Home | History | Annotate | Download | only in chromium 
      1 /*
      2  * Copyright (c) 2010 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef CrossProcessFontLoading_h
     32 #define CrossProcessFontLoading_h
     33 
     34 #import <wtf/RefCounted.h>
     35 #import <wtf/RetainPtr.h>
     36 
     37 typedef struct CGFont* CGFontRef;
     38 typedef UInt32 ATSFontContainerRef;
     39 typedef UInt32 ATSFontRef;
     40 
     41 namespace WebCore {
     42 
     43 // MemoryActivatedFont encapsulates a font loaded from another process and
     44 // activated from memory.
     45 //
     46 // Responsibilities:
     47 // * Holder for the CGFontRef & ATSFontRef belonging to the activated font.
     48 // * Responsible for unloading the font container when done.
     49 //
     50 // Memory Management:
     51 // The class is reference counted, with each instance of FontPlatformData that
     52 // uses this class holding a reference to it.
     53 // Entries are kept track of internally in a hash to allow quick lookup
     54 // of existing instances for reuse:
     55 // - fontCacheBySrcFontContainerRef() - key is the ATSFontContainerRef
     56 //   corresponding to the *original in-process NSFont* whose loading was blocked
     57 //   by the sandbox.
     58 //   This is needed to allow lookup of a pre-existing MemoryActivatedFont when
     59 //   creating a new FontPlatformData object.
     60 //
     61 // Assumptions:
     62 // This code assumes that an ATSFontRef is a unique identifier tied to an
     63 // activated font.  i.e. After we activate a font, its ATSFontRef doesn't
     64 // change.
     65 // It also assumes that the ATSFoncontainerRef for two in-memory NSFonts that
     66 // correspond to the same on-disk font file are always the same and don't change
     67 // with time.
     68 //
     69 // Flushing caches:
     70 // When the system notifies us of a system font cache flush, all FontDataCache
     71 // objects are destroyed.  This should in turn dereference all
     72 // MemoryActivatedFonts and thus unload all in-memory fonts.
     73 class MemoryActivatedFont : public RefCounted<MemoryActivatedFont> {
     74 public:
     75     // Use to create a new object, see docs on constructor below.
     76     static PassRefPtr<MemoryActivatedFont> create(ATSFontContainerRef srcFontContainerRef, ATSFontContainerRef container);
     77     ~MemoryActivatedFont();
     78 
     79     // Get cached CGFontRef corresponding to the in-memory font.
     80     CGFontRef cgFont() { return m_cgFont.get(); }
     81 
     82     // Get cached ATSFontRef corresponding to the in-memory font.
     83     ATSFontRef atsFontRef() { return m_atsFontRef; }
     84 
     85 private:
     86     // srcFontRef - ATSFontRef belonging to the NSFont object that failed to
     87     // load in-process.
     88     // container - a font container corresponding to an identical font that
     89     // we loaded cross-process.
     90     MemoryActivatedFont(ATSFontContainerRef srcFontContainerRef, ATSFontContainerRef container);
     91 
     92     ATSFontContainerRef m_fontContainer;
     93     WTF::RetainPtr<CGFontRef> m_cgFont;
     94     ATSFontRef m_atsFontRef;
     95     ATSFontContainerRef m_srcFontContainerRef;
     96 };
     97 
     98 } // namespace WebCore
     99 
    100 #endif // CrossProcessFontLoading_h
    101