1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "base/threading/platform_thread.h"
6
7#include "base/debug/alias.h"
8#include "base/debug/profiler.h"
9#include "base/logging.h"
10#include "base/threading/thread_id_name_manager.h"
11#include "base/threading/thread_restrictions.h"
12#include "base/tracked_objects.h"
13#include "base/win/scoped_handle.h"
14#include "base/win/windows_version.h"
15
16namespace base {
17
18namespace {
19
20// The information on how to set the thread name comes from
21// a MSDN article: http://msdn2.microsoft.com/en-us/library/xcb2z8hs.aspx
22const DWORD kVCThreadNameException = 0x406D1388;
23
24typedef struct tagTHREADNAME_INFO {
25  DWORD dwType;  // Must be 0x1000.
26  LPCSTR szName;  // Pointer to name (in user addr space).
27  DWORD dwThreadID;  // Thread ID (-1=caller thread).
28  DWORD dwFlags;  // Reserved for future use, must be zero.
29} THREADNAME_INFO;
30
31// This function has try handling, so it is separated out of its caller.
32void SetNameInternal(PlatformThreadId thread_id, const char* name) {
33  THREADNAME_INFO info;
34  info.dwType = 0x1000;
35  info.szName = name;
36  info.dwThreadID = thread_id;
37  info.dwFlags = 0;
38
39  __try {
40    RaiseException(kVCThreadNameException, 0, sizeof(info)/sizeof(DWORD),
41                   reinterpret_cast<DWORD_PTR*>(&info));
42  } __except(EXCEPTION_CONTINUE_EXECUTION) {
43  }
44}
45
46struct ThreadParams {
47  PlatformThread::Delegate* delegate;
48  bool joinable;
49};
50
51DWORD __stdcall ThreadFunc(void* params) {
52  ThreadParams* thread_params = static_cast<ThreadParams*>(params);
53  PlatformThread::Delegate* delegate = thread_params->delegate;
54  if (!thread_params->joinable)
55    base::ThreadRestrictions::SetSingletonAllowed(false);
56
57  // Retrieve a copy of the thread handle to use as the key in the
58  // thread name mapping.
59  PlatformThreadHandle::Handle platform_handle;
60  BOOL did_dup = DuplicateHandle(GetCurrentProcess(),
61                                GetCurrentThread(),
62                                GetCurrentProcess(),
63                                &platform_handle,
64                                0,
65                                FALSE,
66                                DUPLICATE_SAME_ACCESS);
67
68  win::ScopedHandle scoped_platform_handle;
69
70  if (did_dup) {
71    scoped_platform_handle.Set(platform_handle);
72    ThreadIdNameManager::GetInstance()->RegisterThread(
73        scoped_platform_handle.Get(),
74        PlatformThread::CurrentId());
75  }
76
77  delete thread_params;
78  delegate->ThreadMain();
79
80  if (did_dup) {
81    ThreadIdNameManager::GetInstance()->RemoveName(
82        scoped_platform_handle.Get(),
83        PlatformThread::CurrentId());
84  }
85
86  return NULL;
87}
88
89// CreateThreadInternal() matches PlatformThread::Create(), except that
90// |out_thread_handle| may be NULL, in which case a non-joinable thread is
91// created.
92bool CreateThreadInternal(size_t stack_size,
93                          PlatformThread::Delegate* delegate,
94                          PlatformThreadHandle* out_thread_handle) {
95  unsigned int flags = 0;
96  if (stack_size > 0 && base::win::GetVersion() >= base::win::VERSION_XP) {
97    flags = STACK_SIZE_PARAM_IS_A_RESERVATION;
98  } else {
99    stack_size = 0;
100  }
101
102  ThreadParams* params = new ThreadParams;
103  params->delegate = delegate;
104  params->joinable = out_thread_handle != NULL;
105
106  // Using CreateThread here vs _beginthreadex makes thread creation a bit
107  // faster and doesn't require the loader lock to be available.  Our code will
108  // have to work running on CreateThread() threads anyway, since we run code
109  // on the Windows thread pool, etc.  For some background on the difference:
110  //   http://www.microsoft.com/msj/1099/win32/win321099.aspx
111  void* thread_handle = CreateThread(
112      NULL, stack_size, ThreadFunc, params, flags, NULL);
113  if (!thread_handle) {
114    delete params;
115    return false;
116  }
117
118  if (out_thread_handle)
119    *out_thread_handle = PlatformThreadHandle(thread_handle);
120  else
121    CloseHandle(thread_handle);
122  return true;
123}
124
125}  // namespace
126
127// static
128PlatformThreadId PlatformThread::CurrentId() {
129  return GetCurrentThreadId();
130}
131
132// static
133PlatformThreadRef PlatformThread::CurrentRef() {
134  return PlatformThreadRef(GetCurrentThreadId());
135}
136
137// static
138PlatformThreadHandle PlatformThread::CurrentHandle() {
139  NOTIMPLEMENTED(); // See OpenThread()
140  return PlatformThreadHandle();
141}
142
143// static
144void PlatformThread::YieldCurrentThread() {
145  ::Sleep(0);
146}
147
148// static
149void PlatformThread::Sleep(TimeDelta duration) {
150  // When measured with a high resolution clock, Sleep() sometimes returns much
151  // too early. We may need to call it repeatedly to get the desired duration.
152  TimeTicks end = TimeTicks::Now() + duration;
153  TimeTicks now;
154  while ((now = TimeTicks::Now()) < end)
155    ::Sleep((end - now).InMillisecondsRoundedUp());
156}
157
158// static
159void PlatformThread::SetName(const char* name) {
160  ThreadIdNameManager::GetInstance()->SetName(CurrentId(), name);
161
162  // On Windows only, we don't need to tell the profiler about the "BrokerEvent"
163  // thread, as it exists only in the chrome.exe image, and never spawns or runs
164  // tasks (items which could be profiled).  This test avoids the notification,
165  // which would also (as a side effect) initialize the profiler in this unused
166  // context, including setting up thread local storage, etc.  The performance
167  // impact is not terrible, but there is no reason to do initialize it.
168  if (0 != strcmp(name, "BrokerEvent"))
169    tracked_objects::ThreadData::InitializeThreadContext(name);
170
171  // The debugger needs to be around to catch the name in the exception.  If
172  // there isn't a debugger, we are just needlessly throwing an exception.
173  // If this image file is instrumented, we raise the exception anyway
174  // to provide the profiler with human-readable thread names.
175  if (!::IsDebuggerPresent() && !base::debug::IsBinaryInstrumented())
176    return;
177
178  SetNameInternal(CurrentId(), name);
179}
180
181// static
182const char* PlatformThread::GetName() {
183  return ThreadIdNameManager::GetInstance()->GetName(CurrentId());
184}
185
186// static
187bool PlatformThread::Create(size_t stack_size, Delegate* delegate,
188                            PlatformThreadHandle* thread_handle) {
189  DCHECK(thread_handle);
190  return CreateThreadInternal(stack_size, delegate, thread_handle);
191}
192
193// static
194bool PlatformThread::CreateWithPriority(size_t stack_size, Delegate* delegate,
195                                        PlatformThreadHandle* thread_handle,
196                                        ThreadPriority priority) {
197  bool result = Create(stack_size, delegate, thread_handle);
198  if (result)
199    SetThreadPriority(*thread_handle, priority);
200  return result;
201}
202
203// static
204bool PlatformThread::CreateNonJoinable(size_t stack_size, Delegate* delegate) {
205  return CreateThreadInternal(stack_size, delegate, NULL);
206}
207
208// static
209void PlatformThread::Join(PlatformThreadHandle thread_handle) {
210  DCHECK(thread_handle.handle_);
211  // TODO(willchan): Enable this check once I can get it to work for Windows
212  // shutdown.
213  // Joining another thread may block the current thread for a long time, since
214  // the thread referred to by |thread_handle| may still be running long-lived /
215  // blocking tasks.
216#if 0
217  base::ThreadRestrictions::AssertIOAllowed();
218#endif
219
220  // Wait for the thread to exit.  It should already have terminated but make
221  // sure this assumption is valid.
222  DWORD result = WaitForSingleObject(thread_handle.handle_, INFINITE);
223  if (result != WAIT_OBJECT_0) {
224    // Debug info for bug 127931.
225    DWORD error = GetLastError();
226    debug::Alias(&error);
227    debug::Alias(&result);
228    debug::Alias(&thread_handle.handle_);
229    CHECK(false);
230  }
231
232  CloseHandle(thread_handle.handle_);
233}
234
235// static
236void PlatformThread::SetThreadPriority(PlatformThreadHandle handle,
237                                       ThreadPriority priority) {
238  switch (priority) {
239    case kThreadPriority_Normal:
240      ::SetThreadPriority(handle.handle_, THREAD_PRIORITY_NORMAL);
241      break;
242    case kThreadPriority_RealtimeAudio:
243      ::SetThreadPriority(handle.handle_, THREAD_PRIORITY_TIME_CRITICAL);
244      break;
245    default:
246      NOTREACHED() << "Unknown priority.";
247      break;
248  }
249}
250
251}  // namespace base
252