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 | #ifndef _BSDIFF_SPLIT_PATCH_WRITER_H_ |
| 6 | #define _BSDIFF_SPLIT_PATCH_WRITER_H_ |
| 7 | |
| 8 | #include <stdint.h> |
| 9 | |
| 10 | #include <vector> |
| 11 | |
| 12 | #include "bsdiff/patch_writer_interface.h" |
| 13 | |
| 14 | namespace bsdiff { |
| 15 | |
| 16 | // A PatchWriterInterface class that splits the output patch into multiple |
| 17 | // patches of a fixed new-file size. The size of each patch data will depend on |
| 18 | // the contents of the new file data, and won't necessarily be uniform. |
| 19 | class SplitPatchWriter : public PatchWriterInterface { |
| 20 | public: |
Alex Deymo | 30964e8 | 2017-10-26 15:41:25 +0200 | [diff] [blame] | 21 | // Create a PatchWriter that will split the patch in several patches where |
| 22 | // each one will write |new_chunk_size| bytes of new file data. Each patch |
| 23 | // will use the old file as a whole input file. |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 24 | SplitPatchWriter(uint64_t new_chunk_size, |
| 25 | const std::vector<PatchWriterInterface*>& patches) |
| 26 | : new_chunk_size_(new_chunk_size), patches_(patches) { |
| 27 | diff_sizes_.resize(patches.size()); |
| 28 | extra_sizes_.resize(patches.size()); |
| 29 | } |
| 30 | |
| 31 | // PatchWriterInterface overrides. |
| 32 | // Note: Calling WriteDiffStream/WriteExtraStream before calling the |
| 33 | // corresponding AddControlEntry() is not supported and will fail. The reason |
| 34 | // for this is because which underlying patch takes the bytes depends on the |
| 35 | // control entries. |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 36 | bool Init(size_t new_size) override; |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 37 | bool WriteDiffStream(const uint8_t* data, size_t size) override; |
| 38 | bool WriteExtraStream(const uint8_t* data, size_t size) override; |
| 39 | bool AddControlEntry(const ControlEntry& entry) override; |
| 40 | bool Close() override; |
| 41 | |
| 42 | private: |
| 43 | // Add a ControlEntry to the |current_patch_| without splitting it. Updates |
| 44 | // the internal structures of used data. |
| 45 | bool AddControlEntryToCurrentPatch(const ControlEntry& entry); |
| 46 | |
| 47 | using WriteStreamMethod = bool (PatchWriterInterface::*)(const uint8_t* data, |
| 48 | size_t size); |
| 49 | |
| 50 | // Write to the diff or extra stream as determined by |method|. |
| 51 | bool WriteToStream(WriteStreamMethod method, |
| 52 | std::vector<size_t>* sizes_vector, |
| 53 | const uint8_t* data, |
| 54 | size_t size); |
| 55 | |
Alex Deymo | 4dadd8b | 2017-10-26 16:19:33 +0200 | [diff] [blame] | 56 | // The size of the new file for the patch we are writing. |
| 57 | size_t new_size_{0}; |
| 58 | |
Alex Deymo | e1140a2 | 2017-10-02 21:01:15 +0200 | [diff] [blame] | 59 | // The size of each chunk of the new file written to. |
| 60 | uint64_t new_chunk_size_; |
| 61 | std::vector<PatchWriterInterface*> patches_; |
| 62 | |
| 63 | // The size of the diff and extra streams that should go in each patch and has |
| 64 | // been written so far. |
| 65 | std::vector<size_t> diff_sizes_; |
| 66 | std::vector<size_t> extra_sizes_; |
| 67 | |
| 68 | // The current patch number in the |patches_| array we are writing to. |
| 69 | size_t current_patch_{0}; |
| 70 | |
| 71 | // The number of patches we already called Close() on. The patches are always |
| 72 | // closed in order. |
| 73 | size_t closed_patches_{0}; |
| 74 | |
| 75 | // Bytes of the new files already written. Needed to store the new length in |
| 76 | // the header of the file. |
| 77 | uint64_t written_output_{0}; |
| 78 | |
| 79 | // The current pointer into the old stream. |
| 80 | uint64_t old_pos_{0}; |
| 81 | }; |
| 82 | |
| 83 | } // namespace bsdiff |
| 84 | |
| 85 | #endif // _BSDIFF_SPLIT_PATCH_WRITER_H_ |