Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

src/thread/stdcpp/SDL_syscond.cpp

@@ -0,0 +1,164 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 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_internal.h"
+
+extern "C" {
+#include "SDL_thread.h"
+}
+
+#include <chrono>
+#include <condition_variable>
+#include <ratio>
+#include <system_error>
+
+#include "SDL_sysmutex_c.h"
+
+struct SDL_cond
+{
+    std::condition_variable_any cpp_cond;
+};
+
+/* Create a condition variable */
+extern "C"
+SDL_cond *
+SDL_CreateCond(void)
+{
+    /* Allocate and initialize the condition variable */
+    try {
+        SDL_cond * cond = new SDL_cond;
+        return cond;
+    } catch (std::system_error & ex) {
+        SDL_SetError("unable to create a C++ condition variable: code=%d; %s", ex.code(), ex.what());
+        return NULL;
+    } catch (std::bad_alloc &) {
+        SDL_OutOfMemory();
+        return NULL;
+    }
+}
+
+/* Destroy a condition variable */
+extern "C"
+void
+SDL_DestroyCond(SDL_cond * cond)
+{
+    if (cond) {
+        delete cond;
+    }
+}
+
+/* Restart one of the threads that are waiting on the condition variable */
+extern "C"
+int
+SDL_CondSignal(SDL_cond * cond)
+{
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    cond->cpp_cond.notify_one();
+    return 0;
+}
+
+/* Restart all threads that are waiting on the condition variable */
+extern "C"
+int
+SDL_CondBroadcast(SDL_cond * cond)
+{
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    cond->cpp_cond.notify_all();
+    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);
+ */
+extern "C"
+int
+SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
+{
+    if (!cond) {
+        SDL_SetError("Passed a NULL condition variable");
+        return -1;
+    }
+
+    if (!mutex) {
+        SDL_SetError("Passed a NULL mutex variable");
+        return -1;
+    }
+
+    try {
+        std::unique_lock<std::recursive_mutex> cpp_lock(mutex->cpp_mutex, std::defer_lock_t());
+        if (ms == SDL_MUTEX_MAXWAIT) {
+            cond->cpp_cond.wait(
+                cpp_lock
+                );
+            cpp_lock.release();
+            return 0;
+        } else {
+            auto wait_result = cond->cpp_cond.wait_for(
+                cpp_lock,
+                std::chrono::duration<Uint32, std::milli>(ms)
+                );
+            cpp_lock.release();
+            if (wait_result == std::cv_status::timeout) {
+                return SDL_MUTEX_TIMEDOUT;
+            } else {
+                return 0;
+            }
+        }
+    } catch (std::system_error & ex) {
+        SDL_SetError("unable to wait on a C++ condition variable: code=%d; %s", ex.code(), ex.what());
+        return -1;
+    }
+}
+
+/* Wait on the condition variable forever */
+extern "C"
+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.cpp

@@ -0,0 +1,111 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 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_internal.h"
+
+extern "C" {
+#include "SDL_thread.h"
+#include "SDL_systhread_c.h"
+#include "SDL_log.h"
+}
+
+#include <system_error>
+
+#include "SDL_sysmutex_c.h"
+#include <Windows.h>
+
+
+/* Create a mutex */
+extern "C"
+SDL_mutex *
+SDL_CreateMutex(void)
+{
+    /* Allocate and initialize the mutex */
+    try {
+        SDL_mutex * mutex = new SDL_mutex;
+        return mutex;
+    } catch (std::system_error & ex) {
+        SDL_SetError("unable to create a C++ mutex: code=%d; %s", ex.code(), ex.what());
+        return NULL;
+    } catch (std::bad_alloc &) {
+        SDL_OutOfMemory();
+        return NULL;
+    }
+}
+
+/* Free the mutex */
+extern "C"
+void
+SDL_DestroyMutex(SDL_mutex * mutex)
+{
+    if (mutex) {
+        delete mutex;
+    }
+}
+
+/* Lock the semaphore */
+extern "C"
+int
+SDL_mutexP(SDL_mutex * mutex)
+{
+    if (mutex == NULL) {
+        SDL_SetError("Passed a NULL mutex");
+        return -1;
+    }
+
+    try {
+        mutex->cpp_mutex.lock();
+        return 0;
+    } catch (std::system_error & ex) {
+        SDL_SetError("unable to lock a C++ mutex: code=%d; %s", ex.code(), ex.what());
+        return -1;
+    }
+}
+
+/* TryLock the mutex */
+int
+SDL_TryLockMutex(SDL_mutex * mutex)
+{
+    int retval = 0;
+    if (mutex == NULL) {
+        return SDL_SetError("Passed a NULL mutex");
+    }
+
+    if (mutex->cpp_mutex.try_lock() == false) {
+        retval = SDL_MUTEX_TIMEDOUT;
+    }
+    return retval;
+}
+
+/* Unlock the mutex */
+extern "C"
+int
+SDL_mutexV(SDL_mutex * mutex)
+{
+    if (mutex == NULL) {
+        SDL_SetError("Passed a NULL mutex");
+        return -1;
+    }
+
+    mutex->cpp_mutex.unlock();
+    return 0;
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_sysmutex_c.h

@@ -0,0 +1,30 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 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"
+
+#include <mutex>
+
+struct SDL_mutex
+{
+    std::recursive_mutex cpp_mutex;
+};
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_systhread.cpp

@@ -0,0 +1,167 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 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_internal.h"
+
+/* Thread management routines for SDL */
+
+extern "C" {
+#include "SDL_thread.h"
+#include "../SDL_thread_c.h"
+#include "../SDL_systhread.h"
+#include "SDL_log.h"
+}
+
+#include <mutex>
+#include <thread>
+#include <system_error>
+
+#ifdef __WINRT__
+#include <Windows.h>
+#endif
+
+static void
+RunThread(void *args)
+{
+    SDL_RunThread(args);
+}
+
+extern "C"
+int
+SDL_SYS_CreateThread(SDL_Thread * thread, void *args)
+{
+    try {
+        std::thread cpp_thread(RunThread, args);
+        thread->handle = (void *) new std::thread(std::move(cpp_thread));
+        return 0;
+    } catch (std::system_error & ex) {
+        SDL_SetError("unable to start a C++ thread: code=%d; %s", ex.code(), ex.what());
+        return -1;
+    } catch (std::bad_alloc &) {
+        SDL_OutOfMemory();
+        return -1;
+    }
+}
+
+extern "C"
+void
+SDL_SYS_SetupThread(const char *name)
+{
+    // Make sure a thread ID gets assigned ASAP, for debugging purposes:
+    SDL_ThreadID();
+    return;
+}
+
+extern "C"
+SDL_threadID
+SDL_ThreadID(void)
+{
+#ifdef __WINRT__
+    return GetCurrentThreadId();
+#else
+    // HACK: Mimick a thread ID, if one isn't otherwise available.
+    static thread_local SDL_threadID current_thread_id = 0;
+    static SDL_threadID next_thread_id = 1;
+    static std::mutex next_thread_id_mutex;
+
+    if (current_thread_id == 0) {
+        std::lock_guard<std::mutex> lock(next_thread_id_mutex);
+        current_thread_id = next_thread_id;
+        ++next_thread_id;
+    }
+
+    return current_thread_id;
+#endif
+}
+
+extern "C"
+int
+SDL_SYS_SetThreadPriority(SDL_ThreadPriority priority)
+{
+    // Thread priorities do not look to be settable via C++11's thread
+    // interface, at least as of this writing (Nov 2012).  std::thread does
+    // provide access to the OS' native handle, however, and some form of
+    // priority-setting could, in theory, be done through this interface.
+    //
+    // WinRT: UPDATE (Aug 20, 2013): thread priorities cannot be changed
+    // on WinRT, at least not for any thread that's already been created.
+    // WinRT threads appear to be based off of the WinRT class,
+    // ThreadPool, more info on which can be found at:
+    // http://msdn.microsoft.com/en-us/library/windows/apps/windows.system.threading.threadpool.aspx
+    //
+    // For compatibility sake, 0 will be returned here.
+    return (0);
+}
+
+extern "C"
+void
+SDL_SYS_WaitThread(SDL_Thread * thread)
+{
+    if ( ! thread) {
+        return;
+    }
+
+    try {
+        std::thread * cpp_thread = (std::thread *) thread->handle;
+        if (cpp_thread->joinable()) {
+            cpp_thread->join();
+        }
+    } catch (std::system_error &) {
+        // An error occurred when joining the thread.  SDL_WaitThread does not,
+        // however, seem to provide a means to report errors to its callers
+        // though!
+    }
+}
+
+extern "C"
+void
+SDL_SYS_DetachThread(SDL_Thread * thread)
+{
+    if ( ! thread) {
+        return;
+    }
+
+    try {
+        std::thread * cpp_thread = (std::thread *) thread->handle;
+        if (cpp_thread->joinable()) {
+            cpp_thread->detach();
+        }
+    } catch (std::system_error &) {
+        // An error occurred when detaching the thread.  SDL_DetachThread does not,
+        // however, seem to provide a means to report errors to its callers
+        // though!
+    }
+}
+
+extern "C"
+SDL_TLSData *
+SDL_SYS_GetTLSData()
+{
+    return SDL_Generic_GetTLSData();
+}
+
+extern "C"
+int
+SDL_SYS_SetTLSData(SDL_TLSData *data)
+{
+    return SDL_Generic_SetTLSData(data);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/thread/stdcpp/SDL_systhread_c.h

@@ -0,0 +1,26 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2015 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: */