mercurial/cffi/mpatch.py
author Manuel Jacob <me@manueljacob.de>
Tue, 06 Aug 2024 17:53:59 +0200
branchstable
changeset 51788 472699b5ddb3
parent 51786 ecc3a893979d
child 51859 f4733654f144
permissions -rw-r--r--
cffi: pass bytes instead of str to ffi.new("char[]", ?) The type annotations seem to imply that the passed values are always already bytes, but they aren?t necessarily. Before Python 3.11, the documentation stated that bytes can be used to annotate arguments whose type is actually any of bytes, bytearray, or memoryview.

# mpatch.py - CFFI implementation of mpatch.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 typing import List

from ..pure.mpatch import *
from ..pure.mpatch import mpatchError  # silence pyflakes
from . import _mpatch  # pytype: disable=import-error

ffi = _mpatch.ffi
lib = _mpatch.lib


@ffi.def_extern()
def cffi_get_next_item(arg, pos):
    all, bins = ffi.from_handle(arg)
    container = ffi.new("struct mpatch_flist*[1]")
    to_pass = ffi.new("char[]", bytes(bins[pos]))
    all.append(to_pass)
    r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container)
    if r < 0:
        return ffi.NULL
    return container[0]


def patches(text: bytes, bins: List[bytes]) -> bytes:
    lgt = len(bins)
    all = []
    if not lgt:
        return text
    arg = (all, bins)
    patch = lib.mpatch_fold(ffi.new_handle(arg), lib.cffi_get_next_item, 0, lgt)
    if not patch:
        raise mpatchError(b"cannot decode chunk")
    outlen = lib.mpatch_calcsize(len(text), patch)
    if outlen < 0:
        lib.mpatch_lfree(patch)
        raise mpatchError(b"inconsistency detected")
    buf = ffi.new("char[]", outlen)
    if lib.mpatch_apply(buf, text, len(text), patch) < 0:
        lib.mpatch_lfree(patch)
        raise mpatchError(b"error applying patches")
    res = ffi.buffer(buf, outlen)[:]
    lib.mpatch_lfree(patch)
    return res