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// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/filter/brotli_source_stream.h"
#include <stdint.h>
#include <memory>
#include <utility>
#include "base/check_op.h"
#include "base/functional/bind.h"
#include "base/metrics/histogram_macros.h"
#include "net/base/io_buffer.h"
#include "net/filter/source_stream_type.h"
#include "third_party/brotli/include/brotli/decode.h"
#include "third_party/brotli/include/brotli/shared_dictionary.h"
namespace net {
namespace {
const char kBrotli[] = "BROTLI";
struct BrotliDecoderStateDeleter {
void operator()(BrotliDecoderState* ptr) const {
BrotliDecoderDestroyInstance(ptr);
}
};
// BrotliSourceStream applies Brotli content decoding to a data stream.
// Brotli format specification: http://www.ietf.org/id/draft-alakuijala-brotli.
class BrotliSourceStream : public FilterSourceStream {
public:
explicit BrotliSourceStream(std::unique_ptr<SourceStream> upstream,
scoped_refptr<IOBuffer> dictionary = nullptr,
size_t dictionary_size = 0u)
: FilterSourceStream(SourceStreamType::kBrotli, std::move(upstream)),
dictionary_(std::move(dictionary)),
dictionary_size_(dictionary_size),
// The nullptrs mean the decoder will use malloc() and free() directly.
brotli_state_(BrotliDecoderCreateInstance(nullptr, nullptr, nullptr)) {
CHECK(brotli_state_);
if (dictionary_) {
BROTLI_BOOL result = BrotliDecoderAttachDictionary(
brotli_state_.get(), BROTLI_SHARED_DICTIONARY_RAW, dictionary_size_,
reinterpret_cast<const unsigned char*>(dictionary_->data()));
CHECK(result);
}
}
BrotliSourceStream(const BrotliSourceStream&) = delete;
BrotliSourceStream& operator=(const BrotliSourceStream&) = delete;
~BrotliSourceStream() override {
if (decoding_status_ == DecodingStatus::DECODING_DONE) {
// CompressionPercent is undefined when there is no output produced.
if (produced_bytes_ != 0) {
UMA_HISTOGRAM_PERCENTAGE(
"BrotliFilter.CompressionPercent",
static_cast<int>((consumed_bytes_ * 100) / produced_bytes_));
}
}
}
private:
// Reported in UMA and must be kept in sync with the histograms.xml file.
enum class DecodingStatus : int {
DECODING_IN_PROGRESS = 0,
DECODING_DONE,
DECODING_ERROR,
DECODING_STATUS_COUNT
// DECODING_STATUS_COUNT must always be the last element in this enum.
};
// SourceStream implementation
std::string GetTypeAsString() const override { return kBrotli; }
base::expected<size_t, Error> FilterData(
IOBuffer* output_buffer,
size_t output_buffer_size,
IOBuffer* input_buffer,
size_t input_buffer_size,
size_t* consumed_bytes,
bool /*upstream_eof_reached*/) override {
if (decoding_status_ == DecodingStatus::DECODING_DONE) {
*consumed_bytes = input_buffer_size;
return 0;
}
if (decoding_status_ != DecodingStatus::DECODING_IN_PROGRESS)
return base::unexpected(ERR_CONTENT_DECODING_FAILED);
const uint8_t* next_in = reinterpret_cast<uint8_t*>(input_buffer->data());
size_t available_in = input_buffer_size;
uint8_t* next_out = reinterpret_cast<uint8_t*>(output_buffer->data());
size_t available_out = output_buffer_size;
BrotliDecoderResult result = BrotliDecoderDecompressStream(
brotli_state_.get(), &available_in, &next_in, &available_out, &next_out,
nullptr);
size_t bytes_used = input_buffer_size - available_in;
size_t bytes_written = output_buffer_size - available_out;
CHECK_GE(input_buffer_size, available_in);
CHECK_GE(output_buffer_size, available_out);
produced_bytes_ += bytes_written;
consumed_bytes_ += bytes_used;
*consumed_bytes = bytes_used;
switch (result) {
case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
return bytes_written;
case BROTLI_DECODER_RESULT_SUCCESS:
decoding_status_ = DecodingStatus::DECODING_DONE;
// Consume remaining bytes to avoid DCHECK in FilterSourceStream.
// See crbug.com/659311.
*consumed_bytes = input_buffer_size;
return bytes_written;
case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
// Decompress needs more input has consumed all existing input.
DCHECK_EQ(*consumed_bytes, input_buffer_size);
decoding_status_ = DecodingStatus::DECODING_IN_PROGRESS;
return bytes_written;
// If the decompressor threw an error, fail synchronously.
default:
decoding_status_ = DecodingStatus::DECODING_ERROR;
return base::unexpected(ERR_CONTENT_DECODING_FAILED);
}
}
const scoped_refptr<IOBuffer> dictionary_;
const size_t dictionary_size_;
std::unique_ptr<BrotliDecoderState, BrotliDecoderStateDeleter> brotli_state_;
DecodingStatus decoding_status_ = DecodingStatus::DECODING_IN_PROGRESS;
size_t consumed_bytes_ = 0;
size_t produced_bytes_ = 0;
};
} // namespace
std::unique_ptr<FilterSourceStream> CreateBrotliSourceStream(
std::unique_ptr<SourceStream> previous) {
return std::make_unique<BrotliSourceStream>(std::move(previous));
}
std::unique_ptr<FilterSourceStream> CreateBrotliSourceStreamWithDictionary(
std::unique_ptr<SourceStream> previous,
scoped_refptr<IOBuffer> dictionary,
size_t dictionary_size) {
return std::make_unique<BrotliSourceStream>(
std::move(previous), std::move(dictionary), dictionary_size);
}
} // namespace net
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