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 "features/storage/blockdevice/BlockDevice.h"
00027 
00028 namespace mbed {
00029 /** \addtogroup file system */
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 file system object. Provides file system 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 
00052     /** File system lifetime.
00053      *
00054      *  @param name       Name to add file system to tree as.
00055      */
00056     FileSystem(const char *name = NULL);
00057     virtual ~FileSystem() {}
00058 
00059     /** Return the default file system.
00060      *
00061      * Returns the default file system based on the default block device configuration.
00062      * Use the components in target.json or application config to change
00063      * the default block device and affect the default filesystem.
00064      * SD block device => FAT filesystem
00065      * QSPIF, SPIF, DATAFLASH or FLAHIAP block device => LITTLE filesystem
00066      *
00067      * An application can override all target settings by implementing
00068      * FileSystem::get_default_instance() - the default
00069      * definition is weak, and calls get_target_default_instance().
00070      */
00071     static FileSystem *get_default_instance();
00072 
00073     /** Mount a file system to a block device.
00074      *
00075      *  @param bd       Block device to mount to.
00076      *  @return         0 on success, negative error code on failure.
00077      */
00078     virtual int mount(BlockDevice *bd) = 0;
00079 
00080     /** Unmount a file system from the underlying block device.
00081      *
00082      *  @return         0 on success, negative error code on failure.
00083      */
00084     virtual int unmount() = 0;
00085 
00086     /** Reformat a file system. Results in an empty and mounted file system.
00087      *
00088      *  @param bd       Block device to reformat and mount. If NULL, the mounted
00089      *                  Block device is used.
00090      *                  Note: If mount fails, bd must be provided.
00091      *                  Default: NULL
00092      *  @return         0 on success, negative error code on failure.
00093      */
00094     virtual int reformat(BlockDevice *bd = NULL);
00095 
00096     /** Remove a file from the file system.
00097      *
00098      *  @param path     The name of the file to remove.
00099      *  @return         0 on success, negative error code on failure.
00100      */
00101     virtual int remove(const char *path);
00102 
00103     /** Rename a file in the file system.
00104      *
00105      *  @param path     The existing name of the file to rename.
00106      *  @param newpath  The new name of the file.
00107      *  @return         0 on success, negative error code on failure.
00108      */
00109     virtual int rename(const char *path, const char *newpath);
00110 
00111     /** Store information about the file in a stat structure.
00112      *
00113      *  @param path     The name of the file to find information about.
00114      *  @param st       The stat buffer to write to.
00115      *  @return         0 on success, negative error code on failure.
00116      */
00117     virtual int stat(const char *path, struct stat *st);
00118 
00119     /** Create a directory in the file system.
00120      *
00121      *  @param path     The name of the directory to create.
00122      *  @param mode     The permissions with which to create the directory.
00123      *  @return         0 on success, negative error code on failure.
00124      */
00125     virtual int mkdir(const char *path, mode_t mode);
00126 
00127     /** Store information about the mounted file system in a statvfs structure.
00128      *
00129      *  @param path     The name of the file to find information about.
00130      *  @param buf      The stat buffer to write to.
00131      *  @return         0 on success, negative error code on failure.
00132      */
00133     virtual int statvfs(const char *path, struct statvfs *buf);
00134 
00135 protected:
00136     friend class File;
00137     friend class Dir;
00138 
00139 #if !(DOXYGEN_ONLY)
00140     /** Open a file on the file system.
00141      *
00142      *  @param file     Destination of the newly created handle to the referenced file.
00143      *  @param path     The name of the file to open.
00144      *  @param flags    The flags that trigger opening of the file. These flags are O_RDONLY, O_WRONLY, and O_RDWR,
00145      *                  with an O_CREAT, O_TRUNC, or O_APPEND bitwise OR operator.
00146      *  @return         0 on success, negative error code on failure.
00147      */
00148     virtual int file_open(fs_file_t *file, const char *path, int flags) = 0;
00149 
00150     /** Close a file.
00151      *
00152      *  @param file     File handle.
00153      *  return          0 on success, negative error code on failure.
00154      */
00155     virtual int file_close(fs_file_t file) = 0;
00156 
00157     /** Read the contents of a file into a buffer.
00158      *
00159      *  @param file     File handle.
00160      *  @param buffer   The buffer to read in to.
00161      *  @param size     The number of bytes to read.
00162      *  @return         The number of bytes read, 0 at the end of the file, negative error on failure.
00163      */
00164     virtual ssize_t file_read(fs_file_t file, void *buffer, size_t size) = 0;
00165 
00166     /** Write the contents of a buffer to a file.
00167      *
00168      *  @param file     File handle.
00169      *  @param buffer   The buffer to write from.
00170      *  @param size     The number of bytes to write.
00171      *  @return         The number of bytes written, negative error on failure.
00172      */
00173     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t size) = 0;
00174 
00175     /** Flush any buffers associated with the file.
00176      *
00177      *  @param file     File handle.
00178      *  @return         0 on success, negative error code on failure.
00179      */
00180     virtual int file_sync(fs_file_t file);
00181 
00182     /** Check whether the file is an interactive terminal device.
00183      *  If so, line buffered behavior is used by default.
00184      *
00185      *  @param file     File handle.
00186      *  @return         True if the file is a terminal.
00187      */
00188     virtual int file_isatty(fs_file_t file);
00189 
00190     /** Move the file position to a given offset from a given location.
00191      *
00192      *  @param file     File handle.
00193      *  @param offset   The offset from whence to move to.
00194      *  @param whence   The start of where to seek.
00195      *      SEEK_SET to start from the beginning of the file,
00196      *      SEEK_CUR to start from the current position in the file,
00197      *      SEEK_END to start from the end of the file.
00198      *  @return         The new offset of the file
00199      */
00200     virtual off_t file_seek(fs_file_t file, off_t offset, int whence) = 0;
00201 
00202     /** Get the file position of the file.
00203      *
00204      *  @param file     File handle.
00205      *  @return         The current offset in the file.
00206      */
00207     virtual off_t file_tell(fs_file_t file);
00208 
00209     /** Rewind the file position to the beginning of the file.
00210      *
00211      *  @param file     File handle.
00212      *  @note This is equivalent to file_seek(file, 0, FS_SEEK_SET)
00213      */
00214     virtual void file_rewind(fs_file_t file);
00215 
00216     /** Get the size of the file.
00217      *
00218      *  @param file     File handle.
00219      *  @return         Size of the file in bytes.
00220      */
00221     virtual off_t file_size(fs_file_t file);
00222 
00223     /** Truncate or extend a file.
00224      *
00225      * The file's length is set to the specified value. The seek pointer is
00226      * not changed. If the file is extended, the extended area appears as if
00227      * it were zero-filled.
00228      *
00229      *  @param file     File handle.
00230      *  @param length   The requested new length for the file.
00231      *
00232      *  @return         0 on success, negative error code on failure.
00233      */
00234     virtual int file_truncate(fs_file_t file, off_t length);
00235 
00236     /** Open a directory on the file system.
00237      *
00238      *  @param dir      Destination for the handle to the directory.
00239      *  @param path     Name of the directory to open.
00240      *  @return         0 on success, negative error code on failure.
00241      */
00242     virtual int dir_open(fs_dir_t *dir, const char *path);
00243 
00244     /** Close a directory.
00245      *
00246      *  @param dir      Dir handle.
00247      *  @return         0 on success, negative error code on failure.
00248      */
00249     virtual int dir_close(fs_dir_t dir);
00250 
00251     /** Read the next directory entry.
00252      *
00253      *  @param dir      Dir handle.
00254      *  @param ent      The directory entry to fill out.
00255      *  @return         1 on reading a filename, 0 at the end of the directory, negative error on failure.
00256      */
00257     virtual ssize_t dir_read(fs_dir_t dir, struct dirent *ent);
00258 
00259     /** Set the current position of the directory.
00260      *
00261      *  @param dir      Dir handle.
00262      *  @param offset   Offset of the location to seek to,
00263      *                  must be a value returned from dir_tell.
00264      */
00265     virtual void dir_seek(fs_dir_t dir, off_t offset);
00266 
00267     /** Get the current position of the directory.
00268      *
00269      *  @param dir      Dir handle.
00270      *  @return         Directory position, which can be passed to dir_rewind.
00271      */
00272     virtual off_t dir_tell(fs_dir_t dir);
00273 
00274     /** Rewind the current position to the beginning of the directory.
00275      *
00276      *  @param dir      Dir handle.
00277      */
00278     virtual void dir_rewind(fs_dir_t dir);
00279 
00280     /** Get the size of the directory.
00281      *
00282      *  @param dir      Dir handle.
00283      *  @return         Number of files in the directory.
00284      */
00285     virtual size_t dir_size(fs_dir_t dir);
00286 #endif //!defined(DOXYGEN_ONLY)
00287 
00288 protected:
00289     // Hooks for file systemHandle
00290     virtual int open(FileHandle **file, const char *path, int flags);
00291     virtual int open(DirHandle **dir, const char *path);
00292 };
00293 
00294 
00295 /** @}*/
00296 } // namespace mbed
00297 
00298 #endif