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Unified Diff: src/codec/SkPngCodec.cpp

Issue 2026383002: Revert of Make SkPngCodec decode progressively. (Closed) Base URL: https://skia.googlesource.com/skia.git@foil
Patch Set: Created 4 years, 7 months ago
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Index: src/codec/SkPngCodec.cpp
diff --git a/src/codec/SkPngCodec.cpp b/src/codec/SkPngCodec.cpp
index f64843181dc2ace8196671c28cc6b0098758845c..43d1580c176b0b0cfff9b3fda103fd6627f0b765 100644
--- a/src/codec/SkPngCodec.cpp
+++ b/src/codec/SkPngCodec.cpp
@@ -23,20 +23,25 @@
// Callback functions
///////////////////////////////////////////////////////////////////////////////
-// When setjmp is first called, it returns 0, meaning longjmp was not called.
-constexpr int kSetJmpOkay = 0;
-// An error internal to libpng.
-constexpr int kPngError = 1;
-// Passed to longjmp when we have decoded as many lines as we need.
-constexpr int kStopDecoding = 2;
-
static void sk_error_fn(png_structp png_ptr, png_const_charp msg) {
SkCodecPrintf("------ png error %s\n", msg);
- longjmp(png_jmpbuf(png_ptr), kPngError);
+ longjmp(png_jmpbuf(png_ptr), 1);
}
void sk_warning_fn(png_structp, png_const_charp msg) {
SkCodecPrintf("----- png warning %s\n", msg);
+}
+
+static void sk_read_fn(png_structp png_ptr, png_bytep data,
+ png_size_t length) {
+ SkStream* stream = static_cast<SkStream*>(png_get_io_ptr(png_ptr));
+ const size_t bytes = stream->read(data, length);
+ if (bytes != length) {
+ // FIXME: We want to report the fact that the stream was truncated.
+ // One way to do that might be to pass a enum to longjmp so setjmp can
+ // specify the failure.
+ png_error(png_ptr, "Read Error!");
+ }
}
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
@@ -53,22 +58,9 @@
class AutoCleanPng : public SkNoncopyable {
public:
- /*
- * This class does not take ownership of stream or reader, but if codecPtr
- * is non-NULL, and decodeBounds succeeds, it will have created a new
- * SkCodec (pointed to by *codecPtr) which will own/ref them, as well as
- * the png_ptr and info_ptr.
- */
- AutoCleanPng(png_structp png_ptr, SkStream* stream, SkPngChunkReader* reader,
- SkCodec** codecPtr)
+ AutoCleanPng(png_structp png_ptr)
: fPng_ptr(png_ptr)
- , fInfo_ptr(nullptr)
- , fDecodedBounds(false)
- , fReadHeader(false)
- , fStream(stream)
- , fChunkReader(reader)
- , fOutCodec(codecPtr)
- {}
+ , fInfo_ptr(nullptr) {}
~AutoCleanPng() {
// fInfo_ptr will never be non-nullptr unless fPng_ptr is.
@@ -83,117 +75,20 @@
fInfo_ptr = info_ptr;
}
- /**
- * Reads enough of the input stream to decode the bounds.
- * @return false if the stream is not a valid PNG (or too short).
- * true if it read enough of the stream to determine the bounds.
- * In the latter case, the stream may have been read beyond the
- * point to determine the bounds, and the png_ptr will have saved
- * any extra data. Further, if the codecPtr supplied to the
- * constructor was not NULL, it will now point to a new SkCodec,
- * which owns (or refs, in the case of the SkPngChunkReader) the
- * inputs. If codecPtr was NULL, the png_ptr and info_ptr are
- * unowned, and it is up to the caller to destroy them.
- */
- bool decodeBounds();
-
-private:
- png_structp fPng_ptr;
- png_infop fInfo_ptr;
- bool fDecodedBounds;
- bool fReadHeader;
- SkStream* fStream;
- SkPngChunkReader* fChunkReader;
- SkCodec** fOutCodec;
-
- /**
- * Supplied to libpng to call when it has read enough data to determine
- * bounds.
- */
- static void InfoCallback(png_structp png_ptr, png_infop info_ptr) {
- // png_get_progressive_ptr returns the pointer we set on the png_ptr with
- // png_set_progressive_read_fn
- static_cast<AutoCleanPng*>(png_get_progressive_ptr(png_ptr))->infoCallback();
- }
-
- void infoCallback();
-
- void releasePngPtrs() {
+ void release() {
fPng_ptr = nullptr;
fInfo_ptr = nullptr;
}
+
+private:
+ png_structp fPng_ptr;
+ png_infop fInfo_ptr;
};
#define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng)
-bool AutoCleanPng::decodeBounds() {
- if (setjmp(png_jmpbuf(fPng_ptr))) {
- return false;
- }
-
- png_set_progressive_read_fn(fPng_ptr, this, InfoCallback, nullptr, nullptr);
-
- // Arbitrary buffer size, though note that it matches (below)
- // SkPngCodec::processData(). FIXME: Can we better suit this to the size of
- // the PNG header?
- constexpr size_t kBufferSize = 4096;
- char buffer[kBufferSize];
-
- while (true) {
- const size_t bytesRead = fStream->read(buffer, kBufferSize);
- if (!bytesRead) {
- // We have read to the end of the input without decoding bounds.
- break;
- }
-
- png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead);
- if (fReadHeader) {
- break;
- }
- }
-
- // For safety, clear the pointer to this object.
- png_set_progressive_read_fn(fPng_ptr, nullptr, nullptr, nullptr, nullptr);
- return fDecodedBounds;
-}
-
-void SkPngCodec::processData() {
- switch (setjmp(png_jmpbuf(fPng_ptr))) {
- case kPngError:
- // There was an error. Stop processing data.
- // FIXME: Do we need to discard png_ptr?
- return;
- case kStopDecoding:
- // We decoded all the lines we want.
- return;
- case kSetJmpOkay:
- // Everything is okay.
- break;
- default:
- // No other values should be passed to longjmp.
- SkASSERT(false);
- }
-
- // Arbitrary buffer size
- constexpr size_t kBufferSize = 4096;
- char buffer[kBufferSize];
-
- while (true) {
- const size_t bytesRead = this->stream()->read(buffer, kBufferSize);
- png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead);
-
- if (!bytesRead) {
- // We have read to the end of the input. Note that we quit *after*
- // calling png_process_data, because decodeBounds may have told
- // libpng to save the remainder of the buffer, in which case
- // png_process_data will process the saved buffer, though the
- // stream has no more to read.
- break;
- }
- }
-}
-
// Note: SkColorTable claims to store SkPMColors, which is not necessarily
// the case here.
+// TODO: If we add support for non-native swizzles, we'll need to handle that here.
bool SkPngCodec::createColorTable(SkColorType dstColorType, bool premultiply, int* ctableCount) {
int numColors;
@@ -372,254 +267,204 @@
return nullptr;
}
-class SkPngNormalDecoder : public SkPngCodec {
+static int bytes_per_pixel(int bitsPerPixel) {
+ // Note that we will have to change this implementation if we start
+ // supporting outputs from libpng that are less than 8-bits per component.
+ return bitsPerPixel / 8;
+}
+
+// Subclass of SkPngCodec which supports scanline decoding
+class SkPngScanlineDecoder : public SkPngCodec {
public:
- SkPngNormalDecoder(int width, int height, const SkEncodedInfo& info, SkStream* stream,
- SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth,
+ SkPngScanlineDecoder(int width, int height, const SkEncodedInfo& info, SkStream* stream,
+ SkPngChunkReader* chunkReader, png_structp png_ptr, png_infop info_ptr, int bitDepth,
sk_sp<SkColorSpace> colorSpace)
- : INHERITED(width, height, info, stream, reader, png_ptr, info_ptr, bitDepth,
- std::move(colorSpace))
- , fLinesDecoded(0)
- , fDst(nullptr)
- , fRowBytes(0)
- , fFirstRow(0)
- , fLastRow(0)
+ : INHERITED(width, height, info, stream, chunkReader, png_ptr, info_ptr, bitDepth, 1,
+ colorSpace)
+ , fSrcRow(nullptr)
{}
- static void AllRowsCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) {
- GetDecoder(png_ptr)->allRowsCallback(row, rowNum);
- }
-
- static void RowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) {
- GetDecoder(png_ptr)->rowCallback(row, rowNum);
- }
+ Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options,
+ SkPMColor ctable[], int* ctableCount) override {
+ if (!conversion_possible(dstInfo, this->getInfo())) {
+ return kInvalidConversion;
+ }
+
+ const Result result = this->initializeSwizzler(dstInfo, options, ctable,
+ ctableCount);
+ if (result != kSuccess) {
+ return result;
+ }
+
+ fStorage.reset(this->getInfo().width() *
+ (bytes_per_pixel(this->getEncodedInfo().bitsPerPixel())));
+ fSrcRow = fStorage.get();
+
+ return kSuccess;
+ }
+
+ int onGetScanlines(void* dst, int count, size_t rowBytes) override {
+ // Assume that an error in libpng indicates an incomplete input.
+ int row = 0;
+ if (setjmp(png_jmpbuf(this->png_ptr()))) {
+ SkCodecPrintf("setjmp long jump!\n");
+ return row;
+ }
+
+ void* dstRow = dst;
+ for (; row < count; row++) {
+ png_read_row(this->png_ptr(), fSrcRow, nullptr);
+ this->swizzler()->swizzle(dstRow, fSrcRow);
+ dstRow = SkTAddOffset<void>(dstRow, rowBytes);
+ }
+
+ return row;
+ }
+
+ bool onSkipScanlines(int count) override {
+ // Assume that an error in libpng indicates an incomplete input.
+ if (setjmp(png_jmpbuf(this->png_ptr()))) {
+ SkCodecPrintf("setjmp long jump!\n");
+ return false;
+ }
+
+ for (int row = 0; row < count; row++) {
+ png_read_row(this->png_ptr(), fSrcRow, nullptr);
+ }
+ return true;
+ }
+
private:
- int fLinesDecoded; // FIXME: Move to baseclass?
- void* fDst;
- size_t fRowBytes;
-
- // Variables for partial decode
- int fFirstRow; // FIXME: Move to baseclass?
- int fLastRow;
+ SkAutoTMalloc<uint8_t> fStorage;
+ uint8_t* fSrcRow;
typedef SkPngCodec INHERITED;
-
- static SkPngNormalDecoder* GetDecoder(png_structp png_ptr) {
- return static_cast<SkPngNormalDecoder*>(png_get_progressive_ptr(png_ptr));
- }
-
- Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override {
- const int height = this->getInfo().height();
- png_set_progressive_read_fn(this->png_ptr(), this, nullptr, AllRowsCallback, nullptr);
- fDst = dst;
- fRowBytes = rowBytes;
-
- fLinesDecoded = 0;
-
- this->processData();
-
- if (fLinesDecoded == height) {
- return SkCodec::kSuccess;
- }
-
- if (rowsDecoded) {
- *rowsDecoded = fLinesDecoded;
- }
-
- return SkCodec::kIncompleteInput;
- }
-
- void allRowsCallback(png_bytep row, int rowNum) {
- SkASSERT(rowNum - fFirstRow == fLinesDecoded);
- fLinesDecoded++;
- this->swizzler()->swizzle(fDst, row);
- fDst = SkTAddOffset<void>(fDst, fRowBytes);
- }
-
- void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override {
- png_set_progressive_read_fn(this->png_ptr(), this, nullptr, RowCallback, nullptr);
- fFirstRow = firstRow;
- fLastRow = lastRow;
- fDst = dst;
- fRowBytes = rowBytes;
- fLinesDecoded = 0;
- }
-
- SkCodec::Result decode(int* rowsDecoded) override {
- this->processData();
-
- if (fLinesDecoded == fLastRow - fFirstRow + 1) {
- return SkCodec::kSuccess;
- }
-
- if (rowsDecoded) {
- *rowsDecoded = fLinesDecoded;
- }
-
- return SkCodec::kIncompleteInput;
- }
-
- void rowCallback(png_bytep row, int rowNum) {
- if (rowNum < fFirstRow) {
- // Ignore this row.
- return;
- }
-
- SkASSERT(rowNum <= fLastRow);
-
- if (this->swizzler()->rowNeeded(fLinesDecoded)) {
- this->swizzler()->swizzle(fDst, row);
- fDst = SkTAddOffset<void>(fDst, fRowBytes);
- }
-
- fLinesDecoded++;
-
- if (rowNum == fLastRow) {
- // Fake error to stop decoding scanlines.
- longjmp(png_jmpbuf(this->png_ptr()), kStopDecoding);
- }
- }
};
-class SkPngInterlacedDecoder : public SkPngCodec {
+
+class SkPngInterlacedScanlineDecoder : public SkPngCodec {
public:
- SkPngInterlacedDecoder(int width, int height, const SkEncodedInfo& info, SkStream* stream,
- SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth,
- sk_sp<SkColorSpace> colorSpace, int numberPasses)
- : INHERITED(width, height, info, stream, reader, png_ptr, info_ptr, bitDepth,
- std::move(colorSpace))
- , fNumberPasses(numberPasses)
- , fFirstRow(0)
- , fLastRow(0)
- , fLinesDecoded(0)
- , fInterlacedComplete(false)
- , fPng_rowbytes(0)
- {}
-
- static void InterlacedRowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int pass) {
- auto decoder = static_cast<SkPngInterlacedDecoder*>(png_get_progressive_ptr(png_ptr));
- decoder->interlacedRowCallback(row, rowNum, pass);
+ SkPngInterlacedScanlineDecoder(int width, int height, const SkEncodedInfo& info,
+ SkStream* stream, SkPngChunkReader* chunkReader, png_structp png_ptr,
+ png_infop info_ptr, int bitDepth, int numberPasses, sk_sp<SkColorSpace> colorSpace)
+ : INHERITED(width, height, info, stream, chunkReader, png_ptr, info_ptr, bitDepth,
+ numberPasses, colorSpace)
+ , fHeight(-1)
+ , fCanSkipRewind(false)
+ {
+ SkASSERT(numberPasses != 1);
+ }
+
+ Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options,
+ SkPMColor ctable[], int* ctableCount) override {
+ if (!conversion_possible(dstInfo, this->getInfo())) {
+ return kInvalidConversion;
+ }
+
+ const Result result = this->initializeSwizzler(dstInfo, options, ctable,
+ ctableCount);
+ if (result != kSuccess) {
+ return result;
+ }
+
+ fHeight = dstInfo.height();
+ // FIXME: This need not be called on a second call to onStartScanlineDecode.
+ fSrcRowBytes = this->getInfo().width() *
+ (bytes_per_pixel(this->getEncodedInfo().bitsPerPixel()));
+ fGarbageRow.reset(fSrcRowBytes);
+ fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get());
+ fCanSkipRewind = true;
+
+ return SkCodec::kSuccess;
+ }
+
+ int onGetScanlines(void* dst, int count, size_t dstRowBytes) override {
+ // rewind stream if have previously called onGetScanlines,
+ // since we need entire progressive image to get scanlines
+ if (fCanSkipRewind) {
+ // We already rewound in onStartScanlineDecode, so there is no reason to rewind.
+ // Next time onGetScanlines is called, we will need to rewind.
+ fCanSkipRewind = false;
+ } else {
+ // rewindIfNeeded resets fCurrScanline, since it assumes that start
+ // needs to be called again before scanline decoding. PNG scanline
+ // decoding is the exception, since it needs to rewind between
+ // calls to getScanlines. Keep track of fCurrScanline, to undo the
+ // reset.
+ const int currScanline = this->nextScanline();
+ // This method would never be called if currScanline is -1
+ SkASSERT(currScanline != -1);
+
+ if (!this->rewindIfNeeded()) {
+ return kCouldNotRewind;
+ }
+ this->updateCurrScanline(currScanline);
+ }
+
+ if (setjmp(png_jmpbuf(this->png_ptr()))) {
+ SkCodecPrintf("setjmp long jump!\n");
+ // FIXME (msarett): Returning 0 is pessimistic. If we can complete a single pass,
+ // we may be able to report that all of the memory has been initialized. Even if we
+ // fail on the first pass, we can still report than some scanlines are initialized.
+ return 0;
+ }
+ SkAutoTMalloc<uint8_t> storage(count * fSrcRowBytes);
+ uint8_t* storagePtr = storage.get();
+ uint8_t* srcRow;
+ const int startRow = this->nextScanline();
+ for (int i = 0; i < this->numberPasses(); i++) {
+ // read rows we planned to skip into garbage row
+ for (int y = 0; y < startRow; y++){
+ png_read_row(this->png_ptr(), fGarbageRowPtr, nullptr);
+ }
+ // read rows we care about into buffer
+ srcRow = storagePtr;
+ for (int y = 0; y < count; y++) {
+ png_read_row(this->png_ptr(), srcRow, nullptr);
+ srcRow += fSrcRowBytes;
+ }
+ // read rows we don't want into garbage buffer
+ for (int y = 0; y < fHeight - startRow - count; y++) {
+ png_read_row(this->png_ptr(), fGarbageRowPtr, nullptr);
+ }
+ }
+ //swizzle the rows we care about
+ srcRow = storagePtr;
+ void* dstRow = dst;
+ for (int y = 0; y < count; y++) {
+ this->swizzler()->swizzle(dstRow, srcRow);
+ dstRow = SkTAddOffset<void>(dstRow, dstRowBytes);
+ srcRow += fSrcRowBytes;
+ }
+
+ return count;
+ }
+
+ bool onSkipScanlines(int count) override {
+ // The non-virtual version will update fCurrScanline.
+ return true;
+ }
+
+ SkScanlineOrder onGetScanlineOrder() const override {
+ return kNone_SkScanlineOrder;
}
private:
- const int fNumberPasses;
- int fFirstRow;
- int fLastRow;
- void* fDst;
- size_t fRowBytes;
- int fLinesDecoded;
- bool fInterlacedComplete;
- size_t fPng_rowbytes;
- SkAutoTMalloc<png_byte> fInterlaceBuffer;
+ int fHeight;
+ size_t fSrcRowBytes;
+ SkAutoMalloc fGarbageRow;
+ uint8_t* fGarbageRowPtr;
+ // FIXME: This imitates behavior in SkCodec::rewindIfNeeded. That function
+ // is called whenever some action is taken that reads the stream and
+ // therefore the next call will require a rewind. So it modifies a boolean
+ // to note that the *next* time it is called a rewind is needed.
+ // SkPngInterlacedScanlineDecoder has an extra wrinkle - calling
+ // onStartScanlineDecode followed by onGetScanlines does *not* require a
+ // rewind. Since rewindIfNeeded does not have this flexibility, we need to
+ // add another layer.
+ bool fCanSkipRewind;
typedef SkPngCodec INHERITED;
-
- // FIXME: Currently sharing interlaced callback for all rows and subset. It's not
- // as expensive as the subset version of non-interlaced, but it still does extra
- // work.
- void interlacedRowCallback(png_bytep row, int rowNum, int pass) {
- if (rowNum < fFirstRow || rowNum > fLastRow) {
- // Ignore this row
- return;
- }
-
- png_bytep oldRow = fInterlaceBuffer.get() + (rowNum - fFirstRow) * fPng_rowbytes;
- png_progressive_combine_row(this->png_ptr(), oldRow, row);
-
- if (0 == pass) {
- // The first pass initializes all rows.
- SkASSERT(row);
- SkASSERT(fLinesDecoded == rowNum - fFirstRow);
- fLinesDecoded++;
- } else {
- SkASSERT(fLinesDecoded == fLastRow - fFirstRow + 1);
- if (fNumberPasses - 1 == pass && rowNum == fLastRow) {
- // Last pass, and we have read all of the rows we care about. Note that
- // we do not care about reading anything beyond the end of the image (or
- // beyond the last scanline requested).
- fInterlacedComplete = true;
- // Fake error to stop decoding scanlines.
- longjmp(png_jmpbuf(this->png_ptr()), kStopDecoding);
- }
- }
- }
-
- SkCodec::Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override {
- const int height = this->getInfo().height();
- this->setUpInterlaceBuffer(height);
- png_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, nullptr);
-
- fFirstRow = 0;
- fLastRow = height - 1;
- fLinesDecoded = 0;
-
- this->processData();
-
- png_bytep srcRow = fInterlaceBuffer.get();
- // FIXME: When resuming, this may rewrite rows that did not change.
- for (int rowNum = 0; rowNum < fLinesDecoded; rowNum++) {
- this->swizzler()->swizzle(dst, srcRow);
- dst = SkTAddOffset<void>(dst, rowBytes);
- srcRow = SkTAddOffset<png_byte>(srcRow, fPng_rowbytes);
- }
- if (fInterlacedComplete) {
- return SkCodec::kSuccess;
- }
-
- if (rowsDecoded) {
- *rowsDecoded = fLinesDecoded;
- }
-
- return SkCodec::kIncompleteInput;
- }
-
- void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override {
- // FIXME: We could skip rows in the interlace buffer that we won't put in the output.
- this->setUpInterlaceBuffer(lastRow - firstRow + 1);
- png_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, nullptr);
- fFirstRow = firstRow;
- fLastRow = lastRow;
- fDst = dst;
- fRowBytes = rowBytes;
- fLinesDecoded = 0;
- }
-
- SkCodec::Result decode(int* rowsDecoded) override {
- this->processData();
-
- // Now call the callback on all the rows that were decoded.
- if (!fLinesDecoded) {
- return SkCodec::kIncompleteInput;
- }
- const int lastRow = fLinesDecoded + fFirstRow - 1;
- SkASSERT(lastRow <= fLastRow);
-
- // FIXME: For resuming interlace, we may swizzle a row that hasn't changed. But it
- // may be too tricky/expensive to handle that correctly.
- png_bytep srcRow = fInterlaceBuffer.get();
- const int sampleY = this->swizzler()->sampleY();
- void* dst = fDst;
- for (int rowNum = fFirstRow; rowNum <= lastRow; rowNum += sampleY) {
- this->swizzler()->swizzle(dst, srcRow);
- dst = SkTAddOffset<void>(dst, fRowBytes);
- srcRow = SkTAddOffset<png_byte>(srcRow, fPng_rowbytes * sampleY);
- }
-
- if (fInterlacedComplete) {
- return SkCodec::kSuccess;
- }
-
- if (rowsDecoded) {
- *rowsDecoded = fLinesDecoded;
- }
- return SkCodec::kIncompleteInput;
- }
-
- void setUpInterlaceBuffer(int height) {
- fPng_rowbytes = png_get_rowbytes(this->png_ptr(), this->info_ptr());
- fInterlaceBuffer.reset(fPng_rowbytes * height);
- fInterlacedComplete = false;
- }
};
// Reads the header and initializes the output fields, if not NULL.
@@ -647,7 +492,7 @@
return false;
}
- AutoCleanPng autoClean(png_ptr, stream, chunkReader, outCodec);
+ AutoCleanPng autoClean(png_ptr);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (info_ptr == nullptr) {
@@ -661,6 +506,8 @@
if (setjmp(png_jmpbuf(png_ptr))) {
return false;
}
+
+ png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn);
#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
// Hookup our chunkReader so we can see any user-chunks the caller may be interested in.
@@ -672,31 +519,12 @@
}
#endif
- const bool decodedBounds = autoClean.decodeBounds();
-
- if (!decodedBounds) {
- return false;
- }
-
- // On success, decodeBounds releases ownership of png_ptr and info_ptr.
- if (png_ptrp) {
- *png_ptrp = png_ptr;
- }
- if (info_ptrp) {
- *info_ptrp = info_ptr;
- }
-
- // decodeBounds takes care of setting outCodec
- if (outCodec) {
- SkASSERT(*outCodec);
- }
- return true;
-}
-
-void AutoCleanPng::infoCallback() {
+ // The call to png_read_info() gives us all of the information from the
+ // PNG file before the first IDAT (image data chunk).
+ png_read_info(png_ptr, info_ptr);
png_uint_32 origWidth, origHeight;
int bitDepth, encodedColorType;
- png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth,
+ png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
&encodedColorType, nullptr, nullptr, nullptr);
// Tell libpng to strip 16 bit/color files down to 8 bits/color.
@@ -704,7 +532,7 @@
// RAW decodes?
if (bitDepth == 16) {
SkASSERT(PNG_COLOR_TYPE_PALETTE != encodedColorType);
- png_set_strip_16(fPng_ptr);
+ png_set_strip_16(png_ptr);
}
// Now determine the default colorType and alphaType and set the required transforms.
@@ -718,18 +546,18 @@
// byte into separate bytes (useful for paletted and grayscale images).
if (bitDepth < 8) {
// TODO: Should we use SkSwizzler here?
- png_set_packing(fPng_ptr);
+ png_set_packing(png_ptr);
}
color = SkEncodedInfo::kPalette_Color;
// Set the alpha depending on if a transparency chunk exists.
- alpha = png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS) ?
+ alpha = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ?
SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha;
break;
case PNG_COLOR_TYPE_RGB:
- if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) {
+ if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
// Convert to RGBA if transparency chunk exists.
- png_set_tRNS_to_alpha(fPng_ptr);
+ png_set_tRNS_to_alpha(png_ptr);
color = SkEncodedInfo::kRGBA_Color;
alpha = SkEncodedInfo::kBinary_Alpha;
} else {
@@ -741,11 +569,11 @@
// Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel.
if (bitDepth < 8) {
// TODO: Should we use SkSwizzler here?
- png_set_expand_gray_1_2_4_to_8(fPng_ptr);
+ png_set_expand_gray_1_2_4_to_8(png_ptr);
}
- if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) {
- png_set_tRNS_to_alpha(fPng_ptr);
+ if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
+ png_set_tRNS_to_alpha(png_ptr);
color = SkEncodedInfo::kGrayAlpha_Color;
alpha = SkEncodedInfo::kBinary_Alpha;
} else {
@@ -768,55 +596,45 @@
alpha = SkEncodedInfo::kUnpremul_Alpha;
}
- const int numberPasses = png_set_interlace_handling(fPng_ptr);
-
- fReadHeader = true;
-#if PNG_LIBPNG_VER_MAJOR > 1 || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 5)
- // 1 tells libpng to save any extra data. We may be able to be more efficient by saving
- // it ourselves.
- png_process_data_pause(fPng_ptr, 1);
- fDecodedBounds = true;
-#else
- // We may have read more than the header. Empty buffer and move to the end of the
- // header so future calls can read the rows.
- fDecodedBounds = fStream->move(-fPng_ptr->buffer_size);
- fPng_ptr->buffer_size = 0;
- if (!fDecodedBounds) {
- // Stream could not be moved to the correct place.
- return;
- }
-#endif
- if (fOutCodec) {
- SkASSERT(nullptr == *fOutCodec);
- sk_sp<SkColorSpace> colorSpace = read_color_space(fPng_ptr, fInfo_ptr);
+ int numberPasses = png_set_interlace_handling(png_ptr);
+
+ autoClean.release();
+ if (png_ptrp) {
+ *png_ptrp = png_ptr;
+ }
+ if (info_ptrp) {
+ *info_ptrp = info_ptr;
+ }
+
+ if (outCodec) {
+ sk_sp<SkColorSpace> colorSpace = read_color_space(png_ptr, info_ptr);
if (!colorSpace) {
// Treat unmarked pngs as sRGB.
colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
}
+
SkEncodedInfo info = SkEncodedInfo::Make(color, alpha, 8);
+
if (1 == numberPasses) {
- *fOutCodec = new SkPngNormalDecoder(origWidth, origHeight, info, fStream,
- fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, std::move(colorSpace));
+ *outCodec = new SkPngScanlineDecoder(origWidth, origHeight, info, stream,
+ chunkReader, png_ptr, info_ptr, bitDepth, colorSpace);
} else {
- *fOutCodec = new SkPngInterlacedDecoder(origWidth, origHeight, info, fStream,
- fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, std::move(colorSpace),
- numberPasses);
- }
- }
-
-
- // Release the pointers, which are now owned by the codec or the caller is expected to
- // take ownership.
- this->releasePngPtrs();
+ *outCodec = new SkPngInterlacedScanlineDecoder(origWidth, origHeight, info, stream,
+ chunkReader, png_ptr, info_ptr, bitDepth, numberPasses, colorSpace);
+ }
+ }
+
+ return true;
}
SkPngCodec::SkPngCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream,
SkPngChunkReader* chunkReader, png_structp png_ptr, png_infop info_ptr,
- int bitDepth, sk_sp<SkColorSpace> colorSpace)
+ int bitDepth, int numberPasses, sk_sp<SkColorSpace> colorSpace)
: INHERITED(width, height, info, stream, colorSpace)
, fPngChunkReader(SkSafeRef(chunkReader))
, fPng_ptr(png_ptr)
, fInfo_ptr(info_ptr)
+ , fNumberPasses(numberPasses)
, fBitDepth(bitDepth)
{}
@@ -838,19 +656,22 @@
// Getting the pixels
///////////////////////////////////////////////////////////////////////////////
-bool SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
- const Options& options,
- SkPMColor ctable[],
- int* ctableCount) {
+SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
+ const Options& options,
+ SkPMColor ctable[],
+ int* ctableCount) {
+ // FIXME: Could we use the return value of setjmp to specify the type of
+ // error?
if (setjmp(png_jmpbuf(fPng_ptr))) {
- return false;
+ SkCodecPrintf("setjmp long jump!\n");
+ return kInvalidInput;
}
png_read_update_info(fPng_ptr, fInfo_ptr);
if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) {
if (!this->createColorTable(requestedInfo.colorType(),
kPremul_SkAlphaType == requestedInfo.alphaType(), ctableCount)) {
- return false;
+ return kInvalidInput;
}
}
@@ -863,7 +684,7 @@
options));
SkASSERT(fSwizzler);
- return true;
+ return kSuccess;
}
@@ -899,38 +720,77 @@
}
// Note that ctable and ctableCount may be modified if there is a color table
- if (!this->initializeSwizzler(requestedInfo, options, ctable, ctableCount)) {
- return kInvalidInput; // or parameters?
- }
-
- return this->decodeAllRows(dst, dstRowBytes, rowsDecoded);
-}
-
-SkCodec::Result SkPngCodec::onStartIncrementalDecode(const SkImageInfo& dstInfo,
- void* dst, size_t rowBytes, const SkCodec::Options& options,
- SkPMColor* ctable, int* ctableCount) {
- if (!conversion_possible(dstInfo, this->getInfo())) {
- return kInvalidConversion;
- }
-
- if (!this->initializeSwizzler(dstInfo, options, ctable, ctableCount)) {
- return kInvalidInput;
- }
-
- int firstRow, lastRow;
- if (options.fSubset) {
- firstRow = options.fSubset->top();
- lastRow = options.fSubset->bottom() - 1;
+ const Result result = this->initializeSwizzler(requestedInfo, options, ctable, ctableCount);
+ if (result != kSuccess) {
+ return result;
+ }
+
+ const int width = requestedInfo.width();
+ const int height = requestedInfo.height();
+ const int bpp = bytes_per_pixel(this->getEncodedInfo().bitsPerPixel());
+ const size_t srcRowBytes = width * bpp;
+
+ // FIXME: Could we use the return value of setjmp to specify the type of
+ // error?
+ int row = 0;
+ // This must be declared above the call to setjmp to avoid memory leaks on incomplete images.
+ SkAutoTMalloc<uint8_t> storage;
+ if (setjmp(png_jmpbuf(fPng_ptr))) {
+ // Assume that any error that occurs while reading rows is caused by an incomplete input.
+ if (fNumberPasses > 1) {
+ // FIXME (msarett): Handle incomplete interlaced pngs.
+ return (row == height) ? kSuccess : kInvalidInput;
+ }
+ // FIXME: We do a poor job on incomplete pngs compared to other decoders (ex: Chromium,
+ // Ubuntu Image Viewer). This is because we use the default buffer size in libpng (8192
+ // bytes), and if we can't fill the buffer, we immediately fail.
+ // For example, if we try to read 8192 bytes, and the image (incorrectly) only contains
+ // half that, which may have been enough to contain a non-zero number of lines, we fail
+ // when we could have decoded a few more lines and then failed.
+ // The read function that we provide for libpng has no way of indicating that we have
+ // made a partial read.
+ // Making our buffer size smaller improves our incomplete decodes, but what impact does
+ // it have on regular decode performance? Should we investigate using a different API
+ // instead of png_read_row? Chromium uses png_process_data.
+ *rowsDecoded = row;
+ return (row == height) ? kSuccess : kIncompleteInput;
+ }
+
+ // FIXME: We could split these out based on subclass.
+ void* dstRow = dst;
+ if (fNumberPasses > 1) {
+ storage.reset(height * srcRowBytes);
+ uint8_t* const base = storage.get();
+
+ for (int i = 0; i < fNumberPasses; i++) {
+ uint8_t* srcRow = base;
+ for (int y = 0; y < height; y++) {
+ png_read_row(fPng_ptr, srcRow, nullptr);
+ srcRow += srcRowBytes;
+ }
+ }
+
+ // Now swizzle it.
+ uint8_t* srcRow = base;
+ for (; row < height; row++) {
+ fSwizzler->swizzle(dstRow, srcRow);
+ dstRow = SkTAddOffset<void>(dstRow, dstRowBytes);
+ srcRow += srcRowBytes;
+ }
} else {
- firstRow = 0;
- lastRow = dstInfo.height() - 1;
- }
- this->setRange(firstRow, lastRow, dst, rowBytes);
+ storage.reset(srcRowBytes);
+ uint8_t* srcRow = storage.get();
+ for (; row < height; row++) {
+ png_read_row(fPng_ptr, srcRow, nullptr);
+ fSwizzler->swizzle(dstRow, srcRow);
+ dstRow = SkTAddOffset<void>(dstRow, dstRowBytes);
+ }
+ }
+
+ // read rest of file, and get additional comment and time chunks in info_ptr
+ png_read_end(fPng_ptr, fInfo_ptr);
+
return kSuccess;
-}
-
-SkCodec::Result SkPngCodec::onIncrementalDecode(int* rowsDecoded) {
- return this->decode(rowsDecoded);
}
uint32_t SkPngCodec::onGetFillValue(SkColorType colorType) const {
@@ -944,7 +804,7 @@
SkCodec* SkPngCodec::NewFromStream(SkStream* stream, SkPngChunkReader* chunkReader) {
SkAutoTDelete<SkStream> streamDeleter(stream);
- SkCodec* outCodec = nullptr;
+ SkCodec* outCodec;
if (read_header(stream, chunkReader, &outCodec, nullptr, nullptr)) {
// Codec has taken ownership of the stream.
SkASSERT(outCodec);
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