Issue #1101 - Support gzip-compressed SVGs in OpenType+SVG fonts

This commit is contained in:
Gaming4JC 2019-05-23 19:47:59 -04:00 committed by Roy Tam
commit 838eb9a504
5 changed files with 69 additions and 0 deletions

View file

@ -31,6 +31,7 @@
#include "nsSMILAnimationController.h"
#include "gfxContext.h"
#include "harfbuzz/hb.h"
#include "zlib.h"
#include "mozilla/dom/ImageTracker.h"
#define SVG_CONTENT_TYPE NS_LITERAL_CSTRING("image/svg+xml")
@ -285,7 +286,44 @@ gfxSVGGlyphsDocument::gfxSVGGlyphsDocument(const uint8_t *aBuffer,
gfxSVGGlyphs *aSVGGlyphs)
: mOwner(aSVGGlyphs)
{
if (aBufLen >= 14 && aBuffer[0] == 31 && aBuffer[1] == 139) {
// It's a gzip-compressed document; decompress it before parsing.
// The original length (modulo 2^32) is found in the last 4 bytes
// of the data, stored in little-endian format. We read it as
// individual bytes to avoid possible alignment issues.
// (Note that if the original length was >2^32, then origLen here
// will be incorrect; but then the inflate() call will not return
// Z_STREAM_END and we'll bail out safely.)
size_t origLen = (size_t(aBuffer[aBufLen - 1]) << 24) +
(size_t(aBuffer[aBufLen - 2]) << 16) +
(size_t(aBuffer[aBufLen - 3]) << 8) +
size_t(aBuffer[aBufLen - 4]);
AutoTArray<uint8_t, 4096> outBuf;
if (outBuf.SetLength(origLen, mozilla::fallible)) {
z_stream s = {0};
s.next_in = const_cast<Byte*>(aBuffer);
s.avail_in = aBufLen;
s.next_out = outBuf.Elements();
s.avail_out = outBuf.Length();
// The magic number 16 here is the zlib flag to expect gzip format,
// see http://www.zlib.net/manual.html#Advanced
if (Z_OK == inflateInit2(&s, 16 + MAX_WBITS)) {
int result = inflate(&s, Z_FINISH);
if (Z_STREAM_END == result) {
MOZ_ASSERT(size_t(s.next_out - outBuf.Elements()) == origLen);
ParseDocument(outBuf.Elements(), outBuf.Length());
} else {
NS_WARNING("Failed to decompress SVG glyphs document");
}
inflateEnd(&s);
}
} else {
NS_WARNING("Failed to allocate memory for SVG glyphs document");
}
} else {
ParseDocument(aBuffer, aBufLen);
}
if (!mDocument) {
NS_WARNING("Could not parse SVG glyphs document");
return;