view mercurial/cffi/mpatch.py @ 48652:6fd9a17c32ab

requirements: add an official `REVLOG_COMPRESSION_ZSTD` const

Such constant was missing and its value was missing from the set of requirements
that needs to be preserved through stream clone. This did not had any
consequence yet as the "bundle 2 does not filter its requirements" is shadowing
the issue.

However we are now in a situation where we can fix this issue. So lets do it
next.

With the preparation work on test, changing the streamreqs value only impact two
tests, where checking the full value seems to remains relevant.

Important note: Since older version of Mercurial used the old `supportedformat`
class attribute to check for stream requirement they supported, older version
will consider this requirements to prevent them from using streaming clone. Even
as they support this requirements for years. Pack for stable will be send to fix
it, but they will have to be backported to older version if needed.

Differential Revision: https://phab.mercurial-scm.org/D12083

# mpatch.py - CFFI implementation of mpatch.c
#
# Copyright 2016 Maciej Fijalkowski <[e-mail]>
#
# 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 absolute_import

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(b"struct mpatch_flist*[1]")
    to_pass = ffi.new(b"char[]", str(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, bins):
    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(b"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