mercurial/scmposix.py

context: introduce p[12]copies() methods and debugp[12]copies commands

As mentioned earlier, I'm working on support for storing copy metadata
in the changeset instead of in the filelog.

In order to transition a repo from storing metadata in filelogs to
storing it in the changeset, I'm going to provide a config option for
reading the metadata from the changeset, but falling back to getting
it from the filelog if it's not in the changeset. In this compatiblity
mode, the changeset-optmized algorithms will be used. We will then
need to convert the filelog copy metadata to look like that provided
by changeset copy metadata. This patch introduces methods that do just
that.

By having these methods here, we can start writing changeset-optimized
algorithms that should work already before we add any support for
storing the metadata in the changesets.

This commit also includes new debugp[12]copies commands and exercises
them in test-copies.t.

Differential Revision: https://phab.mercurial-scm.org/D5990

from __future__ import absolute_import

import array
import errno
import fcntl
import os
import sys

from . import (
    encoding,
    pycompat,
    util,
)

# BSD 'more' escapes ANSI color sequences by default. This can be disabled by
# $MORE variable, but there's no compatible option with Linux 'more'. Given
# OS X is widely used and most modern Unix systems would have 'less', setting
# 'less' as the default seems reasonable.
fallbackpager = 'less'

def _rcfiles(path):
    rcs = [os.path.join(path, 'hgrc')]
    rcdir = os.path.join(path, 'hgrc.d')
    try:
        rcs.extend([os.path.join(rcdir, f)
                    for f, kind in util.listdir(rcdir)
                    if f.endswith(".rc")])
    except OSError:
        pass
    return rcs

def systemrcpath():
    path = []
    if pycompat.sysplatform == 'plan9':
        root = 'lib/mercurial'
    else:
        root = 'etc/mercurial'
    # old mod_python does not set sys.argv
    if len(getattr(sys, 'argv', [])) > 0:
        p = os.path.dirname(os.path.dirname(pycompat.sysargv[0]))
        if p != '/':
            path.extend(_rcfiles(os.path.join(p, root)))
    path.extend(_rcfiles('/' + root))
    return path

def userrcpath():
    if pycompat.sysplatform == 'plan9':
        return [encoding.environ['home'] + '/lib/hgrc']
    elif pycompat.isdarwin:
        return [os.path.expanduser('~/.hgrc')]
    else:
        confighome = encoding.environ.get('XDG_CONFIG_HOME')
        if confighome is None or not os.path.isabs(confighome):
            confighome = os.path.expanduser('~/.config')

        return [os.path.expanduser('~/.hgrc'),
                os.path.join(confighome, 'hg', 'hgrc')]

def termsize(ui):
    try:
        import termios
        TIOCGWINSZ = termios.TIOCGWINSZ  # unavailable on IRIX (issue3449)
    except (AttributeError, ImportError):
        return 80, 24

    for dev in (ui.ferr, ui.fout, ui.fin):
        try:
            try:
                fd = dev.fileno()
            except AttributeError:
                continue
            if not os.isatty(fd):
                continue
            arri = fcntl.ioctl(fd, TIOCGWINSZ, '\0' * 8)
            height, width = array.array(r'h', arri)[:2]
            if width > 0 and height > 0:
                return width, height
        except ValueError:
            pass
        except IOError as e:
            if e[0] == errno.EINVAL:
                pass
            else:
                raise
    return 80, 24