templates: add filter to reverse list
The filter supports only lists because for lists, it’s straightforward to
implement. Reversing text doesn’t seem very useful and is hard to implement.
Reversing the bytes would break multi-bytes encodings. Reversing the code
points would break characters consisting of multiple code points. Reversing
graphemes is non-trivial without using a library not included in the standard
library.
# coding: utf8
# ext-sidedata-2.py - small extension to test (differently) the sidedata logic
#
# Simulates a client for a complex sidedata exchange.
#
# Copyright 2021 Raphaël Gomès <rgomes@octobus.net>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import hashlib
import struct
from mercurial.revlogutils import sidedata as sidedatamod
from mercurial.revlogutils import constants
NO_FLAGS = (0, 0) # hoot
def compute_sidedata_1(repo, revlog, rev, sidedata, text=None):
sidedata = sidedata.copy()
if text is None:
text = revlog.revision(rev)
sidedata[sidedatamod.SD_TEST1] = struct.pack('>I', len(text))
return sidedata, NO_FLAGS
def compute_sidedata_2(repo, revlog, rev, sidedata, text=None):
sidedata = sidedata.copy()
if text is None:
text = revlog.revision(rev)
sha256 = hashlib.sha256(text).digest()
sidedata[sidedatamod.SD_TEST2] = struct.pack('>32s', sha256)
return sidedata, NO_FLAGS
def reposetup(ui, repo):
# Sidedata keys happen to be the same as the categories, easier for testing.
for kind in constants.ALL_KINDS:
repo.register_sidedata_computer(
kind,
sidedatamod.SD_TEST1,
(sidedatamod.SD_TEST1,),
compute_sidedata_1,
0,
)
repo.register_sidedata_computer(
kind,
sidedatamod.SD_TEST2,
(sidedatamod.SD_TEST2,),
compute_sidedata_2,
0,
)