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"""Module with functions which are supposed to be as fast as possible"""
from stat import S_ISDIR
from git.compat import safe_decode, defenc
# typing ----------------------------------------------
from typing import (
Callable,
List,
MutableSequence,
Sequence,
Tuple,
TYPE_CHECKING,
Union,
overload,
)
if TYPE_CHECKING:
from _typeshed import ReadableBuffer
from git import GitCmdObjectDB
EntryTup = Tuple[bytes, int, str] # same as TreeCacheTup in tree.py
EntryTupOrNone = Union[EntryTup, None]
# ---------------------------------------------------
__all__ = (
"tree_to_stream",
"tree_entries_from_data",
"traverse_trees_recursive",
"traverse_tree_recursive",
)
def tree_to_stream(entries: Sequence[EntryTup], write: Callable[["ReadableBuffer"], Union[int, None]]) -> None:
"""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 = b""
for i in range(6):
mode_str = bytes([((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] == ord_zero:
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, str):
name_bytes = name.encode(defenc)
else:
name_bytes = name # type: ignore[unreachable] # check runtime types - is always str?
write(b"".join((mode_str, b" ", name_bytes, b"\0", binsha)))
# END for each item
def tree_entries_from_data(data: bytes) -> List[EntryTup]:
"""Reads the binary representation of a tree and returns tuples of Tree items
:param data: data block with tree data (as bytes)
:return: list(tuple(binsha, mode, tree_relative_path), ...)"""
ord_zero = ord("0")
space_ord = ord(" ")
len_data = len(data)
i = 0
out = []
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] != space_ord:
# move existing mode integer up one level being 3 bits
# and add the actual ordinal value of the character
mode = (mode << 3) + (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_bytes = data[ns:i]
name = safe_decode(name_bytes)
# 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: MutableSequence[EntryTupOrNone], name: str, is_dir: bool, start_at: int) -> EntryTupOrNone:
"""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
@overload
def _to_full_path(item: None, path_prefix: str) -> None:
...
@overload
def _to_full_path(item: EntryTup, path_prefix: str) -> EntryTup:
...
def _to_full_path(item: EntryTupOrNone, path_prefix: str) -> EntryTupOrNone:
"""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: "GitCmdObjectDB", tree_shas: Sequence[Union[bytes, None]], path_prefix: str
) -> List[Tuple[EntryTupOrNone, ...]]:
"""
:return: list of 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[List[EntryTupOrNone]] = []
nt = len(tree_shas)
for tree_sha in tree_shas:
if tree_sha is None:
data: List[EntryTupOrNone] = []
else:
# make new list for typing as list invariant
data = list(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[Tuple[EntryTupOrNone, ...]] = []
# 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: List[EntryTupOrNone]
entries = [None for _ in range(nt)]
entries[ti] = item
_sha, mode, name = item
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: "GitCmdObjectDB", tree_sha: bytes, path_prefix: str) -> List[EntryTup]:
"""
: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 = []
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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