mirror of
https://github.com/Garmelon/PFERD.git
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128 lines
3.6 KiB
Python
128 lines
3.6 KiB
Python
"""
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Transforms let the user define functions to decide where the downloaded files
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should be placed locally. They let the user do more advanced things like moving
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only files whose names match a regex, or renaming files from one numbering
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scheme to another.
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"""
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from dataclasses import dataclass
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from pathlib import PurePath
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from typing import Callable, List, Optional, TypeVar
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from .utils import PathLike, Regex, to_path, to_pattern
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Transform = Callable[[PurePath], Optional[PurePath]]
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@dataclass
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class Transformable:
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"""
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An object that can be transformed by a Transform.
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"""
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path: PurePath
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TF = TypeVar("TF", bound=Transformable)
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def apply_transform(
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transform: Transform,
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transformables: List[TF],
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) -> List[TF]:
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"""
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Apply a Transform to multiple Transformables, discarding those that were
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not transformed by the Transform.
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"""
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result: List[TF] = []
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for transformable in transformables:
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new_path = transform(transformable.path)
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if new_path:
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transformable.path = new_path
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result.append(transformable)
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return result
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# Transform combinators
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keep = lambda path: path
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def attempt(*args: Transform) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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for transform in args:
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result = transform(path)
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if result:
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return result
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return None
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return inner
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def optionally(transform: Transform) -> Transform:
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return attempt(transform, lambda path: path)
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def do(*args: Transform) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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current = path
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for transform in args:
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result = transform(current)
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if result:
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current = result
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else:
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return None
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return current
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return inner
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def predicate(pred: Callable[[PurePath], bool]) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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if pred(path):
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return path
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return None
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return inner
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def glob(pattern: str) -> Transform:
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return predicate(lambda path: path.match(pattern))
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def move_dir(source_dir: PathLike, target_dir: PathLike) -> Transform:
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source_path = to_path(source_dir)
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target_path = to_path(target_dir)
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def inner(path: PurePath) -> Optional[PurePath]:
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if source_path in path.parents:
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return target_path / path.relative_to(source_path)
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return None
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return inner
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def move(source: PathLike, target: PathLike) -> Transform:
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source_path = to_path(source)
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target_path = to_path(target)
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def inner(path: PurePath) -> Optional[PurePath]:
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if path == source_path:
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return target_path
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return None
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return inner
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def rename(source: str, target: str) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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if path.name == source:
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return path.with_name(target)
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return None
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return inner
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def re_move(regex: Regex, target: str) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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match = to_pattern(regex).fullmatch(str(path))
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if match:
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groups = [match.group(0)]
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groups.extend(match.groups())
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return PurePath(target.format(*groups))
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return None
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return inner
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def re_rename(regex: Regex, target: str) -> Transform:
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def inner(path: PurePath) -> Optional[PurePath]:
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match = to_pattern(regex).fullmatch(path.name)
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if match:
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groups = [match.group(0)]
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groups.extend(match.groups())
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return path.with_name(target.format(*groups))
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return None
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return inner
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