Decode GIF image frames on demand.

Source/WebKit/chromium/tests/GIFImageDecoderTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "core/platform/image-decoders/gif/GIFImageDecoder.h"
 
-#include <gtest/gtest.h>
 #include "core/platform/FileSystem.h"
 #include "core/platform/SharedBuffer.h"
+#include "wtf/OwnPtr.h"

[Alpha Left Google, 2013/05/22 20:18:09]

nit: I'm not sure whether we are moving to use "wtf/..." instead of <wtf/...>.
Other core files seem to remaing using <wtf/...>.

[Xianzhu, 2013/05/22 23:43:29]

Yes, this is the new style. The presubmit script reports errors for <wtf/...>.
For now it seems only changed files need to update this.

+#include "wtf/PassOwnPtr.h"
+#include "wtf/StringHasher.h"
+#include "wtf/Vector.h"
+#include <gtest/gtest.h>
 #include <public/Platform.h>
 #include <public/WebData.h>
 #include <public/WebSize.h>
 #include <public/WebUnitTestSupport.h>
-#include <wtf/OwnPtr.h>
-#include <wtf/PassOwnPtr.h>
-#include <wtf/StringHasher.h>
-#include <wtf/Vector.h>
 
 using namespace WebCore;
 using namespace WebKit;
 
 namespace {
 
 #if !OS(ANDROID)
 
 static PassRefPtr<SharedBuffer> readFile(const char* fileName)
 {
@@ skipping 72 matching lines @@
 TEST(GIFImageDecoderTest, parseByteByByte)
 {
     OwnPtr<GIFImageDecoder> decoder(createDecoder());
 
     RefPtr<SharedBuffer> data = readFile("/LayoutTests/fast/images/resources/animated.gif");
     ASSERT_TRUE(data.get());
 
     size_t frameCount = 0;
 
     // Pass data to decoder byte by byte.
-    for (unsigned length = 1; length <= data->size(); ++length) {
+    for (size_t length = 1; length <= data->size(); ++length) {
         RefPtr<SharedBuffer> tempData = SharedBuffer::create(data->data(), length);
         decoder->setData(tempData.get(), length == data->size());
 
         EXPECT_LE(frameCount, decoder->frameCount());
         frameCount = decoder->frameCount();
     }
 
     EXPECT_EQ(2u, decoder->frameCount());
 
     decoder->frameBufferAtIndex(0);
     decoder->frameBufferAtIndex(1);
     EXPECT_EQ(cAnimationLoopInfinite, decoder->repetitionCount());
 }
 
 TEST(GIFImageDecoderTest, parseAndDecodeByteByByte)
 {
     OwnPtr<GIFImageDecoder> decoder(createDecoder());
 
     RefPtr<SharedBuffer> data = readFile("/LayoutTests/fast/images/resources/animated-gif-with-offsets.gif");
     ASSERT_TRUE(data.get());
 
     size_t frameCount = 0;
     size_t framesDecoded = 0;
 
     // Pass data to decoder byte by byte.
-    for (unsigned length = 1; length <= data->size(); ++length) {
+    for (size_t length = 1; length <= data->size(); ++length) {
         RefPtr<SharedBuffer> tempData = SharedBuffer::create(data->data(), length);
         decoder->setData(tempData.get(), length == data->size());
 
         EXPECT_LE(frameCount, decoder->frameCount());
         frameCount = decoder->frameCount();
 
         ImageFrame* frame = decoder->frameBufferAtIndex(frameCount - 1);
         if (frame && frame->status() == ImageFrame::FrameComplete && framesDecoded < frameCount)
             ++framesDecoded;
     }
@@ skipping 59 matching lines @@
     bool match = true;
     for (size_t i = 0; i < truncatedHashes.size(); ++i) {
         if (truncatedHashes[i] != progressiveHashes[i]) {
             match = false;
             break;
         }
     }
     EXPECT_TRUE(match);
 }
 
+TEST(GIFImageDecoderTest, randomFrameDecode)
+{
+    RefPtr<SharedBuffer> fullData = readFile("/Source/WebKit/chromium/tests/data/radient.gif");
+    ASSERT_TRUE(fullData.get());
+
+    OwnPtr<GIFImageDecoder> decoder;
+
+    // Compute hashes when the frames are requested sequentially.

[Alpha Left Google, 2013/05/22 20:18:09]

This is not really random isn't it?

[Xianzhu, 2013/05/22 23:43:29]

This is to get a baseline for testing the random decoding case. Moved it to a
utility function.

+    decoder = createDecoder();
+    decoder->setData(fullData.get(), true);
+    decoder->frameBufferAtIndex(0); // To trigger parsing.

[Alpha Left Google, 2013/05/22 20:18:09]

frameCount() will trigger parsing already.

[Xianzhu, 2013/05/22 23:43:29]

Done.

+    size_t frameCount = decoder->frameCount();
+    Vector<unsigned> sequentialHashes(frameCount);
+    for (size_t i = 0; i < frameCount; ++i) {
+        ImageFrame* frame = decoder->frameBufferAtIndex(i);
+        sequentialHashes[i] = hashSkBitmap(frame->getSkBitmap());
+    }
+
+    // Compute hashes when frames are requested randomly.
+    decoder = createDecoder();
+    decoder->setData(fullData.get(), true);
+    const size_t skippingStep = 5;
+    for (size_t i = 0; i < skippingStep; ++i) {
+        for (size_t j = i; j < frameCount; j += skippingStep) {
+            ImageFrame* frame = decoder->frameBufferAtIndex(j);
+            EXPECT_EQ(sequentialHashes[j], hashSkBitmap(frame->getSkBitmap()));
+        }
+    }
+
+    // Compute hashes when frames are requested in reverse order.
+    decoder = createDecoder();
+    decoder->setData(fullData.get(), true);
+    for (size_t i = frameCount; i; --i) {
+        ImageFrame* frame = decoder->frameBufferAtIndex(i - 1);
+        EXPECT_EQ(sequentialHashes[i - 1], hashSkBitmap(frame->getSkBitmap()));
+    }
+}
+
+TEST(GIFImageDecoderTest, decodeAfterClearFrameBufferCache)
+{
+    RefPtr<SharedBuffer> fullData = readFile("/Source/WebKit/chromium/tests/data/radient.gif");
+    ASSERT_TRUE(fullData.get());
+
+    OwnPtr<GIFImageDecoder> decoder;
+
+    // Compute hashes when the frames are requested sequentially.
+    decoder = createDecoder();
+    decoder->setData(fullData.get(), true);
+    decoder->frameBufferAtIndex(0); // To trigger parsing.

[Alpha Left Google, 2013/05/22 20:18:09]

frameCount() will trigger parsing so this is not necessary.

[Xianzhu, 2013/05/22 23:43:29]

Done.

+    size_t frameCount = decoder->frameCount();
+    Vector<unsigned> sequentialHashes(frameCount);
+    for (size_t i = 0; i < frameCount; ++i) {
+        ImageFrame* frame = decoder->frameBufferAtIndex(i);
+        sequentialHashes[i] = hashSkBitmap(frame->getSkBitmap());
+    }
+
+    for (size_t clearExceptFrame = 0; clearExceptFrame < frameCount; ++clearExceptFrame) {
+        decoder->clearFrameBufferCache(clearExceptFrame);
+        const size_t skippingStep = 5;
+        for (size_t i = 0; i < skippingStep; ++i) {
+            for (size_t j = 0; j < frameCount; j += skippingStep) {
+                ImageFrame* frame = decoder->frameBufferAtIndex(j);
+                EXPECT_EQ(sequentialHashes[j], hashSkBitmap(frame->getSkBitmap()));
+            }
+        }
+    }
+}
+

[Alpha Left Google, 2013/05/22 20:18:09]

You also need to test this corner case:
1. Frame 1 is partially decoded.
2. Skip to decode other frames and then clear.
3. Come back to resume decoding frame 1.

[Xianzhu, 2013/05/22 23:43:29]

Done.

 TEST(GIFImageDecoderTest, allDataReceivedTruncation)
 {
     OwnPtr<GIFImageDecoder> decoder(createDecoder());
 
     RefPtr<SharedBuffer> data = readFile("/LayoutTests/fast/images/resources/animated.gif");
     ASSERT_TRUE(data.get());
 
     ASSERT_GE(data->size(), 10u);
     RefPtr<SharedBuffer> tempData = SharedBuffer::create(data->data(), data->size() - 10);
     decoder->setData(tempData.get(), true);
@@ skipping 39 matching lines @@
 
     decoder->setData(data.get(), true);
     EXPECT_EQ(2u, decoder->frameCount());
     EXPECT_TRUE(decoder->frameIsCompleteAtIndex(0));
     EXPECT_TRUE(decoder->frameIsCompleteAtIndex(1));
 }
 
 #endif
 
 } // namespace