FileSystem.h

00001 
00002 /* mbed Microcontroller Library
00003  * Copyright (c) 2006-2013 ARM Limited
00004  *
00005  * Licensed under the Apache License, Version 2.0 (the "License");
00006  * you may not use this file except in compliance with the License.
00007  * You may obtain a copy of the License at
00008  *
00009  *     http://www.apache.org/licenses/LICENSE-2.0
00010  *
00011  * Unless required by applicable law or agreed to in writing, software
00012  * distributed under the License is distributed on an "AS IS" BASIS,
00013  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00014  * See the License for the specific language governing permissions and
00015  * limitations under the License.
00016  */
00017 #ifndef MBED_FILESYSTEM_H
00018 #define MBED_FILESYSTEM_H
00019 
00020 #include "platform/platform.h"
00021 
00022 #include "platform/FileBase.h"
00023 #include "platform/FileHandle.h"
00024 #include "platform/DirHandle.h"
00025 #include "platform/FileSystemLike.h"
00026 #include "BlockDevice.h"
00027 
00028 namespace mbed {
00029 /** \addtogroup filesystem */
00030 /** @{*/
00031 
00032 
00033 // Opaque pointer representing files and directories
00034 typedef void *fs_file_t;
00035 typedef void *fs_dir_t;
00036 
00037 // Predeclared classes
00038 class Dir;
00039 class File;
00040 
00041 /** A filesystem object provides filesystem operations and file operations
00042  *  for the File and Dir classes on a block device.
00043  *
00044  *  Implementations must provide at minimum file operations and mount
00045  *  operations for block devices.
00046  *
00047  * @note Synchronization level: Set by subclass
00048  */
00049 class FileSystem : public FileSystemLike {
00050 public:
00051     /** FileSystem lifetime
00052      *
00053      *  @param name       Name to add filesystem to tree as
00054      */
00055     FileSystem(const char *name = NULL);
00056     virtual ~FileSystem() {}
00057 
00058     /** Mounts a filesystem to a block device
00059      *
00060      *  @param bd       BlockDevice to mount to
00061      *  @return         0 on success, negative error code on failure
00062      */
00063     virtual int mount(BlockDevice *bd) = 0;
00064 
00065     /** Unmounts a filesystem from the underlying block device
00066      *
00067      *  @return         0 on success, negative error code on failure
00068      */
00069     virtual int unmount() = 0;
00070 
00071     /** Reformats a filesystem, results in an empty and mounted filesystem
00072      *
00073      *  @param bd       BlockDevice to reformat and mount. If NULL, the mounted
00074      *                  block device will be used.
00075      *                  Note: if mount fails, bd must be provided.
00076      *                  Default: NULL
00077      *  @return         0 on success, negative error code on failure
00078      */
00079     virtual int reformat(BlockDevice *bd = NULL);
00080 
00081     /** Remove a file from the filesystem.
00082      *
00083      *  @param path     The name of the file to remove.
00084      *  @return         0 on success, negative error code on failure
00085      */
00086     virtual int remove(const char *path);
00087 
00088     /** Rename a file in the filesystem.
00089      *
00090      *  @param path     The name of the file to rename.
00091      *  @param newpath  The name to rename it to
00092      *  @return         0 on success, negative error code on failure
00093      */
00094     virtual int rename(const char *path, const char *newpath);
00095 
00096     /** Store information about the file in a stat structure
00097      *
00098      *  @param path     The name of the file to find information about
00099      *  @param st       The stat buffer to write to
00100      *  @return         0 on success, negative error code on failure
00101      */
00102     virtual int stat(const char *path, struct stat *st);
00103 
00104     /** Create a directory in the filesystem.
00105      *
00106      *  @param path     The name of the directory to create.
00107      *  @param mode     The permissions with which to create the directory
00108      *  @return         0 on success, negative error code on failure
00109      */
00110     virtual int mkdir(const char *path, mode_t mode);
00111 
00112     /** Store information about the mounted filesystem in a statvfs structure
00113      *
00114      *  @param path     The name of the file to find information about
00115      *  @param buf      The stat buffer to write to
00116      *  @return         0 on success, negative error code on failure
00117      */
00118      virtual int statvfs(const char *path, struct statvfs *buf);
00119 
00120 protected:
00121     friend class File;
00122     friend class Dir;
00123 
00124     /** Open a file on the filesystem
00125      *
00126      *  @param file     Destination for the handle to a newly created file
00127      *  @param path     The name of the file to open
00128      *  @param flags    The flags to open the file in, one of O_RDONLY, O_WRONLY, O_RDWR,
00129      *                  bitwise or'd with one of O_CREAT, O_TRUNC, O_APPEND
00130      *  @return         0 on success, negative error code on failure
00131      */
00132     virtual int file_open(fs_file_t *file, const char *path, int flags) = 0;
00133 
00134     /** Close a file
00135      *
00136      *  @param file     File handle
00137      *  @return         0 on success, negative error code on failure
00138      */
00139     virtual int file_close(fs_file_t file) = 0;
00140 
00141     /** Read the contents of a file into a buffer
00142      *
00143      *  @param file     File handle
00144      *  @param buffer   The buffer to read in to
00145      *  @param size     The number of bytes to read
00146      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00147      */
00148     virtual ssize_t file_read(fs_file_t file, void *buffer, size_t size) = 0;
00149 
00150     /** Write the contents of a buffer to a file
00151      *
00152      *  @param file     File handle
00153      *  @param buffer   The buffer to write from
00154      *  @param size     The number of bytes to write
00155      *  @return         The number of bytes written, negative error on failure
00156      */
00157     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t size) = 0;
00158 
00159     /** Flush any buffers associated with the file
00160      *
00161      *  @param file     File handle
00162      *  @return         0 on success, negative error code on failure
00163      */
00164     virtual int file_sync(fs_file_t file);
00165 
00166     /** Check if the file in an interactive terminal device
00167      *  If so, line buffered behaviour is used by default
00168      *
00169      *  @param file     File handle
00170      *  @return         True if the file is a terminal
00171      */
00172     virtual int file_isatty(fs_file_t file);
00173 
00174     /** Move the file position to a given offset from from a given location
00175      *
00176      *  @param file     File handle
00177      *  @param offset   The offset from whence to move to
00178      *  @param whence   The start of where to seek
00179      *      SEEK_SET to start from beginning of file,
00180      *      SEEK_CUR to start from current position in file,
00181      *      SEEK_END to start from end of file
00182      *  @return         The new offset of the file
00183      */
00184     virtual off_t file_seek(fs_file_t file, off_t offset, int whence) = 0;
00185 
00186     /** Get the file position of the file
00187      *
00188      *  @param file     File handle
00189      *  @return         The current offset in the file
00190      */
00191     virtual off_t file_tell(fs_file_t file);
00192 
00193     /** Rewind the file position to the beginning of the file
00194      *
00195      *  @param file     File handle
00196      *  @note This is equivalent to file_seek(file, 0, FS_SEEK_SET)
00197      */
00198     virtual void file_rewind(fs_file_t file);
00199 
00200     /** Get the size of the file
00201      *
00202      *  @param file     File handle
00203      *  @return         Size of the file in bytes
00204      */
00205     virtual off_t file_size(fs_file_t file);
00206 
00207     /** Open a directory on the filesystem
00208      *
00209      *  @param dir      Destination for the handle to the directory
00210      *  @param path     Name of the directory to open
00211      *  @return         0 on success, negative error code on failure
00212      */
00213     virtual int dir_open(fs_dir_t *dir, const char *path);
00214 
00215     /** Close a directory
00216      *
00217      *  @param dir      Dir handle
00218      *  @return         0 on success, negative error code on failure
00219      */
00220     virtual int dir_close(fs_dir_t dir);
00221 
00222     /** Read the next directory entry
00223      *
00224      *  @param dir      Dir handle
00225      *  @param ent      The directory entry to fill out
00226      *  @return         1 on reading a filename, 0 at end of directory, negative error on failure
00227      */
00228     virtual ssize_t dir_read(fs_dir_t dir, struct dirent *ent);
00229 
00230     /** Set the current position of the directory
00231      *
00232      *  @param dir      Dir handle
00233      *  @param offset   Offset of the location to seek to,
00234      *                  must be a value returned from dir_tell
00235      */
00236     virtual void dir_seek(fs_dir_t dir, off_t offset);
00237 
00238     /** Get the current position of the directory
00239      *
00240      *  @param dir      Dir handle
00241      *  @return         Position of the directory that can be passed to dir_rewind
00242      */
00243     virtual off_t dir_tell(fs_dir_t dir);
00244 
00245     /** Rewind the current position to the beginning of the directory
00246      *
00247      *  @param dir      Dir handle
00248      */
00249     virtual void dir_rewind(fs_dir_t dir);
00250 
00251     /** Get the sizeof the directory
00252      *
00253      *  @param dir      Dir handle
00254      *  @return         Number of files in the directory
00255      */
00256     virtual size_t dir_size(fs_dir_t dir);
00257 
00258 protected:
00259     // Hooks for FileSystemHandle
00260     virtual int open(FileHandle **file, const char *path, int flags);
00261     virtual int open(DirHandle **dir, const char *path);
00262 };
00263 
00264 
00265 /** @}*/
00266 } // namespace mbed
00267 
00268 #endif