Fix libass w/o fontconfig

Make sure that libass does not crash even if no default font is
provided.  Additionally, fix crashes related to drawings in this and
possibly other unusual cases.

Document the default_path and default_family parameters of
ass_set_fonts.

diff --git a/libass/ass.h b/libass/ass.h
index 3684b4456e114b3cd90843079a1fa0866a9f42ac..9abe6da571635adcbfa535bb33c723152adfd568 100644 (file)
--- a/libass/ass.h
+++ b/libass/ass.h
@@ -195,6 +195,9 @@ void ass_set_line_spacing(ASS_Renderer *priv, double line_spacing);
 
 /**
  * \brief Set font lookup defaults.
+ * \param default_font path to default font to use. Must be supplied if
+ * fontconfig is disabled or unavailable.
+ * \param default_family fallback font family for fontconfig, or NULL
  * \param fc whether to use fontconfig
  * \param config path to fontconfig configuration file, or NULL.  Only relevant
  * if fontconfig is used.

diff --git a/libass/ass_drawing.c b/libass/ass_drawing.c
index 8c5f062bc6e8852023b153512d62b2297f4506fa..a3207c7c3b113e0217a6e399499d04f768845ab0 100644 (file)
--- a/libass/ass_drawing.c
+++ b/libass/ass_drawing.c
@@ -41,14 +41,15 @@ static void drawing_make_glyph(ASS_Drawing *drawing, void *fontconfig_priv,
     // This is hacky...
     glyph = (FT_OutlineGlyph) ass_font_get_glyph(fontconfig_priv, font,
                                                  (uint32_t) ' ', hint, 0);
-
-    FT_Outline_Done(drawing->ftlibrary, &glyph->outline);
-    FT_Outline_New(drawing->ftlibrary, GLYPH_INITIAL_POINTS,
-                   GLYPH_INITIAL_CONTOURS, &glyph->outline);
-
-    glyph->outline.n_contours = 0;
-    glyph->outline.n_points = 0;
-    glyph->root.advance.x = glyph->root.advance.y = 0;
+    if (glyph) {
+        FT_Outline_Done(drawing->ftlibrary, &glyph->outline);
+        FT_Outline_New(drawing->ftlibrary, GLYPH_INITIAL_POINTS,
+                       GLYPH_INITIAL_CONTOURS, &glyph->outline);
+
+        glyph->outline.n_contours = 0;
+        glyph->outline.n_points = 0;
+        glyph->root.advance.x = glyph->root.advance.y = 0;
+    }
     drawing->glyph = glyph;
 }
 
@@ -363,15 +364,17 @@ static void drawing_evaluate_curve(ASS_Drawing *drawing,
 ASS_Drawing *ass_drawing_new(void *fontconfig_priv, ASS_Font *font,
                              ASS_Hinting hint, FT_Library lib)
 {
-    ASS_Drawing* drawing;
+    ASS_Drawing *drawing;
 
     drawing = calloc(1, sizeof(*drawing));
     drawing->text = calloc(1, DRAWING_INITIAL_SIZE);
     drawing->size = DRAWING_INITIAL_SIZE;
 
     drawing->ftlibrary = lib;
-    drawing->library = font->library;
-    drawing_make_glyph(drawing, fontconfig_priv, font, hint);
+    if (font) {
+        drawing->library = font->library;
+        drawing_make_glyph(drawing, fontconfig_priv, font, hint);
+    }
 
     drawing->scale_x = 1.;
     drawing->scale_y = 1.;
@@ -386,8 +389,11 @@ ASS_Drawing *ass_drawing_new(void *fontconfig_priv, ASS_Font *font,
  */
 void ass_drawing_free(ASS_Drawing* drawing)
 {
-    FT_Done_Glyph((FT_Glyph) drawing->glyph);
-    free(drawing->text);
+    if (drawing) {
+        if (drawing->glyph)
+            FT_Done_Glyph((FT_Glyph) drawing->glyph);
+        free(drawing->text);
+    }
     free(drawing);
 }
 
@@ -423,6 +429,9 @@ FT_OutlineGlyph *ass_drawing_parse(ASS_Drawing *drawing, int raw_mode)
     ASS_DrawingToken *token;
     FT_Vector pen = {0, 0};
 
+    if (!drawing->glyph)
+        return NULL;
+
     drawing->tokens = drawing_tokenize(drawing->text);
     drawing_prepare(drawing);
 

diff --git a/libass/ass_fontconfig.c b/libass/ass_fontconfig.c
index 15bc5c7a7471c9439543641a9e246de001d70fd7..83cde1cfc953994bbd560f66807697815faadd49 100644 (file)
--- a/libass/ass_fontconfig.c
+++ b/libass/ass_fontconfig.c
@@ -551,7 +551,7 @@ FCInstance *fontconfig_init(ASS_Library *library,
 
     priv = calloc(1, sizeof(FCInstance));
 
-    priv->path_default = strdup(path);
+    priv->path_default = path ? strdup(path) : 0;
     priv->index_default = 0;
     return priv;
 }

diff --git a/libass/ass_parse.c b/libass/ass_parse.c
index fb407bf7240ae8c10e369fff50b3d93c31645919..a5b9b59eff606e4760944621b388872433eb5205 100644 (file)
--- a/libass/ass_parse.c
+++ b/libass/ass_parse.c
@@ -233,20 +233,20 @@ static char *parse_vector_clip(ASS_Renderer *render_priv, char *p)
     while (*p != ')' && *p != '}' && p != 0)
         ass_drawing_add_char(drawing, *p++);
     skipopt(')');
-    ass_drawing_parse(drawing, 1);
-
-    // We need to translate the clip according to screen borders
-    if (render_priv->settings.left_margin != 0 ||
-        render_priv->settings.top_margin != 0) {
-        FT_Vector trans = {
-            .x = int_to_d6(render_priv->settings.left_margin),
-            .y = -int_to_d6(render_priv->settings.top_margin),
-        };
-        FT_Outline_Translate(&drawing->glyph->outline, trans.x, trans.y);
+    if (ass_drawing_parse(drawing, 1)) {
+        // We need to translate the clip according to screen borders
+        if (render_priv->settings.left_margin != 0 ||
+            render_priv->settings.top_margin != 0) {
+            FT_Vector trans = {
+                .x = int_to_d6(render_priv->settings.left_margin),
+                .y = -int_to_d6(render_priv->settings.top_margin),
+            };
+            FT_Outline_Translate(&drawing->glyph->outline, trans.x, trans.y);
+        }
+        ass_msg(render_priv->library, MSGL_DBG2,
+                "Parsed vector clip: scale %d, scales (%f, %f) string [%s]\n",
+                scale, drawing->scale_x, drawing->scale_y, drawing->text);
     }
-    ass_msg(render_priv->library, MSGL_DBG2,
-            "Parsed vector clip: scale %d, scales (%f, %f) string [%s]\n",
-            scale, drawing->scale_x, drawing->scale_y, drawing->text);
 
     return p;
 }

diff --git a/libass/ass_render.c b/libass/ass_render.c
index c2756fde44b47f3e43a42d9baf97b82cd2c8d8bf..dcecf80705755943e3dd69c789a789babfc77efa 100644 (file)
--- a/libass/ass_render.c
+++ b/libass/ass_render.c
@@ -1132,7 +1132,8 @@ get_outline_glyph(ASS_Renderer *render_priv, int symbol, GlyphInfo *info,
     } else {
         GlyphHashValue v;
         if (drawing->hash) {
-            ass_drawing_parse(drawing, 0);
+            if(!ass_drawing_parse(drawing, 0))
+                return;
             FT_Glyph_Copy((FT_Glyph) drawing->glyph, &info->glyph);
         } else {
             info->glyph =