| /* |
| * Copyright (C) 2006 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. |
| */ |
| |
| // |
| // Class providing access to a read-only asset. Asset objects are NOT |
| // thread-safe, and should not be shared across threads. |
| // |
| #ifndef __LIBS_ASSET_H |
| #define __LIBS_ASSET_H |
| |
| #include <stdio.h> |
| #include <sys/types.h> |
| #include <memory> |
| #include <optional> |
| |
| #include <android-base/unique_fd.h> |
| #include <util/map_ptr.h> |
| |
| #include <utils/Compat.h> |
| #include <utils/Errors.h> |
| #include <utils/String8.h> |
| |
| namespace android { |
| |
| /* |
| * Instances of this class provide read-only operations on a byte stream. |
| * |
| * Access may be optimized for streaming, random, or whole buffer modes. All |
| * operations are supported regardless of how the file was opened, but some |
| * things will be less efficient. [pass that in??] |
| * |
| * "Asset" is the base class for all types of assets. The classes below |
| * provide most of the implementation. The AssetManager uses one of the |
| * static "create" functions defined here to create a new instance. |
| */ |
| class Asset { |
| public: |
| virtual ~Asset(void) = default; |
| Asset(const Asset& src) = delete; |
| Asset& operator=(const Asset& src) = delete; |
| |
| static int32_t getGlobalCount(); |
| static String8 getAssetAllocations(); |
| |
| /* used when opening an asset */ |
| typedef enum AccessMode { |
| ACCESS_UNKNOWN = 0, |
| |
| /* read chunks, and seek forward and backward */ |
| ACCESS_RANDOM, |
| |
| /* read sequentially, with an occasional forward seek */ |
| ACCESS_STREAMING, |
| |
| /* caller plans to ask for a read-only buffer with all data */ |
| ACCESS_BUFFER, |
| } AccessMode; |
| |
| /* |
| * Read data from the current offset. Returns the actual number of |
| * bytes read, 0 on EOF, or -1 on error. |
| */ |
| virtual ssize_t read(void* buf, size_t count) = 0; |
| |
| /* |
| * Seek to the specified offset. "whence" uses the same values as |
| * lseek/fseek. Returns the new position on success, or (off64_t) -1 |
| * on failure. |
| */ |
| virtual off64_t seek(off64_t offset, int whence) = 0; |
| |
| /* |
| * Close the asset, freeing all associated resources. |
| */ |
| virtual void close(void) = 0; |
| |
| /* |
| * Get a pointer to a buffer with the entire contents of the file. |
| * If `aligned` is true, the buffer data will be aligned to a 4-byte boundary. |
| * |
| * If the buffer contents reside on IncFs, the entire buffer will be scanned to ensure the |
| * presence of the data before returning a raw pointer to the buffer. |
| */ |
| virtual const void* getBuffer(bool aligned) = 0; |
| |
| /* |
| * Get a incfs::map_ptr<void> to a buffer with the entire contents of the file. |
| * If `aligned` is true, the buffer data will be aligned to a 4-byte boundary. |
| * |
| * Use this function if the asset can potentially reside on IncFs to avoid the scanning of the |
| * buffer contents done in Asset::getBuffer. |
| */ |
| virtual incfs::map_ptr<void> getIncFsBuffer(bool aligned) = 0; |
| |
| /* |
| * Get the total amount of data that can be read. |
| */ |
| virtual off64_t getLength(void) const = 0; |
| |
| /* |
| * Get the total amount of data that can be read from the current position. |
| */ |
| virtual off64_t getRemainingLength(void) const = 0; |
| |
| /* |
| * Open a new file descriptor that can be used to read this asset. |
| * Returns -1 if you can not use the file descriptor (for example if the |
| * asset is compressed). |
| */ |
| virtual int openFileDescriptor(off64_t* outStart, off64_t* outLength) const = 0; |
| |
| /* |
| * Return whether this asset's buffer is allocated in RAM (not mmapped). |
| * Note: not virtual so it is safe to call even when being destroyed. |
| */ |
| virtual bool isAllocated(void) const { return false; } |
| |
| /* |
| * Get a string identifying the asset's source. This might be a full |
| * path, it might be a colon-separated list of identifiers. |
| * |
| * This is NOT intended to be used for anything except debug output. |
| * DO NOT try to parse this or use it to open a file. |
| */ |
| const char* getAssetSource(void) const { return mAssetSource.string(); } |
| |
| /* |
| * Create the asset from a file descriptor. |
| */ |
| static Asset* createFromFd(const int fd, const char* fileName, AccessMode mode); |
| |
| protected: |
| /* |
| * Adds this Asset to the global Asset list for debugging and |
| * accounting. |
| * Concrete subclasses must call this in their constructor. |
| */ |
| static void registerAsset(Asset* asset); |
| |
| /* |
| * Removes this Asset from the global Asset list. |
| * Concrete subclasses must call this in their destructor. |
| */ |
| static void unregisterAsset(Asset* asset); |
| |
| Asset(void); // constructor; only invoked indirectly |
| |
| /* handle common seek() housekeeping */ |
| off64_t handleSeek(off64_t offset, int whence, off64_t curPosn, off64_t maxPosn); |
| |
| /* set the asset source string */ |
| void setAssetSource(const String8& path) { mAssetSource = path; } |
| |
| AccessMode getAccessMode(void) const { return mAccessMode; } |
| |
| private: |
| /* AssetManager needs access to our "create" functions */ |
| friend class AssetManager; |
| friend struct ZipAssetsProvider; |
| friend struct AssetsProvider; |
| |
| /* |
| * Create the asset from a named file on disk. |
| */ |
| static Asset* createFromFile(const char* fileName, AccessMode mode); |
| |
| /* |
| * Create the asset from a named, compressed file on disk (e.g. ".gz"). |
| */ |
| static Asset* createFromCompressedFile(const char* fileName, AccessMode mode); |
| |
| #if 0 |
| /* |
| * Create the asset from a segment of an open file. This will fail |
| * if "offset" and "length" don't fit within the bounds of the file. |
| * |
| * The asset takes ownership of the file descriptor. |
| */ |
| static Asset* createFromFileSegment(int fd, off64_t offset, size_t length, |
| AccessMode mode); |
| |
| /* |
| * Create from compressed data. "fd" should be seeked to the start of |
| * the compressed data. This could be inside a gzip file or part of a |
| * Zip archive. |
| * |
| * The asset takes ownership of the file descriptor. |
| * |
| * This may not verify the validity of the compressed data until first |
| * use. |
| */ |
| static Asset* createFromCompressedData(int fd, off64_t offset, |
| int compressionMethod, size_t compressedLength, |
| size_t uncompressedLength, AccessMode mode); |
| #endif |
| |
| /* |
| * Create the asset from a memory-mapped file segment. |
| * |
| * The asset takes ownership of the incfs::IncFsFileMap and the file descriptor "fd". The |
| * file descriptor is used to request new file descriptors using "openFileDescriptor". |
| */ |
| static std::unique_ptr<Asset> createFromUncompressedMap(incfs::IncFsFileMap&& dataMap, |
| AccessMode mode, |
| base::unique_fd fd = {}); |
| |
| /* |
| * Create the asset from a memory-mapped file segment with compressed |
| * data. |
| * |
| * The asset takes ownership of the incfs::IncFsFileMap. |
| */ |
| static std::unique_ptr<Asset> createFromCompressedMap(incfs::IncFsFileMap&& dataMap, |
| size_t uncompressedLen, AccessMode mode); |
| |
| /* |
| * Create from a reference-counted chunk of shared memory. |
| */ |
| // TODO |
| |
| AccessMode mAccessMode; // how the asset was opened |
| String8 mAssetSource; // debug string |
| |
| Asset* mNext; // linked list. |
| Asset* mPrev; |
| }; |
| |
| |
| /* |
| * =========================================================================== |
| * |
| * Innards follow. Do not use these classes directly. |
| */ |
| |
| /* |
| * An asset based on an uncompressed file on disk. It may encompass the |
| * entire file or just a piece of it. Access is through fread/fseek. |
| */ |
| class _FileAsset : public Asset { |
| public: |
| _FileAsset(void); |
| ~_FileAsset(void) override; |
| |
| /* |
| * Use a piece of an already-open file. |
| * |
| * On success, the object takes ownership of "fd". |
| */ |
| status_t openChunk(const char* fileName, int fd, off64_t offset, size_t length); |
| |
| /* |
| * Use a memory-mapped region. |
| * |
| * On success, the object takes ownership of "dataMap" and "fd". |
| */ |
| status_t openChunk(incfs::IncFsFileMap&& dataMap, base::unique_fd fd); |
| |
| /* |
| * Standard Asset interfaces. |
| */ |
| ssize_t read(void* buf, size_t count) override; |
| off64_t seek(off64_t offset, int whence) override; |
| void close(void) override; |
| const void* getBuffer(bool aligned) override; |
| incfs::map_ptr<void> getIncFsBuffer(bool aligned) override; |
| off64_t getLength(void) const override { return mLength; } |
| off64_t getRemainingLength(void) const override { return mLength-mOffset; } |
| int openFileDescriptor(off64_t* outStart, off64_t* outLength) const override; |
| bool isAllocated(void) const override { return mBuf != NULL; } |
| |
| private: |
| incfs::map_ptr<void> ensureAlignment(const incfs::IncFsFileMap& map); |
| |
| off64_t mStart; // absolute file offset of start of chunk |
| off64_t mLength; // length of the chunk |
| off64_t mOffset; // current local offset, 0 == mStart |
| FILE* mFp; // for read/seek |
| char* mFileName; // for opening |
| base::unique_fd mFd; // for opening file descriptors |
| |
| /* |
| * To support getBuffer() we either need to read the entire thing into |
| * a buffer or memory-map it. For small files it's probably best to |
| * just read them in. |
| */ |
| enum { kReadVsMapThreshold = 4096 }; |
| |
| unsigned char* mBuf; // for read |
| std::optional<incfs::IncFsFileMap> mMap; // for memory map |
| }; |
| |
| |
| /* |
| * An asset based on compressed data in a file. |
| */ |
| class _CompressedAsset : public Asset { |
| public: |
| _CompressedAsset(void); |
| virtual ~_CompressedAsset(void); |
| |
| /* |
| * Use a piece of an already-open file. |
| * |
| * On success, the object takes ownership of "fd". |
| */ |
| status_t openChunk(int fd, off64_t offset, int compressionMethod, |
| size_t uncompressedLen, size_t compressedLen); |
| |
| /* |
| * Use a memory-mapped region. |
| * |
| * On success, the object takes ownership of "fd". |
| */ |
| status_t openChunk(incfs::IncFsFileMap&& dataMap, size_t uncompressedLen); |
| |
| /* |
| * Standard Asset interfaces. |
| */ |
| virtual ssize_t read(void* buf, size_t count); |
| virtual off64_t seek(off64_t offset, int whence); |
| virtual void close(void); |
| virtual const void* getBuffer(bool aligned); |
| virtual incfs::map_ptr<void> getIncFsBuffer(bool aligned); |
| virtual off64_t getLength(void) const { return mUncompressedLen; } |
| virtual off64_t getRemainingLength(void) const { return mUncompressedLen-mOffset; } |
| virtual int openFileDescriptor(off64_t* /* outStart */, off64_t* /* outLength */) const { return -1; } |
| virtual bool isAllocated(void) const { return mBuf != NULL; } |
| |
| private: |
| off64_t mStart; // offset to start of compressed data |
| off64_t mCompressedLen; // length of the compressed data |
| off64_t mUncompressedLen; // length of the uncompressed data |
| off64_t mOffset; // current offset, 0 == start of uncomp data |
| int mFd; // for file input |
| |
| class StreamingZipInflater* mZipInflater; // for streaming large compressed assets |
| unsigned char* mBuf; // for getBuffer() |
| std::optional<incfs::IncFsFileMap> mMap; // for memory-mapped input |
| }; |
| |
| // need: shared mmap version? |
| |
| }; // namespace android |
| |
| #endif // __LIBS_ASSET_H |