Handle NULL typeface in SkFontMgr_fontconfig::onMatchFaceStyle.

src/ports/SkFontMgr_fontconfig.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDataTable.h"
 #include "SkFontDescriptor.h"
 #include "SkFontHost_FreeType_common.h"
@@ skipping 780 matching lines @@
             return NULL;
         }
 
         return createTypefaceFromFcPattern(font);
     }
 
     virtual SkTypeface* onMatchFaceStyle(const SkTypeface* typeface,
                                          const SkFontStyle& style) const SK_OVERRIDE
     {
         //TODO: should the SkTypeface_fontconfig know its family?
-        const SkTypeface_fontconfig* fcTypeface =
-            static_cast<const SkTypeface_fontconfig*>(typeface);
-        return this->matchFamilyStyle(get_string(fcTypeface->fPattern, FC_FAMILY), style);
+        const char* name = NULL;

[mtklein, 2014/09/12 18:55:27]

not ""?

[bungeman-skia, 2014/09/12 19:02:32]

Yeah, I want no-name not empty-name here. In theory you could have a font with
an empty name. In fact, I've seen one in the wild (it was trying to be sneaky
and have a valid but empty name to prevent people from installing it locally).
NULL means 'default font' or 'I don't care what the name is'.

+        if (typeface) {
+            const SkTypeface_fontconfig* fcTypeface =
+                static_cast<const SkTypeface_fontconfig*>(typeface);
+            name = get_string(fcTypeface->fPattern, FC_FAMILY);
+        }
+        return this->matchFamilyStyle(name, style);
     }
 
     /** @param stream does not take ownership of the reference. */
     virtual SkTypeface* onCreateFromStream(SkStream* stream, int ttcIndex) const SK_OVERRIDE {
         const size_t length = stream->getLength();
         if (length <= 0 || (1u << 30) < length) {
             return NULL;
         }
 
         SkTypeface::Style style = SkTypeface::kNormal;
@@ skipping 30 matching lines @@
             return typeface.detach();
         }
 
         return this->matchFamilyStyle(NULL, style);
     }
 };
 
 SkFontMgr* SkFontMgr::Factory() {
     return SkNEW(SkFontMgr_fontconfig);
 }