frameworks/base refactoring.

/*

 * 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 <utils/Compat.h>

#include <utils/Errors.h>

#include <utils/FileMap.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);

    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.

     */

    virtual const void* getBuffer(bool wordAligned) = 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(); }

protected:

    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:

    /* these operations are not implemented */

    Asset(const Asset& src);

    Asset& operator=(const Asset& src);

    /* AssetManager needs access to our "create" functions */

    friend class AssetManager;

    /*

     * 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 FileMap.

     */

    static Asset* createFromUncompressedMap(FileMap* dataMap, AccessMode mode);

    /*

     * Create the asset from a memory-mapped file segment with compressed

     * data.  "method" is a Zip archive compression method constant.

     *

     * The asset takes ownership of the FileMap.

     */

    static Asset* createFromCompressedMap(FileMap* dataMap, int method,

        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);

    virtual ~_FileAsset(void);

    /*

     * 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".

     */

    status_t openChunk(FileMap* dataMap);

    /*

     * 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 wordAligned);

    virtual off64_t getLength(void) const { return mLength; }

    virtual off64_t getRemainingLength(void) const { return mLength-mOffset; }

    virtual int openFileDescriptor(off64_t* outStart, off64_t* outLength) const;

    virtual bool isAllocated(void) const { return mBuf != NULL; }

private:

    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

    /*

     * 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 };

    FileMap*    mMap;           // for memory map

    unsigned char* mBuf;        // for read

    const void* ensureAlignment(FileMap* 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(FileMap* dataMap, int compressionMethod,

        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 wordAligned);

    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

    FileMap*    mMap;           // for memory-mapped input

    int         mFd;            // for file input

    class StreamingZipInflater* mZipInflater;  // for streaming large compressed assets

    unsigned char*  mBuf;       // for getBuffer()

};

// need: shared mmap version?

}; // namespace android

#endif // __LIBS_ASSET_H

/*

 * 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.

 */

//

// Access a chunk of the asset hierarchy as if it were a single directory.

//

#ifndef __LIBS_ASSETDIR_H

#define __LIBS_ASSETDIR_H

#include <utils/String8.h>

#include <utils/Vector.h>

#include <utils/SortedVector.h>

#include <utils/misc.h>

#include <sys/types.h>

namespace android {

/*

 * This provides vector-style access to a directory.  We do this rather

 * than modeling opendir/readdir access because it's simpler and the

 * nature of the operation requires us to have all data on hand anyway.

 *

 * The list of files will be sorted in ascending order by ASCII value.

 *

 * The contents are populated by our friend, the AssetManager.

 */

class AssetDir {

public:

    AssetDir(void)

        : mFileInfo(NULL)

        {}

    virtual ~AssetDir(void) {

        delete mFileInfo;

    }

    /*

     * Vector-style access.

     */

    size_t getFileCount(void) { return mFileInfo->size(); }

    const String8& getFileName(int idx) {

        return mFileInfo->itemAt(idx).getFileName();

    }

    const String8& getSourceName(int idx) {

        return mFileInfo->itemAt(idx).getSourceName();

    }

    /*

     * Get the type of a file (usually regular or directory).

     */

    FileType getFileType(int idx) {

        return mFileInfo->itemAt(idx).getFileType();

    }

private:

    /* these operations are not implemented */

    AssetDir(const AssetDir& src);

    const AssetDir& operator=(const AssetDir& src);

    friend class AssetManager;

    /*

     * This holds information about files in the asset hierarchy.

     */

    class FileInfo {

    public:

        FileInfo(void) {}

        FileInfo(const String8& path)      // useful for e.g. svect.indexOf

            : mFileName(path), mFileType(kFileTypeUnknown)

            {}

        ~FileInfo(void) {}

        FileInfo(const FileInfo& src) {

            copyMembers(src);

        }

        const FileInfo& operator= (const FileInfo& src) {

            if (this != &src)

                copyMembers(src);

            return *this;

        }

        void copyMembers(const FileInfo& src) {

            mFileName = src.mFileName;

            mFileType = src.mFileType;

            mSourceName = src.mSourceName;

        }

        /* need this for SortedVector; must compare only on file name */

        bool operator< (const FileInfo& rhs) const {

            return mFileName < rhs.mFileName;

        }

        /* used by AssetManager */

        bool operator== (const FileInfo& rhs) const {

            return mFileName == rhs.mFileName;

        }

        void set(const String8& path, FileType type) {

            mFileName = path;

            mFileType = type;

        }

        const String8& getFileName(void) const { return mFileName; }

        void setFileName(const String8& path) { mFileName = path; }

        FileType getFileType(void) const { return mFileType; }

        void setFileType(FileType type) { mFileType = type; }

        const String8& getSourceName(void) const { return mSourceName; }

        void setSourceName(const String8& path) { mSourceName = path; }

        /*

         * Handy utility for finding an entry in a sorted vector of FileInfo.

         * Returns the index of the matching entry, or -1 if none found.

         */

        static int findEntry(const SortedVector<FileInfo>* pVector,

            const String8& fileName);

    private:

        String8    mFileName;      // filename only

        FileType    mFileType;      // regular, directory, etc

        String8    mSourceName;    // currently debug-only

    };

    /* AssetManager uses this to initialize us */

    void setFileList(SortedVector<FileInfo>* list) { mFileInfo = list; }

    SortedVector<FileInfo>* mFileInfo;

};

}; // namespace android

#endif // __LIBS_ASSETDIR_H