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// Copyright 2017 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "bsdiff/patch_writer.h"
#include <string.h>
#include "bsdiff/brotli_compressor.h"
#include "bsdiff/bz2_compressor.h"
#include "bsdiff/constants.h"
#include "bsdiff/control_entry.h"
#include "bsdiff/logging.h"
namespace {
void EncodeInt64(int64_t x, uint8_t* buf) {
uint64_t y = x < 0 ? (1ULL << 63ULL) - x : x;
for (int i = 0; i < 8; ++i) {
buf[i] = y & 0xff;
y /= 256;
}
}
} // namespace
namespace bsdiff {
BsdiffPatchWriter::BsdiffPatchWriter(const std::string& patch_filename)
: patch_filename_(patch_filename), format_(BsdiffFormat::kLegacy) {
ctrl_stream_.reset(new BZ2Compressor());
diff_stream_.reset(new BZ2Compressor());
extra_stream_.reset(new BZ2Compressor());
}
BsdiffPatchWriter::BsdiffPatchWriter(const std::string& patch_filename,
CompressorType type,
int brotli_quality)
: patch_filename_(patch_filename), format_(BsdiffFormat::kBsdf2) {
if (type == CompressorType::kBZ2) {
ctrl_stream_.reset(new BZ2Compressor());
diff_stream_.reset(new BZ2Compressor());
extra_stream_.reset(new BZ2Compressor());
} else if (type == CompressorType::kBrotli) {
ctrl_stream_.reset(new BrotliCompressor(brotli_quality));
diff_stream_.reset(new BrotliCompressor(brotli_quality));
extra_stream_.reset(new BrotliCompressor(brotli_quality));
}
}
bool BsdiffPatchWriter::Init(size_t /* new_size */) {
if (!(ctrl_stream_ && diff_stream_ && extra_stream_)) {
LOG(ERROR) << "uninitialized compressor stream";
return false;
}
fp_ = fopen(patch_filename_.c_str(), "w");
if (!fp_) {
LOG(ERROR) << "Opening " << patch_filename_;
return false;
}
return true;
}
bool BsdiffPatchWriter::WriteDiffStream(const uint8_t* data, size_t size) {
return diff_stream_->Write(data, size);
}
bool BsdiffPatchWriter::WriteExtraStream(const uint8_t* data, size_t size) {
return extra_stream_->Write(data, size);
}
bool BsdiffPatchWriter::AddControlEntry(const ControlEntry& entry) {
// Generate the 24 byte control entry.
uint8_t buf[24];
EncodeInt64(entry.diff_size, buf);
EncodeInt64(entry.extra_size, buf + 8);
EncodeInt64(entry.offset_increment, buf + 16);
if (!ctrl_stream_->Write(buf, sizeof(buf)))
return false;
written_output_ += entry.diff_size + entry.extra_size;
return true;
}
bool BsdiffPatchWriter::Close() {
if (!fp_) {
LOG(ERROR) << "File not open.";
return false;
}
if (!ctrl_stream_->Finish() || !diff_stream_->Finish() ||
!extra_stream_->Finish()) {
LOG(ERROR) << "Finalizing compressed streams.";
return false;
}
auto ctrl_data = ctrl_stream_->GetCompressedData();
auto diff_data = diff_stream_->GetCompressedData();
auto extra_data = extra_stream_->GetCompressedData();
if (!WriteHeader(ctrl_data.size(), diff_data.size()))
return false;
if (fwrite(ctrl_data.data(), 1, ctrl_data.size(), fp_) != ctrl_data.size()) {
LOG(ERROR) << "Writing ctrl_data.";
return false;
}
if (fwrite(diff_data.data(), 1, diff_data.size(), fp_) != diff_data.size()) {
LOG(ERROR) << "Writing diff_data.";
return false;
}
if (fwrite(extra_data.data(), 1, extra_data.size(), fp_) !=
extra_data.size()) {
LOG(ERROR) << "Writing extra_data.";
return false;
}
if (fclose(fp_) != 0) {
LOG(ERROR) << "Closing the patch file.";
return false;
}
fp_ = nullptr;
return true;
}
bool BsdiffPatchWriter::WriteHeader(uint64_t ctrl_size, uint64_t diff_size) {
/* Header format is
* 0 8 magic header
* 8 8 length of compressed ctrl block
* 16 8 length of compressed diff block
* 24 8 length of new file
*
* File format is
* 0 32 Header
* 32 ?? compressed ctrl block
* ?? ?? compressed diff block
* ?? ?? compressed extra block
*/
uint8_t header[32];
if (format_ == BsdiffFormat::kLegacy) {
// The magic header is "BSDIFF40" for legacy format.
memcpy(header, kLegacyMagicHeader, 8);
} else if (format_ == BsdiffFormat::kBsdf2) {
// The magic header for BSDF2 format:
// 0 5 BSDF2
// 5 1 compressed type for control stream
// 6 1 compressed type for diff stream
// 7 1 compressed type for extra stream
memcpy(header, kBSDF2MagicHeader, 5);
header[5] = static_cast<uint8_t>(ctrl_stream_->Type());
header[6] = static_cast<uint8_t>(diff_stream_->Type());
header[7] = static_cast<uint8_t>(extra_stream_->Type());
} else {
LOG(ERROR) << "Unsupported bsdiff format.";
return false;
}
EncodeInt64(ctrl_size, header + 8);
EncodeInt64(diff_size, header + 16);
EncodeInt64(written_output_, header + 24);
if (fwrite(header, sizeof(header), 1, fp_) != 1) {
LOG(ERROR) << "writing to the patch file";
return false;
}
return true;
}
} // namespace bsdiff
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