skia2/tests/GifTest.cpp
Leon Scroggins III 3fc97d75ac Fix SkGifCodec bugs around truncated data
Prior to this CL, if a GIF file was truncated before reading the local
color map of a frame, incremental decode would do the wrong thing. In
onStartIncrementalDecode, we would either create a color table based on
the global color map, or we would create a dummy one with only one
color (transparent). The dummy color table is correct if there is
neither a global nor a local color map, and allows us to fill the frame
with transparent. But if more data is provided, and it includes an
actual color map and image data, one of the following can happen:
- If the created color table is smaller than the actual one, the
  decoded data may include indices outside of the range of the created
  color table, resulting in a crash.
- If we get lucky, and the created color table is large enough, it may
  still be the wrong colors (and most likely is).

To solve this, make onStartIncrementalDecode fail if there is a local
color map that has not been read yet. A future call may read more data
and read the correct color map.

This is done by returning kIncompleteInput in
SkGifCodec::prepareToDecode if there is a local color map that has not
yet been read. (It is possible that there is no color map at all, in
which case we still need to support decoding that frame. Skip
attempting to decode in that case.)

In onGetPixels, if prepareToDecode returned kIncompleteInput, return
kInvalidInput. Although the input is technically incomplete, no future
call will provide more data (unlike in incremental decoding), and there
is nothing interesting for the client to draw. This also prevents
SkCodec from attempting to fill the data with an SkSwizzler, which has
not been created. (An alternative solution would be create the dummy
color table and an SkSwizzler, which would keep the current behavior.
But I think the new behavior of returning kInvalidInput makes more
sense.)

Add tests to verify the intended behavior:
- getPixels fails.
- startIncrementalDecode fails, but after providing more data it will
  succeed and incremental decoding matches the image decoded from the
  full stream.
- Both succeed if there is no color table at all.

Change-Id: Ifb52fe7f723673406a28e80c8805a552f0ac33b6
Reviewed-on: https://skia-review.googlesource.com/5758
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
2016-12-12 17:59:05 +00:00

276 lines
11 KiB
C++

/*
* 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 "CodecPriv.h"
#include "Resources.h"
#include "SkAndroidCodec.h"
#include "SkBitmap.h"
#include "SkData.h"
#include "SkImage.h"
#include "SkStream.h"
#include "SkTypes.h"
#include "Test.h"
static unsigned char gGIFData[] = {
0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x03, 0x00, 0x03, 0x00, 0xe3, 0x08,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00,
0xff, 0x80, 0x80, 0x80, 0x00, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0x2c, 0x00, 0x00, 0x00, 0x00, 0x03, 0x00, 0x03, 0x00, 0x00, 0x04,
0x07, 0x50, 0x1c, 0x43, 0x40, 0x41, 0x23, 0x44, 0x00, 0x3b
};
static unsigned char gGIFDataNoColormap[] = {
// Header
0x47, 0x49, 0x46, 0x38, 0x39, 0x61,
// Screen descriptor
0x01, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
// Graphics control extension
0x21, 0xf9, 0x04, 0x01, 0x0a, 0x00, 0x01, 0x00,
// Image descriptor
0x2c, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00,
// Image data
0x02, 0x02, 0x4c, 0x01, 0x00,
// Trailer
0x3b
};
static unsigned char gInterlacedGIF[] = {
0x47, 0x49, 0x46, 0x38, 0x37, 0x61, 0x09, 0x00, 0x09, 0x00, 0xe3, 0x08, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0xff, 0x00, 0xff, 0x80,
0x80, 0x80, 0x00, 0xff, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x2c, 0x00, 0x00, 0x00,
0x00, 0x09, 0x00, 0x09, 0x00, 0x40, 0x04, 0x1b, 0x50, 0x1c, 0x23, 0xe9, 0x44,
0x23, 0x60, 0x9d, 0x09, 0x28, 0x1e, 0xf8, 0x6d, 0x64, 0x56, 0x9d, 0x53, 0xa8,
0x7e, 0xa8, 0x65, 0x94, 0x5c, 0xb0, 0x8a, 0x45, 0x04, 0x00, 0x3b
};
static void test_gif_data_no_colormap(skiatest::Reporter* r,
void* data,
size_t size) {
SkBitmap bm;
bool imageDecodeSuccess = decode_memory(data, size, &bm);
REPORTER_ASSERT(r, imageDecodeSuccess);
REPORTER_ASSERT(r, bm.width() == 1);
REPORTER_ASSERT(r, bm.height() == 1);
REPORTER_ASSERT(r, !(bm.empty()));
if (!(bm.empty())) {
REPORTER_ASSERT(r, bm.getColor(0, 0) == 0x00000000);
}
}
static void test_gif_data(skiatest::Reporter* r, void* data, size_t size) {
SkBitmap bm;
bool imageDecodeSuccess = decode_memory(data, size, &bm);
REPORTER_ASSERT(r, imageDecodeSuccess);
REPORTER_ASSERT(r, bm.width() == 3);
REPORTER_ASSERT(r, bm.height() == 3);
REPORTER_ASSERT(r, !(bm.empty()));
if (!(bm.empty())) {
REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
REPORTER_ASSERT(r, bm.getColor(0, 1) == 0xff808080);
REPORTER_ASSERT(r, bm.getColor(1, 1) == 0xff000000);
REPORTER_ASSERT(r, bm.getColor(2, 1) == 0xff00ff00);
REPORTER_ASSERT(r, bm.getColor(0, 2) == 0xffffffff);
REPORTER_ASSERT(r, bm.getColor(1, 2) == 0xffff00ff);
REPORTER_ASSERT(r, bm.getColor(2, 2) == 0xff0000ff);
}
}
static void test_gif_data_dims(skiatest::Reporter* r, void* data, size_t size, int width,
int height) {
SkBitmap bm;
bool imageDecodeSuccess = decode_memory(data, size, &bm);
REPORTER_ASSERT(r, imageDecodeSuccess);
REPORTER_ASSERT(r, bm.width() == width);
REPORTER_ASSERT(r, bm.height() == height);
REPORTER_ASSERT(r, !(bm.empty()));
}
static void test_interlaced_gif_data(skiatest::Reporter* r,
void* data,
size_t size) {
SkBitmap bm;
bool imageDecodeSuccess = decode_memory(data, size, &bm);
REPORTER_ASSERT(r, imageDecodeSuccess);
REPORTER_ASSERT(r, bm.width() == 9);
REPORTER_ASSERT(r, bm.height() == 9);
REPORTER_ASSERT(r, !(bm.empty()));
if (!(bm.empty())) {
REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
REPORTER_ASSERT(r, bm.getColor(0, 2) == 0xffffffff);
REPORTER_ASSERT(r, bm.getColor(1, 2) == 0xffff00ff);
REPORTER_ASSERT(r, bm.getColor(2, 2) == 0xff0000ff);
REPORTER_ASSERT(r, bm.getColor(0, 4) == 0xff808080);
REPORTER_ASSERT(r, bm.getColor(1, 4) == 0xff000000);
REPORTER_ASSERT(r, bm.getColor(2, 4) == 0xff00ff00);
REPORTER_ASSERT(r, bm.getColor(0, 6) == 0xffff0000);
REPORTER_ASSERT(r, bm.getColor(1, 6) == 0xffffff00);
REPORTER_ASSERT(r, bm.getColor(2, 6) == 0xff00ffff);
REPORTER_ASSERT(r, bm.getColor(0, 8) == 0xffffffff);
REPORTER_ASSERT(r, bm.getColor(1, 8) == 0xffff00ff);
REPORTER_ASSERT(r, bm.getColor(2, 8) == 0xff0000ff);
}
}
static void test_gif_data_short(skiatest::Reporter* r,
void* data,
size_t size) {
SkBitmap bm;
bool imageDecodeSuccess = decode_memory(data, size, &bm);
REPORTER_ASSERT(r, imageDecodeSuccess);
REPORTER_ASSERT(r, bm.width() == 3);
REPORTER_ASSERT(r, bm.height() == 3);
REPORTER_ASSERT(r, !(bm.empty()));
if (!(bm.empty())) {
REPORTER_ASSERT(r, bm.getColor(0, 0) == 0xffff0000);
REPORTER_ASSERT(r, bm.getColor(1, 0) == 0xffffff00);
REPORTER_ASSERT(r, bm.getColor(2, 0) == 0xff00ffff);
REPORTER_ASSERT(r, bm.getColor(0, 1) == 0xff808080);
REPORTER_ASSERT(r, bm.getColor(1, 1) == 0xff000000);
REPORTER_ASSERT(r, bm.getColor(2, 1) == 0xff00ff00);
}
}
/**
This test will test the ability of the SkCodec to deal with
GIF files which have been mangled somehow. We want to display as
much of the GIF as possible.
*/
DEF_TEST(Gif, reporter) {
// test perfectly good images.
test_gif_data(reporter, static_cast<void *>(gGIFData), sizeof(gGIFData));
test_interlaced_gif_data(reporter, static_cast<void *>(gInterlacedGIF),
sizeof(gInterlacedGIF));
unsigned char badData[sizeof(gGIFData)];
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[6] = 0x01; // image too wide
test_gif_data(reporter, static_cast<void *>(badData), sizeof(gGIFData));
// "libgif warning [image too wide, expanding output to size]"
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[8] = 0x01; // image too tall
test_gif_data(reporter, static_cast<void *>(badData), sizeof(gGIFData));
// "libgif warning [image too tall, expanding output to size]"
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[62] = 0x01; // image shifted right
test_gif_data_dims(reporter, static_cast<void *>(badData), sizeof(gGIFData), 4, 3);
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[64] = 0x01; // image shifted down
test_gif_data_dims(reporter, static_cast<void *>(badData), sizeof(gGIFData), 3, 4);
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[62] = 0xff; // image shifted right
badData[63] = 0xff;
test_gif_data_dims(reporter, static_cast<void *>(badData), sizeof(gGIFData), 3 + 0xFFFF, 3);
memcpy(badData, gGIFData, sizeof(gGIFData));
badData[64] = 0xff; // image shifted down
badData[65] = 0xff;
test_gif_data_dims(reporter, static_cast<void *>(badData), sizeof(gGIFData), 3, 3 + 0xFFFF);
test_gif_data_no_colormap(reporter, static_cast<void *>(gGIFDataNoColormap),
sizeof(gGIFDataNoColormap));
// Since there is no color map, we do not even need to parse the image data
// to know that we should draw transparent. Truncate the file before the
// data. This should still succeed.
test_gif_data_no_colormap(reporter, static_cast<void *>(gGIFDataNoColormap), 31);
// Likewise, incremental decoding should succeed here.
{
sk_sp<SkData> data = SkData::MakeWithoutCopy(gGIFDataNoColormap, 31);
std::unique_ptr<SkCodec> codec(SkCodec::NewFromData(data));
REPORTER_ASSERT(reporter, codec);
if (codec) {
auto info = codec->getInfo().makeColorType(kN32_SkColorType);
SkBitmap bm;
bm.allocPixels(info);
REPORTER_ASSERT(reporter, SkCodec::kSuccess == codec->startIncrementalDecode(
info, bm.getPixels(), bm.rowBytes()));
REPORTER_ASSERT(reporter, SkCodec::kSuccess == codec->incrementalDecode());
REPORTER_ASSERT(reporter, bm.width() == 1);
REPORTER_ASSERT(reporter, bm.height() == 1);
REPORTER_ASSERT(reporter, !(bm.empty()));
if (!(bm.empty())) {
REPORTER_ASSERT(reporter, bm.getColor(0, 0) == 0x00000000);
}
}
}
// test short Gif. 80 is missing a few bytes.
test_gif_data_short(reporter, static_cast<void *>(gGIFData), 80);
// "libgif warning [DGifGetLine]"
test_interlaced_gif_data(reporter, static_cast<void *>(gInterlacedGIF),
100); // 100 is missing a few bytes
// "libgif warning [interlace DGifGetLine]"
}
// Regression test for decoding a gif image with sampleSize of 4, which was
// previously crashing.
DEF_TEST(Gif_Sampled, r) {
std::unique_ptr<SkFILEStream> stream(
new SkFILEStream(GetResourcePath("test640x479.gif").c_str()));
REPORTER_ASSERT(r, stream->isValid());
if (!stream->isValid()) {
return;
}
std::unique_ptr<SkAndroidCodec> codec(SkAndroidCodec::NewFromStream(stream.release()));
REPORTER_ASSERT(r, codec);
if (!codec) {
return;
}
// Construct a color table for the decode if necessary
sk_sp<SkColorTable> colorTable(nullptr);
SkPMColor* colorPtr = nullptr;
int* colorCountPtr = nullptr;
int maxColors = 256;
if (kIndex_8_SkColorType == codec->getInfo().colorType()) {
SkPMColor colors[256];
colorTable.reset(new SkColorTable(colors, maxColors));
colorPtr = const_cast<SkPMColor*>(colorTable->readColors());
colorCountPtr = &maxColors;
}
SkAndroidCodec::AndroidOptions options;
options.fSampleSize = 4;
options.fColorPtr = colorPtr;
options.fColorCount = colorCountPtr;
SkBitmap bm;
bm.allocPixels(codec->getInfo(), nullptr, colorTable.get());
const SkCodec::Result result = codec->getAndroidPixels(codec->getInfo(), bm.getPixels(),
bm.rowBytes(), &options);
REPORTER_ASSERT(r, result == SkCodec::kSuccess);
}
// If a GIF file is truncated before the header for the first image is defined,
// we should not create an SkCodec.
DEF_TEST(Codec_GifTruncated, r) {
SkString path = GetResourcePath("test640x479.gif");
sk_sp<SkData> data(SkData::MakeFromFileName(path.c_str()));
// This is right before the header for the first image.
data = SkData::MakeSubset(data.get(), 0, 446);
std::unique_ptr<SkCodec> codec(SkCodec::NewFromData(data));
REPORTER_ASSERT(r, !codec);
}