Mbed OS Reference | FATFileSystem.h Source File

 /* mbed Microcontroller Library
  * Copyright (c) 2006-2020 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 /** \addtogroup storage */
 /** @{*/
 
 #ifndef MBED_FATFILESYSTEM_H
 #define MBED_FATFILESYSTEM_H
 
 #include "filesystem/FileSystem.h"
 #include "blockdevice/BlockDevice.h"
 #include "FileHandle.h"
 #include <stdint.h>
 #include "PlatformMutex.h"
 #include "storage/filesystem/fat/ChaN/ff.h"
 
 namespace mbed {
 
 /**
  * FAT file system based on ChaN's FAT file system library v0.8
  *
  * Synchronization level: Thread safe
  */
 class FATFileSystem : public FileSystem {
 public:
     /** Lifetime of the FAT file system.
      *
      *  @param name     Name of the file system in the tree.
      *  @param bd       Block device to mount. Mounted immediately if not NULL.
      */
     FATFileSystem(const char *name = NULL, BlockDevice *bd = NULL);
     virtual ~FATFileSystem();
 
     /** Format a logical drive, FDISK partitioning rule.
      *
      *  The block device to format should be mounted when this function is called.
      *
      *  @param bd
      *    This is the block device that will be formatted.
      *
      *  @param cluster_size
      *    This is the number of bytes per cluster. A larger cluster size decreases
      *    the overhead of the FAT table, but also increases the minimum file size. The
      *    cluster size must be a multiple of the underlying device's allocation unit
      *    and is currently limited to a max of 32,768 bytes. If the cluster size is set to zero, a cluster size
      *    is determined from the device's allocation unit. Defaults to zero.
      *
      *  @return         0 on success, negative error code on failure.
      */
     static int format(BlockDevice *bd, bd_size_t cluster_size = 0);
 
     /** Mount a file system to a block device.
      *
      *  @param bd       Block device to mount to.
      *  @return         0 on success, negative error code on failure.
      */
     virtual int mount(BlockDevice *bd);
 
     /** Unmount a file system from the underlying block device.
      *
      *  @return         0 on success, negative error code on failure.
      */
     virtual int unmount();
 
     /** Reformat a file system, results in an empty and mounted file system.
      *
      *  @param bd
      *      Block device to reformat and mount. If NULL, the mounted
      *      Block device is used.
      *      Note: If mount fails, bd must be provided.
      *      Default: NULL
      *
      *  @param allocation_unit
      *      This is the number of bytes per cluster size. The valid value is N
      *      times the sector size. N is a power of 2, from 1 to 128, for the FAT
      *      volume, and up to 16MiB for the exFAT volume. If zero is given,
      *      the default allocation unit size is selected by the underlying
      *      file system, which depends on the volume size.
      *
      *  @return         0 on success, negative error code on failure.
      */
     virtual int reformat(BlockDevice *bd, int allocation_unit);
 
     /** Reformat a file system, results in an empty and mounted file system.
      *
      *  @param bd       Block device to reformat and mount. If NULL, the mounted
      *                  Block device is 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 = NULL)
     {
         // Required for virtual inheritance shenanigans.
         return reformat(bd, 0);
     }
 
     /** Remove a file from the file system.
      *
      *  @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 file system.
      *
      *  @param path     The current name of the file to rename.
      *  @param newpath  The new name of the file.
      *  @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 store 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 file system.
      *
      *  @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);
 
     /** Store information about the mounted file system in a statvfs structure.
      *
      *  @param path     The name of the file to store information about.
      *  @param buf      The stat buffer to write to.
      *  @return         0 on success, negative error code on failure.
      */
     virtual int statvfs(const char *path, struct statvfs *buf);
 
 protected:
 #if !(DOXYGEN_ONLY)
     /** Open a file on the file system.
      *
      *  @param file     Destination for the handle to a newly created file.
      *  @param path     The name of the file to open.
      *  @param flags    The flags that trigger opening of the file. These flags are O_RDONLY, O_WRONLY, and O_RDWR,
      *                  with an O_CREAT, O_TRUNC, or O_APPEND bitwise OR operator.
      *  @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 into.
      *  @param len      The number of bytes to read.
      *  @return         The number of bytes read; 0 at the end of the 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 len      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 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 the beginning of the file,
      *      SEEK_CUR to start from the current position in the file,
      *      SEEK_END to start from the end of the 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);
 
     /** Truncate or extend a file.
      *
      * The file's length is set to the specified value. The seek pointer is
      * not changed. If the file is extended, the extended area appears as if
      * it were zero-filled.
      *
      *  @param file     File handle.
      *  @param length   The requested new length for the file.
      *
      *  @return         0 on success, negative error code on failure.
      */
     virtual int file_truncate(mbed::fs_file_t file, off_t length);
 
     /** Open a directory on the file system.
      *
      *  @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 the end of the 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 by 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         Directory position, which 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);
 #endif //!(DOXYGEN_ONLY)
 
 private:
     FATFS _fs; // Work area (file system object) for logical drive.
     char _fsid[sizeof("0:")];
     int _id;
 
 protected:
     virtual void lock();
     virtual void unlock();
     virtual int mount(BlockDevice *bd, bool mount);
 };
 
 } // namespace mbed
 
 // Added "using" for backwards compatibility.
 #ifndef MBED_NO_GLOBAL_USING_DIRECTIVE
 using mbed::FATFileSystem;
 #endif
 
 #endif
 
 /** @}*/
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