support scaledimagecache instantiable using discardablememory

tests/ImageCacheTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
+#include "SkDiscardableMemory.h"
 #include "SkScaledImageCache.h"
 
 static void make_bm(SkBitmap* bm, int w, int h) {
     bm->setConfig(SkBitmap::kARGB_8888_Config, w, h);
     bm->allocPixels();
 }
 
-static void TestImageCache(skiatest::Reporter* reporter) {
-    static const int COUNT = 10;
-    static const int DIM = 256;
-    static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
-    SkScaledImageCache cache(defLimit);
+static const int COUNT = 10;
+static const int DIM = 256;
+
+static void test_cache(skiatest::Reporter* reporter, SkScaledImageCache& cache,
+                       bool testPurge) {
     SkScaledImageCache::ID* id;
-
+    
     SkBitmap bm[COUNT];
-
+    
     SkScalar scale = 2;
     for (int i = 0; i < COUNT; ++i) {
         SkBitmap tmp;
-
+        
         make_bm(&bm[i], DIM, DIM);
         id = cache.findAndLock(bm[i], scale, scale, &tmp);
         REPORTER_ASSERT(reporter, NULL == id);
-
+        
         make_bm(&tmp, DIM, DIM);
         id = cache.addAndLock(bm[i], scale, scale, tmp);
         REPORTER_ASSERT(reporter, NULL != id);
-
+        
         SkBitmap tmp2;
         SkScaledImageCache::ID* id2 = cache.findAndLock(bm[i], scale, scale,
                                                         &tmp2);
         REPORTER_ASSERT(reporter, id == id2);
         REPORTER_ASSERT(reporter, tmp.pixelRef() == tmp2.pixelRef());
         REPORTER_ASSERT(reporter, tmp.width() == tmp2.width());
         REPORTER_ASSERT(reporter, tmp.height() == tmp2.height());
         cache.unlock(id2);
-
+        
         cache.unlock(id);
     }
+    
+    if (testPurge) {
+        // stress test, should trigger purges
+        for (size_t i = 0; i < COUNT * 100; ++i) {
+            scale += 1;
+            
+            SkBitmap tmp;
+            
+            make_bm(&tmp, DIM, DIM);
+            id = cache.addAndLock(bm[0], scale, scale, tmp);
+            REPORTER_ASSERT(reporter, NULL != id);
+            cache.unlock(id);
+        }
+    }
+    cache.setByteLimit(0);
+}
 
-    // stress test, should trigger purges
-    for (size_t i = 0; i < COUNT * 100; ++i) {
-        scale += 1;
-
-        SkBitmap tmp;
-
-        make_bm(&tmp, DIM, DIM);
-        id = cache.addAndLock(bm[0], scale, scale, tmp);
-        REPORTER_ASSERT(reporter, NULL != id);
-        cache.unlock(id);
+static void TestImageCache(skiatest::Reporter* reporter) {
+    {
+        static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
+        SkScaledImageCache cache(defLimit);
+        test_cache(reporter, cache, true);
     }
-
-    cache.setByteLimit(0);
+    {
+        SkScaledImageCache cache(SkDiscardableMemory::Create);
+        test_cache(reporter, cache, false);
+    }
 }
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("ImageCache", TestImageCacheClass, TestImageCache)
 
 DEF_TEST(ImageCache_doubleAdd, r) {
     // Adding the same key twice should be safe.
     SkScaledImageCache cache(1024);
 
     SkBitmap original;
     original.setConfig(SkBitmap::kARGB_8888_Config, 40, 40);
     original.allocPixels();
 
     SkBitmap scaled;
     scaled.setConfig(SkBitmap::kARGB_8888_Config, 20, 20);
     scaled.allocPixels();
 
     SkScaledImageCache::ID* id1 = cache.addAndLock(original, 0.5f, 0.5f, scaled);
     SkScaledImageCache::ID* id2 = cache.addAndLock(original, 0.5f, 0.5f, scaled);
     // We don't really care if id1 == id2 as long as unlocking both works.
     cache.unlock(id1);
     cache.unlock(id2);
 }