Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +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/split_patch_writer.h" |
| 6 | |
| 7 | #include <algorithm> |
| 8 | |
| 9 | #include "bsdiff/logging.h" |
| 10 | |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 11 | namespace bsdiff { |
| 12 | |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 13 | bool SplitPatchWriter::Init(size_t new_size) { |
| 14 | new_size_ = new_size; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 15 | // Fail gracefully if re-initialized. |
| 16 | if (current_patch_ || patches_.empty()) |
| 17 | return false; |
| 18 | |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 19 | size_t expected_patches = (new_size_ + new_chunk_size_ - 1) / new_chunk_size_; |
| 20 | if (expected_patches == 0) |
| 21 | expected_patches = 1; |
| 22 | if (expected_patches != patches_.size()) { |
| 23 | LOG(ERROR) << "Expected " << expected_patches << " for a new file of size " |
| 24 | << new_size_ << " split in chunks of " << new_chunk_size_ |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 25 | << " but got " << patches_.size() << " instead."; |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 26 | return false; |
| 27 | } |
| 28 | |
| 29 | return patches_[0]->Init( |
| 30 | std::min(static_cast<uint64_t>(new_size_), new_chunk_size_)); |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 31 | } |
| 32 | |
| 33 | bool SplitPatchWriter::WriteDiffStream(const uint8_t* data, size_t size) { |
| 34 | return WriteToStream(&PatchWriterInterface::WriteDiffStream, &diff_sizes_, |
| 35 | data, size); |
| 36 | } |
| 37 | |
| 38 | bool SplitPatchWriter::WriteExtraStream(const uint8_t* data, size_t size) { |
| 39 | return WriteToStream(&PatchWriterInterface::WriteExtraStream, &extra_sizes_, |
| 40 | data, size); |
| 41 | } |
| 42 | |
| 43 | bool SplitPatchWriter::AddControlEntry(const ControlEntry& entry) { |
| 44 | ControlEntry remaining(entry); |
| 45 | while (written_output_ + remaining.diff_size + remaining.extra_size >= |
| 46 | (current_patch_ + 1) * new_chunk_size_) { |
| 47 | // We need to write some of the current ControlEntry to the current patch |
| 48 | // and move on to the next patch if there are more bytes to write. |
| 49 | uint64_t remaining_bytes = |
| 50 | (current_patch_ + 1) * new_chunk_size_ - written_output_; |
| 51 | // The offset_increment is always 0 in this case since we don't plan to read |
| 52 | // for the old file in the current_patch anymore. |
| 53 | ControlEntry current_patch_entry(0, 0, 0); |
| 54 | |
| 55 | current_patch_entry.diff_size = |
| 56 | std::min(remaining.diff_size, remaining_bytes); |
| 57 | remaining_bytes -= current_patch_entry.diff_size; |
| 58 | remaining.diff_size -= current_patch_entry.diff_size; |
| 59 | |
| 60 | // This will be positive only if we used all the diff_size bytes. |
| 61 | current_patch_entry.extra_size = |
| 62 | std::min(remaining.extra_size, remaining_bytes); |
| 63 | remaining_bytes -= current_patch_entry.extra_size; |
| 64 | remaining.extra_size -= current_patch_entry.extra_size; |
| 65 | |
| 66 | AddControlEntryToCurrentPatch(current_patch_entry); |
| 67 | |
| 68 | if (remaining.diff_size + remaining.extra_size > 0) { |
| 69 | current_patch_++; |
| 70 | if (current_patch_ >= patches_.size()) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 71 | LOG(ERROR) << "Writing past the last patch"; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 72 | return false; |
| 73 | } |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 74 | if (!patches_[current_patch_]->Init(std::min( |
| 75 | new_size_ - current_patch_ * new_chunk_size_, new_chunk_size_))) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 76 | LOG(ERROR) << "Failed to initialize patch " << current_patch_; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 77 | return false; |
| 78 | } |
| 79 | if (!remaining.diff_size) { |
| 80 | // When no diff need to be sent to the output, we can just push the |
| 81 | // existing old_pos_ as part of the current triplet, since the extra |
| 82 | // stream doesn't use the old_pos_; |
| 83 | remaining.offset_increment += old_pos_; |
| 84 | old_pos_ = 0; |
| 85 | } |
| 86 | // Need to add a dummy control entry at the beginning of the patch to |
| 87 | // offset the old_pos in the new patch, which would start at 0. |
| 88 | if (old_pos_ != 0) { |
| 89 | if (!patches_[current_patch_]->AddControlEntry( |
| 90 | ControlEntry(0, 0, old_pos_))) |
| 91 | return false; |
| 92 | } |
| 93 | } else { |
| 94 | // There was no need to write more bytes past the current patch, so just |
| 95 | // update the old_pos_ we are tracking for the next patch, if any. |
| 96 | old_pos_ += remaining.offset_increment; |
| 97 | return true; |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | // Trivial entries will be ignored. |
| 102 | return AddControlEntryToCurrentPatch(remaining); |
| 103 | } |
| 104 | |
| 105 | bool SplitPatchWriter::Close() { |
| 106 | uint64_t missing_bytes = 0; |
| 107 | for (auto size : diff_sizes_) |
| 108 | missing_bytes += size; |
| 109 | for (auto size : extra_sizes_) |
| 110 | missing_bytes += size; |
| 111 | if (missing_bytes > 0) { |
| 112 | LOG(ERROR) << "Close() called but there are " << missing_bytes |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 113 | << " bytes missing from Write*Stream() calls"; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 114 | return false; |
| 115 | } |
| 116 | |
| 117 | // |current_patch_| holds the last patch that was Init()'ed. If there are more |
| 118 | // patches in the list those have not been initialized/closed, which is a |
| 119 | // programming error. |
| 120 | if (current_patch_ + 1 != patches_.size()) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 121 | LOG(ERROR) |
| 122 | << "Close() called but no bytes habe been written to the last patch"; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 123 | return false; |
| 124 | } |
| 125 | |
| 126 | // Close all the remaining streams. |
| 127 | for (; closed_patches_ < patches_.size(); closed_patches_++) { |
| 128 | if (!patches_[closed_patches_]->Close()) |
| 129 | return false; |
| 130 | } |
| 131 | return true; |
| 132 | } |
| 133 | |
| 134 | bool SplitPatchWriter::AddControlEntryToCurrentPatch( |
| 135 | const ControlEntry& entry) { |
| 136 | // Ignore trivial control entries that don't modify the state. |
| 137 | if (!entry.diff_size && !entry.extra_size && !entry.offset_increment) |
| 138 | return true; |
| 139 | |
| 140 | if (current_patch_ >= patches_.size()) { |
Tianjie Xu | 18480eb | 2017-11-29 16:21:43 -0800 | [diff] [blame] | 141 | LOG(ERROR) << "Writing past the last patch"; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 142 | return false; |
| 143 | } |
| 144 | old_pos_ += entry.diff_size + entry.offset_increment; |
| 145 | written_output_ += entry.diff_size + entry.extra_size; |
| 146 | // Register the diff/extra sizes as required bytes for the current patch. |
| 147 | diff_sizes_[current_patch_] += entry.diff_size; |
| 148 | extra_sizes_[current_patch_] += entry.extra_size; |
| 149 | return patches_[current_patch_]->AddControlEntry(entry); |
| 150 | } |
| 151 | |
| 152 | bool SplitPatchWriter::WriteToStream(WriteStreamMethod method, |
| 153 | std::vector<size_t>* sizes_vector, |
| 154 | const uint8_t* data, |
| 155 | size_t size) { |
| 156 | size_t written = 0; |
| 157 | for (size_t i = closed_patches_; i <= current_patch_ && written < size; i++) { |
| 158 | if ((*sizes_vector)[i]) { |
| 159 | size_t flush_size = std::min(size - written, (*sizes_vector)[i]); |
| 160 | if (!(patches_[i]->*method)(data + written, flush_size)) |
| 161 | return false; |
| 162 | written += flush_size; |
| 163 | (*sizes_vector)[i] -= flush_size; |
| 164 | } |
| 165 | |
| 166 | if (i < current_patch_ && !diff_sizes_[i] && !extra_sizes_[i]) { |
| 167 | // All bytes expected for the patch i are already sent. |
| 168 | if (!patches_[i]->Close()) |
| 169 | return false; |
| 170 | closed_patches_++; |
| 171 | } |
| 172 | } |
| 173 | if (written < size) { |
| 174 | LOG(ERROR) << "Calling Write*Stream() before the corresponding " |
| 175 | "AddControlEntry() is not supported."; |
| 176 | return false; |
| 177 | } |
| 178 | return true; |
| 179 | } |
| 180 | |
| 181 | } // namespace bsdiff |