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https://github.com/arsenetar/dupeguru.git
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334f4dd2ae
This makes md5 computing faster without using too much memory.
263 lines
8.7 KiB
Python
263 lines
8.7 KiB
Python
# Created By: Virgil Dupras
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# Created On: 2009-10-22
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# Copyright 2015 Hardcoded Software (http://www.hardcoded.net)
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#
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# This software is licensed under the "GPLv3" License as described in the "LICENSE" file,
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# which should be included with this package. The terms are also available at
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# http://www.gnu.org/licenses/gpl-3.0.html
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# This is a fork from hsfs. The reason for this fork is that hsfs has been designed for musicGuru
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# and was re-used for dupeGuru. The problem is that hsfs is way over-engineered for dupeGuru,
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# resulting needless complexity and memory usage. It's been a while since I wanted to do that fork,
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# and I'm doing it now.
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import hashlib
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import logging
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from hscommon.util import nonone, get_file_ext
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__all__ = [
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'File',
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'Folder',
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'get_file',
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'get_files',
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'FSError',
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'AlreadyExistsError',
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'InvalidPath',
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'InvalidDestinationError',
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'OperationError',
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]
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NOT_SET = object()
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class FSError(Exception):
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cls_message = "An error has occured on '{name}' in '{parent}'"
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def __init__(self, fsobject, parent=None):
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message = self.cls_message
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if isinstance(fsobject, str):
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name = fsobject
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elif isinstance(fsobject, File):
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name = fsobject.name
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else:
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name = ''
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parentname = str(parent) if parent is not None else ''
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Exception.__init__(self, message.format(name=name, parent=parentname))
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class AlreadyExistsError(FSError):
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"The directory or file name we're trying to add already exists"
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cls_message = "'{name}' already exists in '{parent}'"
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class InvalidPath(FSError):
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"The path of self is invalid, and cannot be worked with."
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cls_message = "'{name}' is invalid."
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class InvalidDestinationError(FSError):
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"""A copy/move operation has been called, but the destination is invalid."""
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cls_message = "'{name}' is an invalid destination for this operation."
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class OperationError(FSError):
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"""A copy/move/delete operation has been called, but the checkup after the
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operation shows that it didn't work."""
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cls_message = "Operation on '{name}' failed."
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class File:
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"""Represents a file and holds metadata to be used for scanning.
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"""
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INITIAL_INFO = {
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'size': 0,
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'mtime': 0,
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'md5': '',
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'md5partial': '',
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}
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# Slots for File make us save quite a bit of memory. In a memory test I've made with a lot of
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# files, I saved 35% memory usage with "unread" files (no _read_info() call) and gains become
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# even greater when we take into account read attributes (70%!). Yeah, it's worth it.
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__slots__ = ('path', 'is_ref', 'words') + tuple(INITIAL_INFO.keys())
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def __init__(self, path):
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self.path = path
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for attrname in self.INITIAL_INFO:
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setattr(self, attrname, NOT_SET)
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def __repr__(self):
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return "<{} {}>".format(self.__class__.__name__, str(self.path))
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def __getattribute__(self, attrname):
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result = object.__getattribute__(self, attrname)
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if result is NOT_SET:
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try:
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self._read_info(attrname)
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except Exception as e:
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logging.warning("An error '%s' was raised while decoding '%s'", e, repr(self.path))
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result = object.__getattribute__(self, attrname)
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if result is NOT_SET:
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result = self.INITIAL_INFO[attrname]
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return result
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#This offset is where we should start reading the file to get a partial md5
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#For audio file, it should be where audio data starts
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def _get_md5partial_offset_and_size(self):
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return (0x4000, 0x4000) #16Kb
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def _read_info(self, field):
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if field in ('size', 'mtime'):
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stats = self.path.stat()
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self.size = nonone(stats.st_size, 0)
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self.mtime = nonone(stats.st_mtime, 0)
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elif field == 'md5partial':
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try:
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fp = self.path.open('rb')
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offset, size = self._get_md5partial_offset_and_size()
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fp.seek(offset)
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partialdata = fp.read(size)
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md5 = hashlib.md5(partialdata)
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self.md5partial = md5.digest()
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fp.close()
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except Exception:
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pass
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elif field == 'md5':
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try:
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fp = self.path.open('rb')
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md5 = hashlib.md5()
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# The goal here is to not run out of memory on really big files. However, the chunk
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# size has to be large enough so that the python loop isn't too costly in terms of
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# CPU.
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CHUNK_SIZE = 1024 * 1024 # 1 mb
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filedata = fp.read(CHUNK_SIZE)
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while filedata:
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md5.update(filedata)
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filedata = fp.read(CHUNK_SIZE)
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self.md5 = md5.digest()
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fp.close()
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except Exception:
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pass
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def _read_all_info(self, attrnames=None):
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"""Cache all possible info.
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If `attrnames` is not None, caches only attrnames.
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"""
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if attrnames is None:
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attrnames = self.INITIAL_INFO.keys()
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for attrname in attrnames:
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getattr(self, attrname)
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#--- Public
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@classmethod
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def can_handle(cls, path):
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"""Returns whether this file wrapper class can handle ``path``.
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"""
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return not path.islink() and path.isfile()
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def rename(self, newname):
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if newname == self.name:
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return
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destpath = self.path.parent()[newname]
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if destpath.exists():
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raise AlreadyExistsError(newname, self.path.parent())
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try:
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self.path.rename(destpath)
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except EnvironmentError:
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raise OperationError(self)
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if not destpath.exists():
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raise OperationError(self)
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self.path = destpath
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def get_display_info(self, group, delta):
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"""Returns a display-ready dict of dupe's data.
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"""
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raise NotImplementedError()
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#--- Properties
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@property
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def extension(self):
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return get_file_ext(self.name)
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@property
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def name(self):
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return self.path.name
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@property
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def folder_path(self):
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return self.path.parent()
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class Folder(File):
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"""A wrapper around a folder path.
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It has the size/md5 info of a File, but it's value are the sum of its subitems.
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"""
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__slots__ = File.__slots__ + ('_subfolders', )
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def __init__(self, path):
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File.__init__(self, path)
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self._subfolders = None
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def _all_items(self):
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folders = self.subfolders
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files = get_files(self.path)
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return folders + files
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def _read_info(self, field):
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if field in {'size', 'mtime'}:
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size = sum((f.size for f in self._all_items()), 0)
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self.size = size
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stats = self.path.stat()
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self.mtime = nonone(stats.st_mtime, 0)
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elif field in {'md5', 'md5partial'}:
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# What's sensitive here is that we must make sure that subfiles'
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# md5 are always added up in the same order, but we also want a
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# different md5 if a file gets moved in a different subdirectory.
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def get_dir_md5_concat():
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items = self._all_items()
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items.sort(key=lambda f: f.path)
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md5s = [getattr(f, field) for f in items]
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return b''.join(md5s)
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md5 = hashlib.md5(get_dir_md5_concat())
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digest = md5.digest()
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setattr(self, field, digest)
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@property
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def subfolders(self):
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if self._subfolders is None:
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subfolders = [p for p in self.path.listdir() if not p.islink() and p.isdir()]
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self._subfolders = [self.__class__(p) for p in subfolders]
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return self._subfolders
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@classmethod
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def can_handle(cls, path):
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return not path.islink() and path.isdir()
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def get_file(path, fileclasses=[File]):
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"""Wraps ``path`` around its appropriate :class:`File` class.
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Whether a class is "appropriate" is decided by :meth:`File.can_handle`
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:param Path path: path to wrap
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:param fileclasses: List of candidate :class:`File` classes
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"""
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for fileclass in fileclasses:
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if fileclass.can_handle(path):
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return fileclass(path)
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def get_files(path, fileclasses=[File]):
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"""Returns a list of :class:`File` for each file contained in ``path``.
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:param Path path: path to scan
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:param fileclasses: List of candidate :class:`File` classes
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"""
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assert all(issubclass(fileclass, File) for fileclass in fileclasses)
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try:
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result = []
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for path in path.listdir():
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file = get_file(path, fileclasses=fileclasses)
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if file is not None:
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result.append(file)
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return result
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except EnvironmentError:
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raise InvalidPath(path)
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