mbed-os/LittleFileSystem.h

284 lines
11 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2006-2012 ARM Limited
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef MBED_LFSFILESYSTEM_H
#define MBED_LFSFILESYSTEM_H
#include "FileSystem.h"
#include "BlockDevice.h"
#include "PlatformMutex.h"
extern "C" {
#include "lfs.h"
}
using namespace mbed;
/**
* LittleFileSystem, a little filesystem
*/
class LittleFileSystem : public FileSystem {
public:
/** Lifetime of the LittleFileSystem
*
* @param name Name to add filesystem to tree as
* @param bd BlockDevice to mount, may be passed instead to mount call
* @param read_size
* Minimum size of a block read. This determines the size of read buffers.
* This may be larger than the physical read size to improve performance
* by caching more of the block device.
* @param prog_size
* Minimum size of a block program. This determines the size of program
* buffers. This may be larger than the physical program size to improve
* performance by caching more of the block device.
* @param block_size
* Size of an erasable block. This does not impact ram consumption and
* may be larger than the physical erase size. However, this should be
* kept small as each file currently takes up an entire block.
* @param lookahead
* Number of blocks to lookahead during block allocation. A larger
* lookahead reduces the number of passes required to allocate a block.
* The lookahead buffer requires only 1 bit per block so it can be quite
* large with little ram impact. Should be a multiple of 32.
*/
LittleFileSystem(const char *name=NULL, BlockDevice *bd=NULL,
lfs_size_t read_size=MBED_LFS_READ_SIZE,
lfs_size_t prog_size=MBED_LFS_PROG_SIZE,
lfs_size_t block_size=MBED_LFS_BLOCK_SIZE,
lfs_size_t lookahead=MBED_LFS_LOOKAHEAD);
virtual ~LittleFileSystem();
/** Formats a block device with the LittleFileSystem
*
* The block device to format should be mounted when this function is called.
*
* @param bd This is the block device that will be formated.
* @param read_size
* Minimum size of a block read. This determines the size of read buffers.
* This may be larger than the physical read size to improve performance
* by caching more of the block device.
* @param prog_size
* Minimum size of a block program. This determines the size of program
* buffers. This may be larger than the physical program size to improve
* performance by caching more of the block device.
* @param block_size
* Size of an erasable block. This does not impact ram consumption and
* may be larger than the physical erase size. However, this should be
* kept small as each file currently takes up an entire block.
* @param lookahead
* Number of blocks to lookahead during block allocation. A larger
* lookahead reduces the number of passes required to allocate a block.
* The lookahead buffer requires only 1 bit per block so it can be quite
* large with little ram impact. Should be a multiple of 32.
*/
static int format(BlockDevice *bd,
lfs_size_t read_size=MBED_LFS_READ_SIZE,
lfs_size_t prog_size=MBED_LFS_PROG_SIZE,
lfs_size_t block_size=MBED_LFS_BLOCK_SIZE,
lfs_size_t lookahead=MBED_LFS_LOOKAHEAD);
/** Mounts a filesystem to a block device
*
* @param bd BlockDevice to mount to
* @return 0 on success, negative error code on failure
*/
virtual int mount(BlockDevice *bd);
/** Unmounts a filesystem from the underlying block device
*
* @return 0 on success, negative error code on failure
*/
virtual int unmount();
/** Reformats a filesystem, results in an empty and mounted filesystem
*
* @param bd
* BlockDevice to reformat and mount. If NULL, the mounted
* block device will be used.
* Note: if mount fails, bd must be provided.
* Default: NULL
*
* @return 0 on success, negative error code on failure
*/
virtual int reformat(BlockDevice *bd);
/** Remove a file from the filesystem.
*
* @param path The name of the file to remove.
* @return 0 on success, negative error code on failure
*/
virtual int remove(const char *path);
/** Rename a file in the filesystem.
*
* @param path The name of the file to rename.
* @param newpath The name to rename it to
* @return 0 on success, negative error code on failure
*/
virtual int rename(const char *path, const char *newpath);
/** Store information about the file in a stat structure
*
* @param path The name of the file to find information about
* @param st The stat buffer to write to
* @return 0 on success, negative error code on failure
*/
virtual int stat(const char *path, struct stat *st);
/** Create a directory in the filesystem.
*
* @param path The name of the directory to create.
* @param mode The permissions with which to create the directory
* @return 0 on success, negative error code on failure
*/
virtual int mkdir(const char *path, mode_t mode);
protected:
/** Open a file on the filesystem
*
* @param file Destination for the handle to a newly created file
* @param path The name of the file to open
* @param flags The flags to open the file in, one of O_RDONLY, O_WRONLY, O_RDWR,
* bitwise or'd with one of O_CREAT, O_TRUNC, O_APPEND
* @return 0 on success, negative error code on failure
*/
virtual int file_open(fs_file_t *file, const char *path, int flags);
/** Close a file
*
* @param file File handle
* return 0 on success, negative error code on failure
*/
virtual int file_close(fs_file_t file);
/** Read the contents of a file into a buffer
*
* @param file File handle
* @param buffer The buffer to read in to
* @param size The number of bytes to read
* @return The number of bytes read, 0 at end of file, negative error on failure
*/
virtual ssize_t file_read(fs_file_t file, void *buffer, size_t len);
/** Write the contents of a buffer to a file
*
* @param file File handle
* @param buffer The buffer to write from
* @param size The number of bytes to write
* @return The number of bytes written, negative error on failure
*/
virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t len);
/** Flush any buffers associated with the file
*
* @param file File handle
* @return 0 on success, negative error code on failure
*/
virtual int file_sync(fs_file_t file);
/** Move the file position to a given offset from from a given location
*
* @param file File handle
* @param offset The offset from whence to move to
* @param whence The start of where to seek
* SEEK_SET to start from beginning of file,
* SEEK_CUR to start from current position in file,
* SEEK_END to start from end of file
* @return The new offset of the file
*/
virtual off_t file_seek(fs_file_t file, off_t offset, int whence);
/** Get the file position of the file
*
* @param file File handle
* @return The current offset in the file
*/
virtual off_t file_tell(fs_file_t file);
/** Get the size of the file
*
* @param file File handle
* @return Size of the file in bytes
*/
virtual off_t file_size(fs_file_t file);
/** Open a directory on the filesystem
*
* @param dir Destination for the handle to the directory
* @param path Name of the directory to open
* @return 0 on success, negative error code on failure
*/
virtual int dir_open(fs_dir_t *dir, const char *path);
/** Close a directory
*
* @param dir Dir handle
* return 0 on success, negative error code on failure
*/
virtual int dir_close(fs_dir_t dir);
/** Read the next directory entry
*
* @param dir Dir handle
* @param ent The directory entry to fill out
* @return 1 on reading a filename, 0 at end of directory, negative error on failure
*/
virtual ssize_t dir_read(fs_dir_t dir, struct dirent *ent);
/** Set the current position of the directory
*
* @param dir Dir handle
* @param offset Offset of the location to seek to,
* must be a value returned from dir_tell
*/
virtual void dir_seek(fs_dir_t dir, off_t offset);
/** Get the current position of the directory
*
* @param dir Dir handle
* @return Position of the directory that can be passed to dir_rewind
*/
virtual off_t dir_tell(fs_dir_t dir);
/** Rewind the current position to the beginning of the directory
*
* @param dir Dir handle
*/
virtual void dir_rewind(fs_dir_t dir);
private:
lfs_t _lfs; // _the actual filesystem
struct lfs_config _config;
BlockDevice *_bd; // the block device
// default parameters
const lfs_size_t _read_size;
const lfs_size_t _prog_size;
const lfs_size_t _block_size;
const lfs_size_t _lookahead;
// thread-safe locking
PlatformMutex _mutex;
};
#endif