add scaledimagecache

BUG=

Review URL: https://codereview.chromium.org/20005003

git-svn-id: http://skia.googlecode.com/svn/trunk@10286 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ImageCacheTest.cpp b/tests/ImageCacheTest.cpp
new file mode 100644
index 0000000..63b18e8
--- /dev/null
+++ b/tests/ImageCacheTest.cpp
@@ -0,0 +1,65 @@
+/*
+ * 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 "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);
+    SkScaledImageCache::ID* id;
+
+    SkBitmap bm[COUNT];
+    
+    SkScalar scale = 2;
+    for (size_t 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);
+    }
+
+    // stress test, should trigger purges
+    for (size_t i = 0; i < COUNT * 100; ++i) {
+        SkBitmap tmp;
+        
+        make_bm(&tmp, DIM, DIM);
+        id = cache.addAndLock(bm[0], scale, scale, tmp);
+        REPORTER_ASSERT(reporter, NULL != id);
+        cache.unlock(id);
+        
+        scale += 1;
+    }
+
+    cache.setByteLimit(0);
+}
+
+#include "TestClassDef.h"
+DEFINE_TESTCLASS("ImageCache", TestImageCacheClass, TestImageCache)