Add support for multiple frames in SkCodec

tests/CodecTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkAndroidCodec.h"
 #include "SkBitmap.h"
@@ skipping 271 matching lines @@
     SkMD5::Digest codecDigest;
     const SkImageInfo info = codec->getInfo().makeColorType(kN32_SkColorType);
     SkBitmap bm;
     SkCodec::Result expectedResult = isIncomplete ? SkCodec::kIncompleteInput : SkCodec::kSuccess;
     test_codec(r, codec.get(), bm, info, size, expectedResult, &codecDigest, nullptr);
 
     // Scanline decoding follows.
 
     if (supportsNewScanlineDecoding && !isIncomplete) {
         test_incremental_decode(r, codec, info, codecDigest);
-        test_in_stripes(r, codec, info, codecDigest);
+        // FIXME: This is broken for gif.

[scroggo_chromium, 2016/10/13 20:38:16]

Incremental decoding with GIF works for the case where we are sampling, when
SkSampledCodec provides a subset that cuts off lines that would be sampled out
anyway. But the API does not distinguish between that and arbitrary subsets,
which is currently broken for GIF. We do not actually need to support this use
case, since we only need true subsetting for png and jpeg (and webp), for
BitmapRegionDecoder. But a bad client could easily make us do the wrong thing
here.

A proper fix might be for SkSampledCodec to not repurpose the subset to mean
ignore these lines that fall outside the sampled area, which I think msarett@
pushed for anyway.

+        if (SkStrEndsWith(path, "png") || SkStrEndsWith(path, "PNG")) {
+            test_in_stripes(r, codec, info, codecDigest);
+        }
     }
 
     // Need to call startScanlineDecode() first.
     REPORTER_ASSERT(r, codec->getScanlines(bm.getAddr(0, 0), 1, 0) == 0);
     REPORTER_ASSERT(r, !codec->skipScanlines(1));
     const SkCodec::Result startResult = codec->startScanlineDecode(info);
     if (supportsScanlineDecoding) {
         bm.eraseColor(SK_ColorYELLOW);
 
         REPORTER_ASSERT(r, startResult == SkCodec::kSuccess);
@@ skipping 159 matching lines @@
 
     // ICO
     // FIXME: We are not ready to test incomplete ICOs
     // These two tests examine interestingly different behavior:
     // Decodes an embedded BMP image
     check(r, "color_wheel.ico", SkISize::Make(128, 128), true, false, false);
     // Decodes an embedded PNG image
     check(r, "google_chrome.ico", SkISize::Make(256, 256), false, false, false, true);
 
     // GIF
-    // FIXME: We are not ready to test incomplete GIFs
-    check(r, "box.gif", SkISize::Make(200, 55), true, false, false);
-    check(r, "color_wheel.gif", SkISize::Make(128, 128), true, false, false);
+    check(r, "box.gif", SkISize::Make(200, 55), false, false, true, true);
+    check(r, "color_wheel.gif", SkISize::Make(128, 128), false, false, true, true);
     // randPixels.gif is too small to test incomplete
-    check(r, "randPixels.gif", SkISize::Make(8, 8), true, false, false);
+    check(r, "randPixels.gif", SkISize::Make(8, 8), false, false, false, true);
 
     // JPG
     check(r, "CMYK.jpg", SkISize::Make(642, 516), true, false, true);
     check(r, "color_wheel.jpg", SkISize::Make(128, 128), true, false, true);
     // grayscale.jpg is too small to test incomplete
     check(r, "grayscale.jpg", SkISize::Make(128, 128), true, false, false);
     check(r, "mandrill_512_q075.jpg", SkISize::Make(512, 512), true, false, true);
     // randPixels.jpg is too small to test incomplete
     check(r, "randPixels.jpg", SkISize::Make(8, 8), true, false, false);
 
@@ skipping 721 matching lines @@
         REPORTER_ASSERT(r, SkCodec::kUnimplemented == result);
     }
 }
 
 DEF_TEST(Codec_F16ConversionPossible, r) {
     test_conversion_possible(r, "color_wheel.webp", false, false);
     test_conversion_possible(r, "mandrill_512_q075.jpg", true, false);
     test_conversion_possible(r, "yellow_rose.png", false, true);
 }
 
+static void decode_frame(skiatest::Reporter* r, SkCodec* codec, size_t frame) {
+    SkBitmap bm;
+    auto info = codec->getInfo().makeColorType(kN32_SkColorType);
+    bm.allocPixels(info);
+
+    SkCodec::Options opts;
+    SkCodec::MultiFrameOptions multiOpts;
+    multiOpts.fIndex = frame;
+    opts.fFrameOptions = &multiOpts;
+    REPORTER_ASSERT(r, SkCodec::kSuccess == codec->getPixels(info,
+            bm.getPixels(), bm.rowBytes(), &opts, nullptr, nullptr));
+}
+
+// For an animated image, we should only read enough to decode the requested
+// frame if the client never calls getFrameInfo.
+DEF_TEST(Codec_skipFullParse, r) {
+    auto path = "test640x479.gif";
+    SkStream* stream(GetResourceAsStream(path));
+    if (!stream) {
+        return;
+    }
+
+    // Note that we cheat and hold on to the stream pointer, but SkCodec will
+    // take ownership. We will not refer to the stream after the SkCodec
+    // deletes it.
+    std::unique_ptr<SkCodec> codec(SkCodec::NewFromStream(stream));
+    if (!codec) {
+        ERRORF(r, "Failed to create codec for %s", path);
+        return;
+    }
+
+    REPORTER_ASSERT(r, stream->hasPosition());
+    const size_t sizePosition = stream->getPosition();
+    REPORTER_ASSERT(r, stream->hasLength() && sizePosition < stream->getLength());
+
+    // This should read more of the stream, but not the whole stream.
+    decode_frame(r, codec.get(), 0);
+    const size_t positionAfterFirstFrame = stream->getPosition();
+    REPORTER_ASSERT(r, positionAfterFirstFrame > sizePosition
+                       && positionAfterFirstFrame < stream->getLength());
+
+    // Again, this should read more of the stream.
+    decode_frame(r, codec.get(), 2);
+    const size_t positionAfterThirdFrame = stream->getPosition();
+    REPORTER_ASSERT(r, positionAfterThirdFrame > positionAfterFirstFrame
+                       && positionAfterThirdFrame < stream->getLength());
+
+    // This does not need to read any more of the stream, since it has already
+    // parsed the second frame.
+    decode_frame(r, codec.get(), 1);
+    REPORTER_ASSERT(r, stream->getPosition() == positionAfterThirdFrame);
+
+    // This should read the rest of the frames.
+    decode_frame(r, codec.get(), 3);
+    const size_t finalPosition = stream->getPosition();
+    REPORTER_ASSERT(r, finalPosition > positionAfterThirdFrame);
+
+    // There may be more data in the stream.
+    auto frameInfo = codec->getFrameInfo();
+    REPORTER_ASSERT(r, frameInfo.size() == 4);
+    REPORTER_ASSERT(r, stream->getPosition() >= finalPosition);
+}
+
 // Only rewinds up to a limit.
 class LimitedRewindingStream : public SkStream {
 public:
     static SkStream* Make(const char path[], size_t limit) {
         SkStream* stream = GetResourceAsStream(path);
         if (!stream) {
             return nullptr;
         }
         return new LimitedRewindingStream(stream, limit);
     }
@@ skipping 31 matching lines @@
     }
 };
 
 DEF_TEST(Codec_fallBack, r) {
     // SkAndroidCodec needs to be able to fall back to scanline decoding
     // if incremental decoding does not work. Make sure this does not
     // require a rewind.
 
     // Formats that currently do not support incremental decoding
     auto files = {
-            "box.gif",
             "CMYK.jpg",
             "color_wheel.ico",
             "mandrill.wbmp",
             "randPixels.bmp",
             };
     for (auto file : files) {
         SkStream* stream = LimitedRewindingStream::Make(file, 14);
         if (!stream) {
             SkDebugf("Missing resources (%s). Set --resourcePath.\n", file);
             return;
@@ skipping 74 matching lines @@
     auto result = codec->startIncrementalDecode(info, bm.getPixels(), bm.rowBytes());
     REPORTER_ASSERT(r, result == SkCodec::kSuccess);
 
     // This is an arbitrary value. The important fact is that it is not zero, and rowsDecoded
     // should get set to zero by incrementalDecode.
     int rowsDecoded = 77;
     result = codec->incrementalDecode(&rowsDecoded);
     REPORTER_ASSERT(r, result == SkCodec::kIncompleteInput);
     REPORTER_ASSERT(r, rowsDecoded == 0);
 }