From 59f2290907e61038a7f07af536cb56981835b35e Mon Sep 17 00:00:00 2001
From: Grigori Goronzy <greg@chown.ath.cx>
Date: Thu, 29 May 2014 03:59:08 +0200
Subject: shaper: add FriBidi error handling

It is unlikely, but FriBidi might not process a string correctly,
and we should handle that. Tested by making it fail always. This
should also fix some compiler warnings.
---
 libass/ass_render.c | 12 +++++++++++-
 libass/ass_shaper.c | 20 +++++++++++++++-----
 libass/ass_shaper.h |  2 +-
 3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/libass/ass_render.c b/libass/ass_render.c
index 67d1b78..0d08dd9 100644
--- a/libass/ass_render.c
+++ b/libass/ass_render.c
@@ -1985,7 +1985,11 @@ ass_render_event(ASS_Renderer *render_priv, ASS_Event *event,
             resolve_base_direction(render_priv->state.font_encoding));
     ass_shaper_find_runs(render_priv->shaper, render_priv, glyphs,
             text_info->length);
-    ass_shaper_shape(render_priv->shaper, text_info);
+    if (ass_shaper_shape(render_priv->shaper, text_info) < 0) {
+        ass_msg(render_priv->library, MSGL_ERR, "Failed to shape text");
+        free_render_context(render_priv);
+        return 1;
+    }
 
     // Retrieve glyphs
     for (i = 0; i < text_info->length; i++) {
@@ -2075,6 +2079,12 @@ ass_render_event(ASS_Renderer *render_priv, ASS_Event *event,
 
     // Reorder text into visual order
     FriBidiStrIndex *cmap = ass_shaper_reorder(render_priv->shaper, text_info);
+    if (!cmap) {
+        ass_msg(render_priv->library, MSGL_ERR, "Failed to reorder text");
+        ass_shaper_cleanup(render_priv->shaper, text_info);
+        free_render_context(render_priv);
+        return 1;
+    }
 
     // Reposition according to the map
     pen.x = 0;
diff --git a/libass/ass_shaper.c b/libass/ass_shaper.c
index e9f2b53..d79d0f7 100644
--- a/libass/ass_shaper.c
+++ b/libass/ass_shaper.c
@@ -824,10 +824,11 @@ static void ass_shaper_skip_characters(TextInfo *text_info)
 /**
  * \brief Shape an event's text. Calculates directional runs and shapes them.
  * \param text_info event's text
+ * \return success, when 0
  */
-void ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info)
+int ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info)
 {
-    int i, last_break;
+    int i, ret, last_break;
     FriBidiParType dir;
     GlyphInfo *glyphs = text_info->glyphs;
 
@@ -842,8 +843,10 @@ void ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info)
             dir = shaper->base_direction;
             fribidi_get_bidi_types(shaper->event_text + last_break,
                     i - last_break + 1, shaper->ctypes + last_break);
-            fribidi_get_par_embedding_levels(shaper->ctypes + last_break,
+            ret = fribidi_get_par_embedding_levels(shaper->ctypes + last_break,
                     i - last_break + 1, &dir, shaper->emblevels + last_break);
+            if (ret == 0)
+                return -1;
             last_break = i + 1;
         }
     }
@@ -867,6 +870,8 @@ void ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info)
         shape_fribidi(shaper, glyphs, text_info->length);
         ass_shaper_skip_characters(text_info);
 #endif
+
+    return 0;
 }
 
 /**
@@ -910,10 +915,13 @@ void ass_shaper_cleanup(ASS_Shaper *shaper, TextInfo *text_info)
 
 /**
  * \brief Calculate reorder map to render glyphs in visual order
+ * \param shaper shaper instance
+ * \param text_info text to be reordered
+ * \return map of reordered characters, or NULL
  */
 FriBidiStrIndex *ass_shaper_reorder(ASS_Shaper *shaper, TextInfo *text_info)
 {
-    int i;
+    int i, ret;
 
     // Initialize reorder map
     for (i = 0; i < text_info->length; i++)
@@ -924,10 +932,12 @@ FriBidiStrIndex *ass_shaper_reorder(ASS_Shaper *shaper, TextInfo *text_info)
         LineInfo *line = text_info->lines + i;
         FriBidiParType dir = FRIBIDI_PAR_ON;
 
-        fribidi_reorder_line(0,
+        ret = fribidi_reorder_line(0,
                 shaper->ctypes + line->offset, line->len, 0, dir,
                 shaper->emblevels + line->offset, NULL,
                 shaper->cmap + line->offset);
+        if (ret == 0)
+            return NULL;
     }
 
     return shaper->cmap;
diff --git a/libass/ass_shaper.h b/libass/ass_shaper.h
index 824bc22..e6121d1 100644
--- a/libass/ass_shaper.h
+++ b/libass/ass_shaper.h
@@ -33,7 +33,7 @@ void ass_shaper_find_runs(ASS_Shaper *shaper, ASS_Renderer *render_priv,
 void ass_shaper_set_base_direction(ASS_Shaper *shaper, FriBidiParType dir);
 void ass_shaper_set_language(ASS_Shaper *shaper, const char *code);
 void ass_shaper_set_level(ASS_Shaper *shaper, ASS_ShapingLevel level);
-void ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info);
+int ass_shaper_shape(ASS_Shaper *shaper, TextInfo *text_info);
 void ass_shaper_cleanup(ASS_Shaper *shaper, TextInfo *text_info);
 FriBidiStrIndex *ass_shaper_reorder(ASS_Shaper *shaper, TextInfo *text_info);
 FriBidiParType resolve_base_direction(int font_encoding);
-- 
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