AuroraMiddleware/skia2
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Make SkPngCodec support rewinding properly.

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Separate out the code for reading the header, and use it to reinitialize
fPng_ptr and fInfo_ptr after a rewind.

Use common code to clean up fPng_ptr and fInfo_ptr, and set them to
NULL and treat them as NULL as appropriate.

Update the test to expect SkPngCodec to succeed.

BUG=skia:3257

Review URL: https://codereview.chromium.org/1048423003
This commit is contained in:
scroggo 2015-04-01 09:33:23 -07:00 committed by Commit bot
parent 57291dcc95
commit 3eada2a49f
3 changed files with 71 additions and 26 deletions
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69
src/codec/SkCodec_libpng.cpp
View File

@ -201,19 +201,25 @@ bool SkPngCodec::IsPng(SkStream* stream) {
return true;
}
SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
// Reads the header, and initializes the passed in fields, if not NULL (except
// stream, which is passed to the read function).
// Returns true on success, in which case the caller is responsible for calling
// png_destroy_read_struct. If it returns false, the passed in fields (except
// stream) are unchanged.
static bool read_header(SkStream* stream, png_structp* png_ptrp,
png_infop* info_ptrp, SkImageInfo* imageInfo) {
// The image is known to be a PNG. Decode enough to know the SkImageInfo.
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
sk_error_fn, sk_warning_fn);
if (!png_ptr) {
return NULL;
return false;
}
AutoCleanPng autoClean(png_ptr);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == NULL) {
return NULL;
return false;
}
autoClean.setInfoPtr(info_ptr);
@ -221,7 +227,7 @@ SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
// FIXME: Could we use the return value of setjmp to specify the type of
// error?
if (setjmp(png_jmpbuf(png_ptr))) {
return NULL;
return false;
}
png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn);
@ -244,7 +250,7 @@ SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
int64_t size = sk_64_mul(origWidth, origHeight);
// now check that if we are 4-bytes per pixel, we also don't overflow
if (size < 0 || size > (0x7FFFFFFF >> 2)) {
return NULL;
return false;
}
}
@ -325,11 +331,28 @@ SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
// FIXME: Also need to check for sRGB (skbug.com/3471).
SkImageInfo info = SkImageInfo::Make(origWidth, origHeight, skColorType,
skAlphaType);
SkCodec* codec = SkNEW_ARGS(SkPngCodec, (info, stream, png_ptr, info_ptr));
if (imageInfo) {
*imageInfo = SkImageInfo::Make(origWidth, origHeight, skColorType,
skAlphaType);
}
autoClean.detach();
return codec;
if (png_ptrp) {
*png_ptrp = png_ptr;
}
if (info_ptrp) {
*info_ptrp = info_ptr;
}
return true;
}
SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
png_structp png_ptr;
png_infop info_ptr;
SkImageInfo imageInfo;
if (read_header(stream, &png_ptr, &info_ptr, &imageInfo)) {
return SkNEW_ARGS(SkPngCodec, (imageInfo, stream, png_ptr, info_ptr));
}
return NULL;
}
#define INVALID_NUMBER_PASSES -1
@ -344,7 +367,17 @@ SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream,
{}
SkPngCodec::~SkPngCodec() {
png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL);
this->destroyReadStruct();
}
void SkPngCodec::destroyReadStruct() {
if (fPng_ptr) {
// We will never have a NULL fInfo_ptr with a non-NULL fPng_ptr
SkASSERT(fInfo_ptr);
png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL);
fPng_ptr = NULL;
fInfo_ptr = NULL;
}
}
///////////////////////////////////////////////////////////////////////////////
@ -424,8 +457,20 @@ SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void*
if (rewindState == kCouldNotRewind_RewindState) {
return kCouldNotRewind;
} else if (rewindState == kRewound_RewindState) {
// TODO(scroggo): handle rewinds
return kCouldNotRewind;
// This sets fPng_ptr and fInfo_ptr to NULL. If read_header succeeds,
// they will be repopulated, and if it fails, they will remain NULL.
// Any future accesses to fPng_ptr and fInfo_ptr will come through this
// function which will rewind and again attempt to reinitialize them.
this->destroyReadStruct();
png_structp png_ptr;
png_infop info_ptr;
if (read_header(this->stream(), &png_ptr, &info_ptr, NULL)) {
fPng_ptr = png_ptr;
fInfo_ptr = info_ptr;
} else {
return kCouldNotRewind;
}
}
if (requestedInfo.dimensions() != this->getInfo().dimensions()) {
return kInvalidScale;

1
src/codec/SkCodec_libpng.h
View File

@ -50,6 +50,7 @@ private:
size_t rowBytes, const Options&);
bool decodePalette(bool premultiply);
void finish();
void destroyReadStruct();
friend class SkPngScanlineDecoder;

27
tests/CodexTest.cpp
View File

@ -81,18 +81,17 @@ DEF_TEST(Codec, r) {
check(r, "color_wheel.ico", SkISize::Make(128, 128), false);
// PNG
// TODO (scroggo): SkPngCodec should be able to rewind.
check(r, "arrow.png", SkISize::Make(187, 312), false);
check(r, "baby_tux.png", SkISize::Make(240, 246), false);
check(r, "color_wheel.png", SkISize::Make(128, 128), false);
check(r, "half-transparent-white-pixel.png", SkISize::Make(1, 1), false);
check(r, "mandrill_128.png", SkISize::Make(128, 128), false);
check(r, "mandrill_16.png", SkISize::Make(16, 16), false);
check(r, "mandrill_256.png", SkISize::Make(256, 256), false);
check(r, "mandrill_32.png", SkISize::Make(32, 32), false);
check(r, "mandrill_512.png", SkISize::Make(512, 512), false);
check(r, "mandrill_64.png", SkISize::Make(64, 64), false);
check(r, "plane.png", SkISize::Make(250, 126), false);
check(r, "randPixels.png", SkISize::Make(8, 8), false);
check(r, "yellow_rose.png", SkISize::Make(400, 301), false);
check(r, "arrow.png", SkISize::Make(187, 312), true);
check(r, "baby_tux.png", SkISize::Make(240, 246), true);
check(r, "color_wheel.png", SkISize::Make(128, 128), true);
check(r, "half-transparent-white-pixel.png", SkISize::Make(1, 1), true);
check(r, "mandrill_128.png", SkISize::Make(128, 128), true);
check(r, "mandrill_16.png", SkISize::Make(16, 16), true);
check(r, "mandrill_256.png", SkISize::Make(256, 256), true);
check(r, "mandrill_32.png", SkISize::Make(32, 32), true);
check(r, "mandrill_512.png", SkISize::Make(512, 512), true);
check(r, "mandrill_64.png", SkISize::Make(64, 64), true);
check(r, "plane.png", SkISize::Make(250, 126), true);
check(r, "randPixels.png", SkISize::Make(8, 8), true);
check(r, "yellow_rose.png", SkISize::Make(400, 301), true);
}