The Tor Browser: ipc/chromium/src/base/waitable_event

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 // Copyright (c) 2006-2008 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.

     5 #include "base/waitable_event.h"

     7 #include <math.h>

     8 #include <windows.h>

    10 #include "base/logging.h"

    11 #include "base/time.h"

    13 namespace base {

    15 WaitableEvent::WaitableEvent(bool manual_reset, bool signaled)

    16     : handle_(CreateEvent(NULL, manual_reset, signaled, NULL)) {

    17   // We're probably going to crash anyways if this is ever NULL, so we might as

    18   // well make our stack reports more informative by crashing here.

    19   CHECK(handle_);

    20 }

    22 WaitableEvent::WaitableEvent(HANDLE handle)

    23     : handle_(handle) {

    24   CHECK(handle) << "Tried to create WaitableEvent from NULL handle";

    25 }

    27 WaitableEvent::~WaitableEvent() {

    28   CloseHandle(handle_);

    29 }

    31 HANDLE WaitableEvent::Release() {

    32   HANDLE rv = handle_;

    33   handle_ = INVALID_HANDLE_VALUE;

    34   return rv;

    35 }

    37 void WaitableEvent::Reset() {

    38   ResetEvent(handle_);

    39 }

    41 void WaitableEvent::Signal() {

    42   SetEvent(handle_);

    43 }

    45 bool WaitableEvent::IsSignaled() {

    46   return TimedWait(TimeDelta::FromMilliseconds(0));

    47 }

    49 bool WaitableEvent::Wait() {

    50   DWORD result = WaitForSingleObject(handle_, INFINITE);

    51   // It is most unexpected that this should ever fail.  Help consumers learn

    52   // about it if it should ever fail.

    53   DCHECK(result == WAIT_OBJECT_0) << "WaitForSingleObject failed";

    54   return result == WAIT_OBJECT_0;

    55 }

    57 bool WaitableEvent::TimedWait(const TimeDelta& max_time) {

    58   DCHECK(max_time >= TimeDelta::FromMicroseconds(0));

    59   // Be careful here.  TimeDelta has a precision of microseconds, but this API

    60   // is in milliseconds.  If there are 5.5ms left, should the delay be 5 or 6?

    61   // It should be 6 to avoid returning too early.

    62   double timeout = ceil(max_time.InMillisecondsF());

    63   DWORD result = WaitForSingleObject(handle_, static_cast<DWORD>(timeout));

    64   switch (result) {

    65     case WAIT_OBJECT_0:

    66       return true;

    67     case WAIT_TIMEOUT:

    68       return false;

    69   }

    70   // It is most unexpected that this should ever fail.  Help consumers learn

    71   // about it if it should ever fail.

    72   NOTREACHED() << "WaitForSingleObject failed";

    73   return false;

    74 }

    76 // static

    77 size_t WaitableEvent::WaitMany(WaitableEvent** events, size_t count) {

    78   HANDLE handles[MAXIMUM_WAIT_OBJECTS];

    79   CHECK(count <= MAXIMUM_WAIT_OBJECTS)

    80       << "Can only wait on " << MAXIMUM_WAIT_OBJECTS << " with WaitMany";

    82   for (size_t i = 0; i < count; ++i)

    83     handles[i] = events[i]->handle();

    85   DWORD result =

    86       WaitForMultipleObjects(count, handles,

    87                              FALSE,      // don't wait for all the objects

    88                              INFINITE);  // no timeout

    89   if (result < WAIT_OBJECT_0 || result >= WAIT_OBJECT_0 + count) {

    90     NOTREACHED() << "WaitForMultipleObjects failed: " << GetLastError();

    91     return 0;

    92   }

    94   return result - WAIT_OBJECT_0;

    95 }

    97 }  // namespace base

The Tor Browser / file revision