hgext/pager.py

Do not try to load extensions twice (issue811)

# 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, incorporated herein by reference.
#
# To load the extension, add it to your .hgrc file:
#
#   [extension]
#   hgext.pager =
#
# Run "hg help pager" to get info on configuration.

'''browse command output with external pager

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

  [pager]
  pager = LESS='FSRX' less

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.

If you notice "BROKEN PIPE" error messages, you can disable them
by setting:

  [pager]
  quiet = True

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:

  [pager]
  attend = log

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 the global .hgrc
'''

import sys, os, signal
from mercurial import dispatch, util

def uisetup(ui):
    def pagecmd(ui, options, cmd, cmdfunc):
        p = ui.config("pager", "pager", os.environ.get("PAGER"))
        if p and sys.stdout.isatty() and '--debugger' not in sys.argv:
            attend = ui.configlist('pager', 'attend')
            if (cmd in attend or
                (cmd not in ui.configlist('pager', 'ignore') and not attend)):
                sys.stderr = sys.stdout = util.popen(p, "wb")
                if ui.configbool('pager', 'quiet'):
                    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
        return oldrun(ui, options, cmd, cmdfunc)

    oldrun = dispatch._runcommand
    dispatch._runcommand = pagecmd