78 lines
2.4 KiB
Python
78 lines
2.4 KiB
Python
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"""shutil-like functionality while compressing blendfiles on the fly."""
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import gzip
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import logging
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import pathlib
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import shutil
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log = logging.getLogger(__name__)
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# Arbitrarily chosen block size, in bytes.
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BLOCK_SIZE = 256 * 2 ** 10
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def move(src: pathlib.Path, dest: pathlib.Path):
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"""Move a file from src to dest, gzip-compressing if not compressed yet.
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Only compresses files ending in .blend; others are moved as-is.
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"""
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my_log = log.getChild('move')
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my_log.debug('Moving %s to %s', src, dest)
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if src.suffix.lower() == '.blend':
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_move_or_copy(src, dest, my_log, source_must_remain=False)
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else:
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shutil.move(str(src), str(dest))
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def copy(src: pathlib.Path, dest: pathlib.Path):
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"""Copy a file from src to dest, gzip-compressing if not compressed yet.
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Only compresses files ending in .blend; others are copied as-is.
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"""
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my_log = log.getChild('copy')
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my_log.debug('Copying %s to %s', src, dest)
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if src.suffix.lower() == '.blend':
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_move_or_copy(src, dest, my_log, source_must_remain=True)
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else:
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shutil.copy2(str(src), str(dest))
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def _move_or_copy(src: pathlib.Path, dest: pathlib.Path,
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my_log: logging.Logger,
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*,
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source_must_remain: bool):
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"""Either move or copy a file, gzip-compressing if not compressed yet.
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:param src: File to copy/move.
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:param dest: Path to copy/move to.
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:source_must_remain: True to copy, False to move.
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:my_log: Logger to use for logging.
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"""
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srcfile = src.open('rb')
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try:
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first_bytes = srcfile.read(2)
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if first_bytes == b'\x1f\x8b':
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# Already a gzipped file.
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srcfile.close()
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my_log.debug('Source file %s is GZipped already', src)
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if source_must_remain:
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shutil.copy2(str(src), str(dest))
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else:
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shutil.move(str(src), str(dest))
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return
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my_log.debug('Compressing %s on the fly while copying to %s', src, dest)
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with gzip.open(str(dest), mode='wb') as destfile:
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destfile.write(first_bytes)
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shutil.copyfileobj(srcfile, destfile, BLOCK_SIZE)
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srcfile.close()
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if not source_must_remain:
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my_log.debug('Deleting source file %s', src)
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src.unlink()
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finally:
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if not srcfile.closed:
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srcfile.close()
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