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     FileSystem(const char *name = NULL);
00054     virtual ~FileSystem() {}
00055 
00056     /** Mounts a filesystem to a block device
00057      *
00058      *  @param bd       BlockDevice to mount to
00059      *  @return         0 on success, negative error code on failure
00060      */
00061     virtual int mount(BlockDevice *bd) = 0;
00062 
00063     /** Unmounts a filesystem from the underlying block device
00064      *
00065      *  @return         0 on success, negative error code on failure
00066      */
00067     virtual int unmount() = 0;
00068 
00069     /** Remove a file from the filesystem.
00070      *
00071      *  @param path     The name of the file to remove.
00072      *  @return         0 on success, negative error code on failure
00073      */
00074     virtual int remove(const char *path);
00075 
00076     /** Rename a file in the filesystem.
00077      *
00078      *  @param path     The name of the file to rename.
00079      *  @param newpath  The name to rename it to
00080      *  @return         0 on success, negative error code on failure
00081      */
00082     virtual int rename(const char *path, const char *newpath);
00083 
00084     /** Store information about the file in a stat structure
00085      *
00086      *  @param path     The name of the file to find information about
00087      *  @param st       The stat buffer to write to
00088      *  @return         0 on success, negative error code on failure
00089      */
00090     virtual int stat(const char *path, struct stat *st);
00091 
00092     /** Create a directory in the filesystem.
00093      *
00094      *  @param path     The name of the directory to create.
00095      *  @param mode     The permissions with which to create the directory
00096      *  @return         0 on success, negative error code on failure
00097      */
00098     virtual int mkdir(const char *path, mode_t mode);
00099 
00100 protected:
00101     friend class File;
00102     friend class Dir;
00103 
00104     /** Open a file on the filesystem
00105      *
00106      *  @param file     Destination for the handle to a newly created file
00107      *  @param path     The name of the file to open
00108      *  @param flags    The flags to open the file in, one of O_RDONLY, O_WRONLY, O_RDWR,
00109      *                  bitwise or'd with one of O_CREAT, O_TRUNC, O_APPEND
00110      *  @return         0 on success, negative error code on failure
00111      */
00112     virtual int file_open(fs_file_t *file, const char *path, int flags) = 0;
00113 
00114     /** Close a file
00115      *
00116      *  @param file     File handle
00117      *  return          0 on success, negative error code on failure
00118      */
00119     virtual int file_close(fs_file_t file) = 0;
00120 
00121     /** Read the contents of a file into a buffer
00122      *
00123      *  @param file     File handle
00124      *  @param buffer   The buffer to read in to
00125      *  @param size     The number of bytes to read
00126      *  @return         The number of bytes read, 0 at end of file, negative error on failure
00127      */
00128     virtual ssize_t file_read(fs_file_t file, void *buffer, size_t size) = 0;
00129 
00130     /** Write the contents of a buffer to a file
00131      *
00132      *  @param file     File handle
00133      *  @param buffer   The buffer to write from
00134      *  @param size     The number of bytes to write 
00135      *  @return         The number of bytes written, negative error on failure
00136      */
00137     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t size) = 0;
00138 
00139     /** Flush any buffers associated with the file
00140      *
00141      *  @param file     File handle
00142      *  @return         0 on success, negative error code on failure
00143      */
00144     virtual int file_sync(fs_file_t file);
00145 
00146     /** Check if the file in an interactive terminal device
00147      *  If so, line buffered behaviour is used by default
00148      *
00149      *  @param file     File handle
00150      *  @return         True if the file is a terminal
00151      */
00152     virtual int file_isatty(fs_file_t file);
00153 
00154     /** Move the file position to a given offset from from a given location
00155      *
00156      *  @param file     File handle
00157      *  @param offset   The offset from whence to move to
00158      *  @param whence   The start of where to seek
00159      *      SEEK_SET to start from beginning of file,
00160      *      SEEK_CUR to start from current position in file,
00161      *      SEEK_END to start from end of file
00162      *  @return         The new offset of the file
00163      */
00164     virtual off_t file_seek(fs_file_t file, off_t offset, int whence) = 0;
00165 
00166     /** Get the file position of the file
00167      *
00168      *  @param file     File handle
00169      *  @return         The current offset in the file
00170      */
00171     virtual off_t file_tell(fs_file_t file);
00172 
00173     /** Rewind the file position to the beginning of the file
00174      *
00175      *  @param file     File handle
00176      *  @note This is equivalent to file_seek(file, 0, FS_SEEK_SET)
00177      */
00178     virtual void file_rewind(fs_file_t file);
00179 
00180     /** Get the size of the file
00181      *
00182      *  @param file     File handle
00183      *  @return         Size of the file in bytes
00184      */
00185     virtual off_t file_size(fs_file_t file);
00186 
00187     /** Open a directory on the filesystem
00188      *
00189      *  @param dir      Destination for the handle to the directory
00190      *  @param path     Name of the directory to open
00191      *  @return         0 on success, negative error code on failure
00192      */
00193     virtual int dir_open(fs_dir_t *dir, const char *path);
00194 
00195     /** Close a directory
00196      *
00197      *  @param dir      Dir handle
00198      *  return          0 on success, negative error code on failure
00199      */
00200     virtual int dir_close(fs_dir_t dir);
00201 
00202     /** Read the next directory entry
00203      *
00204      *  @param dir      Dir handle
00205      *  @param ent      The directory entry to fill out
00206      *  @return         1 on reading a filename, 0 at end of directory, negative error on failure
00207      */
00208     virtual ssize_t dir_read(fs_dir_t dir, struct dirent *ent);
00209 
00210     /** Set the current position of the directory
00211      *
00212      *  @param dir      Dir handle
00213      *  @param offset   Offset of the location to seek to,
00214      *                  must be a value returned from dir_tell
00215      */
00216     virtual void dir_seek(fs_dir_t dir, off_t offset);
00217 
00218     /** Get the current position of the directory
00219      *
00220      *  @param dir      Dir handle
00221      *  @return         Position of the directory that can be passed to dir_rewind
00222      */
00223     virtual off_t dir_tell(fs_dir_t dir);
00224 
00225     /** Rewind the current position to the beginning of the directory
00226      *
00227      *  @param dir      Dir handle
00228      */
00229     virtual void dir_rewind(fs_dir_t dir);
00230 
00231     /** Get the sizeof the directory 
00232      *
00233      *  @param dir      Dir handle
00234      *  @return         Number of files in the directory
00235      */
00236     virtual size_t dir_size(fs_dir_t dir);
00237 
00238 protected:
00239     // Hooks for FileSystemHandle
00240     virtual int open(FileHandle **file, const char *path, int flags);
00241     virtual int open(DirHandle **dir, const char *path);
00242 };
00243 
00244 
00245 /** @}*/
00246 } // namespace mbed
00247 
00248 #endif
00249