Add missing windows conditions variable
Those are used by generic RW lock implementation. https://bugs.freedesktop.org/show_bug.cgi?id=96754
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Nicolas Dufresne
committed by
Arun Raghavan
Arun Raghavan
parent
db2f422578
commit
6ad2f51e9e
195
webrtc/system_wrappers/source/condition_variable_event_win.cc
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webrtc/system_wrappers/source/condition_variable_event_win.cc
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/*
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Source:
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http://www1.cse.wustl.edu/~schmidt/ACE-copying.html
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License:
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Copyright and Licensing Information for ACE(TM), TAO(TM), CIAO(TM), DAnCE(TM),
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and CoSMIC(TM)
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ACE(TM), TAO(TM), CIAO(TM), DAnCE>(TM), and CoSMIC(TM) (henceforth referred to
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as "DOC software") are copyrighted by Douglas C. Schmidt and his research
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group at Washington University, University of California, Irvine, and
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Vanderbilt University, Copyright (c) 1993-2009, all rights reserved. Since DOC
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software is open-source, freely available software, you are free to use,
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modify, copy, and distribute--perpetually and irrevocably--the DOC software
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source code and object code produced from the source, as well as copy and
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distribute modified versions of this software. You must, however, include this
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copyright statement along with any code built using DOC software that you
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release. No copyright statement needs to be provided if you just ship binary
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executables of your software products.
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You can use DOC software in commercial and/or binary software releases and are
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under no obligation to redistribute any of your source code that is built
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using DOC software. Note, however, that you may not misappropriate the DOC
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DOC software code, in a way that will prevent DOC software from being
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stories.
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The ACE, TAO, CIAO, DAnCE, and CoSMIC web sites are maintained by the DOC
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Group at the Institute for Software Integrated Systems (ISIS) and the Center
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for Distributed Object Computing of Washington University, St. Louis for the
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development of open-source software as part of the open-source software
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indirect, special, exemplary, punitive, or consequential damages, including
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without limitation, lost profits, even if advised of the possibility of such
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damages. Likewise, DOC software is provided as is with no warranties of any
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kind, including the warranties of design, merchantability, and fitness for a
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particular purpose, noninfringement, or arising from a course of dealing,
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usage or trade practice. Washington University, UC Irvine, Vanderbilt
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University, their employees, and students shall have no liability with respect
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to the infringement of copyrights, trade secrets or any patents by DOC
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University, UC Irvine, or Vanderbilt University, their employees, or students
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employees, or students to assist in its use, correction, modification, or
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underlying OS platform is Y2K-compliant. Likewise, DOC software is compliant
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with the new US daylight savings rule passed by Congress as "The Energy Policy
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Act of 2005," which established new daylight savings times (DST) rules for the
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United States that expand DST as of March 2007. Since DOC software obtains
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time/date and calendaring information from operating systems users will not be
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affected by the new DST rules as long as they upgrade their operating systems
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accordingly.
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The names ACE(TM), TAO(TM), CIAO(TM), DAnCE(TM), CoSMIC(TM), Washington
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University, UC Irvine, and Vanderbilt University, may not be used to endorse
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or promote products or services derived from this source without express
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written permission from Washington University, UC Irvine, or Vanderbilt
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University. This license grants no permission to call products or services
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derived from this source ACE(TM), TAO(TM), CIAO(TM), DAnCE(TM), or CoSMIC(TM),
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nor does it grant permission for the name Washington University, UC Irvine, or
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Vanderbilt University to appear in their names.
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*/
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/*
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* This source code contain modifications to the original source code
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* which can be found here:
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* http://www.cs.wustl.edu/~schmidt/win32-cv-1.html (section 3.2).
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* Modifications:
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* 1) Dynamic detection of native support for condition variables.
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* 2) Use of WebRTC defined types and classes. Renaming of some functions.
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* 3) Introduction of a second event for wake all functionality. This prevents
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* a thread from spinning on the same condition variable, preventing other
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* threads from waking up.
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*/
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#include "webrtc/system_wrappers/source/condition_variable_event_win.h"
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#include "webrtc/system_wrappers/source/critical_section_win.h"
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namespace webrtc {
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ConditionVariableEventWin::ConditionVariableEventWin() : eventID_(WAKEALL_0) {
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memset(&num_waiters_[0], 0, sizeof(num_waiters_));
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InitializeCriticalSection(&num_waiters_crit_sect_);
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events_[WAKEALL_0] = CreateEvent(NULL, // no security attributes
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TRUE, // manual-reset, sticky event
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FALSE, // initial state non-signaled
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NULL); // no name for event
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events_[WAKEALL_1] = CreateEvent(NULL, // no security attributes
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TRUE, // manual-reset, sticky event
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FALSE, // initial state non-signaled
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NULL); // no name for event
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events_[WAKE] = CreateEvent(NULL, // no security attributes
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FALSE, // auto-reset, sticky event
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FALSE, // initial state non-signaled
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NULL); // no name for event
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}
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ConditionVariableEventWin::~ConditionVariableEventWin() {
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CloseHandle(events_[WAKE]);
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CloseHandle(events_[WAKEALL_1]);
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CloseHandle(events_[WAKEALL_0]);
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DeleteCriticalSection(&num_waiters_crit_sect_);
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}
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void ConditionVariableEventWin::SleepCS(CriticalSectionWrapper& crit_sect) {
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SleepCS(crit_sect, INFINITE);
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}
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bool ConditionVariableEventWin::SleepCS(CriticalSectionWrapper& crit_sect,
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unsigned long max_time_in_ms) {
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EnterCriticalSection(&num_waiters_crit_sect_);
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// Get the eventID for the event that will be triggered by next
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// WakeAll() call and start waiting for it.
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const EventWakeUpType eventID =
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(WAKEALL_0 == eventID_) ? WAKEALL_1 : WAKEALL_0;
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++(num_waiters_[eventID]);
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LeaveCriticalSection(&num_waiters_crit_sect_);
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CriticalSectionWindows* cs =
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static_cast<CriticalSectionWindows*>(&crit_sect);
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LeaveCriticalSection(&cs->crit);
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HANDLE events[2];
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events[0] = events_[WAKE];
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events[1] = events_[eventID];
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const DWORD result = WaitForMultipleObjects(2, // Wait on 2 events.
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events,
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FALSE, // Wait for either.
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max_time_in_ms);
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const bool ret_val = (result != WAIT_TIMEOUT);
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EnterCriticalSection(&num_waiters_crit_sect_);
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--(num_waiters_[eventID]);
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// Last waiter should only be true for WakeAll(). WakeAll() correspond
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// to position 1 in events[] -> (result == WAIT_OBJECT_0 + 1)
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const bool last_waiter = (result == WAIT_OBJECT_0 + 1) &&
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(num_waiters_[eventID] == 0);
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LeaveCriticalSection(&num_waiters_crit_sect_);
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if (last_waiter) {
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// Reset/unset the WakeAll() event since all threads have been
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// released.
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ResetEvent(events_[eventID]);
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}
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EnterCriticalSection(&cs->crit);
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return ret_val;
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}
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void ConditionVariableEventWin::Wake() {
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EnterCriticalSection(&num_waiters_crit_sect_);
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const bool have_waiters = (num_waiters_[WAKEALL_0] > 0) ||
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(num_waiters_[WAKEALL_1] > 0);
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LeaveCriticalSection(&num_waiters_crit_sect_);
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if (have_waiters) {
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SetEvent(events_[WAKE]);
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}
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}
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void ConditionVariableEventWin::WakeAll() {
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EnterCriticalSection(&num_waiters_crit_sect_);
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// Update current WakeAll() event
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eventID_ = (WAKEALL_0 == eventID_) ? WAKEALL_1 : WAKEALL_0;
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// Trigger current event
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const EventWakeUpType eventID = eventID_;
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const bool have_waiters = num_waiters_[eventID] > 0;
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LeaveCriticalSection(&num_waiters_crit_sect_);
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if (have_waiters) {
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SetEvent(events_[eventID]);
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}
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}
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} // namespace webrtc
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