esp-idf/components/fatfs/fatfsgen_utils/entry.py
2021-11-03 13:06:11 +01:00

128 lines
5.1 KiB
Python

# SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
# SPDX-License-Identifier: Apache-2.0
from typing import Any, Optional
from construct import Const, Int8ul, Int16ul, Int32ul, PaddedString, Struct
from .exceptions import LowerCaseException, TooLongNameException
from .fatfs_state import FATFSState
from .utils import is_valid_fatfs_name, pad_string
class Entry:
"""
The class Entry represents entry of the directory.
"""
ATTR_READ_ONLY = 0x01
ATTR_HIDDEN = 0x02
ATTR_SYSTEM = 0x04
ATTR_VOLUME_ID = 0x08
ATTR_DIRECTORY = 0x10
ATTR_ARCHIVE = 0x20
MAX_NAME_SIZE_S = 8
MAX_EXT_SIZE_S = 3
ENTRY_FORMAT_SHORT_NAME = Struct(
'DIR_Name' / PaddedString(MAX_NAME_SIZE_S, 'utf-8'),
'DIR_Name_ext' / PaddedString(MAX_EXT_SIZE_S, 'utf-8'),
'DIR_Attr' / Int8ul,
'DIR_NTRes' / Const(b'\x00'),
'DIR_CrtTimeTenth' / Const(b'\x00'),
'DIR_CrtTime' / Const(b'\x01\x00'),
'DIR_CrtDate' / Const(b'\x21\x00'),
'DIR_LstAccDate' / Const(b'\x00\x00'),
'DIR_FstClusHI' / Const(b'\x00\x00'),
'DIR_WrtTime' / Const(b'\x01\x00'),
'DIR_WrtDate' / Const(b'\x01\x00'),
'DIR_FstClusLO' / Int16ul,
'DIR_FileSize' / Int32ul,
)
# IDF-4044
ENTRY_FORMAT_LONG_NAME = Struct()
def __init__(self,
entry_id: int,
parent_dir_entries_address: int,
fatfs_state: FATFSState) -> None:
self.fatfs_state = fatfs_state
self.id = entry_id
self.entry_address = parent_dir_entries_address + self.id * self.fatfs_state.entry_size
self._is_alias = False
self._is_empty = True
@property
def is_empty(self) -> bool:
return self._is_empty
def _parse_entry(self, entry_bytearray: Optional[bytearray]) -> dict:
if self.fatfs_state.long_names_enabled:
return Entry.ENTRY_FORMAT_LONG_NAME.parse(entry_bytearray) # type: ignore
return Entry.ENTRY_FORMAT_SHORT_NAME.parse(entry_bytearray) # type: ignore
def _build_entry(self, **kwargs) -> Any: # type: ignore
if self.fatfs_state.long_names_enabled:
return Entry.ENTRY_FORMAT_LONG_NAME.build(dict(**kwargs))
return Entry.ENTRY_FORMAT_SHORT_NAME.build(dict(**kwargs))
@property
def entry_bytes(self) -> Any:
return self.fatfs_state.binary_image[self.entry_address: self.entry_address + self.fatfs_state.entry_size]
@entry_bytes.setter
def entry_bytes(self, value: int) -> None:
self.fatfs_state.binary_image[self.entry_address: self.entry_address + self.fatfs_state.entry_size] = value
def _clean_entry(self) -> None:
self.entry_bytes = self.fatfs_state.entry_size * b'\x00'
def allocate_entry(self,
first_cluster_id: int,
entity_name: str,
entity_type: int,
entity_extension: str = '',
size: int = 0) -> None:
"""
:param first_cluster_id: id of the first data cluster for given entry
:param entity_name: name recorded in the entry
:param entity_extension: extension recorded in the entry
:param size: size of the content of the file
:param entity_type: type of the entity (file [0x20] or directory [0x10])
:returns: None
:raises LowerCaseException: In case when long_names_enabled is set to False and filename exceeds 8 chars
for name or 3 chars for extension the exception is raised
"""
if not ((is_valid_fatfs_name(entity_name) and
is_valid_fatfs_name(entity_extension)) or
self.fatfs_state.long_names_enabled):
raise LowerCaseException('Lower case is not supported because long name support is not enabled!')
# clean entry before allocation
self._clean_entry()
self._is_empty = False
object_name = entity_name.upper()
object_extension = entity_extension.upper()
# implementation of long names support will be part of IDF-4044
exceeds_short_name = len(object_name) > Entry.MAX_NAME_SIZE_S or len(object_extension) > Entry.MAX_EXT_SIZE_S
if not self.fatfs_state.long_names_enabled and exceeds_short_name:
raise TooLongNameException(
'Maximal length of the object name is 8 characters and 3 characters for extension!')
start_address = self.entry_address
end_address = start_address + self.fatfs_state.entry_size
self.fatfs_state.binary_image[start_address: end_address] = self._build_entry(
DIR_Name=pad_string(object_name, size=Entry.MAX_NAME_SIZE_S),
DIR_Name_ext=pad_string(object_extension, size=Entry.MAX_EXT_SIZE_S),
DIR_Attr=entity_type,
DIR_FstClusLO=first_cluster_id,
DIR_FileSize=size
)
def update_content_size(self, content_size: int) -> None:
parsed_entry = self._parse_entry(self.entry_bytes)
parsed_entry.DIR_FileSize = content_size # type: ignore
self.entry_bytes = Entry.ENTRY_FORMAT_SHORT_NAME.build(parsed_entry)