Merge changes from topic 'win-threading-compat'

* changes:
  Makefile.vc: enable WEBP_USE_THREAD for windows phone
  thread: use CreateThread for windows phone
  thread: use WaitForSingleObjectEx if available
  thread: use InitializeCriticalSectionEx if available
  thread: use native windows cond var if available

Makefile.vc

@@ -39,7 +39,7 @@ LNKLIB     = lib.exe $(NOLOGO)
 MT         = mt.exe $(NOLOGO)
 
 !IF "$(ARCH)" == "ARM"
-CFLAGS = $(CFLAGS) /DWINAPI_FAMILY=WINAPI_FAMILY_PHONE_APP
+CFLAGS = $(CFLAGS) /DWINAPI_FAMILY=WINAPI_FAMILY_PHONE_APP /DWEBP_USE_THREAD
 !ELSE
 CFLAGS = $(CFLAGS) /DHAVE_WINCODEC_H /DWEBP_USE_THREAD
 !ENDIF

src/utils/thread.c

@@ -23,11 +23,26 @@
 #include <windows.h>
 typedef HANDLE pthread_t;
 typedef CRITICAL_SECTION pthread_mutex_t;
+
+#if _WIN32_WINNT >= 0x0600  // Windows Vista / Server 2008 or greater
+#define USE_WINDOWS_CONDITION_VARIABLE
+typedef CONDITION_VARIABLE pthread_cond_t;
+#else
 typedef struct {
   HANDLE waiting_sem_;
   HANDLE received_sem_;
   HANDLE signal_event_;
 } pthread_cond_t;
+#endif  // _WIN32_WINNT >= 0x600
+
+#ifndef WINAPI_FAMILY_PARTITION
+#define WINAPI_PARTITION_DESKTOP 1
+#define WINAPI_FAMILY_PARTITION(x) x
+#endif
+
+#if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#define USE_CREATE_THREAD
+#endif
 
 #else  // !_WIN32
 
@@ -52,15 +67,29 @@ struct WebPWorkerImpl {
 #define THREADFN unsigned int __stdcall
 #define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val)
 
+#if _WIN32_WINNT >= 0x0501  // Windows XP or greater
+#define WaitForSingleObject(obj, timeout) \
+  WaitForSingleObjectEx(obj, timeout, FALSE /*bAlertable*/)
+#endif
+
 static int pthread_create(pthread_t* const thread, const void* attr,
                           unsigned int (__stdcall *start)(void*), void* arg) {
   (void)attr;
+#ifdef USE_CREATE_THREAD
+  *thread = CreateThread(NULL,   /* lpThreadAttributes */
+                         0,      /* dwStackSize */
+                         start,
+                         arg,
+                         0,      /* dwStackSize */
+                         NULL);  /* lpThreadId */
+#else
   *thread = (pthread_t)_beginthreadex(NULL,   /* void *security */
                                       0,      /* unsigned stack_size */
                                       start,
                                       arg,
                                       0,      /* unsigned initflag */
                                       NULL);  /* unsigned *thrdaddr */
+#endif
   if (*thread == NULL) return 1;
   SetThreadPriority(*thread, THREAD_PRIORITY_ABOVE_NORMAL);
   return 0;
@@ -75,7 +104,11 @@ static int pthread_join(pthread_t thread, void** value_ptr) {
 // Mutex
 static int pthread_mutex_init(pthread_mutex_t* const mutex, void* mutexattr) {
   (void)mutexattr;
+#if _WIN32_WINNT >= 0x0600  // Windows Vista / Server 2008 or greater
+  InitializeCriticalSectionEx(mutex, 0 /*dwSpinCount*/, 0 /*Flags*/);
+#else
   InitializeCriticalSection(mutex);
+#endif
   return 0;
 }
 
@@ -97,14 +130,21 @@ static int pthread_mutex_destroy(pthread_mutex_t* const mutex) {
 // Condition
 static int pthread_cond_destroy(pthread_cond_t* const condition) {
   int ok = 1;
+#ifdef USE_WINDOWS_CONDITION_VARIABLE
+  (void)condition;
+#else
   ok &= (CloseHandle(condition->waiting_sem_) != 0);
   ok &= (CloseHandle(condition->received_sem_) != 0);
   ok &= (CloseHandle(condition->signal_event_) != 0);
+#endif
   return !ok;
 }
 
 static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) {
   (void)cond_attr;
+#ifdef USE_WINDOWS_CONDITION_VARIABLE
+  InitializeConditionVariable(condition);
+#else
   condition->waiting_sem_ = CreateSemaphore(NULL, 0, 1, NULL);
   condition->received_sem_ = CreateSemaphore(NULL, 0, 1, NULL);
   condition->signal_event_ = CreateEvent(NULL, FALSE, FALSE, NULL);
@@ -114,11 +154,15 @@ static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) {
     pthread_cond_destroy(condition);
     return 1;
   }
+#endif
   return 0;
 }
 
 static int pthread_cond_signal(pthread_cond_t* const condition) {
   int ok = 1;
+#ifdef USE_WINDOWS_CONDITION_VARIABLE
+  WakeConditionVariable(condition);
+#else
   if (WaitForSingleObject(condition->waiting_sem_, 0) == WAIT_OBJECT_0) {
     // a thread is waiting in pthread_cond_wait: allow it to be notified
     ok = SetEvent(condition->signal_event_);
@@ -127,12 +171,16 @@ static int pthread_cond_signal(pthread_cond_t* const condition) {
     ok &= (WaitForSingleObject(condition->received_sem_, INFINITE) !=
            WAIT_OBJECT_0);
   }
+#endif
   return !ok;
 }
 
 static int pthread_cond_wait(pthread_cond_t* const condition,
                              pthread_mutex_t* const mutex) {
   int ok;
+#ifdef USE_WINDOWS_CONDITION_VARIABLE
+  ok = SleepConditionVariableCS(condition, mutex, INFINITE);
+#else
   // note that there is a consumer available so the signal isn't dropped in
   // pthread_cond_signal
   if (!ReleaseSemaphore(condition->waiting_sem_, 1, NULL))
@@ -143,6 +191,7 @@ static int pthread_cond_wait(pthread_cond_t* const condition,
         WAIT_OBJECT_0);
   ok &= ReleaseSemaphore(condition->received_sem_, 1, NULL);
   pthread_mutex_lock(mutex);
+#endif
   return !ok;
 }