bug 874053 - ReadCMAP() must not leave the font entry's mCharacterMap…

… pointer NULL, even if cmap table can't be read. r=roc
Brli · May 21, 2013 · 21e2cea · 21e2cea
1 parent 0373403
commit 21e2cea
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Showing 4 changed files with 23 additions and 12 deletions.
diff --git a/gfx/thebes/gfxDWriteFontList.cpp b/gfx/thebes/gfxDWriteFontList.cpp
@@ -410,6 +410,8 @@ gfxDWriteFontEntry::ReadCMAP()
         rv = gfxFontUtils::ReadCMAP(cmapData, cmapLen,
                                     *charmap, mUVSOffset,
                                     unicodeFont, symbolFont);
+    } else {
+        rv = NS_ERROR_NOT_AVAILABLE;
     }
 
     mHasCmapTable = NS_SUCCEEDED(rv);

diff --git a/gfx/thebes/gfxFont.h b/gfx/thebes/gfxFont.h
@@ -310,6 +310,13 @@ class gfxFontEntry {
     virtual bool TestCharacterMap(uint32_t aCh);
     nsresult InitializeUVSMap();
     uint16_t GetUVSGlyph(uint32_t aCh, uint32_t aVS);
+
+    // All concrete gfxFontEntry subclasses (except gfxProxyFontEntry) need
+    // to override this, otherwise the font will never be used as it will
+    // be considered to support no characters.
+    // ReadCMAP() must *always* set the mCharacterMap pointer to a valid
+    // gfxCharacterMap, even if empty, as other code assumes this pointer
+    // can be safely dereferenced.
     virtual nsresult ReadCMAP();
 
     bool TryGetSVGData();

diff --git a/gfx/thebes/gfxMacPlatformFontList.mm b/gfx/thebes/gfxMacPlatformFontList.mm
@@ -232,18 +232,20 @@ static void GetStringForNSString(const NSString *aSrc, nsAString& aDist)
     uint32_t kCMAP = TRUETYPE_TAG('c','m','a','p');
 
     AutoTable cmapTable(this, kCMAP);
-    if (!cmapTable) {
-        return NS_OK; // leave it empty
-    }
+    nsresult rv;
+
+    if (cmapTable) {
+        bool unicodeFont = false, symbolFont = false; // currently ignored
 
-    bool unicodeFont = false, symbolFont = false; // currently ignored
+        uint32_t cmapLen;
+        const char* cmapData = hb_blob_get_data(cmapTable, &cmapLen);
+        rv = gfxFontUtils::ReadCMAP((const uint8_t*)cmapData, cmapLen,
+                                    *charmap, mUVSOffset,
+                                    unicodeFont, symbolFont);
+    } else {
+        rv = NS_ERROR_NOT_AVAILABLE;
+    }
 
-    uint32_t cmapLen;
-    const char* cmapData = hb_blob_get_data(cmapTable, &cmapLen);
-    nsresult rv = gfxFontUtils::ReadCMAP((const uint8_t*)cmapData, cmapLen,
-                                         *charmap, mUVSOffset,
-                                         unicodeFont, symbolFont);
-
     if (NS_SUCCEEDED(rv) && !HasGraphiteTables()) {
         // We assume a Graphite font knows what it's doing,
         // and provides whatever shaping is needed for the

diff --git a/gfx/thebes/gfxPangoFonts.cpp b/gfx/thebes/gfxPangoFonts.cpp
@@ -410,14 +410,14 @@ void
 gfxSystemFcFontEntry::ForgetHBFace()
 {
     gfxFontEntry::ForgetHBFace();
-    MaybeReleaseFTFace();        
+    MaybeReleaseFTFace();
 }
 
 void
 gfxSystemFcFontEntry::ReleaseGrFace(gr_face* aFace)
 {
     gfxFontEntry::ReleaseGrFace(aFace);
-    MaybeReleaseFTFace();        
+    MaybeReleaseFTFace();
 }
 
 // A namespace for @font-face family names in FcPatterns so that fontconfig