SkDiscardableMemory::Factory class

src/lazy/SkDiscardablePixelRef.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 SkDiscardablePixelRef_DEFINED
 #define SkDiscardablePixelRef_DEFINED
 
+#include "SkDiscardableMemory.h"
 #include "SkPixelRef.h"
 #include "SkImageGenerator.h"
 #include "SkImageInfo.h"
 
-class SkDiscardableMemory;
+#ifdef SK_DEBUG
+    #define LAZY_CACHE_STATS 1
+#elif !defined(LAZY_CACHE_STATS)
+    #define LAZY_CACHE_STATS 0
+#endif
 
 /**
  * An interface that allows a purgable PixelRef to re-decode an image.
  */
 
 class SkDiscardablePixelRef : public SkPixelRef {
 public:
     /**
      *  Takes ownership of SkImageGenerator.  If this method fails for
      *  whatever reason, it will return false and immediatetely delete
      *  the generator.  If it succeeds, it will modify destination
      *  bitmap.
      *
      *  If Install fails or when the SkDiscardablePixelRef that is
      *  installed into destination is destroyed, it will call
      *  SkDELETE() on the generator.  Therefore, generator should be
      *  allocated with SkNEW() or SkNEW_ARGS().
      */
-    static bool Install(SkImageGenerator* generator, SkBitmap* destination);
+    static bool Install(SkImageGenerator* generator, SkBitmap* destination,
+                        SkDiscardableMemory::Factory* factory = NULL);

[scroggo, 2013/12/02 19:00:09]

Can you add a comment explaining how the factory is used?

Please include in the comment whether Install calls ref().

+
+    #if LAZY_CACHE_STATS
+    static int32_t GetCacheHits() { return gCacheHits; }
+    static int32_t GetCacheMisses() { return gCacheMisses; }
+    static void ResetCacheStats() { gCacheHits = gCacheMisses = 0; }
+    #endif
 
     SK_DECLARE_UNFLATTENABLE_OBJECT()
 
 protected:
     ~SkDiscardablePixelRef();
-    virtual void* onLockPixels(SkColorTable**) SK_OVERRIDE;
+    virtual void* onLockPixels(SkColorTable** colorTable) SK_OVERRIDE;
     virtual void onUnlockPixels() SK_OVERRIDE;
     virtual bool onLockPixelsAreWritable() const SK_OVERRIDE { return false; }
 
     virtual SkData* onRefEncodedData() SK_OVERRIDE {
         return fGenerator->refEncodedData();
     }
 
 private:
-    SkImageGenerator* const fGenerator;
-    const SkImageInfo fInfo;
-    const size_t fSize;  // size of memory to be allocated
-    const size_t fRowBytes;
+    SkDiscardableMemory::Factory* const fDMFactory;
+    SkImageGenerator* const             fGenerator;
+    const SkImageInfo                   fInfo;
+    const size_t                        fSize;  // size of allocation
+    const size_t                        fRowBytes;
     // These const members should not change over the life of the
     // PixelRef, since the SkBitmap doesn't expect them to change.
 
-    SkDiscardableMemory* fDiscardableMemory;
+    SkDiscardableMemory*                fDiscardableMemory;
+
+    #if LAZY_CACHE_STATS
+    static int32_t                      gCacheHits;
+    static int32_t                      gCacheMisses;
+    #endif
 
     /* Takes ownership of SkImageGenerator. */
-    SkDiscardablePixelRef(SkImageGenerator* generator,
+    SkDiscardablePixelRef(SkDiscardableMemory::Factory* factory,
+                          SkImageGenerator* generator,
                           const SkImageInfo& info,
                           size_t size,
                           size_t rowBytes);
 };
 #endif  // SkDiscardablePixelRef_DEFINED