Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 1 | // Copyright 2017 The Chromium OS Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include "bsdiff/endsley_patch_writer.h" |
| 6 | |
| 7 | #include <string.h> |
| 8 | |
| 9 | #include <algorithm> |
| 10 | |
Alex Deymo | 19fc575 | 2018-02-15 16:56:39 +0100 | [diff] [blame] | 11 | #include "bsdiff/brotli_compressor.h" |
| 12 | #include "bsdiff/bz2_compressor.h" |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 13 | #include "bsdiff/logging.h" |
| 14 | |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 15 | namespace { |
| 16 | |
| 17 | constexpr uint8_t kEndsleyMagicHeader[] = "ENDSLEY/BSDIFF43"; |
| 18 | |
| 19 | void EncodeInt64(int64_t x, uint8_t* buf) { |
| 20 | uint64_t y = x < 0 ? (1ULL << 63ULL) - x : x; |
| 21 | for (int i = 0; i < 8; ++i) { |
| 22 | buf[i] = y & 0xff; |
| 23 | y /= 256; |
| 24 | } |
| 25 | } |
| 26 | |
| 27 | // The minimum size that we would consider flushing out. |
| 28 | constexpr size_t kMinimumFlushSize = 1024 * 1024; // 1 MiB |
| 29 | |
| 30 | } // namespace |
| 31 | |
| 32 | namespace bsdiff { |
| 33 | |
| 34 | bool EndsleyPatchWriter::Init(size_t new_size) { |
Alex Deymo | 19fc575 | 2018-02-15 16:56:39 +0100 | [diff] [blame] | 35 | switch (compressor_type_) { |
| 36 | case CompressorType::kNoCompression: |
| 37 | // The patch is uncompressed and it will need exactly: |
| 38 | // new_size + 24 * len(control_entries) + sizeof(header) |
| 39 | // We don't know the length of the control entries yet, but we can reserve |
| 40 | // enough space to hold at least |new_size|. |
| 41 | patch_->clear(); |
| 42 | patch_->reserve(new_size); |
| 43 | break; |
| 44 | case CompressorType::kBrotli: |
| 45 | compressor_.reset(new BrotliCompressor(quality_)); |
| 46 | if (!compressor_) { |
| 47 | LOG(ERROR) << "Error creating brotli compressor."; |
| 48 | return false; |
| 49 | } |
| 50 | break; |
| 51 | case CompressorType::kBZ2: |
| 52 | compressor_.reset(new BZ2Compressor()); |
| 53 | if (!compressor_) { |
| 54 | LOG(ERROR) << "Error creating BZ2 compressor."; |
| 55 | return false; |
| 56 | } |
| 57 | break; |
| 58 | } |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 59 | |
| 60 | // Header is the magic followed by the new length. |
| 61 | uint8_t header[24]; |
| 62 | memcpy(header, kEndsleyMagicHeader, 16); |
| 63 | EncodeInt64(new_size, header + 16); |
| 64 | EmitBuffer(header, sizeof(header)); |
| 65 | return true; |
| 66 | } |
| 67 | |
| 68 | bool EndsleyPatchWriter::WriteDiffStream(const uint8_t* data, size_t size) { |
| 69 | if (!size) |
| 70 | return true; |
| 71 | // Speed-up the common case where the diff stream data is added right after |
| 72 | // the control entry that refers to it. |
| 73 | if (control_.empty() && pending_diff_ >= size) { |
| 74 | pending_diff_ -= size; |
| 75 | EmitBuffer(data, size); |
| 76 | return true; |
| 77 | } |
| 78 | |
| 79 | diff_data_.insert(diff_data_.end(), data, data + size); |
| 80 | return true; |
| 81 | } |
| 82 | |
| 83 | bool EndsleyPatchWriter::WriteExtraStream(const uint8_t* data, size_t size) { |
| 84 | if (!size) |
| 85 | return true; |
| 86 | // Speed-up the common case where the extra stream data is added right after |
| 87 | // the diff stream data and the control entry that refers to it. Note that |
| 88 | // the diff data comes first so we need to make sure it is all out. |
| 89 | if (control_.empty() && !pending_diff_ && pending_extra_ >= size) { |
| 90 | pending_extra_ -= size; |
| 91 | EmitBuffer(data, size); |
| 92 | return true; |
| 93 | } |
| 94 | |
| 95 | extra_data_.insert(extra_data_.end(), data, data + size); |
| 96 | return true; |
| 97 | } |
| 98 | |
| 99 | bool EndsleyPatchWriter::AddControlEntry(const ControlEntry& entry) { |
| 100 | // Speed-up the common case where the control entry is added when there's |
| 101 | // nothing else pending. |
| 102 | if (control_.empty() && diff_data_.empty() && extra_data_.empty() && |
| 103 | !pending_diff_ && !pending_extra_) { |
| 104 | pending_diff_ = entry.diff_size; |
| 105 | pending_extra_ = entry.extra_size; |
| 106 | EmitControlEntry(entry); |
| 107 | return true; |
| 108 | } |
| 109 | |
| 110 | control_.push_back(entry); |
| 111 | pending_control_data_ += entry.diff_size + entry.extra_size; |
| 112 | |
| 113 | // Check whether it is worth Flushing the entries now that the we have more |
| 114 | // control entries. We need control entries to write enough output data, and |
| 115 | // we need that output data to be at least 50% of the available diff and extra |
| 116 | // data. This last requirement is to reduce the overhead of removing the |
| 117 | // flushed data. |
| 118 | if (pending_control_data_ > kMinimumFlushSize && |
| 119 | (diff_data_.size() + extra_data_.size()) / 2 <= pending_control_data_) { |
| 120 | Flush(); |
| 121 | } |
| 122 | |
| 123 | return true; |
| 124 | } |
| 125 | |
| 126 | bool EndsleyPatchWriter::Close() { |
| 127 | // Flush any pending data. |
| 128 | Flush(); |
| 129 | |
| 130 | if (pending_diff_ || pending_extra_ || !control_.empty()) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 131 | LOG(ERROR) << "Insufficient data sent to diff/extra streams"; |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 132 | return false; |
| 133 | } |
| 134 | |
| 135 | if (!diff_data_.empty() || !extra_data_.empty()) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 136 | LOG(ERROR) << "Pending data to diff/extra not flushed out on Close()"; |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 137 | return false; |
| 138 | } |
Alex Deymo | 19fc575 | 2018-02-15 16:56:39 +0100 | [diff] [blame] | 139 | |
| 140 | if (compressor_) { |
| 141 | if (!compressor_->Finish()) |
| 142 | return false; |
| 143 | *patch_ = compressor_->GetCompressedData(); |
| 144 | } |
| 145 | |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 146 | return true; |
| 147 | } |
| 148 | |
| 149 | void EndsleyPatchWriter::EmitControlEntry(const ControlEntry& entry) { |
| 150 | // Generate the 24 byte control entry. |
| 151 | uint8_t buf[24]; |
| 152 | EncodeInt64(entry.diff_size, buf); |
| 153 | EncodeInt64(entry.extra_size, buf + 8); |
| 154 | EncodeInt64(entry.offset_increment, buf + 16); |
| 155 | EmitBuffer(buf, sizeof(buf)); |
| 156 | } |
| 157 | |
| 158 | void EndsleyPatchWriter::EmitBuffer(const uint8_t* data, size_t size) { |
Alex Deymo | 19fc575 | 2018-02-15 16:56:39 +0100 | [diff] [blame] | 159 | if (compressor_) { |
| 160 | compressor_->Write(data, size); |
| 161 | } else { |
| 162 | patch_->insert(patch_->end(), data, data + size); |
| 163 | } |
Alex Deymo | 710b3da | 2017-10-26 13:13:28 +0200 | [diff] [blame] | 164 | } |
| 165 | |
| 166 | void EndsleyPatchWriter::Flush() { |
| 167 | size_t used_diff = 0; |
| 168 | size_t used_extra = 0; |
| 169 | size_t used_control = 0; |
| 170 | do { |
| 171 | if (!pending_diff_ && !pending_extra_ && used_control < control_.size()) { |
| 172 | // We can emit a control entry in these conditions. |
| 173 | const ControlEntry& entry = control_[used_control]; |
| 174 | used_control++; |
| 175 | |
| 176 | pending_diff_ = entry.diff_size; |
| 177 | pending_extra_ = entry.extra_size; |
| 178 | pending_control_data_ -= entry.extra_size + entry.diff_size; |
| 179 | EmitControlEntry(entry); |
| 180 | } |
| 181 | |
| 182 | if (pending_diff_) { |
| 183 | size_t diff_size = std::min(diff_data_.size() - used_diff, pending_diff_); |
| 184 | EmitBuffer(diff_data_.data() + used_diff, diff_size); |
| 185 | pending_diff_ -= diff_size; |
| 186 | used_diff += diff_size; |
| 187 | } |
| 188 | |
| 189 | if (!pending_diff_ && pending_extra_) { |
| 190 | size_t extra_size = |
| 191 | std::min(extra_data_.size() - used_extra, pending_extra_); |
| 192 | EmitBuffer(extra_data_.data() + used_extra, extra_size); |
| 193 | pending_extra_ -= extra_size; |
| 194 | used_extra += extra_size; |
| 195 | } |
| 196 | } while (!pending_diff_ && !pending_extra_ && used_control < control_.size()); |
| 197 | |
| 198 | if (used_diff) |
| 199 | diff_data_.erase(diff_data_.begin(), diff_data_.begin() + used_diff); |
| 200 | if (used_extra) |
| 201 | extra_data_.erase(extra_data_.begin(), extra_data_.begin() + used_extra); |
| 202 | if (used_control) |
| 203 | control_.erase(control_.begin(), control_.begin() + used_control); |
| 204 | } |
| 205 | |
| 206 | } // namespace bsdiff |