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