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.

diff --git a/src/threading/CMakeLists.txt b/src/threading/CMakeLists.txt
index f3d0efc18085eff6107e3595e2680f42f80f1907..5dd60ef1a4dc424e6ef2176fd362e3b14634362e 100644 (file)
--- a/src/threading/CMakeLists.txt
+++ b/src/threading/CMakeLists.txt
@@ -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

diff --git a/src/threading/event.cpp b/src/threading/event.cpp
new file mode 100644 (file)
index 0000000..1c458bf
--- /dev/null
+++ b/src/threading/event.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
+}
+

diff --git a/src/threading/event.h b/src/threading/event.h
index 0105630e5dbaf897965eb308bd4d80ee5153bb32..ea087e53f4ceb16452cd2e1c017efe42e6ff7990 100644 (file)
--- a/src/threading/event.h
+++ b/src/threading/event.h
@@ -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
 };