esp-idf/components/fatfs/fatfsgen_utils/fs_object.py

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# SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
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# SPDX-License-Identifier: Apache-2.0
import os
from datetime import datetime
from typing import List, Optional, Tuple, Union
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from .entry import Entry
from .exceptions import FatalError, WriteDirectoryException
from .fat import FAT, Cluster
from .fatfs_state import FATFSState
from .long_filename_utils import (build_lfn_full_name, build_lfn_unique_entry_name_order,
get_required_lfn_entries_count, split_name_to_lfn_entries,
split_name_to_lfn_entry_blocks)
from .utils import (DATETIME, MAX_EXT_SIZE, MAX_NAME_SIZE, build_lfn_short_entry_name, lfn_checksum,
required_clusters_count, split_content_into_sectors, split_to_name_and_extension)
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class File:
"""
The class File provides API to write into the files. It represents file in the FS.
"""
ATTR_ARCHIVE: int = 0x20
ENTITY_TYPE: int = ATTR_ARCHIVE
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def __init__(self, name: str, fat: FAT, fatfs_state: FATFSState, entry: Entry, extension: str = '') -> None:
self.name: str = name
self.extension: str = extension
self.fatfs_state: FATFSState = fatfs_state
self.fat: FAT = fat
self.size: int = 0
self._first_cluster: Optional[Cluster] = None
self._entry: Entry = entry
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@property
def entry(self) -> Entry:
return self._entry
@property
def first_cluster(self) -> Optional[Cluster]:
return self._first_cluster
@first_cluster.setter
def first_cluster(self, value: Cluster) -> None:
self._first_cluster = value
def name_equals(self, name: str, extension: str) -> bool:
return self.name == name and self.extension == extension
def write(self, content: bytes) -> None:
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self.entry.update_content_size(len(content))
# we assume that the correct amount of clusters is allocated
current_cluster = self._first_cluster
for content_part in split_content_into_sectors(content, self.fatfs_state.sector_size):
content_as_list = content_part
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if current_cluster is None:
raise FatalError('No free space left!')
address: int = current_cluster.cluster_data_address
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self.fatfs_state.binary_image[address: address + len(content_part)] = content_as_list
current_cluster = current_cluster.next_cluster
class Directory:
"""
The Directory class provides API to add files and directories into the directory
and to find the file according to path and write it.
"""
ATTR_DIRECTORY: int = 0x10
ATTR_ARCHIVE: int = 0x20
ENTITY_TYPE: int = ATTR_DIRECTORY
CURRENT_DIRECTORY = '.'
PARENT_DIRECTORY = '..'
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def __init__(self,
name,
fat,
fatfs_state,
entry=None,
cluster=None,
size=None,
extension='',
parent=None):
# type: (str, FAT, FATFSState, Optional[Entry], Cluster, Optional[int], str, Directory) -> None
self.name: str = name
self.fatfs_state: FATFSState = fatfs_state
self.extension: str = extension
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self.fat: FAT = fat
self.size: int = size or self.fatfs_state.sector_size
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# if directory is root its parent is itself
self.parent: Directory = parent or self
self._first_cluster: Cluster = cluster
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# entries will be initialized after the cluster allocation
self.entries: List[Entry] = []
self.entities: List[Union[File, Directory]] = [] # type: ignore
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self._entry = entry # currently not in use (will use later for e.g. modification time, etc.)
@property
def is_root(self) -> bool:
return self.parent is self
@property
def first_cluster(self) -> Cluster:
return self._first_cluster
@first_cluster.setter
def first_cluster(self, value: Cluster) -> None:
self._first_cluster = value
def name_equals(self, name: str, extension: str) -> bool:
return self.name == name and self.extension == extension
def create_entries(self, cluster: Cluster) -> List[Entry]:
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return [Entry(entry_id=i,
parent_dir_entries_address=cluster.cluster_data_address,
fatfs_state=self.fatfs_state)
for i in range(self.size // self.fatfs_state.entry_size)]
def init_directory(self) -> None:
self.entries = self.create_entries(self._first_cluster)
# the root directory doesn't contain link to itself nor the parent
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if not self.is_root:
self_dir_reference: Entry = self.find_free_entry() or self.chain_directory()
self_dir_reference.allocate_entry(first_cluster_id=self.first_cluster.id,
entity_name=self.CURRENT_DIRECTORY,
entity_extension='',
entity_type=self.ENTITY_TYPE)
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self.first_cluster = self._first_cluster
parent_dir_reference: Entry = self.find_free_entry() or self.chain_directory()
parent_dir_reference.allocate_entry(first_cluster_id=self.parent.first_cluster.id,
entity_name=self.PARENT_DIRECTORY,
entity_extension='',
entity_type=self.parent.ENTITY_TYPE)
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self.parent.first_cluster = self.parent.first_cluster
def lookup_entity(self, object_name: str, extension: str): # type: ignore
for entity in self.entities:
if entity.name == object_name and entity.extension == extension:
return entity
return None
def recursive_search(self, path_as_list, current_dir): # type: ignore
name, extension = split_to_name_and_extension(path_as_list[0])
next_obj = current_dir.lookup_entity(name, extension)
if next_obj is None:
raise FileNotFoundError('No such file or directory!')
if len(path_as_list) == 1 and next_obj.name_equals(name, extension):
return next_obj
return self.recursive_search(path_as_list[1:], next_obj)
def find_free_entry(self) -> Optional[Entry]:
for entry in self.entries:
if entry.is_empty:
return entry
return None
def _extend_directory(self) -> None:
current: Cluster = self.first_cluster
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while current.next_cluster is not None:
current = current.next_cluster
new_cluster: Cluster = self.fat.find_free_cluster()
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current.set_in_fat(new_cluster.id)
current.next_cluster = new_cluster
self.entries += self.create_entries(new_cluster)
def chain_directory(self) -> Entry:
self._extend_directory()
free_entry: Entry = self.find_free_entry()
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if free_entry is None:
raise FatalError('No more space left!')
return free_entry
@staticmethod
def allocate_long_name_object(free_entry,
name,
extension,
target_dir,
free_cluster,
entity_type,
date,
time):
# type: (Entry, str, str, Directory, Cluster, int, DATETIME, DATETIME) -> Tuple[Cluster, Entry, Directory]
lfn_full_name: str = build_lfn_full_name(name, extension)
lfn_unique_entry_order: int = build_lfn_unique_entry_name_order(target_dir.entities, name)
lfn_short_entry_name: str = build_lfn_short_entry_name(name, extension, lfn_unique_entry_order)
checksum: int = lfn_checksum(lfn_short_entry_name)
entries_count: int = get_required_lfn_entries_count(lfn_full_name)
# entries in long file name entries chain starts with the last entry
split_names_reversed = reversed(list(enumerate(split_name_to_lfn_entries(lfn_full_name, entries_count))))
for i, name_split_to_entry in split_names_reversed:
order: int = i + 1
lfn_names: List[bytes] = list(
map(lambda x: x.lower(), split_name_to_lfn_entry_blocks(name_split_to_entry))) # type: ignore
free_entry.allocate_entry(first_cluster_id=free_cluster.id,
entity_name=name,
entity_extension=extension,
entity_type=entity_type,
lfn_order=order,
lfn_names=lfn_names,
lfn_checksum_=checksum,
lfn_is_last=order == entries_count)
free_entry = target_dir.find_free_entry() or target_dir.chain_directory()
free_entry.allocate_entry(first_cluster_id=free_cluster.id,
entity_name=lfn_short_entry_name[:MAX_NAME_SIZE],
entity_extension=lfn_short_entry_name[MAX_NAME_SIZE:],
entity_type=entity_type,
lfn_order=Entry.SHORT_ENTRY_LN,
date=date,
time=time)
return free_cluster, free_entry, target_dir
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def allocate_object(self,
name,
entity_type,
object_timestamp_,
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path_from_root=None,
extension=''):
# type: (str, int, datetime, Optional[List[str]], str) -> Tuple[Cluster, Entry, Directory]
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"""
Method finds the target directory in the path
and allocates cluster (both the record in FAT and cluster in the data region)
and entry in the specified directory
"""
free_cluster: Cluster = self.fat.find_free_cluster()
target_dir: Directory = self if not path_from_root else self.recursive_search(path_from_root, self)
free_entry: Entry = target_dir.find_free_entry() or target_dir.chain_directory()
name_fits_short_struct: bool = len(name) <= MAX_NAME_SIZE and len(extension) <= MAX_EXT_SIZE
fatfs_date_ = (object_timestamp_.year, object_timestamp_.month, object_timestamp_.day)
fatfs_time_ = (object_timestamp_.hour, object_timestamp_.minute, object_timestamp_.second)
if not self.fatfs_state.long_names_enabled or name_fits_short_struct:
free_entry.allocate_entry(first_cluster_id=free_cluster.id,
entity_name=name,
entity_extension=extension,
date=fatfs_date_,
time=fatfs_time_,
entity_type=entity_type)
return free_cluster, free_entry, target_dir
return self.allocate_long_name_object(free_entry=free_entry,
name=name,
extension=extension,
target_dir=target_dir,
free_cluster=free_cluster,
entity_type=entity_type,
date=fatfs_date_,
time=fatfs_time_)
def new_file(self,
name: str,
extension: str,
path_from_root: Optional[List[str]],
object_timestamp_: datetime) -> None:
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free_cluster, free_entry, target_dir = self.allocate_object(name=name,
extension=extension,
entity_type=Directory.ATTR_ARCHIVE,
path_from_root=path_from_root,
object_timestamp_=object_timestamp_)
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file: File = File(name=name,
fat=self.fat,
extension=extension,
fatfs_state=self.fatfs_state,
entry=free_entry)
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file.first_cluster = free_cluster
target_dir.entities.append(file)
def new_directory(self, name, parent, path_from_root, object_timestamp_):
# type: (str, Directory, Optional[List[str]], datetime) -> None
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free_cluster, free_entry, target_dir = self.allocate_object(name=name,
entity_type=Directory.ATTR_DIRECTORY,
path_from_root=path_from_root,
object_timestamp_=object_timestamp_)
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directory: Directory = Directory(name=name,
fat=self.fat,
parent=parent,
fatfs_state=self.fatfs_state,
entry=free_entry)
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directory.first_cluster = free_cluster
directory.init_directory()
target_dir.entities.append(directory)
def write_to_file(self, path: List[str], content: bytes) -> None:
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"""
Writes to file existing in the directory structure.
:param path: path split into the list
:param content: content as a string to be written into a file
:returns: None
:raises WriteDirectoryException: raised is the target object for writing is a directory
"""
entity_to_write: Entry = self.recursive_search(path, self)
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if isinstance(entity_to_write, File):
clusters_cnt: int = required_clusters_count(cluster_size=self.fatfs_state.sector_size, content=content)
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self.fat.allocate_chain(entity_to_write.first_cluster, clusters_cnt)
entity_to_write.write(content)
else:
raise WriteDirectoryException(f'`{os.path.join(*path)}` is a directory!')