WinRT: added a skeleton SDL backend for C++11-based threads

src/thread/SDL_thread_c.h

@@ -36,6 +36,8 @@
 #include "windows/SDL_systhread_c.h"
 #elif SDL_THREAD_NDS
 #include "nds/SDL_systhread_c.h"
+#elif SDL_THREAD_STDCPP
+#include "stdcpp/SDL_systhread_c.h"
 #else
 #error Need thread implementation for this platform
 #include "generic/SDL_systhread_c.h"

src/thread/stdcpp/SDL_syscond.c

@@ -0,0 +1,223 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* An implementation of condition variables using semaphores and mutexes */
+/*
+   This implementation borrows heavily from the BeOS condition variable
+   implementation, written by Christopher Tate and Owen Smith.  Thanks!
+ */
+
+#include "SDL_thread.h"
+
+struct SDL_cond
+{
+    SDL_mutex *lock;
+    int waiting;
+    int signals;
+    SDL_sem *wait_sem;
+    SDL_sem *wait_done;
+};
+
+/* Create a condition variable */
+SDL_cond *
+SDL_CreateCond(void)
+{
+    SDL_cond *cond;
+
+    cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
+    if (cond) {
+        cond->lock = SDL_CreateMutex();
+        cond->wait_sem = SDL_CreateSemaphore(0);
+        cond->wait_done = SDL_CreateSemaphore(0);
+        cond->waiting = cond->signals = 0;
+        if (!cond->lock || !cond->wait_sem || !cond->wait_done) {
+            SDL_DestroyCond(cond);
+            cond = NULL;
+        }
+    } else {
+        SDL_OutOfMemory();
+    }
+    return (cond);
+}
+
+/* Destroy a condition variable */
+void
+SDL_DestroyCond(SDL_cond * cond)
+{
+    if (cond) {
+        if (cond->wait_sem) {
+            SDL_DestroySemaphore(cond->wait_sem);
+        }
+        if (cond->wait_done) {
+            SDL_DestroySemaphore(cond->wait_done);
+        }
+        if (cond->lock) {
+            SDL_DestroyMutex(cond->lock);
+        }
+        SDL_free(cond);
+    }
+}
+
+/* Restart one of the threads that are waiting on the condition variable */
+int
+SDL_CondSignal(SDL_cond * cond)
+{
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    /* If there are waiting threads not already signalled, then
+       signal the condition and wait for the thread to respond.
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->waiting > cond->signals) {
+        ++cond->signals;
+        SDL_SemPost(cond->wait_sem);
+        SDL_UnlockMutex(cond->lock);
+        SDL_SemWait(cond->wait_done);
+    } else {
+        SDL_UnlockMutex(cond->lock);
+    }
+
+    return 0;
+}
+
+/* Restart all threads that are waiting on the condition variable */
+int
+SDL_CondBroadcast(SDL_cond * cond)
+{
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    /* If there are waiting threads not already signalled, then
+       signal the condition and wait for the thread to respond.
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->waiting > cond->signals) {
+        int i, num_waiting;
+
+        num_waiting = (cond->waiting - cond->signals);
+        cond->signals = cond->waiting;
+        for (i = 0; i < num_waiting; ++i) {
+            SDL_SemPost(cond->wait_sem);
+        }
+        /* Now all released threads are blocked here, waiting for us.
+           Collect them all (and win fabulous prizes!) :-)
+         */
+        SDL_UnlockMutex(cond->lock);
+        for (i = 0; i < num_waiting; ++i) {
+            SDL_SemWait(cond->wait_done);
+        }
+    } else {
+        SDL_UnlockMutex(cond->lock);
+    }
+
+    return 0;
+}
+
+/* Wait on the condition variable for at most 'ms' milliseconds.
+   The mutex must be locked before entering this function!
+   The mutex is unlocked during the wait, and locked again after the wait.
+
+Typical use:
+
+Thread A:
+    SDL_LockMutex(lock);
+    while ( ! condition ) {
+        SDL_CondWait(cond, lock);
+    }
+    SDL_UnlockMutex(lock);
+
+Thread B:
+    SDL_LockMutex(lock);
+    ...
+    condition = true;
+    ...
+    SDL_CondSignal(cond);
+    SDL_UnlockMutex(lock);
+ */
+int
+SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
+{
+    int retval;
+
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    /* Obtain the protection mutex, and increment the number of waiters.
+       This allows the signal mechanism to only perform a signal if there
+       are waiting threads.
+     */
+    SDL_LockMutex(cond->lock);
+    ++cond->waiting;
+    SDL_UnlockMutex(cond->lock);
+
+    /* Unlock the mutex, as is required by condition variable semantics */
+    SDL_UnlockMutex(mutex);
+
+    /* Wait for a signal */
+    if (ms == SDL_MUTEX_MAXWAIT) {
+        retval = SDL_SemWait(cond->wait_sem);
+    } else {
+        retval = SDL_SemWaitTimeout(cond->wait_sem, ms);
+    }
+
+    /* Let the signaler know we have completed the wait, otherwise
+       the signaler can race ahead and get the condition semaphore
+       if we are stopped between the mutex unlock and semaphore wait,
+       giving a deadlock.  See the following URL for details:
+       http://www-classic.be.com/aboutbe/benewsletter/volume_III/Issue40.html
+     */
+    SDL_LockMutex(cond->lock);
+    if (cond->signals > 0) {
+        /* If we timed out, we need to eat a condition signal */
+        if (retval > 0) {
+            SDL_SemWait(cond->wait_sem);
+        }
+        /* We always notify the signal thread that we are done */
+        SDL_SemPost(cond->wait_done);
+
+        /* Signal handshake complete */
+        --cond->signals;
+    }
+    --cond->waiting;
+    SDL_UnlockMutex(cond->lock);
+
+    /* Lock the mutex, as is required by condition variable semantics */
+    SDL_LockMutex(mutex);
+
+    return retval;
+}
+
+/* Wait on the condition variable forever */
+int
+SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
+{
+    return SDL_CondWaitTimeout(cond, mutex, SDL_MUTEX_MAXWAIT);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_sysmutex.c

@@ -0,0 +1,135 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* An implementation of mutexes using semaphores */
+
+#include "SDL_thread.h"
+#include "SDL_systhread_c.h"
+
+
+struct SDL_mutex
+{
+    int recursive;
+    SDL_threadID owner;
+    SDL_sem *sem;
+};
+
+/* Create a mutex */
+SDL_mutex *
+SDL_CreateMutex(void)
+{
+    SDL_mutex *mutex;
+
+    /* Allocate mutex memory */
+    mutex = (SDL_mutex *) SDL_malloc(sizeof(*mutex));
+    if (mutex) {
+        /* Create the mutex semaphore, with initial value 1 */
+        mutex->sem = SDL_CreateSemaphore(1);
+        mutex->recursive = 0;
+        mutex->owner = 0;
+        if (!mutex->sem) {
+            SDL_free(mutex);
+            mutex = NULL;
+        }
+    } else {
+        SDL_OutOfMemory();
+    }
+    return mutex;
+}
+
+/* Free the mutex */
+void
+SDL_DestroyMutex(SDL_mutex * mutex)
+{
+    if (mutex) {
+        if (mutex->sem) {
+            SDL_DestroySemaphore(mutex->sem);
+        }
+        SDL_free(mutex);
+    }
+}
+
+/* Lock the semaphore */
+int
+SDL_mutexP(SDL_mutex * mutex)
+{
+#if SDL_THREADS_DISABLED
+    return 0;
+#else
+    SDL_threadID this_thread;
+
+    if (mutex == NULL) {
+        SDL_SetError("Passed a NULL mutex");
+        return -1;
+    }
+
+    this_thread = SDL_ThreadID();
+    if (mutex->owner == this_thread) {
+        ++mutex->recursive;
+    } else {
+        /* The order of operations is important.
+           We set the locking thread id after we obtain the lock
+           so unlocks from other threads will fail.
+         */
+        SDL_SemWait(mutex->sem);
+        mutex->owner = this_thread;
+        mutex->recursive = 0;
+    }
+
+    return 0;
+#endif /* SDL_THREADS_DISABLED */
+}
+
+/* Unlock the mutex */
+int
+SDL_mutexV(SDL_mutex * mutex)
+{
+#if SDL_THREADS_DISABLED
+    return 0;
+#else
+    if (mutex == NULL) {
+        SDL_SetError("Passed a NULL mutex");
+        return -1;
+    }
+
+    /* If we don't own the mutex, we can't unlock it */
+    if (SDL_ThreadID() != mutex->owner) {
+        SDL_SetError("mutex not owned by this thread");
+        return -1;
+    }
+
+    if (mutex->recursive) {
+        --mutex->recursive;
+    } else {
+        /* The order of operations is important.
+           First reset the owner so another thread doesn't lock
+           the mutex and set the ownership before we reset it,
+           then release the lock semaphore.
+         */
+        mutex->owner = 0;
+        SDL_SemPost(mutex->sem);
+    }
+    return 0;
+#endif /* SDL_THREADS_DISABLED */
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_sysmutex_c.h

@@ -0,0 +1,22 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_systhread.c

@@ -0,0 +1,59 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* Thread management routines for SDL */
+
+#include "SDL_thread.h"
+#include "../SDL_systhread.h"
+
+int
+SDL_SYS_CreateThread(SDL_Thread * thread, void *args)
+{
+    SDL_SetError("Threads are not supported on this platform");
+    return (-1);
+}
+
+void
+SDL_SYS_SetupThread(const char *name)
+{
+    return;
+}
+
+SDL_threadID
+SDL_ThreadID(void)
+{
+    return (0);
+}
+
+int
+SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
+{
+    return (0);
+}
+
+void
+SDL_SYS_WaitThread(SDL_Thread * thread)
+{
+    return;
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_systhread_c.h

@@ -0,0 +1,26 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* For a thread handle, use a void pointer to a std::thread */
+typedef void * SYS_ThreadHandle;
+
+/* vi: set ts=4 sw=4 expandtab: */