PassRefPtr<SharedBuffer> OpenTypeSanitizer::sanitize()
{
if (!m_buffer) {
setErrorString("Empty Buffer");
return nullptr;
}
// This is the largest web font size which we'll try to transcode.
static const size_t maxWebFontSize = 30 * 1024 * 1024; // 30 MB
if (m_buffer->size() > maxWebFontSize) {
setErrorString("Web font size more than 30MB");
return nullptr;
}
// A transcoded font is usually smaller than an original font.
// However, it can be slightly bigger than the original one due to
// name table replacement and/or padding for glyf table.
//
// With WOFF fonts, however, we'll be decompressing, so the result can be
// much larger than the original.
ots::ExpandingMemoryStream output(m_buffer->size(), maxWebFontSize);
BlinkOTSContext otsContext;
if (!otsContext.Process(&output, reinterpret_cast<const uint8_t*>(m_buffer->data()), m_buffer->size())) {
setErrorString(otsContext.getErrorString());
return nullptr;
}
const size_t transcodeLen = output.Tell();
return SharedBuffer::create(static_cast<unsigned char*>(output.get()), transcodeLen);
}
sk_sp<SkTypeface> WebFontDecoder::decode(SharedBuffer* buffer) {
if (!buffer) {
setErrorString("Empty Buffer");
return nullptr;
}
// This is the largest web font size which we'll try to transcode.
// TODO(bashi): 30MB seems low. Update the limit if necessary.
static const size_t maxWebFontSize = 30 * 1024 * 1024; // 30 MB
if (buffer->size() > maxWebFontSize) {
setErrorString("Web font size more than 30MB");
return nullptr;
}
// Most web fonts are compressed, so the result can be much larger than
// the original.
ots::ExpandingMemoryStream output(buffer->size(), maxWebFontSize);
double start = currentTime();
BlinkOTSContext otsContext;
const char* data = buffer->data();
TRACE_EVENT_BEGIN0("blink", "DecodeFont");
bool ok = otsContext.Process(&output, reinterpret_cast<const uint8_t*>(data),
buffer->size());
TRACE_EVENT_END0("blink", "DecodeFont");
if (!ok) {
setErrorString(otsContext.getErrorString());
return nullptr;
}
const size_t decodedLength = output.Tell();
recordDecodeSpeedHistogram(data, buffer->size(), currentTime() - start,
decodedLength);
sk_sp<SkData> skData = SkData::MakeWithCopy(output.get(), decodedLength);
SkMemoryStream* stream = new SkMemoryStream(skData);
#if OS(WIN)
sk_sp<SkTypeface> typeface(
FontCache::fontCache()->fontManager()->createFromStream(stream));
#else
sk_sp<SkTypeface> typeface = SkTypeface::MakeFromStream(stream);
#endif
if (!typeface) {
setErrorString("Not a valid font data");
return nullptr;
}
m_decodedSize = decodedLength;
return typeface;
}
