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      1 /*
      2  * libjingle
      3  * Copyright 2004--2008, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/base/event.h"
     29 
     30 #if defined(WIN32)
     31 #include <windows.h>
     32 #elif defined(POSIX)
     33 #include <pthread.h>
     34 #include <sys/time.h>
     35 #include <time.h>
     36 #else
     37 #error "Must define either WIN32 or POSIX."
     38 #endif
     39 
     40 namespace talk_base {
     41 
     42 #if defined(WIN32)
     43 
     44 Event::Event(bool manual_reset, bool initially_signaled)
     45     : is_manual_reset_(manual_reset),
     46       is_initially_signaled_(initially_signaled) {
     47   event_handle_ = ::CreateEvent(NULL,                 // Security attributes.
     48                                 is_manual_reset_,
     49                                 is_initially_signaled_,
     50                                 NULL);                // Name.
     51   ASSERT(event_handle_ != NULL);
     52 }
     53 
     54 Event::~Event() {
     55   CloseHandle(event_handle_);
     56 }
     57 
     58 void Event::Set() {
     59   SetEvent(event_handle_);
     60 }
     61 
     62 void Event::Reset() {
     63   ResetEvent(event_handle_);
     64 }
     65 
     66 bool Event::Wait(int cms) {
     67   DWORD ms = (cms == kForever)? INFINITE : cms;
     68   return (WaitForSingleObject(event_handle_, ms) == WAIT_OBJECT_0);
     69 }
     70 
     71 #elif defined(POSIX)
     72 
     73 Event::Event(bool manual_reset, bool initially_signaled)
     74     : is_manual_reset_(manual_reset),
     75       event_status_(initially_signaled) {
     76   VERIFY(pthread_mutex_init(&event_mutex_, NULL) == 0);
     77   VERIFY(pthread_cond_init(&event_cond_, NULL) == 0);
     78 }
     79 
     80 Event::~Event() {
     81   pthread_mutex_destroy(&event_mutex_);
     82   pthread_cond_destroy(&event_cond_);
     83 }
     84 
     85 void Event::Set() {
     86   pthread_mutex_lock(&event_mutex_);
     87   event_status_ = true;
     88   pthread_cond_broadcast(&event_cond_);
     89   pthread_mutex_unlock(&event_mutex_);
     90 }
     91 
     92 void Event::Reset() {
     93   pthread_mutex_lock(&event_mutex_);
     94   event_status_ = false;
     95   pthread_mutex_unlock(&event_mutex_);
     96 }
     97 
     98 bool Event::Wait(int cms) {
     99   pthread_mutex_lock(&event_mutex_);
    100   int error = 0;
    101 
    102   if (cms != kForever) {
    103     // Converting from seconds and microseconds (1e-6) plus
    104     // milliseconds (1e-3) to seconds and nanoseconds (1e-9).
    105 
    106     struct timespec ts;
    107 #if HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
    108     // Use relative time version, which tends to be more efficient for
    109     // pthread implementations where provided (like on Android).
    110     ts.tv_sec = cms / 1000;
    111     ts.tv_nsec = (cms % 1000) * 1000000;
    112 #else
    113     struct timeval tv;
    114     gettimeofday(&tv, NULL);
    115 
    116     ts.tv_sec = tv.tv_sec + (cms / 1000);
    117     ts.tv_nsec = tv.tv_usec * 1000 + (cms % 1000) * 1000000;
    118 
    119     // Handle overflow.
    120     if (ts.tv_nsec >= 1000000000) {
    121       ts.tv_sec++;
    122       ts.tv_nsec -= 1000000000;
    123     }
    124 #endif
    125 
    126     while (!event_status_ && error == 0) {
    127 #if HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE
    128       error = pthread_cond_timedwait_relative_np(
    129           &event_cond_, &event_mutex_, &ts);
    130 #else
    131       error = pthread_cond_timedwait(&event_cond_, &event_mutex_, &ts);
    132 #endif
    133     }
    134   } else {
    135     while (!event_status_ && error == 0)
    136       error = pthread_cond_wait(&event_cond_, &event_mutex_);
    137   }
    138 
    139   // NOTE(liulk): Exactly one thread will auto-reset this event. All
    140   // the other threads will think it's unsignaled.  This seems to be
    141   // consistent with auto-reset events in WIN32.
    142   if (error == 0 && !is_manual_reset_)
    143     event_status_ = false;
    144 
    145   pthread_mutex_unlock(&event_mutex_);
    146 
    147   return (error == 0);
    148 }
    149 
    150 #endif
    151 
    152 }  // namespace talk_base
    153