// 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 "base/threading/platform_thread.h"
#include "base/debug/alias.h"
#include "base/debug/profiler.h"
#include "base/logging.h"
#include "base/threading/thread_id_name_manager.h"
#include "base/threading/thread_restrictions.h"
#include "base/tracked_objects.h"
#include "base/win/windows_version.h"
namespace base {
namespace {
// The information on how to set the thread name comes from
// a MSDN article: http://msdn2.microsoft.com/en-us/library/xcb2z8hs.aspx
const DWORD kVCThreadNameException = 0x406D1388;
typedef struct tagTHREADNAME_INFO {
DWORD dwType; // Must be 0x1000.
LPCSTR szName; // Pointer to name (in user addr space).
DWORD dwThreadID; // Thread ID (-1=caller thread).
DWORD dwFlags; // Reserved for future use, must be zero.
} THREADNAME_INFO;
// This function has try handling, so it is separated out of its caller.
void SetNameInternal(PlatformThreadId thread_id, const char* name) {
THREADNAME_INFO info;
info.dwType = 0x1000;
info.szName = name;
info.dwThreadID = thread_id;
info.dwFlags = 0;
__try {
RaiseException(kVCThreadNameException, 0, sizeof(info)/sizeof(DWORD),
reinterpret_cast<DWORD_PTR*>(&info));
} __except(EXCEPTION_CONTINUE_EXECUTION) {
}
}
struct ThreadParams {
PlatformThread::Delegate* delegate;
bool joinable;
};
DWORD __stdcall ThreadFunc(void* params) {
ThreadParams* thread_params = static_cast<ThreadParams*>(params);
PlatformThread::Delegate* delegate = thread_params->delegate;
if (!thread_params->joinable)
base::ThreadRestrictions::SetSingletonAllowed(false);
/* Retrieve a copy of the thread handle to use as the key in the
* thread name mapping. */
PlatformThreadHandle::Handle platform_handle;
DuplicateHandle(
GetCurrentProcess(),
GetCurrentThread(),
GetCurrentProcess(),
&platform_handle,
0,
FALSE,
DUPLICATE_SAME_ACCESS);
ThreadIdNameManager::GetInstance()->RegisterThread(
platform_handle,
PlatformThread::CurrentId());
delete thread_params;
delegate->ThreadMain();
ThreadIdNameManager::GetInstance()->RemoveName(
platform_handle,
PlatformThread::CurrentId());
return NULL;
}
// CreateThreadInternal() matches PlatformThread::Create(), except that
// |out_thread_handle| may be NULL, in which case a non-joinable thread is
// created.
bool CreateThreadInternal(size_t stack_size,
PlatformThread::Delegate* delegate,
PlatformThreadHandle* out_thread_handle) {
unsigned int flags = 0;
if (stack_size > 0 && base::win::GetVersion() >= base::win::VERSION_XP) {
flags = STACK_SIZE_PARAM_IS_A_RESERVATION;
} else {
stack_size = 0;
}
ThreadParams* params = new ThreadParams;
params->delegate = delegate;
params->joinable = out_thread_handle != NULL;
// Using CreateThread here vs _beginthreadex makes thread creation a bit
// faster and doesn't require the loader lock to be available. Our code will
// have to work running on CreateThread() threads anyway, since we run code
// on the Windows thread pool, etc. For some background on the difference:
// http://www.microsoft.com/msj/1099/win32/win321099.aspx
void* thread_handle = CreateThread(
NULL, stack_size, ThreadFunc, params, flags, NULL);
if (!thread_handle) {
delete params;
return false;
}
if (out_thread_handle)
*out_thread_handle = PlatformThreadHandle(thread_handle);
else
CloseHandle(thread_handle);
return true;
}
} // namespace
// static
PlatformThreadId PlatformThread::CurrentId() {
return GetCurrentThreadId();
}
// static
PlatformThreadHandle PlatformThread::CurrentHandle() {
NOTIMPLEMENTED(); // See OpenThread()
return PlatformThreadHandle();
}
// static
void PlatformThread::YieldCurrentThread() {
::Sleep(0);
}
// static
void PlatformThread::Sleep(TimeDelta duration) {
// When measured with a high resolution clock, Sleep() sometimes returns much
// too early. We may need to call it repeatedly to get the desired duration.
TimeTicks end = TimeTicks::Now() + duration;
TimeTicks now;
while ((now = TimeTicks::Now()) < end)
::Sleep((end - now).InMillisecondsRoundedUp());
}
// static
void PlatformThread::SetName(const char* name) {
ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
// On Windows only, we don't need to tell the profiler about the "BrokerEvent"
// thread, as it exists only in the chrome.exe image, and never spawns or runs
// tasks (items which could be profiled). This test avoids the notification,
// which would also (as a side effect) initialize the profiler in this unused
// context, including setting up thread local storage, etc. The performance
// impact is not terrible, but there is no reason to do initialize it.
if (0 != strcmp(name, "BrokerEvent"))
tracked_objects::ThreadData::InitializeThreadContext(name);
// The debugger needs to be around to catch the name in the exception. If
// there isn't a debugger, we are just needlessly throwing an exception.
// If this image file is instrumented, we raise the exception anyway
// to provide the profiler with human-readable thread names.
if (!::IsDebuggerPresent() && !base::debug::IsBinaryInstrumented())
return;
SetNameInternal(CurrentId(), name);
}
// static
const char* PlatformThread::GetName() {
return ThreadIdNameManager::GetInstance()->GetName(CurrentId());
}
// static
bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
PlatformThreadHandle* thread_handle) {
DCHECK(thread_handle);
return CreateThreadInternal(stack_size, delegate, thread_handle);
}
// static
bool PlatformThread::CreateWithPriority(size_t stack_size, Delegate* delegate,
PlatformThreadHandle* thread_handle,
ThreadPriority priority) {
bool result = Create(stack_size, delegate, thread_handle);
if (result)
SetThreadPriority(*thread_handle, priority);
return result;
}
// static
bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
return CreateThreadInternal(stack_size, delegate, NULL);
}
// static
void PlatformThread::Join(PlatformThreadHandle thread_handle) {
DCHECK(thread_handle.handle_);
// TODO(willchan): Enable this check once I can get it to work for Windows
// shutdown.
// Joining another thread may block the current thread for a long time, since
// the thread referred to by |thread_handle| may still be running long-lived /
// blocking tasks.
#if 0
base::ThreadRestrictions::AssertIOAllowed();
#endif
// Wait for the thread to exit. It should already have terminated but make
// sure this assumption is valid.
DWORD result = WaitForSingleObject(thread_handle.handle_, INFINITE);
if (result != WAIT_OBJECT_0) {
// Debug info for bug 127931.
DWORD error = GetLastError();
debug::Alias(&error);
debug::Alias(&result);
debug::Alias(&thread_handle.handle_);
CHECK(false);
}
CloseHandle(thread_handle.handle_);
}
// static
void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
ThreadPriority priority) {
switch (priority) {
case kThreadPriority_Normal:
::SetThreadPriority(handle.handle_, THREAD_PRIORITY_NORMAL);
break;
case kThreadPriority_RealtimeAudio:
::SetThreadPriority(handle.handle_, THREAD_PRIORITY_TIME_CRITICAL);
break;
default:
NOTREACHED() << "Unknown priority.";
break;
}
}
} // namespace base