frameworks/base refactoring.

step 2: move libutils headers to their new home: androidfw

Change-Id: I14624ba23db92a81f2cb929f104386e1fab293ef

1 files changed, 322 insertions, 0 deletions

diff --git a/include/androidfw/Asset.h b/include/androidfw/Asset.h
new file mode 100644
index 000000000000..1fe0e063c886
--- /dev/null
+++ b/include/androidfw/Asset.h
@@ -0,0 +1,322 @@
+/*
+ * 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