hgext/beautifygraph.py

branchmap: avoid ancestor computations in absence of non-continous branches

The branchhead computation is one of the more heavy operations for
bigger repositories as it has to scan all changesets and potentially
involves the expensive computation of the ancestor sets. Redo the
computation to handle the common cases directly and use tighter
conditions for when the ancestor scan is necessary. Most importantly,
avoid it completely if the non-continous branches are processed in one
update as seen in the initial computation after a clone.

For the Mercurial repository, it gives a small 2-3% performance boost.
For the NetBSD test repository, it cuts the time in half.

Differential Revision: https://phab.mercurial-scm.org/D9631

# -*- 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\x89'  # U+25C9 ◉
    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)