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FileSystemStore Class Reference

FileSystemStore is a lightweight implementation of the KVStore interface over file systems. More...

#include <FileSystemStore.h>

Inheritance diagram for FileSystemStore:
KVStore

Public Types

typedef struct mbed::KVStore::info info_t
 Holds key information. More...
 

Public Member Functions

 FileSystemStore (FileSystem *fs)
 Create FileSystemStore - A Key Value API on top of FS. More...
 
virtual ~FileSystemStore ()
 Destroy FileSystemStore instance. More...
 
virtual int init ()
 Initialize FileSystemStore, checking validity of KVStore writing folder and if it doesn't exist, creating it. More...
 
virtual int deinit ()
 Deinitialize FileSystemStore, release and free resources. More...
 
virtual int reset ()
 Reset FileSystemStore contents (clear all keys) More...
 
virtual int set (const char *key, const void *buffer, size_t size, uint32_t create_flags)
 Set one FileSystemStore item, given key and value. More...
 
virtual int get (const char *key, void *buffer, size_t buffer_size, size_t *actual_size=NULL, size_t offset=0)
 Get one FileSystemStore item by given key. More...
 
virtual int get_info (const char *key, info_t *info)
 Get information of a given key. More...
 
virtual int remove (const char *key)
 Remove a FileSystemStore item by given key. More...
 
virtual int set_start (set_handle_t *handle, const char *key, size_t final_data_size, uint32_t create_flags)
 Start an incremental FileSystemStore set sequence. More...
 
virtual int set_add_data (set_handle_t handle, const void *value_data, size_t data_size)
 Add data to incremental FileSystemStore set sequence. More...
 
virtual int set_finalize (set_handle_t handle)
 Finalize an incremental FileSystemStore set sequence. More...
 
virtual int iterator_open (iterator_t *it, const char *prefix=NULL)
 Start an iteration over FileSystemStore keys. More...
 
virtual int iterator_next (iterator_t it, char *key, size_t key_size)
 Get next key in iteration. More...
 
virtual int iterator_close (iterator_t it)
 Close iteration. More...
 
bool is_valid_key (const char *key) const
 Convenience function for checking key validity. More...
 

Detailed Description

FileSystemStore is a lightweight implementation of the KVStore interface over file systems.

FileSystemStore implements the get/set interface using files, where a single file represents each key. A key is represented by the file name, and its value is stored as file data. Therefore, FileSystemStore imitates the get/set actions using simple file operations. Set is achieved using open-write-close, get using open-read-close and so on.

All files are concentrated under a single directory, whose name is hard coded. So actions such as "reset" are mapped to the deletion of all files under this directory, and iteration actions use file system APIs to traverse the directory.

Definition at line 42 of file FileSystemStore.h.

Member Typedef Documentation

◆ info_t

typedef struct mbed::KVStore::info info_t
inherited

Holds key information.

Constructor & Destructor Documentation

◆ FileSystemStore()

Create FileSystemStore - A Key Value API on top of FS.

Parameters
fsFile system (FAT/LITTLE) on top of which FileSystemStore is adding KV API

◆ ~FileSystemStore()

virtual ~FileSystemStore ( )
virtual

Destroy FileSystemStore instance.

Definition at line 54 of file FileSystemStore.h.

Member Function Documentation

◆ init()

virtual int init ( )
virtual

Initialize FileSystemStore, checking validity of KVStore writing folder and if it doesn't exist, creating it.

Returns
MBED_SUCCESS Success. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation.

Implements KVStore.

◆ deinit()

virtual int deinit ( )
virtual

Deinitialize FileSystemStore, release and free resources.

Returns
MBED_SUCCESS Success.

Implements KVStore.

◆ reset()

virtual int reset ( )
virtual

Reset FileSystemStore contents (clear all keys)

Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation.

Implements KVStore.

◆ set()

virtual int set ( const char *  key,
const void *  buffer,
size_t  size,
uint32_t  create_flags 
)
virtual

Set one FileSystemStore item, given key and value.

Parameters
[in]keyKey - must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.
[in]bufferValue data buffer.
[in]sizeValue data size.
[in]create_flagsFlag mask.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_INVALID_SIZE Invalid size given in function arguments. MBED_ERROR_WRITE_PROTECTED Already stored with "write once" flag.

Implements KVStore.

◆ get()

virtual int get ( const char *  key,
void *  buffer,
size_t  buffer_size,
size_t *  actual_size = NULL,
size_t  offset = 0 
)
virtual

Get one FileSystemStore item by given key.

Parameters
[in]keyKey - must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.
[in]bufferValue data buffer.
[in]buffer_sizeValue data buffer size.
[out]actual_sizeActual read size.
[in]offsetOffset to read from in data.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_INVALID_SIZE Invalid size given in function arguments. MBED_ERROR_INVALID_DATA_DETECTED Data is corrupted. MBED_ERROR_ITEM_NOT_FOUND No such key.

Implements KVStore.

◆ get_info()

virtual int get_info ( const char *  key,
info_t info 
)
virtual

Get information of a given key.

The returned info contains size and flags

Parameters
[in]keyKey - must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.
[out]infoReturned information structure.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_INVALID_SIZE Invalid size given in function arguments. MBED_ERROR_INVALID_DATA_DETECTED Data is corrupted. MBED_ERROR_ITEM_NOT_FOUND No such key.

Implements KVStore.

◆ remove()

virtual int remove ( const char *  key)
virtual

Remove a FileSystemStore item by given key.

Parameters
[in]keyKey - must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_ITEM_NOT_FOUND No such key. MBED_ERROR_WRITE_PROTECTED Already stored with "write once" flag.

Implements KVStore.

◆ set_start()

virtual int set_start ( set_handle_t *  handle,
const char *  key,
size_t  final_data_size,
uint32_t  create_flags 
)
virtual

Start an incremental FileSystemStore set sequence.

This operation is blocking other operations. Any get/set/remove/iterator operation will be blocked until set_finalize is called.

Parameters
[out]handleReturned incremental set handle.
[in]keyKey - must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.
[in]final_data_sizeFinal value data size.
[in]create_flagsFlag mask.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_INVALID_SIZE Invalid size given in function arguments. MBED_ERROR_WRITE_PROTECTED Already stored with "write once" flag.

Implements KVStore.

◆ set_add_data()

virtual int set_add_data ( set_handle_t  handle,
const void *  value_data,
size_t  data_size 
)
virtual

Add data to incremental FileSystemStore set sequence.

This operation is blocking other operations. Any get/set/remove operation will be blocked until set_finalize is called.

Parameters
[in]handleIncremental set handle.
[in]value_dataValue data to add.
[in]data_sizeValue data size.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_INVALID_SIZE Invalid size given in function arguments. MBED_ERROR_WRITE_PROTECTED Already stored with "write once" flag.

Implements KVStore.

◆ set_finalize()

virtual int set_finalize ( set_handle_t  handle)
virtual

Finalize an incremental FileSystemStore set sequence.

Parameters
[in]handleIncremental set handle.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_FAILED_OPERATION Underlying file system failed operation. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments.

Implements KVStore.

◆ iterator_open()

virtual int iterator_open ( iterator_t *  it,
const char *  prefix = NULL 
)
virtual

Start an iteration over FileSystemStore keys.

There are no issues with any other operations while iterator is open.

Parameters
[out]itReturned iterator handle.
[in]prefixKey prefix (null for all keys).
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments.

Implements KVStore.

◆ iterator_next()

virtual int iterator_next ( iterator_t  it,
char *  key,
size_t  key_size 
)
virtual

Get next key in iteration.

There are no issues with any other operations while iterator is open.

Parameters
[in]itIterator handle.
[in]keyBuffer for returned key.
[in]key_sizeKey buffer size.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments. MBED_ERROR_ITEM_NOT_FOUND No more keys found.

Implements KVStore.

◆ iterator_close()

virtual int iterator_close ( iterator_t  it)
virtual

Close iteration.

Parameters
[in]itIterator handle.
Returns
MBED_SUCCESS Success. MBED_ERROR_NOT_READY Not initialized. MBED_ERROR_INVALID_ARGUMENT Invalid argument given in function arguments.

Implements KVStore.

◆ is_valid_key()

bool is_valid_key ( const char *  key) const
inherited

Convenience function for checking key validity.

Key must not include '*' '/' '?' ':' ';' '\' '"' '|' ' ' '<' '>' '\'.

Parameters
[in]keyKey buffer.
Returns
MBED_SUCCESS on success or an error code on failure

Definition at line 208 of file KVStore.h.