Signal can_rewind for use by user interfaces.

(cherry picked from commit: 3a632c159fd106e8150aef6dc6b6b41903009989)
Signed-off-by: Jean-Paul Saman <jpsaman@videolan.org>

src/control/media_player.c

@@ -922,16 +922,24 @@ 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 );
 }
@@ -942,12 +950,19 @@ 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

@@ -1628,6 +1628,7 @@ 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 )
@@ -2179,6 +2180,7 @@ 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 );
+        var_SetBool( p_input, "can-rewind", !in->b_rescale_ts );
 
         int ret = demux_Control( in->p_demux, DEMUX_CAN_SEEK,
                         &val.b_bool );
@@ -2263,7 +2265,10 @@ 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 );
+            var_SetBool( p_input, "can-rewind", !in->b_rescale_ts );
+
             access_Control( in->p_access, ACCESS_CAN_SEEK,
                              &val.b_bool );
             var_Set( p_input, "seekable", val );

src/input/var.c

@@ -66,6 +66,7 @@ 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 * );
 
@@ -471,6 +472,11 @@ void input_ConfigVarInit ( input_thread_t *p_input )
     var_Create( p_input, "can-pause", VLC_VAR_BOOL );
     val.b_bool = true; /* Fixed later*/
     var_Change( p_input, "can-pause", VLC_VAR_SETVALUE, &val, NULL );
+
+    var_Create( p_input, "can-rewind", VLC_VAR_BOOL );
+    val.b_bool = false;
+    var_Change( p_input, "can-rewind", VLC_VAR_SETVALUE, &val, NULL );
+
     var_Create( p_input, "teletext-es", VLC_VAR_INTEGER );
     var_SetInteger( p_input, "teletext-es", -1 );
 
@@ -502,6 +508,7 @@ 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 )
 {
@@ -511,6 +518,7 @@ static void InputDelCallbacks( input_thread_t *p_input,
                          p_callbacks[i].psz_name,
                          p_callbacks[i].callback, NULL );
 }
+
 /*****************************************************************************
  * All Callbacks:
  *****************************************************************************/
@@ -549,7 +557,6 @@ static int RateCallback( vlc_object_t *p_this, char const *psz_cmd,
     {
         input_ControlPush( p_input, INPUT_CONTROL_SET_RATE, &newval );
     }
-
     return VLC_SUCCESS;
 }