Allow usage of the new Condition Variable code with Critical Sections

Vista and later provide the SleepConditionVariableCS() function for this.

Since SDL_syscond_srw.c doesn't require SRW locks anymore, rename it to
SDL_syscond_cv.c which better reflects the implementation of condition
variables rather than the implementation of mutexes.

Fixes #4051.

src/thread/windows/SDL_syscond_cv.c

@@ -0,0 +1,299 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2021 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"
+
+#include "SDL_hints.h"
+#include "SDL_thread.h"
+
+#include "../generic/SDL_syscond_c.h"
+#include "SDL_sysmutex_c.h"
+
+typedef SDL_cond * (*pfnSDL_CreateCond)(void);
+typedef void (*pfnSDL_DestroyCond)(SDL_cond *);
+typedef int (*pfnSDL_CondSignal)(SDL_cond *);
+typedef int (*pfnSDL_CondBroadcast)(SDL_cond *);
+typedef int (*pfnSDL_CondWait)(SDL_cond *, SDL_mutex *);
+typedef int (*pfnSDL_CondWaitTimeout)(SDL_cond *, SDL_mutex *, Uint32);
+
+typedef struct SDL_cond_impl_t
+{
+    pfnSDL_CreateCond       Create;
+    pfnSDL_DestroyCond      Destroy;
+    pfnSDL_CondSignal       Signal;
+    pfnSDL_CondBroadcast    Broadcast;
+    pfnSDL_CondWait         Wait;
+    pfnSDL_CondWaitTimeout  WaitTimeout;
+} SDL_cond_impl_t;
+
+/* Implementation will be chosen at runtime based on available Kernel features */
+static SDL_cond_impl_t SDL_cond_impl_active = {0};
+
+
+/**
+ * Native Windows Condition Variable (SRW Locks)
+ */
+
+#ifndef CONDITION_VARIABLE_INIT
+#define CONDITION_VARIABLE_INIT {0}
+typedef struct CONDITION_VARIABLE {
+    PVOID Ptr;
+} CONDITION_VARIABLE, *PCONDITION_VARIABLE;
+#endif
+
+#if __WINRT__
+#define pWakeConditionVariable WakeConditionVariable
+#define pWakeAllConditionVariable WakeAllConditionVariable
+#define pSleepConditionVariableSRW SleepConditionVariableSRW
+#define pSleepConditionVariableCS SleepConditionVariableCS
+#else
+typedef VOID(WINAPI *pfnWakeConditionVariable)(PCONDITION_VARIABLE);
+typedef VOID(WINAPI *pfnWakeAllConditionVariable)(PCONDITION_VARIABLE);
+typedef BOOL(WINAPI *pfnSleepConditionVariableSRW)(PCONDITION_VARIABLE, PSRWLOCK, DWORD, ULONG);
+typedef BOOL(WINAPI* pfnSleepConditionVariableCS)(PCONDITION_VARIABLE, PCRITICAL_SECTION, DWORD);
+
+static pfnWakeConditionVariable pWakeConditionVariable = NULL;
+static pfnWakeAllConditionVariable pWakeAllConditionVariable = NULL;
+static pfnSleepConditionVariableSRW pSleepConditionVariableSRW = NULL;
+static pfnSleepConditionVariableCS pSleepConditionVariableCS = NULL;
+#endif
+
+typedef struct SDL_cond_cv
+{
+    CONDITION_VARIABLE cond;
+} SDL_cond_cv;
+
+
+static SDL_cond *
+SDL_CreateCond_cv(void)
+{
+    SDL_cond_cv *cond;
+
+    /* Relies on CONDITION_VARIABLE_INIT == 0. */
+    cond = (SDL_cond_cv *) SDL_calloc(1, sizeof(*cond));
+    if (!cond) {
+        SDL_OutOfMemory();
+    }
+
+    return (SDL_cond *)cond;
+}
+
+static void
+SDL_DestroyCond_cv(SDL_cond * cond)
+{
+    if (cond) {
+        /* There are no kernel allocated resources */
+        SDL_free(cond);
+    }
+}
+
+static int
+SDL_CondSignal_cv(SDL_cond * _cond)
+{
+    SDL_cond_cv *cond = (SDL_cond_cv *)_cond;
+    if (!cond) {
+        return SDL_SetError("Passed a NULL condition variable");
+    }
+
+    pWakeConditionVariable(&cond->cond);
+
+    return 0;
+}
+
+static int
+SDL_CondBroadcast_cv(SDL_cond * _cond)
+{
+    SDL_cond_cv *cond = (SDL_cond_cv *)_cond;
+    if (!cond) {
+        return SDL_SetError("Passed a NULL condition variable");
+    }
+
+    pWakeAllConditionVariable(&cond->cond);
+
+    return 0;
+}
+
+static int
+SDL_CondWaitTimeout_cv(SDL_cond * _cond, SDL_mutex * _mutex, Uint32 ms)
+{
+    SDL_cond_cv *cond = (SDL_cond_cv *)_cond;
+    DWORD timeout;
+    int ret;
+
+    if (!cond) {
+        return SDL_SetError("Passed a NULL condition variable");
+    }
+    if (!_mutex) {
+        return SDL_SetError("Passed a NULL mutex");
+    }
+
+    if (ms == SDL_MUTEX_MAXWAIT) {
+        timeout = INFINITE;
+    } else {
+        timeout = (DWORD) ms;
+    }
+
+    if (SDL_mutex_impl_active.Type == SDL_MUTEX_SRW) {
+        SDL_mutex_srw *mutex = (SDL_mutex_srw *)_mutex;
+
+        if (mutex->count != 1 || mutex->owner != GetCurrentThreadId()) {
+            return SDL_SetError("Passed mutex is not locked or locked recursively");
+        }
+
+        /* The mutex must be updated to the released state */
+        mutex->count = 0;
+        mutex->owner = 0;
+
+        if (pSleepConditionVariableSRW(&cond->cond, &mutex->srw, timeout, 0) == FALSE) {
+            if (GetLastError() == ERROR_TIMEOUT) {
+                ret = SDL_MUTEX_TIMEDOUT;
+            } else {
+                ret = SDL_SetError("SleepConditionVariableSRW() failed");
+            }
+        } else {
+            ret = 0;
+        }
+
+        /* The mutex is owned by us again, regardless of status of the wait */
+        SDL_assert(mutex->count == 0 && mutex->owner == 0);
+        mutex->count = 1;
+        mutex->owner = GetCurrentThreadId();
+    } else {
+        SDL_mutex_cs *mutex = (SDL_mutex_cs *)_mutex;
+
+        SDL_assert(SDL_mutex_impl_active.Type == SDL_MUTEX_CS);
+
+        if (pSleepConditionVariableCS(&cond->cond, &mutex->cs, timeout) == FALSE) {
+            if (GetLastError() == ERROR_TIMEOUT) {
+                ret = SDL_MUTEX_TIMEDOUT;
+            } else {
+                ret = SDL_SetError("SleepConditionVariableCS() failed");
+            }
+        } else {
+            ret = 0;
+        }
+    }
+
+    return ret;
+}
+
+static int
+SDL_CondWait_cv(SDL_cond * cond, SDL_mutex * mutex) {
+    return SDL_CondWaitTimeout_cv(cond, mutex, SDL_MUTEX_MAXWAIT);
+}
+
+static const SDL_cond_impl_t SDL_cond_impl_cv =
+{
+    &SDL_CreateCond_cv,
+    &SDL_DestroyCond_cv,
+    &SDL_CondSignal_cv,
+    &SDL_CondBroadcast_cv,
+    &SDL_CondWait_cv,
+    &SDL_CondWaitTimeout_cv,
+};
+
+/**
+ * Generic Condition Variable implementation using SDL_mutex and SDL_sem
+ */
+
+static const SDL_cond_impl_t SDL_cond_impl_generic =
+{
+    &SDL_CreateCond_generic,
+    &SDL_DestroyCond_generic,
+    &SDL_CondSignal_generic,
+    &SDL_CondBroadcast_generic,
+    &SDL_CondWait_generic,
+    &SDL_CondWaitTimeout_generic,
+};
+
+
+SDL_cond *
+SDL_CreateCond(void)
+{
+    if (SDL_cond_impl_active.Create == NULL) {
+        /* Default to generic implementation, works with all mutex implementations */
+        const SDL_cond_impl_t * impl = &SDL_cond_impl_generic;
+
+        if (SDL_mutex_impl_active.Type == SDL_MUTEX_INVALID) {
+            /* The mutex implementation isn't decided yet, trigger it */
+            SDL_mutex *mutex = SDL_CreateMutex();
+            if (!mutex) {
+                return NULL;
+            }
+            SDL_DestroyMutex(mutex);
+
+            SDL_assert(SDL_mutex_impl_active.Type != SDL_MUTEX_INVALID);
+        }
+
+#if __WINRT__
+        /* Link statically on this platform */
+        impl = &SDL_cond_impl_cv;
+#else
+        {
+            HMODULE kernel32 = GetModuleHandle(TEXT("kernel32.dll"));
+            if (kernel32) {
+                pWakeConditionVariable = (pfnWakeConditionVariable) GetProcAddress(kernel32, "WakeConditionVariable");
+                pWakeAllConditionVariable = (pfnWakeAllConditionVariable) GetProcAddress(kernel32, "WakeAllConditionVariable");
+                pSleepConditionVariableSRW = (pfnSleepConditionVariableSRW) GetProcAddress(kernel32, "SleepConditionVariableSRW");
+                pSleepConditionVariableCS = (pfnSleepConditionVariableCS) GetProcAddress(kernel32, "SleepConditionVariableCS");
+                if (pWakeConditionVariable && pWakeAllConditionVariable && pSleepConditionVariableSRW && pSleepConditionVariableCS) {
+                    /* Use the Windows provided API */
+                    impl = &SDL_cond_impl_cv;
+                }
+            }
+        }
+#endif
+
+        SDL_memcpy(&SDL_cond_impl_active, impl, sizeof(SDL_cond_impl_active));
+    }
+    return SDL_cond_impl_active.Create();
+}
+
+void
+SDL_DestroyCond(SDL_cond * cond)
+{
+    SDL_cond_impl_active.Destroy(cond);
+}
+
+int
+SDL_CondSignal(SDL_cond * cond)
+{
+    return SDL_cond_impl_active.Signal(cond);
+}
+
+int
+SDL_CondBroadcast(SDL_cond * cond)
+{
+    return SDL_cond_impl_active.Broadcast(cond);
+}
+
+int
+SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
+{
+    return SDL_cond_impl_active.WaitTimeout(cond, mutex, ms);
+}
+
+int
+SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
+{
+    return SDL_cond_impl_active.Wait(cond, mutex);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */