Update SkImageFilter's cache to handle SkSpecialImages and add unit test

tests/ImageFilterCacheTest.cpp

Index: tests/ImageFilterCacheTest.cpp
diff --git a/tests/ImageFilterCacheTest.cpp b/tests/ImageFilterCacheTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f2e662f56c8b7ed6b2c7a7022fb1304398e21b45
--- /dev/null
+++ b/tests/ImageFilterCacheTest.cpp
@@ -0,0 +1,208 @@
+ /*
+  * Copyright 2016 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 "SkBitmap.h"
+#include "SkImage.h"
+#include "SkImageFilter.h"
+#include "SkImageFilterCacheKey.h"
+#include "SkMatrix.h"
+#include "SkSpecialImage.h"
+
+static const int kSmallerSize = 10;
+static const int kPad = 3;
+static const int kFullSize = kSmallerSize + 2 * kPad;
+
+static SkBitmap create_bm() {
+    SkBitmap bm;
+    bm.allocN32Pixels(kFullSize, kFullSize, true);
+    bm.eraseColor(SK_ColorTRANSPARENT);
+    return bm;
+}
+
+// Ensure the cache can return a cached image
+static void test_find_existing(skiatest::Reporter* reporter,
+                               SkSpecialImage* image,
+                               SkSpecialImage* subset) {
+    static const size_t kCacheSize = 1000000;
+    SkAutoTUnref<SkImageFilter::Cache> cache(SkImageFilter::Cache::Create(kCacheSize));
+
+    SkIRect clip = SkIRect::MakeWH(100, 100);
+    SkImageFilter::Cache::Key key1(0, SkMatrix::I(), clip, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key2(0, SkMatrix::I(), clip, subset->uniqueID(), subset->subset());
+
+    SkIPoint offset = SkIPoint::Make(3, 4);
+    cache->set(key1, image, offset);
+
+    SkIPoint foundOffset;
+
+    SkSpecialImage* foundImage = cache->get(key1, &foundOffset);
+    REPORTER_ASSERT(reporter, foundImage);
+    REPORTER_ASSERT(reporter, offset == foundOffset);
+
+    REPORTER_ASSERT(reporter, !cache->get(key2, &foundOffset));
+}
+
+// If either id is different or the clip or the matrix are different the
+// cached image won't be found. Even if it is caching the same bitmap.
+static void test_dont_find_if_diff_key(skiatest::Reporter* reporter,
+                                       SkSpecialImage* image,
+                                       SkSpecialImage* subset) {
+    static const size_t kCacheSize = 1000000;
+    SkAutoTUnref<SkImageFilter::Cache> cache(SkImageFilter::Cache::Create(kCacheSize));
+
+    SkIRect clip1 = SkIRect::MakeWH(100, 100);
+    SkIRect clip2 = SkIRect::MakeWH(200, 200);
+    SkImageFilter::Cache::Key key0(0, SkMatrix::I(), clip1, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key1(1, SkMatrix::I(), clip1, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key2(0, SkMatrix::MakeTrans(5, 5), clip1,
+                                   image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key3(0, SkMatrix::I(), clip2, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key4(0, SkMatrix::I(), clip1, subset->uniqueID(), subset->subset());
+
+    SkIPoint offset = SkIPoint::Make(3, 4);
+    cache->set(key0, image, offset);
+
+    SkIPoint foundOffset;
+    REPORTER_ASSERT(reporter, !cache->get(key1, &foundOffset));
+    REPORTER_ASSERT(reporter, !cache->get(key2, &foundOffset));
+    REPORTER_ASSERT(reporter, !cache->get(key3, &foundOffset));
+    REPORTER_ASSERT(reporter, !cache->get(key4, &foundOffset));
+}
+
+// Test purging when the max cache size is exceeded
+static void test_internal_purge(skiatest::Reporter* reporter, SkSpecialImage* image) {
+    SkASSERT(image->getSize());
+    static const size_t kCacheSize = image->getSize() + 10;
+    SkAutoTUnref<SkImageFilter::Cache> cache(SkImageFilter::Cache::Create(kCacheSize));
+
+    SkIRect clip = SkIRect::MakeWH(100, 100);
+    SkImageFilter::Cache::Key key1(0, SkMatrix::I(), clip, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key2(1, SkMatrix::I(), clip, image->uniqueID(), image->subset());
+
+    SkIPoint offset = SkIPoint::Make(3, 4);
+    cache->set(key1, image, offset);
+
+    SkIPoint foundOffset;
+
+    REPORTER_ASSERT(reporter, cache->get(key1, &foundOffset));
+
+    // This should knock the first one out of the cache
+    cache->set(key2, image, offset);
+
+    REPORTER_ASSERT(reporter, cache->get(key2, &foundOffset));
+    REPORTER_ASSERT(reporter, !cache->get(key1, &foundOffset));
+}
+
+// Exercise the purgeByKeys and purge methods
+static void test_explicit_purging(skiatest::Reporter* reporter,
+                                  SkSpecialImage* image,
+                                  SkSpecialImage* subset) {
+    static const size_t kCacheSize = 1000000;
+    SkAutoTUnref<SkImageFilter::Cache> cache(SkImageFilter::Cache::Create(kCacheSize));
+
+    SkIRect clip = SkIRect::MakeWH(100, 100);
+    SkImageFilter::Cache::Key key1(0, SkMatrix::I(), clip, image->uniqueID(), image->subset());
+    SkImageFilter::Cache::Key key2(1, SkMatrix::I(), clip, subset->uniqueID(), image->subset());
+
+    SkIPoint offset = SkIPoint::Make(3, 4);
+    cache->set(key1, image, offset);
+    cache->set(key2, image, offset);
+
+    SkIPoint foundOffset;
+
+    REPORTER_ASSERT(reporter, cache->get(key1, &foundOffset));
+    REPORTER_ASSERT(reporter, cache->get(key2, &foundOffset));
+
+    cache->purgeByKeys(&key1, 1);
+
+    REPORTER_ASSERT(reporter, !cache->get(key1, &foundOffset));
+    REPORTER_ASSERT(reporter, cache->get(key2, &foundOffset));
+
+    cache->purge();
+
+    REPORTER_ASSERT(reporter, !cache->get(key1, &foundOffset));
+    REPORTER_ASSERT(reporter, !cache->get(key2, &foundOffset));
+}
+
+DEF_TEST(ImageFilterCache_RasterBacked, reporter) {
+    SkBitmap srcBM = create_bm();

[Stephen White, 2016/02/18 21:14:28]

Not sure I understand why these paths are testing the SkBitmap path. Shouldn't
they be testing the SkSpecialImage path instead?

[robertphillips, 2016/02/19 15:27:10]

They should be testing the raster, gpu, and SkImage -backed SkSpecialImage
paths. I should only be using the initial bitmap to create the SkSpecialImages.

[Stephen White, 2016/02/19 15:32:09]

Shouldn't we be creating an SkImage, then doing a NewFromImage() on that? Isn't
the SkBitmap path in SkSpecialImage going to go away at some point?

[robertphillips, 2016/02/19 16:04:52]

Right - once images are everywhere the _RasterBacked and _GPUBacked cases will
go away and only the _ImageBacked flavor will remain.

I will add an _ImageBacked variant with a GrTexture behind it.

+
+    const SkIRect& full = SkIRect::MakeWH(kFullSize, kFullSize);
+
+    SkAutoTUnref<SkSpecialImage> fullImg(SkSpecialImage::NewFromRaster(nullptr, full, srcBM));
+
+    const SkIRect& subset = SkIRect::MakeXYWH(kPad, kPad, kSmallerSize, kSmallerSize);
+
+    SkAutoTUnref<SkSpecialImage> subsetImg(SkSpecialImage::NewFromRaster(nullptr, subset, srcBM));
+
+    test_find_existing(reporter, fullImg, subsetImg);
+    test_dont_find_if_diff_key(reporter, fullImg, subsetImg);
+    test_internal_purge(reporter, fullImg);
+    test_explicit_purging(reporter, fullImg, subsetImg);
+}
+
+DEF_TEST(ImageFilterCache_ImageBacked, reporter) {
+    SkBitmap srcBM = create_bm();
+
+    SkAutoTUnref<SkImage> srcImage(SkImage::NewFromBitmap(srcBM));
+
+    const SkIRect& full = SkIRect::MakeWH(kFullSize, kFullSize);
+
+    SkAutoTUnref<SkSpecialImage> fullImg(SkSpecialImage::NewFromImage(full, srcImage));
+
+    const SkIRect& subset = SkIRect::MakeXYWH(kPad, kPad, kSmallerSize, kSmallerSize);
+
+    SkAutoTUnref<SkSpecialImage> subsetImg(SkSpecialImage::NewFromImage(subset, srcImage));
+
+    test_find_existing(reporter, fullImg, subsetImg);
+    test_dont_find_if_diff_key(reporter, fullImg, subsetImg);
+    test_internal_purge(reporter, fullImg);
+    test_explicit_purging(reporter, fullImg, subsetImg);
+}
+
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+
+DEF_GPUTEST_FOR_RENDERING_CONTEXTS(ImageFilterCache_GPUBacked, reporter, context) {
+    SkBitmap srcBM = create_bm();
+
+    GrSurfaceDesc desc;
+    desc.fConfig = kSkia8888_GrPixelConfig;
+    desc.fFlags  = kNone_GrSurfaceFlags;
+    desc.fWidth  = kFullSize;
+    desc.fHeight = kFullSize;
+
+    SkAutoTUnref<GrTexture> srcTexture(context->textureProvider()->createTexture(desc, false,
+                                                                                 srcBM.getPixels(),
+                                                                                 0));
+    if (!srcTexture) {
+        return;
+    }
+
+    const SkIRect& full = SkIRect::MakeWH(kFullSize, kFullSize);
+
+    SkAutoTUnref<SkSpecialImage> fullImg(SkSpecialImage::NewFromGpu(
+                                                                nullptr, full, 
+                                                                kNeedNewImageUniqueID_SpecialImage,
+                                                                srcTexture));
+
+    const SkIRect& subset = SkIRect::MakeXYWH(kPad, kPad, kSmallerSize, kSmallerSize);
+
+    SkAutoTUnref<SkSpecialImage> subsetImg(SkSpecialImage::NewFromGpu(
+                                                                nullptr, subset, 
+                                                                kNeedNewImageUniqueID_SpecialImage,
+                                                                srcTexture));
+
+    test_find_existing(reporter, fullImg, subsetImg);
+    test_dont_find_if_diff_key(reporter, fullImg, subsetImg);
+    test_internal_purge(reporter, fullImg);
+    test_explicit_purging(reporter, fullImg, subsetImg);
+}
+#endif
+