Break up SkLazyPixelRef functionally into class hierarchy.

src/core/SkScaledImageCache.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkScaledImageCache_DEFINED
 #define SkScaledImageCache_DEFINED
 
@@ skipping 13 matching lines @@
  */
 class SkScaledImageCache {
 public:
     struct ID;
 
     /*
      *  The following static methods are thread-safe wrappers around a global
      *  instance of this cache.
      */
 
+    static SkScaledImageCache* Instance();

[scroggo, 2013/10/31 21:53:06]

I think typically our functions to get the global instance are named something
like "Get*". Maybe this should be GetGlobalInstance?

[hal.canary, 2013/11/01 03:29:24]

Done.

+
     static ID* FindAndLock(uint32_t pixelGenerationID,
                            int32_t width,
                            int32_t height,
                            SkBitmap* returnedBitmap);
 
     static ID* FindAndLock(const SkBitmap& original, SkScalar scaleX,
                            SkScalar scaleY, SkBitmap* returnedBitmap);
     static ID* FindAndLockMip(const SkBitmap& original,
                               SkMipMap const** returnedMipMap);
 
 
     static ID* AddAndLock(uint32_t pixelGenerationID,
                           int32_t width,
                           int32_t height,
                           const SkBitmap& bitmap);
 
     static ID* AddAndLock(const SkBitmap& original, SkScalar scaleX,
                           SkScalar scaleY, const SkBitmap& bitmap);
     static ID* AddAndLockMip(const SkBitmap& original, const SkMipMap* mipMap);
 
     static void Unlock(ID*);
 
     static size_t GetBytesUsed();
     static size_t GetByteLimit();
     static size_t SetByteLimit(size_t newLimit);
 
     ///////////////////////////////////////////////////////////////////////////
 
-    SkScaledImageCache(size_t byteLimit);
+    SkScaledImageCache(size_t byteLimit, SkBaseMutex* mutex = NULL);
     ~SkScaledImageCache();
 
     /**
      *  Search the cache for a matching bitmap (using generationID,
      *  width, and height as a search key). If found, return it in
      *  returnedBitmap, and return its ID pointer. Use the returned
      *  ptr to unlock the cache when you are done using
      *  returnedBitmap.
      *
      *  If a match is not found, returnedBitmap will be unmodifed, and
@@ skipping 34 matching lines @@
     ID* addAndLockMip(const SkBitmap& original, const SkMipMap* mipMap);
 
     /**
      *  Given a non-null ID ptr returned by either findAndLock or addAndLock,
      *  this releases the associated resources to be available to be purged
      *  if needed. After this, the cached bitmap should no longer be
      *  referenced by the caller.
      */
     void unlock(ID*);
 
-    size_t getBytesUsed() const { return fBytesUsed; }
-    size_t getByteLimit() const { return fByteLimit; }
+    size_t getBytesUsed() const;
+    size_t getByteLimit() const;
 
     /**
      *  Set the maximum number of bytes available to this cache. If the current
      *  cache exceeds this new value, it will be purged to try to fit within
      *  this new limit.
      */
     size_t setByteLimit(size_t newLimit);
 
 public:
     struct Rec;
 private:
+    SkBaseMutex* fMutex;  // can be NULL
+
     Rec*    fHead;
     Rec*    fTail;
 
     class Hash;
     Hash*   fHash;
 
     size_t  fBytesUsed;
     size_t  fByteLimit;
     int     fCount;
 
     Rec* findAndLock(uint32_t generationID, SkScalar sx, SkScalar sy,
                      const SkIRect& bounds);
     void addAndLock(Rec* rec);
 
     void purgeAsNeeded();
 
     // linklist management
     void moveToHead(Rec*);
     void addToHead(Rec*);
     void detach(Rec*);
 #ifdef SK_DEBUG
     void validate() const;
 #else
     void validate() const {}
 #endif
 };
 #endif