Diff: mbed-os/features/filesystem/littlefs/littlefs/lfs.h

Revision:

0:02dd72d1d465

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed-os/features/filesystem/littlefs/littlefs/lfs.h	Tue Apr 24 11:45:18 2018 +0000
@@ -0,0 +1,478 @@
+/*
+ * The little filesystem
+ *
+ * Copyright (c) 2017 ARM Limited
+ *
+ * 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.
+ */
+#ifndef LFS_H
+#define LFS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+
+/// Version info ///
+
+// Software library version
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS_VERSION 0x00010003
+#define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
+#define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >>  0))
+
+// Version of On-disk data structures
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS_DISK_VERSION 0x00010001
+#define LFS_DISK_VERSION_MAJOR (0xffff & (LFS_DISK_VERSION >> 16))
+#define LFS_DISK_VERSION_MINOR (0xffff & (LFS_DISK_VERSION >>  0))
+
+
+/// Definitions ///
+
+// Type definitions
+typedef uint32_t lfs_size_t;
+typedef uint32_t lfs_off_t;
+
+typedef int32_t  lfs_ssize_t;
+typedef int32_t  lfs_soff_t;
+
+typedef uint32_t lfs_block_t;
+
+// Max name size in bytes
+#ifndef LFS_NAME_MAX
+#define LFS_NAME_MAX 255
+#endif
+
+// Possible error codes, these are negative to allow
+// valid positive return values
+enum lfs_error {
+    LFS_ERR_OK       = 0,    // No error
+    LFS_ERR_IO       = -5,   // Error during device operation
+    LFS_ERR_CORRUPT  = -52,  // Corrupted
+    LFS_ERR_NOENT    = -2,   // No directory entry
+    LFS_ERR_EXIST    = -17,  // Entry already exists
+    LFS_ERR_NOTDIR   = -20,  // Entry is not a dir
+    LFS_ERR_ISDIR    = -21,  // Entry is a dir
+    LFS_ERR_NOTEMPTY = -39,  // Dir is not empty
+    LFS_ERR_BADF     = -9,   // Bad file number
+    LFS_ERR_INVAL    = -22,  // Invalid parameter
+    LFS_ERR_NOSPC    = -28,  // No space left on device
+    LFS_ERR_NOMEM    = -12,  // No more memory available
+};
+
+// File types
+enum lfs_type {
+    LFS_TYPE_REG        = 0x11,
+    LFS_TYPE_DIR        = 0x22,
+    LFS_TYPE_SUPERBLOCK = 0x2e,
+};
+
+// File open flags
+enum lfs_open_flags {
+    // open flags
+    LFS_O_RDONLY = 1,        // Open a file as read only
+    LFS_O_WRONLY = 2,        // Open a file as write only
+    LFS_O_RDWR   = 3,        // Open a file as read and write
+    LFS_O_CREAT  = 0x0100,   // Create a file if it does not exist
+    LFS_O_EXCL   = 0x0200,   // Fail if a file already exists
+    LFS_O_TRUNC  = 0x0400,   // Truncate the existing file to zero size
+    LFS_O_APPEND = 0x0800,   // Move to end of file on every write
+
+    // internally used flags
+    LFS_F_DIRTY   = 0x10000, // File does not match storage
+    LFS_F_WRITING = 0x20000, // File has been written since last flush
+    LFS_F_READING = 0x40000, // File has been read since last flush
+    LFS_F_ERRED   = 0x80000, // An error occurred during write
+};
+
+// File seek flags
+enum lfs_whence_flags {
+    LFS_SEEK_SET = 0,   // Seek relative to an absolute position
+    LFS_SEEK_CUR = 1,   // Seek relative to the current file position
+    LFS_SEEK_END = 2,   // Seek relative to the end of the file
+};
+
+
+// Configuration provided during initialization of the littlefs
+struct lfs_config {
+    // Opaque user provided context that can be used to pass
+    // information to the block device operations
+    void *context;
+
+    // Read a region in a block. Negative error codes are propogated
+    // to the user.
+    int (*read)(const struct lfs_config *c, lfs_block_t block,
+            lfs_off_t off, void *buffer, lfs_size_t size);
+
+    // Program a region in a block. The block must have previously
+    // been erased. Negative error codes are propogated to the user.
+    // May return LFS_ERR_CORRUPT if the block should be considered bad.
+    int (*prog)(const struct lfs_config *c, lfs_block_t block,
+            lfs_off_t off, const void *buffer, lfs_size_t size);
+
+    // Erase a block. A block must be erased before being programmed.
+    // The state of an erased block is undefined. Negative error codes
+    // are propogated to the user.
+    // May return LFS_ERR_CORRUPT if the block should be considered bad.
+    int (*erase)(const struct lfs_config *c, lfs_block_t block);
+
+    // Sync the state of the underlying block device. Negative error codes
+    // are propogated to the user.
+    int (*sync)(const struct lfs_config *c);
+
+    // Minimum size of a block read. This determines the size of read buffers.
+    // This may be larger than the physical read size to improve performance
+    // by caching more of the block device.
+    lfs_size_t read_size;
+
+    // Minimum size of a block program. This determines the size of program
+    // buffers. This may be larger than the physical program size to improve
+    // performance by caching more of the block device.
+    // Must be a multiple of the read size.
+    lfs_size_t prog_size;
+
+    // Size of an erasable block. This does not impact ram consumption and
+    // may be larger than the physical erase size. However, this should be
+    // kept small as each file currently takes up an entire block.
+    // Must be a multiple of the program size.
+    lfs_size_t block_size;
+
+    // Number of erasable blocks on the device.
+    lfs_size_t block_count;
+
+    // Number of blocks to lookahead during block allocation. A larger
+    // lookahead reduces the number of passes required to allocate a block.
+    // The lookahead buffer requires only 1 bit per block so it can be quite
+    // large with little ram impact. Should be a multiple of 32.
+    lfs_size_t lookahead;
+
+    // Optional, statically allocated read buffer. Must be read sized.
+    void *read_buffer;
+
+    // Optional, statically allocated program buffer. Must be program sized.
+    void *prog_buffer;
+
+    // Optional, statically allocated lookahead buffer. Must be 1 bit per
+    // lookahead block.
+    void *lookahead_buffer;
+
+    // Optional, statically allocated buffer for files. Must be program sized.
+    // If enabled, only one file may be opened at a time.
+    void *file_buffer;
+};
+
+
+// File info structure
+struct lfs_info {
+    // Type of the file, either LFS_TYPE_REG or LFS_TYPE_DIR
+    uint8_t type;
+
+    // Size of the file, only valid for REG files
+    lfs_size_t size;
+
+    // Name of the file stored as a null-terminated string
+    char name[LFS_NAME_MAX+1];
+};
+
+
+/// littlefs data structures ///
+typedef struct lfs_entry {
+    lfs_off_t off;
+
+    struct lfs_disk_entry {
+        uint8_t type;
+        uint8_t elen;
+        uint8_t alen;
+        uint8_t nlen;
+        union {
+            struct {
+                lfs_block_t head;
+                lfs_size_t size;
+            } file;
+            lfs_block_t dir[2];
+        } u;
+    } d;
+} lfs_entry_t;
+
+typedef struct lfs_cache {
+    lfs_block_t block;
+    lfs_off_t off;
+    uint8_t *buffer;
+} lfs_cache_t;
+
+typedef struct lfs_file {
+    struct lfs_file *next;
+    lfs_block_t pair[2];
+    lfs_off_t poff;
+
+    lfs_block_t head;
+    lfs_size_t size;
+
+    uint32_t flags;
+    lfs_off_t pos;
+    lfs_block_t block;
+    lfs_off_t off;
+    lfs_cache_t cache;
+} lfs_file_t;
+
+typedef struct lfs_dir {
+    struct lfs_dir *next;
+    lfs_block_t pair[2];
+    lfs_off_t off;
+
+    lfs_block_t head[2];
+    lfs_off_t pos;
+
+    struct lfs_disk_dir {
+        uint32_t rev;
+        lfs_size_t size;
+        lfs_block_t tail[2];
+    } d;
+} lfs_dir_t;
+
+typedef struct lfs_superblock {
+    lfs_off_t off;
+
+    struct lfs_disk_superblock {
+        uint8_t type;
+        uint8_t elen;
+        uint8_t alen;
+        uint8_t nlen;
+        lfs_block_t root[2];
+        uint32_t block_size;
+        uint32_t block_count;
+        uint32_t version;
+        char magic[8];
+    } d;
+} lfs_superblock_t;
+
+typedef struct lfs_free {
+    lfs_block_t begin;
+    lfs_block_t size;
+    lfs_block_t off;
+    lfs_block_t ack;
+    uint32_t *buffer;
+} lfs_free_t;
+
+// The littlefs type
+typedef struct lfs {
+    const struct lfs_config *cfg;
+
+    lfs_block_t root[2];
+    lfs_file_t *files;
+    lfs_dir_t *dirs;
+
+    lfs_cache_t rcache;
+    lfs_cache_t pcache;
+
+    lfs_free_t free;
+    bool deorphaned;
+} lfs_t;
+
+
+/// Filesystem functions ///
+
+// Format a block device with the littlefs
+//
+// Requires a littlefs object and config struct. This clobbers the littlefs
+// object, and does not leave the filesystem mounted.
+//
+// Returns a negative error code on failure.
+int lfs_format(lfs_t *lfs, const struct lfs_config *config);
+
+// Mounts a littlefs
+//
+// Requires a littlefs object and config struct. Multiple filesystems
+// may be mounted simultaneously with multiple littlefs objects. Both
+// lfs and config must be allocated while mounted.
+//
+// Returns a negative error code on failure.
+int lfs_mount(lfs_t *lfs, const struct lfs_config *config);
+
+// Unmounts a littlefs
+//
+// Does nothing besides releasing any allocated resources.
+// Returns a negative error code on failure.
+int lfs_unmount(lfs_t *lfs);
+
+/// General operations ///
+
+// Removes a file or directory
+//
+// If removing a directory, the directory must be empty.
+// Returns a negative error code on failure.
+int lfs_remove(lfs_t *lfs, const char *path);
+
+// Rename or move a file or directory
+//
+// If the destination exists, it must match the source in type.
+// If the destination is a directory, the directory must be empty.
+//
+// Note: If power loss occurs, it is possible that the file or directory
+// will exist in both the oldpath and newpath simultaneously after the
+// next mount.
+//
+// Returns a negative error code on failure.
+int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath);
+
+// Find info about a file or directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
+
+
+/// File operations ///
+
+// Open a file
+//
+// The mode that the file is opened in is determined
+// by the flags, which are values from the enum lfs_open_flags
+// that are bitwise-ored together.
+//
+// Returns a negative error code on failure.
+int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
+        const char *path, int flags);
+
+// Close a file
+//
+// Any pending writes are written out to storage as though
+// sync had been called and releases any allocated resources.
+//
+// Returns a negative error code on failure.
+int lfs_file_close(lfs_t *lfs, lfs_file_t *file);
+
+// Synchronize a file on storage
+//
+// Any pending writes are written out to storage.
+// Returns a negative error code on failure.
+int lfs_file_sync(lfs_t *lfs, lfs_file_t *file);
+
+// Read data from file
+//
+// Takes a buffer and size indicating where to store the read data.
+// Returns the number of bytes read, or a negative error code on failure.
+lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
+        void *buffer, lfs_size_t size);
+
+// Write data to file
+//
+// Takes a buffer and size indicating the data to write. The file will not
+// actually be updated on the storage until either sync or close is called.
+//
+// Returns the number of bytes written, or a negative error code on failure.
+lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
+        const void *buffer, lfs_size_t size);
+
+// Change the position of the file
+//
+// The change in position is determined by the offset and whence flag.
+// Returns the old position of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
+        lfs_soff_t off, int whence);
+
+// Truncates the size of the file to the specified size
+//
+// Returns a negative error code on failure.
+int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size);
+
+// Return the position of the file
+//
+// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
+// Returns the position of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file);
+
+// Change the position of the file to the beginning of the file
+//
+// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
+// Returns a negative error code on failure.
+int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file);
+
+// Return the size of the file
+//
+// Similar to lfs_file_seek(lfs, file, 0, LFS_SEEK_END)
+// Returns the size of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file);
+
+
+/// Directory operations ///
+
+// Create a directory
+//
+// Returns a negative error code on failure.
+int lfs_mkdir(lfs_t *lfs, const char *path);
+
+// Open a directory
+//
+// Once open a directory can be used with read to iterate over files.
+// Returns a negative error code on failure.
+int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path);
+
+// Close a directory
+//
+// Releases any allocated resources.
+// Returns a negative error code on failure.
+int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir);
+
+// Read an entry in the directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info);
+
+// Change the position of the directory
+//
+// The new off must be a value previous returned from tell and specifies
+// an absolute offset in the directory seek.
+//
+// Returns a negative error code on failure.
+int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off);
+
+// Return the position of the directory
+//
+// The returned offset is only meant to be consumed by seek and may not make
+// sense, but does indicate the current position in the directory iteration.
+//
+// Returns the position of the directory, or a negative error code on failure.
+lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir);
+
+// Change the position of the directory to the beginning of the directory
+//
+// Returns a negative error code on failure.
+int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir);
+
+
+/// Miscellaneous littlefs specific operations ///
+
+// Traverse through all blocks in use by the filesystem
+//
+// The provided callback will be called with each block address that is
+// currently in use by the filesystem. This can be used to determine which
+// blocks are in use or how much of the storage is available.
+//
+// Returns a negative error code on failure.
+int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
+
+// Prunes any recoverable errors that may have occurred in the filesystem
+//
+// Not needed to be called by user unless an operation is interrupted
+// but the filesystem is still mounted. This is already called on first
+// allocation.
+//
+// Returns a negative error code on failure.
+int lfs_deorphan(lfs_t *lfs);
+
+
+#endif