mdiff: convert a few block definitions from lists to tuples
These were flagged by adding type hints. Some places were using a tuple of 4
ints to define a block, and others were using a list of 4. A tuple is better
for typing, because we can define the length and the type of each entry. One of
the places had to redefine the tuple, since writing to a tuple at an index isn't
supported.
This change spills out into the tests, and archeology says it was added to the
repo in this state. There was no reason given for the divergence, and I suspect
it wasn't intentional.
It looks like `splitblock()` is completely unused in the codebase.
# bdiff.py - CFFI implementation of bdiff.c
#
# Copyright 2016 Maciej Fijalkowski <fijall@gmail.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import annotations
import struct
import typing
from typing import (
List,
Optional,
Tuple,
)
from ..pure.bdiff import *
from ..interfaces import (
modules as intmod,
)
from . import _bdiff # pytype: disable=import-error
ffi = _bdiff.ffi
lib = _bdiff.lib
def blocks(sa: bytes, sb: bytes) -> List[Tuple[int, int, int, int]]:
a = ffi.new("struct bdiff_line**")
b = ffi.new("struct bdiff_line**")
ac = ffi.new("char[]", bytes(sa))
bc = ffi.new("char[]", bytes(sb))
l = ffi.new("struct bdiff_hunk*")
try:
an = lib.bdiff_splitlines(ac, len(sa), a)
bn = lib.bdiff_splitlines(bc, len(sb), b)
if not a[0] or not b[0]:
raise MemoryError
count = lib.bdiff_diff(a[0], an, b[0], bn, l)
if count < 0:
raise MemoryError
rl = [(0, 0, 0, 0)] * count
h = l.next
i = 0
while h:
rl[i] = (h.a1, h.a2, h.b1, h.b2)
h = h.next
i += 1
finally:
lib.free(a[0])
lib.free(b[0])
lib.bdiff_freehunks(l.next)
return rl
def bdiff(sa: bytes, sb: bytes) -> bytes:
a = ffi.new("struct bdiff_line**")
b = ffi.new("struct bdiff_line**")
ac = ffi.new("char[]", bytes(sa))
bc = ffi.new("char[]", bytes(sb))
l = ffi.new("struct bdiff_hunk*")
try:
an = lib.bdiff_splitlines(ac, len(sa), a)
bn = lib.bdiff_splitlines(bc, len(sb), b)
if not a[0] or not b[0]:
raise MemoryError
count = lib.bdiff_diff(a[0], an, b[0], bn, l)
if count < 0:
raise MemoryError
rl = []
h = l.next
la = lb = 0
while h:
if h.a1 != la or h.b1 != lb:
lgt = (b[0] + h.b1).l - (b[0] + lb).l
rl.append(
struct.pack(
b">lll",
(a[0] + la).l - a[0].l,
(a[0] + h.a1).l - a[0].l,
lgt,
)
)
rl.append(bytes(ffi.buffer((b[0] + lb).l, lgt)))
la = h.a2
lb = h.b2
h = h.next
finally:
lib.free(a[0])
lib.free(b[0])
lib.bdiff_freehunks(l.next)
return b"".join(rl)
# In order to adhere to the module protocol, these functions must be visible to
# the type checker, though they aren't actually implemented by this
# implementation of the module protocol. Callers are responsible for
# checking that the implementation is available before using them.
if typing.TYPE_CHECKING:
xdiffblocks: Optional[intmod.BDiffBlocksFnc] = None