Sharpen: thread safety and don't retain useless value

modules/video_filter/sharpen.c

@@ -87,7 +87,7 @@ static const char *const ppsz_filter_options[] = {
 
 struct filter_sys_t
 {
-    float f_sigma;
+    vlc_mutex_t lock;
     int tab_precalc[512];
 };
 
@@ -99,10 +99,8 @@ inline static int32_t clip( int32_t a )
     return (a > 255) ? 255 : (a < 0) ? 0 : a;
 }
 
-static void init_precalc_table(filter_sys_t *p_filter)
+static void init_precalc_table(filter_sys_t *p_filter, float sigma)
 {
-    float sigma = p_filter->f_sigma;
-
     for(int i = 0; i < 512; ++i)
     {
         p_filter->tab_precalc[i] = (i - 256) * sigma;
@@ -128,13 +126,13 @@ static int Create( vlc_object_t *p_this )
     config_ChainParse( p_filter, FILTER_PREFIX, ppsz_filter_options,
                    p_filter->p_cfg );
 
-    p_filter->p_sys->f_sigma =
-        var_CreateGetFloatCommand( p_filter, FILTER_PREFIX "sigma" );
+    float sigma = var_CreateGetFloatCommand( p_filter, FILTER_PREFIX "sigma" );
+    init_precalc_table(p_filter->p_sys, sigma);
+
+    vlc_mutex_init( &p_filter->p_sys->lock );
     var_AddCallback( p_filter, FILTER_PREFIX "sigma",
                      SharpenCallback, p_filter->p_sys );
 
-    init_precalc_table(p_filter->p_sys);
-
     return VLC_SUCCESS;
 }
 
@@ -147,9 +145,11 @@ static int Create( vlc_object_t *p_this )
 static void Destroy( vlc_object_t *p_this )
 {
     filter_t *p_filter = (filter_t *)p_this;
-    var_DelCallback( p_filter, FILTER_PREFIX "sigma",
-                     SharpenCallback, p_filter->p_sys );
-    free( p_filter->p_sys );
+    filter_sys_t *p_sys = p_filter->p_sys;
+
+    var_DelCallback( p_filter, FILTER_PREFIX "sigma", SharpenCallback, p_sys );
+    vlc_mutex_destroy( &p_sys->lock );
+    free( p_sys );
 }
 
 /*****************************************************************************
@@ -185,6 +185,7 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
     i_src_pitch = p_pic->p[Y_PLANE].i_visible_pitch;
 
     /* perform convolution only on Y plane. Avoid border line. */
+    vlc_mutex_lock( &p_filter->p_sys->lock );
     for( i = 0; i < p_pic->p[Y_PLANE].i_visible_lines; i++ )
     {
         if( (i == 0) || (i == p_pic->p[Y_PLANE].i_visible_lines - 1) )
@@ -216,7 +217,7 @@ static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
                p_filter->p_sys->tab_precalc[pix + 256] );
         }
     }
-
+    vlc_mutex_unlock( &p_filter->p_sys->lock );
 
     vlc_memcpy( p_outpic->p[U_PLANE].p_pixels, p_pic->p[U_PLANE].p_pixels,
                 p_outpic->p[U_PLANE].i_lines * p_outpic->p[U_PLANE].i_pitch );
@@ -232,10 +233,11 @@ static int SharpenCallback( vlc_object_t *p_this, char const *psz_var,
                             vlc_value_t oldval, vlc_value_t newval,
                             void *p_data )
 {
-    VLC_UNUSED(p_this); VLC_UNUSED(oldval);
+    VLC_UNUSED(p_this); VLC_UNUSED(oldval); VLC_UNUSED(psz_var);
     filter_sys_t *p_sys = (filter_sys_t *)p_data;
-    if( !strcmp( psz_var, FILTER_PREFIX "sigma" ) )
-        p_sys->f_sigma = __MIN( 2., __MAX( 0., newval.f_float ) );
-    init_precalc_table(p_sys);
+
+    vlc_mutex_lock( &p_sys->lock );
+    init_precalc_table(p_sys,  __MIN( 2., __MAX( 0., newval.f_float ) ));
+    vlc_mutex_unlock( &p_sys->lock );
     return VLC_SUCCESS;
 }