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Fix Event implementation

On non-windows platforms this just used a semaphore,
which meant that multiple calls to signal() would
result in wait() returning multiple times.
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ShadowNinja committed Dec 7, 2015
1 parent ea2964f commit 696148e29889b2923f926b27f76979454676506d
Showing with 121 additions and 13 deletions.
  1. +1 −0 src/threading/CMakeLists.txt
  2. +95 −0 src/threading/event.cpp
  3. +25 −13 src/threading/event.h
@@ -1,4 +1,5 @@
set(JTHREAD_SRCS
${CMAKE_CURRENT_SOURCE_DIR}/event.cpp
${CMAKE_CURRENT_SOURCE_DIR}/mutex.cpp
${CMAKE_CURRENT_SOURCE_DIR}/thread.cpp
${CMAKE_CURRENT_SOURCE_DIR}/semaphore.cpp
@@ -0,0 +1,95 @@
/*
This file is a part of the JThread package, which contains some object-
oriented thread wrappers for different thread implementations.
Copyright (c) 2000-2006 Jori Liesenborgs (jori.liesenborgs@gmail.com)
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
*/

#include "threading/event.h"

#if defined(_WIN32)
#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
#endif
#include <windows.h>
#endif


#if __cplusplus < 201103L
Event::Event()
{
#ifdef _WIN32
event = CreateEvent(NULL, false, false, NULL);
#else
pthread_cond_init(&cv, NULL);
pthread_mutex_init(&mutex, NULL);
#endif
}

Event::~Event()
{
#ifdef _WIN32
CloseHandle(event);
#else
pthread_cond_destroy(&cv);
pthread_mutex_destroy(&mutex);
#endif
}
#endif


void Event::wait()
{
#if __cplusplus >= 201103L
MutexAutoLock lock(mutex);
while (!notified) {
cv.wait(lock);
}
notified = false;
#elif defined(_WIN32)
WaitForSingleObject(event, INFINITE);
#else
pthread_mutex_lock(&mutex);
while (!notified) {
pthread_cond_wait(&cv, &mutex);
}
notified = false;
pthread_mutex_unlock(&mutex);
#endif
}


void Event::signal()
{
#if __cplusplus >= 201103L
MutexAutoLock lock(mutex);
notified = true;
cv.notify_one();
#elif defined(_WIN32)
SetEvent(event);
#else
pthread_mutex_lock(&mutex);
notified = true;
pthread_cond_signal(&cv);
pthread_mutex_unlock(&mutex);
#endif
}

@@ -26,30 +26,42 @@ DEALINGS IN THE SOFTWARE.
#ifndef THREADING_EVENT_H
#define THREADING_EVENT_H

#ifdef _WIN32
#include <windows.h>
#if __cplusplus >= 201103L
#include <condition_variable>
#include "threading/mutex.h"
#elif defined(_WIN32)
#include <windef.h>
#else
#include "threading/semaphore.h"
#include <pthread.h>
#endif


/** A syncronization primitive that will wake up one waiting thread when signaled.
* Calling @c signal() multiple times before a waiting thread has had a chance
* to notice the signal will wake only one thread. Additionally, if no threads
* are waiting on the event when it is signaled, the next call to @c wait()
* will return (almost) immediately.
*/
class Event {
public:
#ifdef _WIN32
Event() { event = CreateEvent(NULL, false, false, NULL); }
~Event() { CloseHandle(event); }
void wait() { WaitForSingleObject(event, INFINITE); }
void signal() { SetEvent(event); }
#else
void wait() { sem.wait(); }
void signal() { sem.post(); }
#if __cplusplus < 201103L
Event();
~Event();
#endif
void wait();
void signal();

private:
#ifdef _WIN32
#if __cplusplus >= 201103L
std::condition_variable cv;
Mutex mutex;
bool notified;
#elif defined(_WIN32)
HANDLE event;
#else
Semaphore sem;
pthread_cond_t cv;
pthread_mutex_t mutex;
bool notified;
#endif
};

3 comments on commit 696148e

@MoNTE48

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@MoNTE48 MoNTE48 replied Dec 10, 2015

I get an error when building for Android

@kilbith

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@kilbith kilbith replied Dec 10, 2015

I get an error when building for Android

This would be relevant with a backtrace...

@nerzhul

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@nerzhul nerzhul replied Dec 10, 2015

@MoNTE48 please send a proper issue.

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