pferd/PFERD/deduplicator.py
2022-01-15 12:00:30 +01:00

86 lines
2.7 KiB
Python

from pathlib import PurePath
from typing import Iterator, Set
from .logging import log
from .utils import fmt_path
def name_variants(path: PurePath) -> Iterator[PurePath]:
separator = " " if " " in path.stem else "_"
i = 1
while True:
yield path.parent / f"{path.stem}{separator}{i}{path.suffix}"
i += 1
class Deduplicator:
FORBIDDEN_CHARS = '<>:"/\\|?*'
FORBIDDEN_NAMES = {
"CON", "PRN", "AUX", "NUL",
"COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9",
"LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9",
}
def __init__(self, windows_paths: bool) -> None:
self._windows_paths = windows_paths
self._known: Set[PurePath] = set()
def _add(self, path: PurePath) -> None:
self._known.add(path)
# The last parent is just "."
for parent in list(path.parents)[:-1]:
self._known.add(parent)
def _fixup_element(self, name: str) -> str:
# For historical reasons, windows paths have some odd restrictions that
# we're trying to avoid. See:
# https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
for char in self.FORBIDDEN_CHARS:
name = name.replace(char, "_")
path = PurePath(name)
if path.stem in self.FORBIDDEN_NAMES:
name = f"{path.stem}_{path.suffix}"
if name.endswith(" ") or name.endswith("."):
name += "_"
return name
def _fixup_for_windows(self, path: PurePath) -> PurePath:
new_path = PurePath(*[self._fixup_element(elem) for elem in path.parts])
if new_path != path:
log.explain(f"Changed path to {fmt_path(new_path)} for windows compatibility")
return new_path
def fixup_path(self, path: PurePath) -> PurePath:
"""Fixes up the path for windows, if enabled. Returns the path unchanged otherwise."""
if self._windows_paths:
return self._fixup_for_windows(path)
return path
def mark(self, path: PurePath) -> PurePath:
if self._windows_paths:
path = self._fixup_for_windows(path)
if path not in self._known:
self._add(path)
return path
log.explain(f"Path {fmt_path(path)} is already taken, finding a new name")
for variant in name_variants(path):
if variant in self._known:
log.explain(f"Path {fmt_path(variant)} is taken as well")
continue
log.explain(f"Found unused path {fmt_path(variant)}")
self._add(variant)
return variant
# The "name_variants" iterator returns infinitely many paths
raise RuntimeError("Unreachable")