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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 "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