De-inline mutex and condition functions. Document them.

The overhead of calling a function is rather tiny compared to the
overhead of doing the system call these typically involve.

Also refs #1392

include/vlc_threads.h

@@ -132,10 +132,15 @@ typedef DWORD   vlc_threadvar_t;
  *****************************************************************************/
 VLC_EXPORT( int,  vlc_mutex_init,    ( vlc_mutex_t * ) );
 VLC_EXPORT( int,  vlc_mutex_init_recursive, ( vlc_mutex_t * ) );
-VLC_EXPORT( void,  __vlc_mutex_destroy, ( const char *, int, vlc_mutex_t * ) );
+VLC_EXPORT( void, vlc_mutex_destroy, ( vlc_mutex_t * ) );
+VLC_EXPORT( void, vlc_mutex_lock, ( vlc_mutex_t * ) );
+VLC_EXPORT( void, vlc_mutex_unlock, ( vlc_mutex_t * ) );
 VLC_EXPORT( int,  vlc_cond_init,     ( vlc_cond_t * ) );
-VLC_EXPORT( void,  __vlc_cond_destroy,  ( const char *, int, vlc_cond_t * ) );
+VLC_EXPORT( void, vlc_cond_destroy,  ( vlc_cond_t * ) );
+VLC_EXPORT( void, vlc_cond_signal, (vlc_cond_t *) );
 VLC_EXPORT( void, vlc_cond_broadcast, (vlc_cond_t *) );
+VLC_EXPORT( void, vlc_cond_wait, (vlc_cond_t *, vlc_mutex_t *) );
+VLC_EXPORT( int, vlc_cond_timedwait, (vlc_cond_t *, vlc_mutex_t *, mtime_t) );
 VLC_EXPORT( int, vlc_threadvar_create, (vlc_threadvar_t * , void (*) (void *) ) );
 VLC_EXPORT( void, vlc_threadvar_delete, (vlc_threadvar_t *) );
 VLC_EXPORT( int,  __vlc_thread_create, ( vlc_object_t *, const char *, int, const char *, void * ( * ) ( vlc_object_t * ), int, bool ) );
@@ -160,80 +165,15 @@ enum {
 
 #define vlc_thread_ready vlc_object_signal
 
-/*****************************************************************************
- * vlc_mutex_lock: lock a mutex
- *****************************************************************************/
-#define vlc_mutex_lock( P_MUTEX )                                           \
-    __vlc_mutex_lock( __FILE__, __LINE__, P_MUTEX )
-
 VLC_EXPORT(void, vlc_thread_fatal, (const char *action, int error, const char *function, const char *file, unsigned line));
 
-#if defined(LIBVLC_USE_PTHREAD)
-# define VLC_THREAD_ASSERT( action ) \
-    if (val) \
-        vlc_thread_fatal (action, val, __func__, psz_file, i_line)
-#else
-# define VLC_THREAD_ASSERT ((void)(val))
-#endif
-
-static inline void __vlc_mutex_lock( const char * psz_file, int i_line,
-                                    vlc_mutex_t * p_mutex )
-{
 #if defined(LIBVLC_USE_PTHREAD)
 #   define vlc_assert_locked( m ) \
            assert (pthread_mutex_lock (m) == EDEADLK)
-    int val = pthread_mutex_lock( p_mutex );
-    VLC_THREAD_ASSERT ("locking mutex");
-
-#elif defined( UNDER_CE )
-    (void)psz_file; (void)i_line;
-
-    EnterCriticalSection( &p_mutex->csection );
-
-#elif defined( WIN32 )
-    (void)psz_file; (void)i_line;
-
-    WaitForSingleObject( *p_mutex, INFINITE );
-
-#endif
-}
-
-#ifndef vlc_assert_locked
+#else
 # define vlc_assert_locked( m ) (void)m
 #endif
 
-/*****************************************************************************
- * vlc_mutex_unlock: unlock a mutex
- *****************************************************************************/
-#define vlc_mutex_unlock( P_MUTEX )                                         \
-    __vlc_mutex_unlock( __FILE__, __LINE__, P_MUTEX )
-
-static inline void __vlc_mutex_unlock( const char * psz_file, int i_line,
-                                      vlc_mutex_t *p_mutex )
-{
-#if defined(LIBVLC_USE_PTHREAD)
-    int val = pthread_mutex_unlock( p_mutex );
-    VLC_THREAD_ASSERT ("unlocking mutex");
-
-#elif defined( UNDER_CE )
-    (void)psz_file; (void)i_line;
-
-    LeaveCriticalSection( &p_mutex->csection );
-
-#elif defined( WIN32 )
-    (void)psz_file; (void)i_line;
-
-    ReleaseMutex( *p_mutex );
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_mutex_destroy: destroy a mutex
- *****************************************************************************/
-#define vlc_mutex_destroy( P_MUTEX )                                        \
-    __vlc_mutex_destroy( __FILE__, __LINE__, P_MUTEX )
-
 /**
  * Save the cancellation state and disable cancellation for the calling thread.
  * This function must be called before entering a piece of code that is not
@@ -339,137 +279,6 @@ static inline void vlc_cleanup_lock (void *lock)
 }
 #define mutex_cleanup_push( lock ) vlc_cleanup_push (vlc_cleanup_lock, lock)
 
-/*****************************************************************************
- * vlc_cond_signal: start a thread on condition completion
- *****************************************************************************/
-#define vlc_cond_signal( P_COND )                                           \
-    __vlc_cond_signal( __FILE__, __LINE__, P_COND )
-
-static inline void __vlc_cond_signal( const char * psz_file, int i_line,
-                                      vlc_cond_t *p_condvar )
-{
-#if defined(LIBVLC_USE_PTHREAD)
-    int val = pthread_cond_signal( p_condvar );
-    VLC_THREAD_ASSERT ("signaling condition variable");
-
-#elif defined( UNDER_CE ) || defined( WIN32 )
-    (void)psz_file; (void)i_line;
-
-    /* Release one waiting thread if one is available. */
-    /* For this trick to work properly, the vlc_cond_signal must be surrounded
-     * by a mutex. This will prevent another thread from stealing the signal */
-    /* PulseEvent() only works if none of the waiting threads is suspended.
-     * This is particularily problematic under a debug session.
-     * as documented in http://support.microsoft.com/kb/q173260/ */
-    PulseEvent( *p_condvar );
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_cond_wait: wait until condition completion
- *****************************************************************************/
-#define vlc_cond_wait( P_COND, P_MUTEX )                                     \
-    __vlc_cond_wait( __FILE__, __LINE__, P_COND, P_MUTEX  )
-
-static inline void __vlc_cond_wait( const char * psz_file, int i_line,
-                                    vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex )
-{
-#if defined(LIBVLC_USE_PTHREAD)
-    int val = pthread_cond_wait( p_condvar, p_mutex );
-    VLC_THREAD_ASSERT ("waiting on condition");
-
-#elif defined( UNDER_CE )
-    LeaveCriticalSection( &p_mutex->csection );
-    WaitForSingleObject( *p_condvar, INFINITE );
-
-    /* Reacquire the mutex before returning. */
-    vlc_mutex_lock( p_mutex );
-
-#elif defined( WIN32 )
-    do
-        vlc_testcancel ();
-    while (SignalObjectAndWait (*p_mutex, *p_condvar, INFINITE, TRUE)
-            == WAIT_IO_COMPLETION);
-
-    /* Reacquire the mutex before returning. */
-    vlc_mutex_lock( p_mutex );
-
-    (void)psz_file; (void)i_line;
-
-#endif
-}
-
-
-/*****************************************************************************
- * vlc_cond_timedwait: wait until condition completion or expiration
- *****************************************************************************
- * Returns 0 if object signaled, an error code in case of timeout or error.
- *****************************************************************************/
-#define vlc_cond_timedwait( c, m, d ) \
-    __vlc_cond_timedwait( __FILE__, __LINE__, c, m, check_deadline(d) )
-
-static inline int __vlc_cond_timedwait( const char * psz_file, int i_line,
-                                        vlc_cond_t *p_condvar,
-                                        vlc_mutex_t *p_mutex,
-                                        mtime_t deadline )
-{
-#if defined(LIBVLC_USE_PTHREAD)
-    lldiv_t d = lldiv( deadline, CLOCK_FREQ );
-    struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
-
-    int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
-    if (val != ETIMEDOUT)
-        VLC_THREAD_ASSERT ("timed-waiting on condition");
-    return val;
-
-#elif defined( UNDER_CE )
-    mtime_t delay_ms = (deadline - mdate()) / (CLOCK_FREQ / 1000);
-    DWORD result;
-    if( delay_ms < 0 )
-        delay_ms = 0;
-
-    LeaveCriticalSection( &p_mutex->csection );
-    result = WaitForSingleObject( *p_condvar, delay_ms );
-
-    /* Reacquire the mutex before returning. */
-    vlc_mutex_lock( p_mutex );
-
-    (void)psz_file; (void)i_line;
-
-    return (result == WAIT_TIMEOUT) ? ETIMEDOUT : 0;
-
-#elif defined( WIN32 )
-    DWORD result;
-
-    (void)psz_file; (void)i_line;
-
-    do
-    {
-        vlc_testcancel ();
-
-        mtime_t total = (deadline - mdate ())/1000;
-        if( total < 0 )
-            total = 0;
-
-        DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
-        result = SignalObjectAndWait (*p_mutex, *p_condvar, delay, TRUE);
-    }
-    while (result == WAIT_IO_COMPLETION);
-
-    /* Reacquire the mutex before return/cancel. */
-    vlc_mutex_lock (p_mutex);
-    return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_cond_destroy: destroy a condition
- *****************************************************************************/
-#define vlc_cond_destroy( P_COND )                                          \
-    __vlc_cond_destroy( __FILE__, __LINE__, P_COND )
-
 /*****************************************************************************
  * vlc_threadvar_set: create: set the value of a thread-local variable
  *****************************************************************************/

src/libvlccore.sym

@@ -427,8 +427,11 @@ VLC_CompileDomain
 VLC_CompileHost
 VLC_Compiler
 vlc_cond_broadcast
-__vlc_cond_destroy
+vlc_cond_destroy
 vlc_cond_init
+vlc_cond_signal
+vlc_cond_timedwait
+vlc_cond_wait
 vlc_config_create
 vlc_config_set
 vlc_control_cancel
@@ -463,9 +466,11 @@ vlc_memcpy
 vlc_memset
 vlc_module_create
 vlc_module_set
-__vlc_mutex_destroy
+vlc_mutex_destroy
 vlc_mutex_init
 vlc_mutex_init_recursive
+vlc_mutex_lock
+vlc_mutex_unlock
 __vlc_object_attach
 __vlc_object_create
 __vlc_object_detach

src/misc/threads.c

@@ -147,6 +147,13 @@ void vlc_thread_fatal (const char *action, int error, const char *function,
     abort ();
 }
 
+#ifndef NDEBUG
+# define VLC_THREAD_ASSERT( action ) \
+    if (val) vlc_thread_fatal (action, val, __func__, __FILE__, __LINE__)
+#else
+# define VLC_THREAD_ASSERT( action ) ((void)val)
+#endif
+
 /**
  * Per-thread cancellation data
  */
@@ -298,28 +305,70 @@ int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
 }
 
 
-/*****************************************************************************
- * vlc_mutex_destroy: destroy a mutex, inner version
- *****************************************************************************/
-void __vlc_mutex_destroy( const char * psz_file, int i_line, vlc_mutex_t *p_mutex )
+/**
+ * Destroys a mutex. The mutex must not be locked.
+ *
+ * @param p_mutex mutex to destroy
+ * @return always succeeds
+ */
+void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
 {
 #if defined( LIBVLC_USE_PTHREAD )
     int val = pthread_mutex_destroy( p_mutex );
     VLC_THREAD_ASSERT ("destroying mutex");
 
 #elif defined( UNDER_CE )
-    VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
-
     DeleteCriticalSection( &p_mutex->csection );
 
 #elif defined( WIN32 )
-    VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
-
     CloseHandle( *p_mutex );
 
 #endif
 }
 
+/**
+ * Acquires a mutex. If needed, waits for any other thread to release it.
+ * Beware of deadlocks when locking multiple mutexes at the same time,
+ * or when using mutexes from callbacks.
+ *
+ * @param p_mutex mutex initialized with vlc_mutex_init() or
+ *                vlc_mutex_init_recursive()
+ */
+void vlc_mutex_lock (vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+    int val = pthread_mutex_lock( p_mutex );
+    VLC_THREAD_ASSERT ("locking mutex");
+
+#elif defined( UNDER_CE )
+    EnterCriticalSection( &p_mutex->csection );
+
+#elif defined( WIN32 )
+    WaitForSingleObject( *p_mutex, INFINITE );
+
+#endif
+}
+
+
+/**
+ * Releases a mutex (or crashes if the mutex is not locked by the caller).
+ * @param p_mutex mutex locked with vlc_mutex_lock().
+ */
+void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+    int val = pthread_mutex_unlock( p_mutex );
+    VLC_THREAD_ASSERT ("unlocking mutex");
+
+#elif defined( UNDER_CE )
+    LeaveCriticalSection( &p_mutex->csection );
+
+#elif defined( WIN32 )
+    ReleaseMutex( *p_mutex );
+
+#endif
+}
+
 /*****************************************************************************
  * vlc_cond_init: initialize a condition variable
  *****************************************************************************/
@@ -357,23 +406,45 @@ int vlc_cond_init( vlc_cond_t *p_condvar )
 #endif
 }
 
-/*****************************************************************************
- * vlc_cond_destroy: destroy a condition, inner version
- *****************************************************************************/
-void __vlc_cond_destroy( const char * psz_file, int i_line, vlc_cond_t *p_condvar )
+/**
+ * Destroys a condition variable. No threads shall be waiting or signaling the
+ * condition.
+ * @param p_condvar condition variable to destroy
+ */
+void vlc_cond_destroy (vlc_cond_t *p_condvar)
 {
 #if defined( LIBVLC_USE_PTHREAD )
     int val = pthread_cond_destroy( p_condvar );
     VLC_THREAD_ASSERT ("destroying condition");
 
 #elif defined( UNDER_CE ) || defined( WIN32 )
-    VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
-
     CloseHandle( *p_condvar );
 
 #endif
 }
 
+/**
+ * Wakes up one thread waiting on a condition variable, if any.
+ * @param p_condvar condition variable
+ */
+void vlc_cond_signal (vlc_cond_t *p_condvar)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+    int val = pthread_cond_signal( p_condvar );
+    VLC_THREAD_ASSERT ("signaling condition variable");
+
+#elif defined( UNDER_CE ) || defined( WIN32 )
+    /* Release one waiting thread if one is available. */
+    /* For this trick to work properly, the vlc_cond_signal must be surrounded
+     * by a mutex. This will prevent another thread from stealing the signal */
+    /* PulseEvent() only works if none of the waiting threads is suspended.
+     * This is particularily problematic under a debug session.
+     * as documented in http://support.microsoft.com/kb/q173260/ */
+    PulseEvent( *p_condvar );
+
+#endif
+}
+
 /**
  * Wakes up all threads (if any) waiting on a condition variable.
  * @param p_cond condition variable
@@ -389,6 +460,124 @@ void vlc_cond_broadcast (vlc_cond_t *p_condvar)
 #endif
 }
 
+/**
+ * Waits for a condition variable. The calling thread will be suspended until
+ * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
+ * condition variable, the thread is cancelled with vlc_cancel(), or the
+ * system causes a "spurious" unsolicited wake-up.
+ *
+ * A mutex is needed to wait on a condition variable. It must <b>not</b> be
+ * a recursive mutex. Although it is possible to use the same mutex for
+ * multiple condition, it is not valid to use different mutexes for the same
+ * condition variable at the same time from different threads.
+ *
+ * In case of thread cancellation, the mutex is always locked before
+ * cancellation proceeds.
+ *
+ * The canonical way to use a condition variable to wait for event foobar is:
+ @code
+   vlc_mutex_lock (&lock);
+   mutex_cleanup_push (&lock); // release the mutex in case of cancellation
+
+   while (!foobar)
+       vlc_cond_wait (&wait, &lock);
+
+   --- foobar is now true, do something about it here --
+
+   vlc_cleanup_run (); // release the mutex
+  @endcode
+ *
+ * @param p_condvar condition variable to wait on
+ * @param p_mutex mutex which is unlocked while waiting,
+ *                then locked again when waking up.
+ * @param deadline <b>absolute</b> timeout
+ *
+ * @return 0 if the condition was signaled, an error code in case of timeout.
+ */
+void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+    int val = pthread_cond_wait( p_condvar, p_mutex );
+    VLC_THREAD_ASSERT ("waiting on condition");
+
+#elif defined( UNDER_CE )
+    LeaveCriticalSection( &p_mutex->csection );
+    WaitForSingleObject( *p_condvar, INFINITE );
+
+    /* Reacquire the mutex before returning. */
+    vlc_mutex_lock( p_mutex );
+
+#elif defined( WIN32 )
+    do
+        vlc_testcancel ();
+    while (SignalObjectAndWait (*p_mutex, *p_condvar, INFINITE, TRUE)
+            == WAIT_IO_COMPLETION);
+
+    /* Reacquire the mutex before returning. */
+    vlc_mutex_lock( p_mutex );
+
+#endif
+}
+
+/**
+ * Waits for a condition variable up to a certain date.
+ * This works like vlc_cond_wait(), except for the additional timeout.
+ *
+ * @param p_condvar condition variable to wait on
+ * @param p_mutex mutex which is unlocked while waiting,
+ *                then locked again when waking up.
+ * @param deadline <b>absolute</b> timeout
+ *
+ * @return 0 if the condition was signaled, an error code in case of timeout.
+ */
+int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
+                        mtime_t deadline)
+{
+#if defined(LIBVLC_USE_PTHREAD)
+    lldiv_t d = lldiv( deadline, CLOCK_FREQ );
+    struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
+
+    int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
+    if (val != ETIMEDOUT)
+        VLC_THREAD_ASSERT ("timed-waiting on condition");
+    return val;
+
+#elif defined( UNDER_CE )
+    mtime_t delay_ms = (deadline - mdate()) / (CLOCK_FREQ / 1000);
+    DWORD result;
+    if( delay_ms < 0 )
+        delay_ms = 0;
+
+    LeaveCriticalSection( &p_mutex->csection );
+    result = WaitForSingleObject( *p_condvar, delay_ms );
+
+    /* Reacquire the mutex before returning. */
+    vlc_mutex_lock( p_mutex );
+
+    return (result == WAIT_TIMEOUT) ? ETIMEDOUT : 0;
+
+#elif defined( WIN32 )
+    DWORD result;
+
+    do
+    {
+        vlc_testcancel ();
+
+        mtime_t total = (deadline - mdate ())/1000;
+        if( total < 0 )
+            total = 0;
+
+        DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
+        result = SignalObjectAndWait (*p_mutex, *p_condvar, delay, TRUE);
+    }
+    while (result == WAIT_IO_COMPLETION);
+
+    /* Reacquire the mutex before return/cancel. */
+    vlc_mutex_lock (p_mutex);
+    return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
+
+#endif
+}
 
 /*****************************************************************************
  * vlc_tls_create: create a thread-local variable