threads: remove unused recursive mutex support

After removal of `MP_MUTEX_RECURSIVE` from vdpau.c there are no more
clients of recursive mutex. Remove all the code related to it. This
commit can be reverted if in the future it is needed again. For now
let's not keep dead code.

osdep/threads-posix.h

@@ -106,22 +106,13 @@ typedef pthread_t       mp_thread;
 #define MP_STATIC_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
 #define MP_STATIC_ONCE_INITIALIZER PTHREAD_ONCE_INIT
 
-static inline int mp_mutex_init_type_internal(mp_mutex *mutex, enum mp_mutex_type mtype)
+static inline int mp_mutex_init(mp_mutex *mutex)
 {
-    int mutex_type;
-    switch (mtype) {
-    case MP_MUTEX_RECURSIVE:
-        mutex_type = PTHREAD_MUTEX_RECURSIVE;
-        break;
-    case MP_MUTEX_NORMAL:
-    default:
 #ifndef NDEBUG
-        mutex_type = PTHREAD_MUTEX_ERRORCHECK;
+    int mutex_type = PTHREAD_MUTEX_ERRORCHECK;
 #else
-        mutex_type = PTHREAD_MUTEX_DEFAULT;
+    int mutex_type = PTHREAD_MUTEX_DEFAULT;
 #endif
-        break;
-    }
 
     int ret = 0;
     pthread_mutexattr_t attr;

osdep/threads-win32.h

@@ -24,64 +24,42 @@
 #include "common/common.h"
 #include "timer.h"
 
-typedef struct {
-    char use_cs;
-    union {
-        CRITICAL_SECTION cs;
-        SRWLOCK srw;
-    };
-} mp_mutex;
-
 typedef CONDITION_VARIABLE mp_cond;
 typedef INIT_ONCE          mp_once;
+typedef SRWLOCK            mp_mutex;
 typedef mp_mutex           mp_static_mutex;
 typedef HANDLE             mp_thread;
 typedef DWORD              mp_thread_id;
 
 #define MP_STATIC_COND_INITIALIZER CONDITION_VARIABLE_INIT
-#define MP_STATIC_MUTEX_INITIALIZER { .srw = SRWLOCK_INIT }
+#define MP_STATIC_MUTEX_INITIALIZER SRWLOCK_INIT
 #define MP_STATIC_ONCE_INITIALIZER INIT_ONCE_STATIC_INIT
 
-static inline int mp_mutex_init_type_internal(mp_mutex *mutex, enum mp_mutex_type mtype)
+static inline int mp_mutex_init(mp_mutex *mutex)
 {
-    mutex->use_cs = mtype == MP_MUTEX_RECURSIVE;
-    if (mutex->use_cs)
-        return !InitializeCriticalSectionEx(&mutex->cs, 0, 0);
-    InitializeSRWLock(&mutex->srw);
+    InitializeSRWLock(mutex);
     return 0;
 }
 
 static inline int mp_mutex_destroy(mp_mutex *mutex)
 {
-    if (mutex->use_cs)
-        DeleteCriticalSection(&mutex->cs);
     return 0;
 }
 
 static inline int mp_mutex_lock(mp_mutex *mutex)
 {
-    if (mutex->use_cs) {
-        EnterCriticalSection(&mutex->cs);
-    } else {
-        AcquireSRWLockExclusive(&mutex->srw);
-    }
+    AcquireSRWLockExclusive(mutex);
     return 0;
 }
 
 static inline int mp_mutex_trylock(mp_mutex *mutex)
 {
-    if (mutex->use_cs)
-        return !TryEnterCriticalSection(&mutex->cs);
-    return !TryAcquireSRWLockExclusive(&mutex->srw);
+    return !TryAcquireSRWLockExclusive(mutex);
 }
 
 static inline int mp_mutex_unlock(mp_mutex *mutex)
 {
-    if (mutex->use_cs) {
-        LeaveCriticalSection(&mutex->cs);
-    } else {
-        ReleaseSRWLockExclusive(&mutex->srw);
-    }
+    ReleaseSRWLockExclusive(mutex);
     return 0;
 }
 
@@ -116,14 +94,8 @@ static inline int mp_cond_timedwait(mp_cond *cond, mp_mutex *mutex, int64_t time
 
     int ret = 0;
     int64_t hrt = mp_start_hires_timers(MP_TIME_MS_TO_NS(timeout));
-    BOOL bRet;
 
-    if (mutex->use_cs) {
-        bRet = SleepConditionVariableCS(cond, &mutex->cs, timeout);
-    } else {
-        bRet = SleepConditionVariableSRW(cond, &mutex->srw, timeout, 0);
-    }
-    if (bRet == FALSE)
+    if (!SleepConditionVariableSRW(cond, mutex, timeout, 0))
         ret = GetLastError() == ERROR_TIMEOUT ? ETIMEDOUT : EINVAL;
 
     mp_end_hires_timers(hrt);

osdep/threads.h

@@ -3,17 +3,6 @@
 
 #include "config.h"
 
-enum mp_mutex_type {
-    MP_MUTEX_NORMAL = 0,
-    MP_MUTEX_RECURSIVE,
-};
-
-#define mp_mutex_init(mutex) \
-    mp_mutex_init_type(mutex, MP_MUTEX_NORMAL)
-
-#define mp_mutex_init_type(mutex, mtype) \
-    mp_mutex_init_type_internal(mutex, mtype)
-
 #if HAVE_WIN32_THREADS
 #include "threads-win32.h"
 #else