allow SkBitmapCache to operate on a local instance, for testability

src/core/SkBitmapCache.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 "SkBitmapCache.h"
 #include "SkResourceCache.h"
 #include "SkMipMap.h"
@@ skipping 52 matching lines @@
     static bool Visitor(const SkResourceCache::Rec& baseRec, void* contextBitmap) {
         const BitmapRec& rec = static_cast<const BitmapRec&>(baseRec);
         SkBitmap* result = (SkBitmap*)contextBitmap;
 
         *result = rec.fBitmap;
         result->lockPixels();
         return SkToBool(result->getPixels());
     }
 };
 
-bool SkBitmapCache::Find(const SkBitmap& src, SkScalar invScaleX, SkScalar invScaleY,
-                         SkBitmap* result) {
+#define CHECK_LOCAL(localCache, localName, globalName, args...) \
+    (localCache) ? localCache->localName(args) : SkResourceCache::globalName(args)
+
+bool SkBitmapCache::Find(const SkBitmap& src, SkScalar invScaleX, SkScalar invScaleY, SkBitmap* result,
+                         SkResourceCache* localCache) {
     if (0 == invScaleX || 0 == invScaleY) {
         // degenerate, and the key we use for mipmaps
         return false;
     }
     BitmapKey key(src.getGenerationID(), invScaleX, invScaleY, get_bounds_from_bitmap(src));
-    return SkResourceCache::Find(key, BitmapRec::Visitor, result);
+
+    return CHECK_LOCAL(localCache, find, Find, key, BitmapRec::Visitor, result);

[danakj, 2014/09/16 15:26:27]

This is really awkward to read :(

Tho, given you have to use a static method or a local method, I'm not sure what
else to suggest either, other than to stop using static methods to access
SkResourceCache (that'd be nice for many reasons).

[reed1, 2014/09/16 17:31:12]

I find it very nice for calls sites that want to access the global cache to
consolidate their access pattern (scoping the lock on the mutex).

 }
 
 void SkBitmapCache::Add(const SkBitmap& src, SkScalar invScaleX, SkScalar invScaleY,
-                        const SkBitmap& result) {
+                        const SkBitmap& result, SkResourceCache* localCache) {
     if (0 == invScaleX || 0 == invScaleY) {
         // degenerate, and the key we use for mipmaps
         return;
     }
     SkASSERT(result.isImmutable());
-    SkResourceCache::Add(SkNEW_ARGS(BitmapRec, (src.getGenerationID(), invScaleX, invScaleY,
-                                                get_bounds_from_bitmap(src), result)));
+    BitmapRec* rec = SkNEW_ARGS(BitmapRec, (src.getGenerationID(), invScaleX, invScaleY,
+                                            get_bounds_from_bitmap(src), result));
+    CHECK_LOCAL(localCache, add, Add, rec);
 }
 
-bool SkBitmapCache::Find(uint32_t genID, const SkIRect& subset, SkBitmap* result) {
+bool SkBitmapCache::Find(uint32_t genID, const SkIRect& subset, SkBitmap* result,
+                         SkResourceCache* localCache) {
     BitmapKey key(genID, SK_Scalar1, SK_Scalar1, subset);
-    return SkResourceCache::Find(key, BitmapRec::Visitor, result);
+
+    return CHECK_LOCAL(localCache, find, Find, key, BitmapRec::Visitor, result);
 }
 
-bool SkBitmapCache::Add(uint32_t genID, const SkIRect& subset, const SkBitmap& result) {
+bool SkBitmapCache::Add(uint32_t genID, const SkIRect& subset, const SkBitmap& result,
+                        SkResourceCache* localCache) {
     SkASSERT(result.isImmutable());
 
     if (subset.isEmpty()
         || subset.top() < 0
         || subset.left() < 0
         || result.width() != subset.width()
         || result.height() != subset.height()) {
         return false;
     } else {
-        SkResourceCache::Add(SkNEW_ARGS(BitmapRec, (genID, SK_Scalar1, SK_Scalar1,
-                                                    subset, result)));
+        BitmapRec* rec = SkNEW_ARGS(BitmapRec, (genID, SK_Scalar1, SK_Scalar1, subset, result));
 
+        CHECK_LOCAL(localCache, add, Add, rec);
         return true;
     }
 }
 //////////////////////////////////////////////////////////////////////////////////////////
 
 struct MipMapRec : public SkResourceCache::Rec {
     MipMapRec(const SkBitmap& src, const SkMipMap* result)
         : fKey(src.getGenerationID(), 0, 0, get_bounds_from_bitmap(src))
         , fMipMap(SkRef(result))
     {}
@@ skipping 26 matching lines @@
     }
     return result;
 }
 
 void SkMipMapCache::Add(const SkBitmap& src, const SkMipMap* result) {
     if (result) {
         SkResourceCache::Add(SkNEW_ARGS(MipMapRec, (src, result)));
     }
 }