mirror of
https://github.com/thegeeklab/ansible-later.git
synced 2024-11-14 17:20:39 +00:00
208 lines
7.2 KiB
Python
208 lines
7.2 KiB
Python
"""Module with functions which are supposed to be as fast as possible"""
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from stat import S_ISDIR
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from git.compat import (
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byte_ord,
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safe_decode,
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defenc,
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xrange,
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text_type,
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bchr
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)
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__all__ = ('tree_to_stream', 'tree_entries_from_data', 'traverse_trees_recursive',
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'traverse_tree_recursive')
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def tree_to_stream(entries, write):
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"""Write the give list of entries into a stream using its write method
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:param entries: **sorted** list of tuples with (binsha, mode, name)
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:param write: write method which takes a data string"""
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ord_zero = ord('0')
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bit_mask = 7 # 3 bits set
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for binsha, mode, name in entries:
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mode_str = b''
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for i in xrange(6):
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mode_str = bchr(((mode >> (i * 3)) & bit_mask) + ord_zero) + mode_str
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# END for each 8 octal value
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# git slices away the first octal if its zero
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if byte_ord(mode_str[0]) == ord_zero:
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mode_str = mode_str[1:]
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# END save a byte
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# here it comes: if the name is actually unicode, the replacement below
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# will not work as the binsha is not part of the ascii unicode encoding -
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# hence we must convert to an utf8 string for it to work properly.
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# According to my tests, this is exactly what git does, that is it just
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# takes the input literally, which appears to be utf8 on linux.
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if isinstance(name, text_type):
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name = name.encode(defenc)
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write(b''.join((mode_str, b' ', name, b'\0', binsha)))
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# END for each item
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def tree_entries_from_data(data):
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"""Reads the binary representation of a tree and returns tuples of Tree items
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:param data: data block with tree data (as bytes)
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:return: list(tuple(binsha, mode, tree_relative_path), ...)"""
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ord_zero = ord('0')
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space_ord = ord(' ')
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len_data = len(data)
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i = 0
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out = []
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while i < len_data:
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mode = 0
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# read mode
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# Some git versions truncate the leading 0, some don't
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# The type will be extracted from the mode later
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while byte_ord(data[i]) != space_ord:
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# move existing mode integer up one level being 3 bits
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# and add the actual ordinal value of the character
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mode = (mode << 3) + (byte_ord(data[i]) - ord_zero)
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i += 1
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# END while reading mode
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# byte is space now, skip it
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i += 1
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# parse name, it is NULL separated
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ns = i
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while byte_ord(data[i]) != 0:
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i += 1
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# END while not reached NULL
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# default encoding for strings in git is utf8
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# Only use the respective unicode object if the byte stream was encoded
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name = data[ns:i]
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name = safe_decode(name)
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# byte is NULL, get next 20
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i += 1
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sha = data[i:i + 20]
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i = i + 20
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out.append((sha, mode, name))
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# END for each byte in data stream
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return out
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def _find_by_name(tree_data, name, is_dir, start_at):
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"""return data entry matching the given name and tree mode
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or None.
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Before the item is returned, the respective data item is set
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None in the tree_data list to mark it done"""
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try:
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item = tree_data[start_at]
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if item and item[2] == name and S_ISDIR(item[1]) == is_dir:
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tree_data[start_at] = None
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return item
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except IndexError:
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pass
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# END exception handling
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for index, item in enumerate(tree_data):
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if item and item[2] == name and S_ISDIR(item[1]) == is_dir:
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tree_data[index] = None
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return item
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# END if item matches
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# END for each item
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return None
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def _to_full_path(item, path_prefix):
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"""Rebuild entry with given path prefix"""
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if not item:
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return item
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return (item[0], item[1], path_prefix + item[2])
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def traverse_trees_recursive(odb, tree_shas, path_prefix):
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"""
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:return: list with entries according to the given binary tree-shas.
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The result is encoded in a list
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of n tuple|None per blob/commit, (n == len(tree_shas)), where
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* [0] == 20 byte sha
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* [1] == mode as int
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* [2] == path relative to working tree root
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The entry tuple is None if the respective blob/commit did not
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exist in the given tree.
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:param tree_shas: iterable of shas pointing to trees. All trees must
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be on the same level. A tree-sha may be None in which case None
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:param path_prefix: a prefix to be added to the returned paths on this level,
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set it '' for the first iteration
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:note: The ordering of the returned items will be partially lost"""
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trees_data = []
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nt = len(tree_shas)
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for tree_sha in tree_shas:
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if tree_sha is None:
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data = []
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else:
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data = tree_entries_from_data(odb.stream(tree_sha).read())
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# END handle muted trees
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trees_data.append(data)
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# END for each sha to get data for
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out = []
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out_append = out.append
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# find all matching entries and recursively process them together if the match
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# is a tree. If the match is a non-tree item, put it into the result.
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# Processed items will be set None
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for ti, tree_data in enumerate(trees_data):
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for ii, item in enumerate(tree_data):
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if not item:
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continue
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# END skip already done items
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entries = [None for _ in range(nt)]
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entries[ti] = item
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sha, mode, name = item # its faster to unpack @UnusedVariable
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is_dir = S_ISDIR(mode) # type mode bits
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# find this item in all other tree data items
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# wrap around, but stop one before our current index, hence
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# ti+nt, not ti+1+nt
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for tio in range(ti + 1, ti + nt):
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tio = tio % nt
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entries[tio] = _find_by_name(trees_data[tio], name, is_dir, ii)
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# END for each other item data
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# if we are a directory, enter recursion
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if is_dir:
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out.extend(traverse_trees_recursive(
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odb, [((ei and ei[0]) or None) for ei in entries], path_prefix + name + '/'))
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else:
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out_append(tuple(_to_full_path(e, path_prefix) for e in entries))
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# END handle recursion
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# finally mark it done
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tree_data[ii] = None
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# END for each item
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# we are done with one tree, set all its data empty
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del(tree_data[:])
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# END for each tree_data chunk
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return out
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def traverse_tree_recursive(odb, tree_sha, path_prefix):
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"""
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:return: list of entries of the tree pointed to by the binary tree_sha. An entry
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has the following format:
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* [0] 20 byte sha
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* [1] mode as int
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* [2] path relative to the repository
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:param path_prefix: prefix to prepend to the front of all returned paths"""
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entries = []
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data = tree_entries_from_data(odb.stream(tree_sha).read())
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# unpacking/packing is faster than accessing individual items
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for sha, mode, name in data:
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if S_ISDIR(mode):
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entries.extend(traverse_tree_recursive(odb, sha, path_prefix + name + '/'))
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else:
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entries.append((sha, mode, path_prefix + name))
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# END for each item
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return entries
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