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Diffstat (limited to '')
-rw-r--r-- | applypatch/include/applypatch/imgdiff_image.h | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/applypatch/include/applypatch/imgdiff_image.h b/applypatch/include/applypatch/imgdiff_image.h new file mode 100644 index 000000000..221dd5ab5 --- /dev/null +++ b/applypatch/include/applypatch/imgdiff_image.h @@ -0,0 +1,247 @@ +/* + * Copyright (C) 2017 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#ifndef _APPLYPATCH_IMGDIFF_IMAGE_H +#define _APPLYPATCH_IMGDIFF_IMAGE_H + +#include <stddef.h> +#include <stdio.h> +#include <sys/types.h> + +#include <string> +#include <vector> + +#include <bsdiff.h> +#include <ziparchive/zip_archive.h> +#include <zlib.h> + +#include "imgdiff.h" +#include "rangeset.h" + +class ImageChunk { + public: + static constexpr auto WINDOWBITS = -15; // 32kb window; negative to indicate a raw stream. + static constexpr auto MEMLEVEL = 8; // the default value. + static constexpr auto METHOD = Z_DEFLATED; + static constexpr auto STRATEGY = Z_DEFAULT_STRATEGY; + + ImageChunk(int type, size_t start, const std::vector<uint8_t>* file_content, size_t raw_data_len, + std::string entry_name = {}); + + int GetType() const { + return type_; + } + size_t GetRawDataLength() const { + return raw_data_len_; + } + const std::string& GetEntryName() const { + return entry_name_; + } + size_t GetStartOffset() const { + return start_; + } + int GetCompressLevel() const { + return compress_level_; + } + + // CHUNK_DEFLATE will return the uncompressed data for diff, while other types will simply return + // the raw data. + const uint8_t* DataForPatch() const; + size_t DataLengthForPatch() const; + + void Dump() const { + printf("type: %d, start: %zu, len: %zu, name: %s\n", type_, start_, DataLengthForPatch(), + entry_name_.c_str()); + } + + void SetUncompressedData(std::vector<uint8_t> data); + bool SetBonusData(const std::vector<uint8_t>& bonus_data); + + bool operator==(const ImageChunk& other) const; + bool operator!=(const ImageChunk& other) const { + return !(*this == other); + } + + /* + * Cause a gzip chunk to be treated as a normal chunk (ie, as a blob of uninterpreted data). + * The resulting patch will likely be about as big as the target file, but it lets us handle + * the case of images where some gzip chunks are reconstructible but others aren't (by treating + * the ones that aren't as normal chunks). + */ + void ChangeDeflateChunkToNormal(); + + /* + * Verify that we can reproduce exactly the same compressed data that we started with. Sets the + * level, method, windowBits, memLevel, and strategy fields in the chunk to the encoding + * parameters needed to produce the right output. + */ + bool ReconstructDeflateChunk(); + bool IsAdjacentNormal(const ImageChunk& other) const; + void MergeAdjacentNormal(const ImageChunk& other); + + /* + * Compute a bsdiff patch between |src| and |tgt|; Store the result in the patch_data. + * |bsdiff_cache| can be used to cache the suffix array if the same |src| chunk is used + * repeatedly, pass nullptr if not needed. + */ + static bool MakePatch(const ImageChunk& tgt, const ImageChunk& src, + std::vector<uint8_t>* patch_data, saidx_t** bsdiff_cache); + + private: + const uint8_t* GetRawData() const; + bool TryReconstruction(int level); + + int type_; // CHUNK_NORMAL, CHUNK_DEFLATE, CHUNK_RAW + size_t start_; // offset of chunk in the original input file + const std::vector<uint8_t>* input_file_ptr_; // ptr to the full content of original input file + size_t raw_data_len_; + + // deflate encoder parameters + int compress_level_; + + // --- for CHUNK_DEFLATE chunks only: --- + std::vector<uint8_t> uncompressed_data_; + std::string entry_name_; // used for zip entries +}; + +// PatchChunk stores the patch data between a source chunk and a target chunk. It also keeps track +// of the metadata of src&tgt chunks (e.g. offset, raw data length, uncompressed data length). +class PatchChunk { + public: + PatchChunk(const ImageChunk& tgt, const ImageChunk& src, std::vector<uint8_t> data); + + // Construct a CHUNK_RAW patch from the target data directly. + explicit PatchChunk(const ImageChunk& tgt); + + // Return true if raw data size is smaller than the patch size. + static bool RawDataIsSmaller(const ImageChunk& tgt, size_t patch_size); + + static bool WritePatchDataToFd(const std::vector<PatchChunk>& patch_chunks, int patch_fd); + + private: + size_t GetHeaderSize() const; + size_t WriteHeaderToFd(int fd, size_t offset) const; + + // The patch chunk type is the same as the target chunk type. The only exception is we change + // the |type_| to CHUNK_RAW if target length is smaller than the patch size. + int type_; + + size_t source_start_; + size_t source_len_; + size_t source_uncompressed_len_; + + size_t target_start_; // offset of the target chunk within the target file + size_t target_len_; + size_t target_uncompressed_len_; + size_t target_compress_level_; // the deflate compression level of the target chunk. + + std::vector<uint8_t> data_; // storage for the patch data +}; + +// Interface for zip_mode and image_mode images. We initialize the image from an input file and +// split the file content into a list of image chunks. +class Image { + public: + explicit Image(bool is_source) : is_source_(is_source) {} + + virtual ~Image() {} + + // Create a list of image chunks from input file. + virtual bool Initialize(const std::string& filename) = 0; + + // Look for runs of adjacent normal chunks and compress them down into a single chunk. (Such + // runs can be produced when deflate chunks are changed to normal chunks.) + void MergeAdjacentNormalChunks(); + + void DumpChunks() const; + + // Non const iterators to access the stored ImageChunks. + std::vector<ImageChunk>::iterator begin() { + return chunks_.begin(); + } + + std::vector<ImageChunk>::iterator end() { + return chunks_.end(); + } + + ImageChunk& operator[](size_t i); + const ImageChunk& operator[](size_t i) const; + + size_t NumOfChunks() const { + return chunks_.size(); + } + + protected: + bool ReadFile(const std::string& filename, std::vector<uint8_t>* file_content); + + bool is_source_; // True if it's for source chunks. + std::vector<ImageChunk> chunks_; // Internal storage of ImageChunk. + std::vector<uint8_t> file_content_; // Store the whole input file in memory. +}; + +class ZipModeImage : public Image { + public: + explicit ZipModeImage(bool is_source) : Image(is_source) {} + + bool Initialize(const std::string& filename) override; + + // The pesudo source chunk for bsdiff if there's no match for the given target chunk. It's in + // fact the whole source file. + ImageChunk PseudoSource() const; + + // Find the matching deflate source chunk by entry name. Search for normal chunks also if + // |find_normal| is true. + ImageChunk* FindChunkByName(const std::string& name, bool find_normal = false); + + const ImageChunk* FindChunkByName(const std::string& name, bool find_normal = false) const; + + // Verify that we can reconstruct the deflate chunks; also change the type to CHUNK_NORMAL if + // src and tgt are identical. + static bool CheckAndProcessChunks(ZipModeImage* tgt_image, ZipModeImage* src_image); + + // Compute the patch between tgt & src images, and write the data into |patch_name|. + static bool GeneratePatches(const ZipModeImage& tgt_image, const ZipModeImage& src_image, + const std::string& patch_name); + + private: + // Initialize image chunks based on the zip entries. + bool InitializeChunks(const std::string& filename, ZipArchiveHandle handle); + // Add the a zip entry to the list. + bool AddZipEntryToChunks(ZipArchiveHandle handle, const std::string& entry_name, ZipEntry* entry); + // Return the real size of the zip file. (omit the trailing zeros that used for alignment) + bool GetZipFileSize(size_t* input_file_size); +}; + +class ImageModeImage : public Image { + public: + explicit ImageModeImage(bool is_source) : Image(is_source) {} + + // Initialize the image chunks list by searching the magic numbers in an image file. + bool Initialize(const std::string& filename) override; + + bool SetBonusData(const std::vector<uint8_t>& bonus_data); + + // In Image Mode, verify that the source and target images have the same chunk structure (ie, the + // same sequence of deflate and normal chunks). + static bool CheckAndProcessChunks(ImageModeImage* tgt_image, ImageModeImage* src_image); + + // In image mode, generate patches against the given source chunks and bonus_data; write the + // result to |patch_name|. + static bool GeneratePatches(const ImageModeImage& tgt_image, const ImageModeImage& src_image, + const std::string& patch_name); +}; + +#endif // _APPLYPATCH_IMGDIFF_IMAGE_H |