thread.h"
#if !defined(WEBRTC_WIN)
#include <sched.h>
#endif
#include <stdint.h>
#include <time.h>
#include <algorithm>
#include "rtc_base/checks.h"
namespace rtc {
namespace {
#if !defined(WEBRTC_WIN)
struct ThreadAttributes {
ThreadAttributes() { pthread_attr_init(&attr); }
~ThreadAttributes() { pthread_attr_destroy(&attr); }
pthread_attr_t* operator&() { return &attr; }
pthread_attr_t attr;
};
#endif // defined(WEBRTC_WIN)
} // namespace
PlatformThread::PlatformThread(ThreadRunFunction func,
void* obj,
absl::string_view thread_name,
ThreadPriority priority /*= kNormalPriority*/)
: run_function_(func), priority_(priority), obj_(obj), name_(thread_name) {
RTC_DCHECK(func);
RTC_DCHECK(!name_.empty());
// TODO(tommi): Consider lowering the limit to 15 (limit on Linux).
RTC_DCHECK(name_.length() < 64);
spawned_thread_checker_.Detach();
}
PlatformThread::~PlatformThread() {
RTC_DCHECK(thread_checker_.IsCurrent());
#if defined(WEBRTC_WIN)
RTC_DCHECK(!thread_);
RTC_DCHECK(!thread_id_);
#endif // defined(WEBRTC_WIN)
}
#if defined(WEBRTC_WIN)
DWORD WINAPI PlatformThread::StartThread(void* param) {
// The GetLastError() function only returns valid results when it is called
// after a Win32 API function that returns a "failed" result. A crash dump
// contains the result from GetLastError() and to make sure it does not
// falsely report a Windows error we call SetLastError here.
::SetLastError(ERROR_SUCCESS);
static_cast<PlatformThread*>(param)->Run();
return 0;
}
#else
void* PlatformThread::StartThread(void* param) {
static_cast<PlatformThread*>(param)->Run();
return 0;
}
#endif // defined(WEBRTC_WIN)
void PlatformThread::Start() {
RTC_DCHECK(thread_checker_.IsCurrent());
RTC_DCHECK(!thread_) << "Thread already started?";
#if defined(WEBRTC_WIN)
// See bug 2902 for background on STACK_SIZE_PARAM_IS_A_RESERVATION.
// Set the reserved stack stack size to 1M, which is the default on Windows
// and Linux.
thread_ = ::CreateThread(nullptr, 1024 * 1024, &StartThread, this,
STACK_SIZE_PARAM_IS_A_RESERVATION, &thread_id_);
RTC_CHECK(thread_) << "CreateThread failed";
RTC_DCHECK(thread_id_);
#else
ThreadAttributes attr;
// Set the stack stack size to 1M.
pthread_attr_setstacksize(&attr, 1024 * 1024);
RTC_CHECK_EQ(0, pthread_create(&thread_, &attr, &StartThread, this));
#endif // defined(WEBRTC_WIN)
}
bool PlatformThread::IsRunning() const {
RTC_DCHECK(thread_checker_.IsCurrent());
#if defined(WEBRTC_WIN)
return thread_ != nullptr;
#else
return thread_ != 0;
#endif // defined(WEBRTC_WIN)
}
PlatformThreadRef PlatformThread::GetThreadRef() const {
#if defined(WEBRTC_WIN)
return thread_id_;
#else
return thread_;
#endif // defined(WEBRTC_WIN)
}
void PlatformThread::Stop() {
RTC_DCHECK(thread_checker_.IsCurrent());
if (!IsRunning())
return;
#if defined(WEBRTC_WIN)
WaitForSingleObject(thread_, INFINITE);
CloseHandle(thread_);
thread_ = nullptr;
thread_id_ = 0;
#else
RTC_CHECK_EQ(0, pthread_join(thread_, nullptr));
thread_ = 0;
#endif // defined(WEBRTC_WIN)
spawned_thread_checker_.Detach();
}
void PlatformThread::Run() {
// Attach the worker thread checker to this thread.
RTC_DCHECK(spawned_thread_checker_.IsCurrent());
rtc::SetCurrentThreadName(name_.c_str());
SetPriority(priority_);
run_function_(obj_);
}
bool PlatformThread::SetPriority(ThreadPriority priority) {
RTC_DCHECK(spawned_thread_checker_.IsCurrent());
#if defined(WEBRTC_WIN)
return SetThreadPriority(thread_, priority) != FALSE;
#elif defined(__native_client__) || defined(WEBRTC_FUCHSIA)
// Setting thread priorities is not supported in NaCl or Fuchsia.
return true;
#elif defined(WEBRTC_CHROMIUM_BUILD) && defined(WEBRTC_LINUX)
// TODO(tommi): Switch to the same mechanism as Chromium uses for changing
// thread priorities.
return true;
#else
const int policy = SCHED_FIFO;
const int min_prio = sched_get_priority_min(policy);
const int max_prio = sched_get_priority_max(policy);
if (min_prio == -1 || max_prio == -1) {
return false;
}
if (max_prio - min_prio <= 2)
return false;
// Convert webrtc priority to system priorities:
sched_param param;
const int top_prio = max_prio - 1;
const int low_prio = min_prio + 1;
switch (priority) {
case kLowPriority:
param.sched_priority = low_prio;
break;
case kNormalPriority:
// The -1 ensures that the kHighPriority is always greater or equal to
// kNormalPriority.
param.sched_priority = (low_prio + top_prio - 1) / 2;
break;
case kHighPriority:
param.sched_priority = std::max(top_prio - 2, low_prio);
break;
case kHighestPriority:
param.sched_priority = std::max(top_prio - 1, low_prio);
break;
case kRealtimePriority:
param.sched_priority = top_prio;
break;
}
return pthread_setschedparam(thread_, policy, ¶m) == 0;
#endif // defined(WEBRTC_WIN)
}
#if defined(WEBRTC_WIN)
bool PlatformThread::QueueAPC(PAPCFUNC function, ULONG_PTR data) {
RTC_DCHECK(thread_checker_.IsCurrent());
RTC_DCHECK(IsRunning());
return QueueUserAPC(function, thread_, data) != FALSE;
}
#endif
} // namespace rtc
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