Signal can_rewind for use by user interfaces.

src/control/media_player.c

@@ -1044,16 +1044,24 @@ void libvlc_media_player_set_rate(
 {
     input_thread_t *p_input_thread;
     vlc_value_t val;
+    bool b_can_rewind;
 
-    if( rate <= 0 )
+    if( rate != 0 )
         RAISEVOID( "Rate value is invalid" );
 
-    val.i_int = 1000.0f/rate;
-
     p_input_thread = libvlc_get_input_thread ( p_mi, p_e);
-    if ( !p_input_thread )
+    if( !p_input_thread )
         return;
 
+    b_can_rewind = var_GetBool( p_input_thread, "can-rewind" );
+    if( (rate < 0) && !b_can_rewind )
+    {
+        vlc_object_release( p_input_thread );
+        libvlc_exception_raise( p_e, "Rate value is invalid" );
+        return;
+    }
+
+    val.i_int = 1000.0f/rate;
     var_Set( p_input_thread, "rate", val );
     vlc_object_release( p_input_thread );
 }
@@ -1064,12 +1072,19 @@ float libvlc_media_player_get_rate(
 {
     input_thread_t *p_input_thread;
     vlc_value_t val;
+    bool b_can_rewind;
 
-    p_input_thread = libvlc_get_input_thread ( p_mi, p_e);
-    if ( !p_input_thread )
-        return -1.0;
+    p_input_thread = libvlc_get_input_thread ( p_mi, p_e );
+    if( !p_input_thread )
+        return 0.0;  /* rate < 0 indicates rewind */
 
     var_Get( p_input_thread, "rate", &val );
+    b_can_rewind = var_GetBool( p_input_thread, "can-rewind" );
+    if( (val.i_int < 0) && !b_can_rewind )
+    {
+        libvlc_exception_raise( p_e, "invalid rate" );
+        return 0.0;
+    }
     vlc_object_release( p_input_thread );
 
     return (float)1000.0f/val.i_int;

src/input/input.c

@@ -1746,6 +1746,7 @@ static bool Control( input_thread_t *p_input, int i_type,
                         i_error = i_test_e;
                     }
                 }
+
                 assert( i_idx >= 0 && ppi_factor[i_idx][0] != 0 );
 
                 if( i_type == INPUT_CONTROL_SET_RATE_SLOWER )
@@ -2359,6 +2360,7 @@ static int InputSourceInit( input_thread_t *p_input,
                             &in->b_can_pause ) )
             in->b_can_pause = false;
         var_SetBool( p_input, "can-pause", in->b_can_pause || !in->b_can_pace_control ); /* XXX temporary because of es_out_timeshift*/
+        var_SetBool( p_input, "can-rewind", !in->b_rescale_ts && !in->b_can_pace_control );
 
         int ret = demux_Control( in->p_demux, DEMUX_CAN_SEEK,
                         &val.b_bool );
@@ -2443,6 +2445,8 @@ static int InputSourceInit( input_thread_t *p_input,
             access_Control( in->p_access, ACCESS_CAN_PAUSE,
                              &in->b_can_pause );
             var_SetBool( p_input, "can-pause", in->b_can_pause || !in->b_can_pace_control ); /* XXX temporary because of es_out_timeshift*/
+            var_SetBool( p_input, "can-rewind", !in->b_rescale_ts && !in->b_can_pace_control );
+
             access_Control( in->p_access, ACCESS_CAN_SEEK,
                              &val.b_bool );
             var_Set( p_input, "seekable", val );

src/input/var.c

@@ -73,6 +73,7 @@ typedef struct
     const char *psz_name;
     vlc_callback_t callback;
 } vlc_input_callback_t;
+
 static void InputAddCallbacks( input_thread_t *, const vlc_input_callback_t * );
 static void InputDelCallbacks( input_thread_t *, const vlc_input_callback_t * );
 
@@ -478,6 +479,9 @@ void input_ConfigVarInit ( input_thread_t *p_input )
     var_Create( p_input, "can-pause", VLC_VAR_BOOL );
     var_SetBool( p_input, "can-pause", true ); /* Fixed later*/
 
+    var_Create( p_input, "can-rewind", VLC_VAR_BOOL );
+    var_SetBool( p_input, "can-rewind", false );
+
     var_Create( p_input, "can-record", VLC_VAR_BOOL );
     var_SetBool( p_input, "can-record", false ); /* Fixed later*/
 
@@ -521,6 +525,7 @@ static void InputAddCallbacks( input_thread_t *p_input,
                          p_callbacks[i].psz_name,
                          p_callbacks[i].callback, NULL );
 }
+
 static void InputDelCallbacks( input_thread_t *p_input,
                                const vlc_input_callback_t *p_callbacks )
 {
@@ -530,6 +535,7 @@ static void InputDelCallbacks( input_thread_t *p_input,
                          p_callbacks[i].psz_name,
                          p_callbacks[i].callback, NULL );
 }
+
 /*****************************************************************************
  * All Callbacks:
  *****************************************************************************/
@@ -568,7 +574,6 @@ static int RateCallback( vlc_object_t *p_this, char const *psz_cmd,
     {
         input_ControlPush( p_input, INPUT_CONTROL_SET_RATE, &newval );
     }
-
     return VLC_SUCCESS;
 }
 
@@ -812,6 +817,7 @@ static int RecordCallback( vlc_object_t *p_this, char const *psz_cmd,
 
     return VLC_SUCCESS;
 }
+
 static int FrameNextCallback( vlc_object_t *p_this, char const *psz_cmd,
                               vlc_value_t oldval, vlc_value_t newval,
                               void *p_data )