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 "drivers/FileBase.h"
00023 #include "BlockDevice.h"
00024 
00025 namespace mbed {
00026 /** \addtogroup filesystem */
00027 /** @{*/
00028 
00029 
00030 // Opaque pointer representing files and directories
00031 typedef void *fs_file_t;
00032 typedef void *fs_dir_t;
00033 
00034 /** A filesystem-like object is one that can be used to open files
00035  *  though it by fopen("/name/filename", flags)
00036  *
00037  *  Implementations must define at least open (the default definitions
00038  *  of the rest of the functions just return error values).
00039  *
00040  * @Note Synchronization level: Set by subclass
00041  */
00042 class FileSystem : public FileBase {
00043 public:
00044     /** FileSystem lifetime
00045      */
00046     FileSystem(const char *name = NULL);
00047     virtual ~FileSystem() {}
00048 
00049     /** Mounts a filesystem to a block device
00050      *
00051      *  @param bd       BlockDevice to mount to
00052      *  @return         0 on success, negative error code on failure
00053      */
00054     virtual int mount(BlockDevice *bd) = 0;
00055 
00056     /** Unmounts a filesystem from the underlying block device
00057      *
00058      *  @return         0 on success, negative error code on failure
00059      */
00060     virtual int unmount() = 0;
00061 
00062     /** Remove a file from the filesystem.
00063      *
00064      *  @param path     The name of the file to remove.
00065      *  @return         0 on success, negative error code on failure
00066      */
00067     virtual int remove(const char *path) = 0;
00068 
00069     /** Rename a file in the filesystem.
00070      *
00071      *  @param path     The name of the file to rename.
00072      *  @param newpath  The name to rename it to
00073      *  @return         0 on success, negative error code on failure
00074      */
00075     virtual int rename(const char *path, const char *newpath) = 0;
00076 
00077     /** Store information about the file in a stat structure
00078      *
00079      *  @param path     The name of the file to find information about
00080      *  @param st       The stat buffer to write to
00081      *  @return         0 on success, negative error code on failure
00082      */
00083     virtual int stat(const char *path, struct stat *st) = 0;
00084 
00085     /** Create a directory in the filesystem.
00086      *
00087      *  @param path     The name of the directory to create.
00088      *  @param mode     The permissions with which to create the directory
00089      *  @return         0 on success, negative error code on failure
00090      */
00091     virtual int mkdir(const char *path, mode_t mode);
00092 
00093 protected:
00094     friend class File;
00095     friend class Dir;
00096 
00097     /** Open a file on the filesystem
00098      *
00099      *  @param file     Destination for the handle to a newly created file
00100      *  @param path     The name of the file to open
00101      *  @param flags    The flags to open the file in, one of O_RDONLY, O_WRONLY, O_RDWR,
00102      *                  bitwise or'd with one of O_CREAT, O_TRUNC, O_APPEND
00103      *  @return         0 on success, negative error code on failure
00104      */
00105     virtual int file_open(fs_file_t *file, const char *path, int flags) = 0;
00106 
00107     /** Close a file
00108      *
00109      *  @param file     File handle
00110      *  return          0 on success, negative error code on failure
00111      */
00112     virtual int file_close(fs_file_t file) = 0;
00113 
00114     /** Read the contents of a file into a buffer
00115      *
00116      *  @param file     File handle
00117      *  @param buffer   The buffer to read in to
00118      *  @param size     The number of bytes to read
00119      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00120      */
00121     virtual ssize_t file_read(fs_file_t file, void *buffer, size_t len) = 0;
00122 
00123     /** Write the contents of a buffer to a file
00124      *
00125      *  @param file     File handle
00126      *  @param buffer   The buffer to write from
00127      *  @param size     The number of bytes to write 
00128      *  @return         The number of bytes written, negative error on failure
00129      */
00130     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t len) = 0;
00131 
00132     /** Flush any buffers associated with the file
00133      *
00134      *  @param file     File handle
00135      *  @return         0 on success, negative error code on failure
00136      */
00137     virtual int file_sync(fs_file_t file);
00138 
00139     /** Check if the file in an interactive terminal device
00140      *  If so, line buffered behaviour is used by default
00141      *
00142      *  @param file     File handle
00143      *  @return         True if the file is a terminal
00144      */
00145     virtual int file_isatty(fs_file_t file);
00146 
00147     /** Move the file position to a given offset from from a given location
00148      *
00149      *  @param file     File handle
00150      *  @param offset   The offset from whence to move to
00151      *  @param whence   The start of where to seek
00152      *      SEEK_SET to start from beginning of file,
00153      *      SEEK_CUR to start from current position in file,
00154      *      SEEK_END to start from end of file
00155      *  @return         The new offset of the file
00156      */
00157     virtual off_t file_seek(fs_file_t file, off_t offset, int whence) = 0;
00158 
00159     /** Get the file position of the file
00160      *
00161      *  @param file     File handle
00162      *  @return         The current offset in the file
00163      */
00164     virtual off_t file_tell(fs_file_t file);
00165 
00166     /** Rewind the file position to the beginning of the file
00167      *
00168      *  @param file     File handle
00169      *  @note This is equivalent to file_seek(file, 0, FS_SEEK_SET)
00170      */
00171     virtual void file_rewind(fs_file_t file);
00172 
00173     /** Get the size of the file
00174      *
00175      *  @param file     File handle
00176      *  @return         Size of the file in bytes
00177      */
00178     virtual size_t file_size(fs_file_t file);
00179 
00180     /** Open a directory on the filesystem
00181      *
00182      *  @param dir      Destination for the handle to the directory
00183      *  @param path     Name of the directory to open
00184      *  @return         0 on success, negative error code on failure
00185      */
00186     virtual int dir_open(fs_dir_t *dir, const char *path);
00187 
00188     /** Close a directory
00189      *
00190      *  @param dir      Dir handle
00191      *  return          0 on success, negative error code on failure
00192      */
00193     virtual int dir_close(fs_dir_t dir);
00194 
00195     /** Read the next directory entry
00196      *
00197      *  @param dir      Dir handle
00198      *  @param ent      The directory entry to fill out
00199      *  @return         1 on reading a filename, 0 at end of directory, negative error on failure
00200      */
00201     virtual ssize_t dir_read(fs_dir_t dir, struct dirent *ent);
00202 
00203     /** Set the current position of the directory
00204      *
00205      *  @param dir      Dir handle
00206      *  @param offset   Offset of the location to seek to,
00207      *                  must be a value returned from dir_tell
00208      */
00209     virtual void dir_seek(fs_dir_t dir, off_t offset);
00210 
00211     /** Get the current position of the directory
00212      *
00213      *  @param dir      Dir handle
00214      *  @return         Position of the directory that can be passed to dir_rewind
00215      */
00216     virtual off_t dir_tell(fs_dir_t dir);
00217 
00218     /** Rewind the current position to the beginning of the directory
00219      *
00220      *  @param dir      Dir handle
00221      */
00222     virtual void dir_rewind(fs_dir_t dir);
00223 
00224     /** Get the sizeof the directory 
00225      *
00226      *  @param dir      Dir handle
00227      *  @return         Number of files in the directory
00228      */
00229     virtual size_t dir_size(fs_dir_t dir);
00230 };
00231 
00232 
00233 /** @}*/
00234 } // namespace mbed
00235 
00236 #endif