hgext/pager.py

revset: add destination() predicate

This predicate is used to find csets that were created because of a graft,
transplant or rebase --keep.  An optional revset can be supplied, in which case
the result will be limited to those copies which specified one of the revs as
the source for the command.

    hg log -r destination()                 # csets copied from anywhere
    hg log -r destination(branch(default))  # all csets copied from default

    hg log -r origin(x) or destination(origin(x))  # all instances of x

This predicate will follow a cset through different types of copies.  Given a
repo with a cset 'S' that is grafted to create G(S), which itself is
transplanted to become T(G(S)):

    o-S
   /
  o-o-G(S)
   \
    o-T(G(S))

    hg log -r destination( S )    # { G(S), T(G(S)) }
    hg log -r destination( G(S) ) # { T(G(S)) }

The implementation differences between the three different copy commands (see
the origin() predicate) are not intentionally exposed, however if the
transplant was a graft instead:

	hg log -r destination( G(S) )   # {}

because the 'extra' field in G(G(S)) is S, not G(S).  The implementation cannot
correct this by following sources before G(S) and then select the csets that
reference those sources because the cset provided to the predicate would also
end up selected.  If there were more than two copies, sources of the argument
would also get selected.

Note that the convert extension does not currently update the 'extra' map in its
destination csets, and therefore copies made prior to the convert will be
missing from the resulting set.

Instead of the loop over 'subset', the following almost works, but does not
select a transplant of a transplant.  That is, 'destination(S)' will only
select T(S).

    dests = set([r for r in subset if _getrevsource(repo, r) in args])

# pager.py - display output using a pager
#
# Copyright 2008 David Soria Parra <[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.
#
# To load the extension, add it to your configuration file:
#
#   [extension]
#   pager =
#
# Run "hg help pager" to get info on configuration.

'''browse command output with an external pager

To set the pager that should be used, set the application variable::

  [pager]
  pager = less -FRSX

If no pager is set, the pager extensions uses the environment variable
$PAGER. If neither pager.pager, nor $PAGER is set, no pager is used.

You can disable the pager for certain commands by adding them to the
pager.ignore list::

  [pager]
  ignore = version, help, update

You can also enable the pager only for certain commands using
pager.attend. Below is the default list of commands to be paged::

  [pager]
  attend = annotate, cat, diff, export, glog, log, qdiff

Setting pager.attend to an empty value will cause all commands to be
paged.

If pager.attend is present, pager.ignore will be ignored.

To ignore global commands like :hg:`version` or :hg:`help`, you have
to specify them in your user configuration file.

The --pager=... option can also be used to control when the pager is
used. Use a boolean value like yes, no, on, off, or use auto for
normal behavior.
'''

import atexit, sys, os, signal, subprocess
from mercurial import commands, dispatch, util, extensions
from mercurial.i18n import _

testedwith = 'internal'

def _runpager(ui, p):
    pager = subprocess.Popen(p, shell=True, bufsize=-1,
                             close_fds=util.closefds, stdin=subprocess.PIPE,
                             stdout=sys.stdout, stderr=sys.stderr)

    stdout = os.dup(sys.stdout.fileno())
    stderr = os.dup(sys.stderr.fileno())
    os.dup2(pager.stdin.fileno(), sys.stdout.fileno())
    if ui._isatty(sys.stderr):
        os.dup2(pager.stdin.fileno(), sys.stderr.fileno())

    @atexit.register
    def killpager():
        pager.stdin.close()
        os.dup2(stdout, sys.stdout.fileno())
        os.dup2(stderr, sys.stderr.fileno())
        pager.wait()

def uisetup(ui):
    if '--debugger' in sys.argv or not ui.formatted():
        return

    def pagecmd(orig, ui, options, cmd, cmdfunc):
        p = ui.config("pager", "pager", os.environ.get("PAGER"))

        if p:
            attend = ui.configlist('pager', 'attend', attended)
            auto = options['pager'] == 'auto'
            always = util.parsebool(options['pager'])
            if (always or auto and
                (cmd in attend or
                 (cmd not in ui.configlist('pager', 'ignore') and not attend))):
                ui.setconfig('ui', 'formatted', ui.formatted())
                ui.setconfig('ui', 'interactive', False)
                if util.safehasattr(signal, "SIGPIPE"):
                    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
                _runpager(ui, p)
        return orig(ui, options, cmd, cmdfunc)

    extensions.wrapfunction(dispatch, '_runcommand', pagecmd)

def extsetup(ui):
    commands.globalopts.append(
        ('', 'pager', 'auto',
         _("when to paginate (boolean, always, auto, or never)"),
         _('TYPE')))

attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']