Attempted mitigation of font tables released early.

src/ports/SkFontHost_mac.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTypes.h"  // Keep this before any #ifdef ...
 
@@ skipping 435 matching lines @@
 static const uint32_t SkCTFontColorGlyphsTrait = (1 << 13);
 #endif
 
 class SkTypeface_Mac : public SkTypeface {
 public:
     SkTypeface_Mac(const SkFontStyle& fs, SkFontID fontID, bool isFixedPitch,
                    CTFontRef fontRef, const char requestedName[], bool isLocalStream)
         : SkTypeface(fs, fontID, isFixedPitch)
         , fRequestedName(requestedName)
         , fFontRef(fontRef) // caller has already called CFRetain for us
+        , fHasColorGlyphs(SkToBool(CTFontGetSymbolicTraits(fFontRef) & SkCTFontColorGlyphsTrait))
         , fIsLocalStream(isLocalStream)
-        , fHasColorGlyphs(CTFontGetSymbolicTraits(fFontRef) & SkCTFontColorGlyphsTrait)
     {
         SkASSERT(fontRef);
     }
 
     SkString fRequestedName;
     AutoCFRelease<CTFontRef> fFontRef;
+    const bool fHasColorGlyphs;
 
 protected:
     int onGetUPEM() const override;
     SkStreamAsset* onOpenStream(int* ttcIndex) const override;
     void onGetFamilyName(SkString* familyName) const override;
     SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const override;
     int onGetTableTags(SkFontTableTag tags[]) const override;
     virtual size_t onGetTableData(SkFontTableTag, size_t offset,
                                   size_t length, void* data) const override;
     SkScalerContext* onCreateScalerContext(const SkDescriptor*) const override;
     void onFilterRec(SkScalerContextRec*) const override;
     void onGetFontDescriptor(SkFontDescriptor*, bool*) const override;
     virtual SkAdvancedTypefaceMetrics* onGetAdvancedTypefaceMetrics(
                                 SkAdvancedTypefaceMetrics::PerGlyphInfo,
                                 const uint32_t*, uint32_t) const override;
     virtual int onCharsToGlyphs(const void* chars, Encoding, uint16_t glyphs[],
                                 int glyphCount) const override;
     int onCountGlyphs() const override;
 
 private:
     bool fIsLocalStream;
-    bool fHasColorGlyphs;
 
     typedef SkTypeface INHERITED;
 };
 
 static SkTypeface* NewFromFontRef(CTFontRef fontRef, const char name[], bool isLocalStream) {
     SkASSERT(fontRef);
     bool isFixedPitch;
     SkFontStyle style = SkFontStyle(computeStyleBits(fontRef, &isFixedPitch));
     SkFontID fontID = CTFontRef_to_SkFontID(fontRef);
 
@@ skipping 404 matching lines @@
     CGPoint point = CGPointMake(-glyph.fLeft + subX, glyph.fTop + glyph.fHeight - subY);
     // Prior to 10.10, CTFontDrawGlyphs acted like CGContextShowGlyphsAtPositions and took
     // 'positions' which are in text space. The glyph location (in device space) must be
     // mapped into text space, so that CG can convert it back into device space.
     // In 10.10.1, this is handled directly in CTFontDrawGlyphs.
 
     // However, in 10.10.2 color glyphs no longer rotate based on the font transform.
     // So always make the font transform identity and place the transform on the context.
     point = CGPointApplyAffineTransform(point, context.fInvTransform);
 
+    // Attempt to keep on the stack a hard reference to the font tables.
+    // This is an experiment to see if this affects crbug.com/413332 .
+    // When 10.6 headers are no longer supported, 'sbix' can be replaced with kCTFontTableSbix.
+    AutoCFRelease<CFDataRef> sbix;
+    if (static_cast<SkTypeface_Mac*>(context.getTypeface())->fHasColorGlyphs) {
+        sbix.reset(CGFontCopyTableForTag(context.fCGFont, 'sbix'));
+    }
     ctFontDrawGlyphs(context.fCTUnrotatedFont, &glyphID, &point, 1, fCG);
 
     SkASSERT(rowBytesPtr);
     *rowBytesPtr = rowBytes;
     return image;
 }
 
 void SkScalerContext_Mac::getVerticalOffset(CGGlyph glyphID, SkPoint* offset) const {
     // Snow Leopard returns cgVertOffset in completely un-transformed FUnits (em space, y up).
     // Lion and Leopard return cgVertOffset in CG units (pixels, y up).
@@ skipping 1366 matching lines @@
         }
         return face;
     }
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkFontMgr* SkFontMgr::Factory() {
     return SkNEW(SkFontMgr_Mac);
 }