80 lines
2.1 KiB
Python
80 lines
2.1 KiB
Python
import marisa_trie
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import os
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import tarfile
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AUFS_METADATA = u'.wh..wh.'
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AUFS_WHITEOUT = u'.wh.'
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AUFS_WHITEOUT_PREFIX_LENGTH = len(AUFS_WHITEOUT)
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ALLOWED_TYPES = {tarfile.REGTYPE, tarfile.AREGTYPE}
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def files_and_dirs_from_tar(source_stream, removed_prefix_collector):
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tar_stream = tarfile.open(mode='r|*', fileobj=source_stream)
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for tar_info in tar_stream:
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absolute = os.path.relpath(tar_info.name.decode('utf-8'), './')
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dirname = os.path.dirname(absolute)
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filename = os.path.basename(absolute)
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# Skip directories and metadata
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if (filename.startswith(AUFS_METADATA) or
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absolute.startswith(AUFS_METADATA)):
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# Skip
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continue
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elif filename.startswith(AUFS_WHITEOUT):
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removed_filename = filename[AUFS_WHITEOUT_PREFIX_LENGTH:]
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removed_prefix = os.path.join('/', dirname, removed_filename)
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removed_prefix_collector.add(removed_prefix)
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continue
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elif tar_info.type in ALLOWED_TYPES:
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yield '/' + absolute
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def __compute_removed(base_trie, removed_prefixes):
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for prefix in removed_prefixes:
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for filename in base_trie.keys(prefix):
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yield filename
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def __compute_added_changed(base_trie, delta_trie):
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added = set()
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changed = set()
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for filename in delta_trie.keys():
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if filename not in base_trie:
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added.add(filename)
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else:
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changed.add(filename)
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return added, changed
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def __new_fs(base_trie, added, removed):
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for filename in base_trie.keys():
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if filename not in removed:
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yield filename
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for filename in added:
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yield filename
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def empty_fs():
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return marisa_trie.Trie()
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def compute_new_diffs_and_fs(base_trie, filename_source,
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removed_prefix_collector):
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new_trie = marisa_trie.Trie(filename_source)
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(new_added, new_changed) = __compute_added_changed(base_trie, new_trie)
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new_removed = marisa_trie.Trie(__compute_removed(base_trie,
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removed_prefix_collector))
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new_fs = marisa_trie.Trie(__new_fs(base_trie, new_added, new_removed))
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return (new_fs, new_added, new_changed, new_removed.keys())
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