Add SkCachedData and use it for SkMipMap

tests/MaskCacheTest.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 "SkCachedData.h"
+#include "SkMaskCache.h"
+#include "SkResourceCache.h"
+#include "Test.h"
+
+enum LockedState {
+    kUnlocked,
+    kLocked
+};
+
+static void check_data(skiatest::Reporter* reporter, SkCachedData* data,
+                       int refcnt, bool isInCache, LockedState lockedState) {
+    REPORTER_ASSERT(reporter, data->testing_only_getRefCnt() == refcnt);
+    REPORTER_ASSERT(reporter, data->testing_only_isInCache() == isInCache);
+    bool isLocked = (data->data() != NULL);
+    REPORTER_ASSERT(reporter, isLocked == (lockedState == kLocked));
+}
+
+DEF_TEST(MaskCache, reporter) {
+    
+    SkResourceCache cache(1024);
+    
+    SkScalar sigma = 2;
+    SkRect r = SkRect::MakeWH(10, 10);
+    SkMask mask;
+
+    SkCachedData* data = SkMaskCache::FindAndLock(sigma, r, &mask, &cache);
+    REPORTER_ASSERT(reporter, NULL == data);
+
+    size_t size = 100;
+    data = cache.newCachedData(size);
+    check_data(reporter, data, 1, false, kLocked);
+
+    memset(data->writable_data(), 0x80, size);  // just to use writable_data()
+    mask.fBounds.setXYWH(1, 2, 3, 4);
+    SkMaskCache::Add(sigma, r, mask, data, &cache);
+    check_data(reporter, data, 2, true, kLocked);
+
+    data->unref();
+    check_data(reporter, data, 1, true, kUnlocked);
+
+    sk_bzero(&mask, sizeof(mask));
+    data = SkMaskCache::FindAndLock(sigma, r, &mask, &cache);
+    check_data(reporter, data, 2, true, kLocked);
+
+    REPORTER_ASSERT(reporter, data);
+    REPORTER_ASSERT(reporter, data->size() == size);
+    REPORTER_ASSERT(reporter, mask.fBounds.top() == 2);
+    REPORTER_ASSERT(reporter, data->data() == (const void*)mask.fImage);
+
+    cache.purgeAll();
+    check_data(reporter, data, 1, false, kLocked);
+    data->unref();
+}
+