hgext/beautifygraph.py

extdiff: refactor logic which does diff of patches

The current extdiff code is hard to understand on first look. Took me few hours
to grasp the code. Before adding more things, decided to do some refactoring.

Differential Revision: https://phab.mercurial-scm.org/D8686

# -*- coding: UTF-8 -*-
# beautifygraph.py - improve graph output by using Unicode characters
#
# Copyright 2018 John Stiles <[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.

'''beautify log -G output by using Unicode characters (EXPERIMENTAL)

   A terminal with UTF-8 support and monospace narrow text are required.
'''

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    encoding,
    extensions,
    graphmod,
    pycompat,
    templatekw,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'


def prettyedge(before, edge, after):
    if edge == b'~':
        return b'\xE2\x95\xA7'  # U+2567 ╧
    if edge == b'/':
        return b'\xE2\x95\xB1'  # U+2571 ╱
    if edge == b'-':
        return b'\xE2\x94\x80'  # U+2500 ─
    if edge == b'|':
        return b'\xE2\x94\x82'  # U+2502 │
    if edge == b':':
        return b'\xE2\x94\x86'  # U+2506 ┆
    if edge == b'\\':
        return b'\xE2\x95\xB2'  # U+2572 ╲
    if edge == b'+':
        if before == b' ' and not after == b' ':
            return b'\xE2\x94\x9C'  # U+251C ├
        if after == b' ' and not before == b' ':
            return b'\xE2\x94\xA4'  # U+2524 ┤
        return b'\xE2\x94\xBC'  # U+253C ┼
    return edge


def convertedges(line):
    line = b' %s ' % line
    pretty = []
    for idx in pycompat.xrange(len(line) - 2):
        pretty.append(
            prettyedge(
                line[idx : idx + 1],
                line[idx + 1 : idx + 2],
                line[idx + 2 : idx + 3],
            )
        )
    return b''.join(pretty)


def getprettygraphnode(orig, *args, **kwargs):
    node = orig(*args, **kwargs)
    if node == b'o':
        return b'\xE2\x97\x8B'  # U+25CB ○
    if node == b'@':
        return b'\xE2\x97\x8D'  # U+25CD ◍
    if node == b'%':
        return b'\xE2\x97\x8D'  # U+25CE ◎
    if node == b'*':
        return b'\xE2\x88\x97'  # U+2217 ∗
    if node == b'x':
        return b'\xE2\x97\x8C'  # U+25CC ◌
    if node == b'_':
        return b'\xE2\x95\xA4'  # U+2564 ╤
    return node


def outputprettygraph(orig, ui, graph, *args, **kwargs):
    (edges, text) = zip(*graph)
    graph = zip([convertedges(e) for e in edges], text)
    return orig(ui, graph, *args, **kwargs)


def extsetup(ui):
    if ui.plain(b'graph'):
        return

    if encoding.encoding != b'UTF-8':
        ui.warn(_(b'beautifygraph: unsupported encoding, UTF-8 required\n'))
        return

    if 'A' in encoding._wide:
        ui.warn(
            _(
                b'beautifygraph: unsupported terminal settings, '
                b'monospace narrow text required\n'
            )
        )
        return

    extensions.wrapfunction(graphmod, b'outputgraph', outputprettygraph)
    extensions.wrapfunction(templatekw, b'getgraphnode', getprettygraphnode)