OXYGENHUB
◆ main openmsx / build / extract.py
3.5 KiB · Python · last changed chore(): initial commit 1 month ago source blame history raw
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# Extract files from archives.
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from pathlib import Path
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from os import O_CREAT, O_WRONLY, fdopen, open as osopen, utime
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try:
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	from os import O_BINARY
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except ImportError:
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	# Platforms that do not define O_BINARY do not need it either.
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	O_BINARY = 0
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try:
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	from os import symlink
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except ImportError:
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	def symlink(source, link_name):
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		raise OSError('OS does not support symlink creation')
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from os.path import abspath, isdir, join as joinpath, sep, split as splitpath
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from stat import S_IRWXU, S_IRWXG, S_IRWXO, S_IXUSR, S_IXGRP, S_IXOTH
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from tarfile import TarFile
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import sys
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from detectsys import detectOS
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hostOS = detectOS()
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# Note: Larger buffers might make extraction slower.
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bufSize = 16384
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def extract(archivePath, destDir, rename = None):
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	'''Extract the given archive to the given directory.
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	If a rename function is given, it is called with the output path relative
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	to the destination directory; the value returned by the rename function is
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	used as the actual relative destination file path.
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	This function sets file ownership and permissions like is done in newly
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	created files and ignores the ownership and permissions from the archive,
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	since we are not restoring a backup.
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	'''
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	absDestDir = Path(destDir).resolve()
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	if not absDestDir.is_dir():
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		raise ValueError(
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			f'Destination directory "{absDestDir}" does not exist'
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		)
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	createdDirs = set()
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	with TarFile.open(archivePath, errorlevel=2) as tar:
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		for member in tar.getmembers():
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			absMemberPath = absDestDir / member.name
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			if not absMemberPath.is_relative_to(absDestDir):
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				raise ValueError(
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					f'Refusing to extract tar entry "{member.name}" '
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					'outside destination directory'
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				)
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			if rename:
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				absMemberPath = absDestDir / rename(
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					absMemberPath.relative_to(absDestDir)
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				)
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			if member.isfile():
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				parent = absMemberPath.parent
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				if parent not in createdDirs:
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					parent.mkdir(parents=True, exist_ok=True)
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					createdDirs.add(parent)
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				mode = S_IRWXU | S_IRWXG | S_IRWXO
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				if not (member.mode & S_IXUSR):
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					mode &= ~(S_IXUSR | S_IXGRP | S_IXOTH)
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				fd = osopen(absMemberPath, O_CREAT | O_WRONLY | O_BINARY, mode)
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				with fdopen(fd, 'wb') as out:
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					inp = tar.extractfile(member)
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					bytesLeft = member.size
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					while bytesLeft > 0:
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						buf = inp.read(bufSize)
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						out.write(buf)
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						bytesLeft -= len(buf)
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			elif member.isdir():
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				absMemberPath.mkdir(parents=True, exist_ok=True)
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				createdDirs.add(absMemberPath)
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			elif member.issym():
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				try:
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					symlink(member.linkname, absMemberPath)
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				except OSError as ex:
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					print(
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						'WARNING: Skipping symlink creation: '
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						f'{absMemberPath} -> {member.linkname}: {ex}'
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					)
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			else:
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				raise ValueError(
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					f'Cannot extract tar entry "{member.name}": '
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					'not a regular file, symlink or directory'
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				)
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			# Set file/directory modification time to match the archive.
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			# For example autotools track dependencies between archived files
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			# and will attempt to regenerate them if the time stamps indicate
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			# one is older than the other.
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			if member.isfile():
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				utime(absMemberPath, (member.mtime, member.mtime))
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class TopLevelDirRenamer:
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	def __init__(self, newName):
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		self.newName = newName
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	def __call__(self, oldPath):
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		return Path(self.newName, *oldPath.parts[1:])
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if __name__ == '__main__':
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	if 3 <= len(sys.argv) <= 4:
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		if len(sys.argv) == 4:
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			renameTopLevelDir = TopLevelDirRenamer(sys.argv[3])
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		else:
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			renameTopLevelDir = None
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		extract(sys.argv[1], sys.argv[2], renameTopLevelDir)
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	else:
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		print('Usage: python3 extract.py archive destination [new-top-level-dir]', file=sys.stderr)
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		sys.exit(2)