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nsPNGDecoder.cpp
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nsPNGDecoder.cpp
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ImageLogging.h" // Must appear first
#include "nsPNGDecoder.h"
#include <algorithm>
#include <cstdint>
#include "gfxColor.h"
#include "gfxPlatform.h"
#include "imgFrame.h"
#include "nsColor.h"
#include "nsIInputStream.h"
#include "nsMemory.h"
#include "nsRect.h"
#include "nspr.h"
#include "png.h"
#include "RasterImage.h"
#include "SurfaceCache.h"
#include "SurfacePipeFactory.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/Telemetry.h"
using namespace mozilla::gfx;
using std::min;
namespace mozilla {
namespace image {
static LazyLogModule sPNGLog("PNGDecoder");
static LazyLogModule sPNGDecoderAccountingLog("PNGDecoderAccounting");
// limit image dimensions (bug #251381, #591822, #967656, and #1283961)
#ifndef MOZ_PNG_MAX_WIDTH
# define MOZ_PNG_MAX_WIDTH 0x7fffffff // Unlimited
#endif
#ifndef MOZ_PNG_MAX_HEIGHT
# define MOZ_PNG_MAX_HEIGHT 0x7fffffff // Unlimited
#endif
/* Controls the maximum chunk size configuration for libpng. We set this to a
* very large number, 256MB specifically. */
static constexpr png_alloc_size_t kPngMaxChunkSize = 0x10000000;
nsPNGDecoder::AnimFrameInfo::AnimFrameInfo()
: mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {}
#ifdef PNG_APNG_SUPPORTED
int32_t GetNextFrameDelay(png_structp aPNG, png_infop aInfo) {
// Delay, in seconds, is delayNum / delayDen.
png_uint_16 delayNum = png_get_next_frame_delay_num(aPNG, aInfo);
png_uint_16 delayDen = png_get_next_frame_delay_den(aPNG, aInfo);
if (delayNum == 0) {
return 0; // SetFrameTimeout() will set to a minimum.
}
if (delayDen == 0) {
delayDen = 100; // So says the APNG spec.
}
// Need to cast delay_num to float to have a proper division and
// the result to int to avoid a compiler warning.
return static_cast<int32_t>(static_cast<double>(delayNum) * 1000 / delayDen);
}
nsPNGDecoder::AnimFrameInfo::AnimFrameInfo(png_structp aPNG, png_infop aInfo)
: mDispose(DisposalMethod::KEEP), mBlend(BlendMethod::OVER), mTimeout(0) {
png_byte dispose_op = png_get_next_frame_dispose_op(aPNG, aInfo);
png_byte blend_op = png_get_next_frame_blend_op(aPNG, aInfo);
if (dispose_op == PNG_DISPOSE_OP_PREVIOUS) {
mDispose = DisposalMethod::RESTORE_PREVIOUS;
} else if (dispose_op == PNG_DISPOSE_OP_BACKGROUND) {
mDispose = DisposalMethod::CLEAR;
} else {
mDispose = DisposalMethod::KEEP;
}
if (blend_op == PNG_BLEND_OP_SOURCE) {
mBlend = BlendMethod::SOURCE;
} else {
mBlend = BlendMethod::OVER;
}
mTimeout = GetNextFrameDelay(aPNG, aInfo);
}
#endif
// First 8 bytes of a PNG file
const uint8_t nsPNGDecoder::pngSignatureBytes[] = {137, 80, 78, 71,
13, 10, 26, 10};
nsPNGDecoder::nsPNGDecoder(RasterImage* aImage)
: Decoder(aImage),
mLexer(Transition::ToUnbuffered(State::FINISHED_PNG_DATA, State::PNG_DATA,
SIZE_MAX),
Transition::TerminateSuccess()),
mNextTransition(Transition::ContinueUnbuffered(State::PNG_DATA)),
mLastChunkLength(0),
mPNG(nullptr),
mInfo(nullptr),
mCMSLine(nullptr),
interlacebuf(nullptr),
mInProfile(nullptr),
mTransform(nullptr),
mFormat(SurfaceFormat::UNKNOWN),
mCMSMode(0),
mChannels(0),
mPass(0),
mFrameIsHidden(false),
mDisablePremultipliedAlpha(false),
mGotInfoCallback(false),
mNumFrames(0) {}
nsPNGDecoder::~nsPNGDecoder() {
if (mPNG) {
png_destroy_read_struct(&mPNG, mInfo ? &mInfo : nullptr, nullptr);
}
if (mCMSLine) {
free(mCMSLine);
}
if (interlacebuf) {
free(interlacebuf);
}
if (mInProfile) {
qcms_profile_release(mInProfile);
// mTransform belongs to us only if mInProfile is non-null
if (mTransform) {
qcms_transform_release(mTransform);
}
}
}
nsPNGDecoder::TransparencyType nsPNGDecoder::GetTransparencyType(
const IntRect& aFrameRect) {
// Check if the image has a transparent color in its palette.
if (HasAlphaChannel()) {
return TransparencyType::eAlpha;
}
if (!aFrameRect.IsEqualEdges(FullFrame())) {
MOZ_ASSERT(HasAnimation());
return TransparencyType::eFrameRect;
}
return TransparencyType::eNone;
}
void nsPNGDecoder::PostHasTransparencyIfNeeded(
TransparencyType aTransparencyType) {
switch (aTransparencyType) {
case TransparencyType::eNone:
return;
case TransparencyType::eAlpha:
PostHasTransparency();
return;
case TransparencyType::eFrameRect:
// If the first frame of animated image doesn't draw into the whole image,
// then record that it is transparent. For subsequent frames, this doesn't
// affect transparency, because they're composited on top of all previous
// frames.
if (mNumFrames == 0) {
PostHasTransparency();
}
return;
}
}
// CreateFrame() is used for both simple and animated images.
nsresult nsPNGDecoder::CreateFrame(const FrameInfo& aFrameInfo) {
MOZ_ASSERT(HasSize());
MOZ_ASSERT(!IsMetadataDecode());
// Check if we have transparency, and send notifications if needed.
auto transparency = GetTransparencyType(aFrameInfo.mFrameRect);
PostHasTransparencyIfNeeded(transparency);
mFormat = transparency == TransparencyType::eNone ? SurfaceFormat::B8G8R8X8
: SurfaceFormat::B8G8R8A8;
// Make sure there's no animation or padding if we're downscaling.
MOZ_ASSERT_IF(Size() != OutputSize(), mNumFrames == 0);
MOZ_ASSERT_IF(Size() != OutputSize(), !GetImageMetadata().HasAnimation());
MOZ_ASSERT_IF(Size() != OutputSize(),
transparency != TransparencyType::eFrameRect);
Maybe<AnimationParams> animParams;
#ifdef PNG_APNG_SUPPORTED
if (!IsFirstFrameDecode() && png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
mAnimInfo = AnimFrameInfo(mPNG, mInfo);
if (mAnimInfo.mDispose == DisposalMethod::CLEAR) {
// We may have to display the background under this image during
// animation playback, so we regard it as transparent.
PostHasTransparency();
}
animParams.emplace(
AnimationParams{aFrameInfo.mFrameRect,
FrameTimeout::FromRawMilliseconds(mAnimInfo.mTimeout),
mNumFrames, mAnimInfo.mBlend, mAnimInfo.mDispose});
}
#endif
// If this image is interlaced, we can display better quality intermediate
// results to the user by post processing them with ADAM7InterpolatingFilter.
SurfacePipeFlags pipeFlags = aFrameInfo.mIsInterlaced
? SurfacePipeFlags::ADAM7_INTERPOLATE
: SurfacePipeFlags();
if (mNumFrames == 0) {
// The first frame may be displayed progressively.
pipeFlags |= SurfacePipeFlags::PROGRESSIVE_DISPLAY;
}
Maybe<SurfacePipe> pipe = SurfacePipeFactory::CreateSurfacePipe(
this, Size(), OutputSize(), aFrameInfo.mFrameRect, mFormat, animParams,
pipeFlags);
if (!pipe) {
mPipe = SurfacePipe();
return NS_ERROR_FAILURE;
}
mPipe = std::move(*pipe);
mFrameRect = aFrameInfo.mFrameRect;
mPass = 0;
MOZ_LOG(sPNGDecoderAccountingLog, LogLevel::Debug,
("PNGDecoderAccounting: nsPNGDecoder::CreateFrame -- created "
"image frame with %dx%d pixels for decoder %p",
mFrameRect.Width(), mFrameRect.Height(), this));
return NS_OK;
}
// set timeout and frame disposal method for the current frame
void nsPNGDecoder::EndImageFrame() {
if (mFrameIsHidden) {
return;
}
mNumFrames++;
Opacity opacity = mFormat == SurfaceFormat::B8G8R8X8
? Opacity::FULLY_OPAQUE
: Opacity::SOME_TRANSPARENCY;
PostFrameStop(opacity);
}
nsresult nsPNGDecoder::InitInternal() {
mCMSMode = gfxPlatform::GetCMSMode();
if (GetSurfaceFlags() & SurfaceFlags::NO_COLORSPACE_CONVERSION) {
mCMSMode = eCMSMode_Off;
}
mDisablePremultipliedAlpha =
bool(GetSurfaceFlags() & SurfaceFlags::NO_PREMULTIPLY_ALPHA);
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
static png_byte color_chunks[] = {99, 72, 82, 77, '\0', // cHRM
105, 67, 67, 80, '\0'}; // iCCP
static png_byte unused_chunks[] = {98, 75, 71, 68, '\0', // bKGD
101, 88, 73, 102, '\0', // eXIf
104, 73, 83, 84, '\0', // hIST
105, 84, 88, 116, '\0', // iTXt
111, 70, 70, 115, '\0', // oFFs
112, 67, 65, 76, '\0', // pCAL
115, 67, 65, 76, '\0', // sCAL
112, 72, 89, 115, '\0', // pHYs
115, 66, 73, 84, '\0', // sBIT
115, 80, 76, 84, '\0', // sPLT
116, 69, 88, 116, '\0', // tEXt
116, 73, 77, 69, '\0', // tIME
122, 84, 88, 116, '\0'}; // zTXt
#endif
// Initialize the container's source image header
// Always decode to 24 bit pixdepth
mPNG = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr,
nsPNGDecoder::error_callback,
nsPNGDecoder::warning_callback);
if (!mPNG) {
return NS_ERROR_OUT_OF_MEMORY;
}
mInfo = png_create_info_struct(mPNG);
if (!mInfo) {
png_destroy_read_struct(&mPNG, nullptr, nullptr);
return NS_ERROR_OUT_OF_MEMORY;
}
#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
// Ignore unused chunks
if (mCMSMode == eCMSMode_Off || IsMetadataDecode()) {
png_set_keep_unknown_chunks(mPNG, 1, color_chunks, 2);
}
png_set_keep_unknown_chunks(mPNG, 1, unused_chunks,
(int)sizeof(unused_chunks) / 5);
#endif
#ifdef PNG_SET_USER_LIMITS_SUPPORTED
png_set_user_limits(mPNG, MOZ_PNG_MAX_WIDTH, MOZ_PNG_MAX_HEIGHT);
png_set_chunk_malloc_max(mPNG, kPngMaxChunkSize);
#endif
#ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
// Disallow palette-index checking, for speed; we would ignore the warning
// anyhow. This feature was added at libpng version 1.5.10 and is disabled
// in the embedded libpng but enabled by default in the system libpng. This
// call also disables it in the system libpng, for decoding speed.
// Bug #745202.
png_set_check_for_invalid_index(mPNG, 0);
#endif
#ifdef PNG_SET_OPTION_SUPPORTED
# if defined(PNG_sRGB_PROFILE_CHECKS) && PNG_sRGB_PROFILE_CHECKS >= 0
// Skip checking of sRGB ICC profiles
png_set_option(mPNG, PNG_SKIP_sRGB_CHECK_PROFILE, PNG_OPTION_ON);
# endif
# ifdef PNG_MAXIMUM_INFLATE_WINDOW
// Force a larger zlib inflate window as some images in the wild have
// incorrectly set metadata (specifically CMF bits) which prevent us from
// decoding them otherwise.
png_set_option(mPNG, PNG_MAXIMUM_INFLATE_WINDOW, PNG_OPTION_ON);
# endif
#endif
// use this as libpng "progressive pointer" (retrieve in callbacks)
png_set_progressive_read_fn(
mPNG, static_cast<png_voidp>(this), nsPNGDecoder::info_callback,
nsPNGDecoder::row_callback, nsPNGDecoder::end_callback);
return NS_OK;
}
LexerResult nsPNGDecoder::DoDecode(SourceBufferIterator& aIterator,
IResumable* aOnResume) {
MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
return mLexer.Lex(aIterator, aOnResume,
[=](State aState, const char* aData, size_t aLength) {
switch (aState) {
case State::PNG_DATA:
return ReadPNGData(aData, aLength);
case State::FINISHED_PNG_DATA:
return FinishedPNGData();
}
MOZ_CRASH("Unknown State");
});
}
LexerTransition<nsPNGDecoder::State> nsPNGDecoder::ReadPNGData(
const char* aData, size_t aLength) {
// If we were waiting until after returning from a yield to call
// CreateFrame(), call it now.
if (mNextFrameInfo) {
if (NS_FAILED(CreateFrame(*mNextFrameInfo))) {
return Transition::TerminateFailure();
}
MOZ_ASSERT(mImageData, "Should have a buffer now");
mNextFrameInfo = Nothing();
}
// libpng uses setjmp/longjmp for error handling.
if (setjmp(png_jmpbuf(mPNG))) {
return Transition::TerminateFailure();
}
// Pass the data off to libpng.
mLastChunkLength = aLength;
mNextTransition = Transition::ContinueUnbuffered(State::PNG_DATA);
png_process_data(mPNG, mInfo,
reinterpret_cast<unsigned char*>(const_cast<char*>((aData))),
aLength);
// Make sure that we've reached a terminal state if decoding is done.
MOZ_ASSERT_IF(GetDecodeDone(), mNextTransition.NextStateIsTerminal());
MOZ_ASSERT_IF(HasError(), mNextTransition.NextStateIsTerminal());
// Continue with whatever transition the callback code requested. We
// initialized this to Transition::ContinueUnbuffered(State::PNG_DATA) above,
// so by default we just continue the unbuffered read.
return mNextTransition;
}
LexerTransition<nsPNGDecoder::State> nsPNGDecoder::FinishedPNGData() {
// Since we set up an unbuffered read for SIZE_MAX bytes, if we actually read
// all that data something is really wrong.
MOZ_ASSERT_UNREACHABLE("Read the entire address space?");
return Transition::TerminateFailure();
}
// Sets up gamma pre-correction in libpng before our callback gets called.
// We need to do this if we don't end up with a CMS profile.
static void PNGDoGammaCorrection(png_structp png_ptr, png_infop info_ptr) {
double aGamma;
if (png_get_gAMA(png_ptr, info_ptr, &aGamma)) {
if ((aGamma <= 0.0) || (aGamma > 21474.83)) {
aGamma = 0.45455;
png_set_gAMA(png_ptr, info_ptr, aGamma);
}
png_set_gamma(png_ptr, 2.2, aGamma);
} else {
png_set_gamma(png_ptr, 2.2, 0.45455);
}
}
// Adapted from http://www.littlecms.com/pngchrm.c example code
static qcms_profile* PNGGetColorProfile(png_structp png_ptr, png_infop info_ptr,
int color_type, qcms_data_type* inType,
uint32_t* intent) {
qcms_profile* profile = nullptr;
*intent = QCMS_INTENT_PERCEPTUAL; // Our default
// First try to see if iCCP chunk is present
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_iCCP)) {
png_uint_32 profileLen;
png_bytep profileData;
png_charp profileName;
int compression;
png_get_iCCP(png_ptr, info_ptr, &profileName, &compression, &profileData,
&profileLen);
profile = qcms_profile_from_memory((char*)profileData, profileLen);
if (profile) {
uint32_t profileSpace = qcms_profile_get_color_space(profile);
bool mismatch = false;
if (color_type & PNG_COLOR_MASK_COLOR) {
if (profileSpace != icSigRgbData) {
mismatch = true;
}
} else {
if (profileSpace == icSigRgbData) {
png_set_gray_to_rgb(png_ptr);
} else if (profileSpace != icSigGrayData) {
mismatch = true;
}
}
if (mismatch) {
qcms_profile_release(profile);
profile = nullptr;
} else {
*intent = qcms_profile_get_rendering_intent(profile);
}
}
}
// Check sRGB chunk
if (!profile && png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) {
profile = qcms_profile_sRGB();
if (profile) {
int fileIntent;
png_set_gray_to_rgb(png_ptr);
png_get_sRGB(png_ptr, info_ptr, &fileIntent);
uint32_t map[] = {
QCMS_INTENT_PERCEPTUAL, QCMS_INTENT_RELATIVE_COLORIMETRIC,
QCMS_INTENT_SATURATION, QCMS_INTENT_ABSOLUTE_COLORIMETRIC};
*intent = map[fileIntent];
}
}
// Check gAMA/cHRM chunks
if (!profile && png_get_valid(png_ptr, info_ptr, PNG_INFO_gAMA) &&
png_get_valid(png_ptr, info_ptr, PNG_INFO_cHRM)) {
qcms_CIE_xyYTRIPLE primaries;
qcms_CIE_xyY whitePoint;
png_get_cHRM(png_ptr, info_ptr, &whitePoint.x, &whitePoint.y,
&primaries.red.x, &primaries.red.y, &primaries.green.x,
&primaries.green.y, &primaries.blue.x, &primaries.blue.y);
whitePoint.Y = primaries.red.Y = primaries.green.Y = primaries.blue.Y = 1.0;
double gammaOfFile;
png_get_gAMA(png_ptr, info_ptr, &gammaOfFile);
profile = qcms_profile_create_rgb_with_gamma(whitePoint, primaries,
1.0 / gammaOfFile);
if (profile) {
png_set_gray_to_rgb(png_ptr);
}
}
if (profile) {
uint32_t profileSpace = qcms_profile_get_color_space(profile);
if (profileSpace == icSigGrayData) {
if (color_type & PNG_COLOR_MASK_ALPHA) {
*inType = QCMS_DATA_GRAYA_8;
} else {
*inType = QCMS_DATA_GRAY_8;
}
} else {
if (color_type & PNG_COLOR_MASK_ALPHA ||
png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
*inType = QCMS_DATA_RGBA_8;
} else {
*inType = QCMS_DATA_RGB_8;
}
}
}
return profile;
}
void nsPNGDecoder::info_callback(png_structp png_ptr, png_infop info_ptr) {
png_uint_32 width, height;
int bit_depth, color_type, interlace_type, compression_type, filter_type;
unsigned int channels;
png_bytep trans = nullptr;
int num_trans = 0;
nsPNGDecoder* decoder =
static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
if (decoder->mGotInfoCallback) {
MOZ_LOG(sPNGLog, LogLevel::Warning,
("libpng called info_callback more than once\n"));
return;
}
decoder->mGotInfoCallback = true;
// Always decode to 24-bit RGB or 32-bit RGBA
png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
&interlace_type, &compression_type, &filter_type);
const IntRect frameRect(0, 0, width, height);
// Post our size to the superclass
decoder->PostSize(frameRect.Width(), frameRect.Height());
if (width > SurfaceCache::MaximumCapacity() / (bit_depth > 8 ? 16 : 8)) {
// libpng needs space to allocate two row buffers
png_error(decoder->mPNG, "Image is too wide");
}
if (decoder->HasError()) {
// Setting the size led to an error.
png_error(decoder->mPNG, "Sizing error");
}
if (color_type == PNG_COLOR_TYPE_PALETTE) {
png_set_expand(png_ptr);
}
if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {
png_set_expand(png_ptr);
}
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
png_color_16p trans_values;
png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, &trans_values);
// libpng doesn't reject a tRNS chunk with out-of-range samples
// so we check it here to avoid setting up a useless opacity
// channel or producing unexpected transparent pixels (bug #428045)
if (bit_depth < 16) {
png_uint_16 sample_max = (1 << bit_depth) - 1;
if ((color_type == PNG_COLOR_TYPE_GRAY &&
trans_values->gray > sample_max) ||
(color_type == PNG_COLOR_TYPE_RGB &&
(trans_values->red > sample_max ||
trans_values->green > sample_max ||
trans_values->blue > sample_max))) {
// clear the tRNS valid flag and release tRNS memory
png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
num_trans = 0;
}
}
if (num_trans != 0) {
png_set_expand(png_ptr);
}
}
if (bit_depth == 16) {
png_set_scale_16(png_ptr);
}
qcms_data_type inType = QCMS_DATA_RGBA_8;
uint32_t intent = -1;
uint32_t pIntent;
if (decoder->mCMSMode != eCMSMode_Off) {
intent = gfxPlatform::GetRenderingIntent();
decoder->mInProfile =
PNGGetColorProfile(png_ptr, info_ptr, color_type, &inType, &pIntent);
// If we're not mandating an intent, use the one from the image.
if (intent == uint32_t(-1)) {
intent = pIntent;
}
}
if (decoder->mInProfile && gfxPlatform::GetCMSOutputProfile()) {
qcms_data_type outType;
if (color_type & PNG_COLOR_MASK_ALPHA || num_trans) {
outType = QCMS_DATA_RGBA_8;
} else {
outType = QCMS_DATA_RGB_8;
}
decoder->mTransform = qcms_transform_create(
decoder->mInProfile, inType, gfxPlatform::GetCMSOutputProfile(),
outType, (qcms_intent)intent);
} else {
png_set_gray_to_rgb(png_ptr);
// only do gamma correction if CMS isn't entirely disabled
if (decoder->mCMSMode != eCMSMode_Off) {
PNGDoGammaCorrection(png_ptr, info_ptr);
}
if (decoder->mCMSMode == eCMSMode_All) {
if (color_type & PNG_COLOR_MASK_ALPHA || num_trans) {
decoder->mTransform = gfxPlatform::GetCMSRGBATransform();
} else {
decoder->mTransform = gfxPlatform::GetCMSRGBTransform();
}
}
}
// Let libpng expand interlaced images.
const bool isInterlaced = interlace_type == PNG_INTERLACE_ADAM7;
if (isInterlaced) {
png_set_interlace_handling(png_ptr);
}
// now all of those things we set above are used to update various struct
// members and whatnot, after which we can get channels, rowbytes, etc.
png_read_update_info(png_ptr, info_ptr);
decoder->mChannels = channels = png_get_channels(png_ptr, info_ptr);
//---------------------------------------------------------------//
// copy PNG info into imagelib structs (formerly png_set_dims()) //
//---------------------------------------------------------------//
if (channels < 1 || channels > 4) {
png_error(decoder->mPNG, "Invalid number of channels");
}
#ifdef PNG_APNG_SUPPORTED
bool isAnimated = png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL);
if (isAnimated) {
int32_t rawTimeout = GetNextFrameDelay(png_ptr, info_ptr);
decoder->PostIsAnimated(FrameTimeout::FromRawMilliseconds(rawTimeout));
if (decoder->Size() != decoder->OutputSize() &&
!decoder->IsFirstFrameDecode()) {
MOZ_ASSERT_UNREACHABLE(
"Doing downscale-during-decode "
"for an animated image?");
png_error(decoder->mPNG, "Invalid downscale attempt"); // Abort decode.
}
}
#endif
if (decoder->IsMetadataDecode()) {
// If we are animated then the first frame rect is either:
// 1) the whole image if the IDAT chunk is part of the animation
// 2) the frame rect of the first fDAT chunk otherwise.
// If we are not animated then we want to make sure to call
// PostHasTransparency in the metadata decode if we need to. So it's
// okay to pass IntRect(0, 0, width, height) here for animated images;
// they will call with the proper first frame rect in the full decode.
auto transparency = decoder->GetTransparencyType(frameRect);
decoder->PostHasTransparencyIfNeeded(transparency);
// We have the metadata we're looking for, so stop here, before we allocate
// buffers below.
return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
}
#ifdef PNG_APNG_SUPPORTED
if (isAnimated) {
png_set_progressive_frame_fn(png_ptr, nsPNGDecoder::frame_info_callback,
nullptr);
}
if (png_get_first_frame_is_hidden(png_ptr, info_ptr)) {
decoder->mFrameIsHidden = true;
} else {
#endif
nsresult rv = decoder->CreateFrame(FrameInfo{frameRect, isInterlaced});
if (NS_FAILED(rv)) {
png_error(decoder->mPNG, "CreateFrame failed");
}
MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
#ifdef PNG_APNG_SUPPORTED
}
#endif
if (decoder->mTransform && (channels <= 2 || isInterlaced)) {
uint32_t bpp[] = {0, 3, 4, 3, 4};
decoder->mCMSLine =
static_cast<uint8_t*>(malloc(bpp[channels] * frameRect.Width()));
if (!decoder->mCMSLine) {
png_error(decoder->mPNG, "malloc of mCMSLine failed");
}
}
if (interlace_type == PNG_INTERLACE_ADAM7) {
if (frameRect.Height() <
INT32_MAX / (frameRect.Width() * int32_t(channels))) {
const size_t bufferSize =
channels * frameRect.Width() * frameRect.Height();
if (bufferSize > SurfaceCache::MaximumCapacity()) {
png_error(decoder->mPNG, "Insufficient memory to deinterlace image");
}
decoder->interlacebuf = static_cast<uint8_t*>(malloc(bufferSize));
}
if (!decoder->interlacebuf) {
png_error(decoder->mPNG, "malloc of interlacebuf failed");
}
}
}
void nsPNGDecoder::PostInvalidationIfNeeded() {
Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
if (!invalidRect) {
return;
}
PostInvalidation(invalidRect->mInputSpaceRect,
Some(invalidRect->mOutputSpaceRect));
}
static NextPixel<uint32_t> PackRGBPixelAndAdvance(uint8_t*& aRawPixelInOut) {
const uint32_t pixel = gfxPackedPixel(0xFF, aRawPixelInOut[0],
aRawPixelInOut[1], aRawPixelInOut[2]);
aRawPixelInOut += 3;
return AsVariant(pixel);
}
static NextPixel<uint32_t> PackRGBAPixelAndAdvance(uint8_t*& aRawPixelInOut) {
const uint32_t pixel = gfxPackedPixel(aRawPixelInOut[3], aRawPixelInOut[0],
aRawPixelInOut[1], aRawPixelInOut[2]);
aRawPixelInOut += 4;
return AsVariant(pixel);
}
static NextPixel<uint32_t> PackUnpremultipliedRGBAPixelAndAdvance(
uint8_t*& aRawPixelInOut) {
const uint32_t pixel =
gfxPackedPixelNoPreMultiply(aRawPixelInOut[3], aRawPixelInOut[0],
aRawPixelInOut[1], aRawPixelInOut[2]);
aRawPixelInOut += 4;
return AsVariant(pixel);
}
void nsPNGDecoder::row_callback(png_structp png_ptr, png_bytep new_row,
png_uint_32 row_num, int pass) {
/* libpng comments:
*
* This function is called for every row in the image. If the
* image is interlacing, and you turned on the interlace handler,
* this function will be called for every row in every pass.
* Some of these rows will not be changed from the previous pass.
* When the row is not changed, the new_row variable will be
* nullptr. The rows and passes are called in order, so you don't
* really need the row_num and pass, but I'm supplying them
* because it may make your life easier.
*
* For the non-nullptr rows of interlaced images, you must call
* png_progressive_combine_row() passing in the row and the
* old row. You can call this function for nullptr rows (it will
* just return) and for non-interlaced images (it just does the
* memcpy for you) if it will make the code easier. Thus, you
* can just do this for all cases:
*
* png_progressive_combine_row(png_ptr, old_row, new_row);
*
* where old_row is what was displayed for previous rows. Note
* that the first pass (pass == 0 really) will completely cover
* the old row, so the rows do not have to be initialized. After
* the first pass (and only for interlaced images), you will have
* to pass the current row, and the function will combine the
* old row and the new row.
*/
nsPNGDecoder* decoder =
static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
if (decoder->mFrameIsHidden) {
return; // Skip this frame.
}
MOZ_ASSERT_IF(decoder->IsFirstFrameDecode(), decoder->mNumFrames == 0);
while (pass > decoder->mPass) {
// Advance to the next pass. We may have to do this multiple times because
// libpng will skip passes if the image is so small that no pixels have
// changed on a given pass, but ADAM7InterpolatingFilter needs to be reset
// once for every pass to perform interpolation properly.
decoder->mPipe.ResetToFirstRow();
decoder->mPass++;
}
const png_uint_32 height =
static_cast<png_uint_32>(decoder->mFrameRect.Height());
if (row_num >= height) {
// Bail if we receive extra rows. This is especially important because if we
// didn't, we might overflow the deinterlacing buffer.
MOZ_ASSERT_UNREACHABLE("libpng producing extra rows?");
return;
}
// Note that |new_row| may be null here, indicating that this is an interlaced
// image and |row_callback| is being called for a row that hasn't changed.
MOZ_ASSERT_IF(!new_row, decoder->interlacebuf);
uint8_t* rowToWrite = new_row;
if (decoder->interlacebuf) {
uint32_t width = uint32_t(decoder->mFrameRect.Width());
// We'll output the deinterlaced version of the row.
rowToWrite = decoder->interlacebuf + (row_num * decoder->mChannels * width);
// Update the deinterlaced version of this row with the new data.
png_progressive_combine_row(png_ptr, rowToWrite, new_row);
}
decoder->WriteRow(rowToWrite);
}
void nsPNGDecoder::WriteRow(uint8_t* aRow) {
MOZ_ASSERT(aRow);
uint8_t* rowToWrite = aRow;
uint32_t width = uint32_t(mFrameRect.Width());
// Apply color management to the row, if necessary, before writing it out.
if (mTransform) {
if (mCMSLine) {
qcms_transform_data(mTransform, rowToWrite, mCMSLine, width);
// Copy alpha over.
if (HasAlphaChannel()) {
for (uint32_t i = 0; i < width; ++i) {
mCMSLine[4 * i + 3] = rowToWrite[mChannels * i + mChannels - 1];
}
}
rowToWrite = mCMSLine;
} else {
qcms_transform_data(mTransform, rowToWrite, rowToWrite, width);
}
}
// Write this row to the SurfacePipe.
DebugOnly<WriteState> result;
if (HasAlphaChannel()) {
if (mDisablePremultipliedAlpha) {
result = mPipe.WritePixelsToRow<uint32_t>(
[&] { return PackUnpremultipliedRGBAPixelAndAdvance(rowToWrite); });
} else {
result = mPipe.WritePixelsToRow<uint32_t>(
[&] { return PackRGBAPixelAndAdvance(rowToWrite); });
}
} else {
result = mPipe.WritePixelsToRow<uint32_t>(
[&] { return PackRGBPixelAndAdvance(rowToWrite); });
}
MOZ_ASSERT(WriteState(result) != WriteState::FAILURE);
PostInvalidationIfNeeded();
}
void nsPNGDecoder::DoTerminate(png_structp aPNGStruct, TerminalState aState) {
// Stop processing data. Note that we intentionally ignore the return value of
// png_process_data_pause(), which tells us how many bytes of the data that
// was passed to png_process_data() have not been consumed yet, because now
// that we've reached a terminal state, we won't do any more decoding or call
// back into libpng anymore.
png_process_data_pause(aPNGStruct, /* save = */ false);
mNextTransition = aState == TerminalState::SUCCESS
? Transition::TerminateSuccess()
: Transition::TerminateFailure();
}
void nsPNGDecoder::DoYield(png_structp aPNGStruct) {
// Pause data processing. png_process_data_pause() returns how many bytes of
// the data that was passed to png_process_data() have not been consumed yet.
// We use this information to tell StreamingLexer where to place us in the
// input stream when we come back from the yield.
png_size_t pendingBytes = png_process_data_pause(aPNGStruct,
/* save = */ false);
MOZ_ASSERT(pendingBytes < mLastChunkLength);
size_t consumedBytes = mLastChunkLength - min(pendingBytes, mLastChunkLength);
mNextTransition =
Transition::ContinueUnbufferedAfterYield(State::PNG_DATA, consumedBytes);
}
nsresult nsPNGDecoder::FinishInternal() {
// We shouldn't be called in error cases.
MOZ_ASSERT(!HasError(), "Can't call FinishInternal on error!");
if (IsMetadataDecode()) {
return NS_OK;
}
int32_t loop_count = 0;
#ifdef PNG_APNG_SUPPORTED
if (png_get_valid(mPNG, mInfo, PNG_INFO_acTL)) {
int32_t num_plays = png_get_num_plays(mPNG, mInfo);
loop_count = num_plays - 1;
}
#endif
if (InFrame()) {
EndImageFrame();
}
PostDecodeDone(loop_count);
return NS_OK;
}
#ifdef PNG_APNG_SUPPORTED
// got the header of a new frame that's coming
void nsPNGDecoder::frame_info_callback(png_structp png_ptr,
png_uint_32 frame_num) {
nsPNGDecoder* decoder =
static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));
// old frame is done
decoder->EndImageFrame();
const bool previousFrameWasHidden = decoder->mFrameIsHidden;
if (!previousFrameWasHidden && decoder->IsFirstFrameDecode()) {
// We're about to get a second non-hidden frame, but we only want the first.
// Stop decoding now. (And avoid allocating the unnecessary buffers below.)
return decoder->DoTerminate(png_ptr, TerminalState::SUCCESS);
}
// Only the first frame can be hidden, so unhide unconditionally here.
decoder->mFrameIsHidden = false;
// Save the information necessary to create the frame; we'll actually create
// it when we return from the yield.
const IntRect frameRect(png_get_next_frame_x_offset(png_ptr, decoder->mInfo),
png_get_next_frame_y_offset(png_ptr, decoder->mInfo),
png_get_next_frame_width(png_ptr, decoder->mInfo),
png_get_next_frame_height(png_ptr, decoder->mInfo));
const bool isInterlaced = bool(decoder->interlacebuf);
# ifndef MOZ_EMBEDDED_LIBPNG
// if using system library, check frame_width and height against 0
if (frameRect.width == 0) {
png_error(png_ptr, "Frame width must not be 0");
}
if (frameRect.height == 0) {
png_error(png_ptr, "Frame height must not be 0");
}
# endif
const FrameInfo info{frameRect, isInterlaced};
// If the previous frame was hidden, skip the yield (which will mislead the
// caller, who will think the previous frame was real) and just allocate the
// new frame here.
if (previousFrameWasHidden) {
if (NS_FAILED(decoder->CreateFrame(info))) {
return decoder->DoTerminate(png_ptr, TerminalState::FAILURE);
}
MOZ_ASSERT(decoder->mImageData, "Should have a buffer now");
return; // No yield, so we'll just keep decoding.
}
// Yield to the caller to notify them that the previous frame is now complete.
decoder->mNextFrameInfo = Some(info);
return decoder->DoYield(png_ptr);
}
#endif