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/*
* Copyright (C) 2009 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "third_party/blink/renderer/platform/fonts/web_font_decoder.h"
#include <hb.h>
#include <stdarg.h>
#include "base/compiler_specific.h"
#include "base/numerics/safe_conversions.h"
#include "build/build_config.h"
#include "third_party/blink/public/platform/platform.h"
#include "third_party/blink/renderer/platform/fonts/font_cache.h"
#include "third_party/blink/renderer/platform/fonts/web_font_typeface_factory.h"
#include "third_party/blink/renderer/platform/instrumentation/tracing/trace_event.h"
#include "third_party/blink/renderer/platform/wtf/shared_buffer.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/ots/src/include/ots-memory-stream.h"
#include "third_party/skia/include/core/SkStream.h"
namespace blink {
namespace {
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
const size_t kMaxDecompressedSizeMb = 30;
#else
const size_t kMaxDecompressedSizeMb = 128;
#endif
class BlinkOTSContext final : public ots::OTSContext {
DISALLOW_NEW();
public:
void Message(int level, const char* format, ...) override;
ots::TableAction GetTableAction(uint32_t tag) override;
const String& GetErrorString() { return error_string_; }
private:
String error_string_;
};
void BlinkOTSContext::Message(int level, const char* format, ...) {
va_list args;
va_start(args, format);
#if defined(COMPILER_MSVC)
int result = _vscprintf(format, args);
#else
char ch;
int result = UNSAFE_TODO(vsnprintf(&ch, 1, format, args));
#endif
va_end(args);
if (result <= 0) {
error_string_ = String("OTS Error");
} else {
Vector<char, 256> buffer;
unsigned len = result;
buffer.Grow(len + 1);
va_start(args, format);
UNSAFE_TODO(vsnprintf(buffer.data(), buffer.size(), format, args));
va_end(args);
error_string_ = StringImpl::Create(base::span(buffer).first(len));
}
}
#if !defined(HB_VERSION_ATLEAST)
#define HB_VERSION_ATLEAST(major, minor, micro) 0
#endif
ots::TableAction BlinkOTSContext::GetTableAction(uint32_t tag) {
const uint32_t kCbdtTag = OTS_TAG('C', 'B', 'D', 'T');
const uint32_t kCblcTag = OTS_TAG('C', 'B', 'L', 'C');
const uint32_t kColrTag = OTS_TAG('C', 'O', 'L', 'R');
const uint32_t kCpalTag = OTS_TAG('C', 'P', 'A', 'L');
const uint32_t kCff2Tag = OTS_TAG('C', 'F', 'F', '2');
const uint32_t kSbixTag = OTS_TAG('s', 'b', 'i', 'x');
const uint32_t kStatTag = OTS_TAG('S', 'T', 'A', 'T');
#if HB_VERSION_ATLEAST(1, 0, 0)
const uint32_t kBaseTag = OTS_TAG('B', 'A', 'S', 'E');
const uint32_t kGdefTag = OTS_TAG('G', 'D', 'E', 'F');
const uint32_t kGposTag = OTS_TAG('G', 'P', 'O', 'S');
const uint32_t kGsubTag = OTS_TAG('G', 'S', 'U', 'B');
// Font Variations related tables
// See "Variation Tables" in Terminology section of
// https://www.microsoft.com/typography/otspec/otvaroverview.htm
const uint32_t kAvarTag = OTS_TAG('a', 'v', 'a', 'r');
const uint32_t kCvarTag = OTS_TAG('c', 'v', 'a', 'r');
const uint32_t kFvarTag = OTS_TAG('f', 'v', 'a', 'r');
const uint32_t kGvarTag = OTS_TAG('g', 'v', 'a', 'r');
const uint32_t kHvarTag = OTS_TAG('H', 'V', 'A', 'R');
const uint32_t kMvarTag = OTS_TAG('M', 'V', 'A', 'R');
const uint32_t kVvarTag = OTS_TAG('V', 'V', 'A', 'R');
#endif
switch (tag) {
// Google Color Emoji Tables
case kCbdtTag:
case kCblcTag:
// Windows Color Emoji Tables
case kColrTag:
case kCpalTag:
case kCff2Tag:
case kSbixTag:
case kStatTag:
#if HB_VERSION_ATLEAST(1, 0, 0)
// Let HarfBuzz handle how to deal with broken tables.
case kAvarTag:
case kBaseTag:
case kCvarTag:
case kFvarTag:
case kGvarTag:
case kHvarTag:
case kMvarTag:
case kVvarTag:
case kGdefTag:
case kGposTag:
case kGsubTag:
#endif
return ots::TABLE_ACTION_PASSTHRU;
default:
return ots::TABLE_ACTION_DEFAULT;
}
}
} // namespace
sk_sp<SkTypeface> WebFontDecoder::Decode(SegmentedBuffer* buffer) {
if (!buffer) {
SetErrorString("Empty Buffer");
return nullptr;
}
// This is the largest web font size which we'll try to transcode.
static const size_t kMaxDecompressedSize =
kMaxDecompressedSizeMb * 1024 * 1024;
if (buffer->size() > kMaxDecompressedSize) {
String error_message =
String::Format("Web font size more than %zuMB", kMaxDecompressedSizeMb);
SetErrorString(error_message.Utf8().c_str());
return nullptr;
}
// Most web fonts are compressed, so the result can be much larger than
// the original.
ots::ExpandingMemoryStream output(buffer->size(), kMaxDecompressedSize);
BlinkOTSContext ots_context;
SegmentedBuffer::DeprecatedFlatData flattened_buffer(buffer);
TRACE_EVENT_BEGIN0("blink", "DecodeFont");
bool ok = ots_context.Process(
&output, reinterpret_cast<const uint8_t*>(flattened_buffer.data()),
buffer->size());
TRACE_EVENT_END0("blink", "DecodeFont");
if (!ok) {
SetErrorString(ots_context.GetErrorString());
return nullptr;
}
const size_t decoded_length = base::checked_cast<size_t>(output.Tell());
sk_sp<SkData> sk_data = SkData::MakeWithCopy(output.get(), decoded_length);
sk_sp<SkTypeface> new_typeface;
if (!WebFontTypefaceFactory::CreateTypeface(sk_data, new_typeface)) {
SetErrorString("Unable to instantiate font face from font data.");
return nullptr;
}
decoded_size_ = decoded_length;
return new_typeface;
}
} // namespace blink
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