blob: 7086aefa5b24641ec087fdb8bca0ebb6849bcfaf [file] [log] [blame]
#
# Copyright (C) 2008 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import os
import select
import sys
active = False
def RunPager(globalConfig):
global active
if not os.isatty(0) or not os.isatty(1):
return
pager = _SelectPager(globalConfig)
if pager == '' or pager == 'cat':
return
# This process turns into the pager; a child it forks will
# do the real processing and output back to the pager. This
# is necessary to keep the pager in control of the tty.
#
try:
r, w = os.pipe()
pid = os.fork()
if not pid:
os.dup2(w, 1)
os.dup2(w, 2)
os.close(r)
os.close(w)
active = True
return
os.dup2(r, 0)
os.close(r)
os.close(w)
_BecomePager(pager)
except Exception:
print >>sys.stderr, "fatal: cannot start pager '%s'" % pager
sys.exit(255)
def _SelectPager(globalConfig):
try:
return os.environ['GIT_PAGER']
except KeyError:
pass
pager = globalConfig.GetString('core.pager')
if pager:
return pager
try:
return os.environ['PAGER']
except KeyError:
pass
return 'less'
def _BecomePager(pager):
# Delaying execution of the pager until we have output
# ready works around a long-standing bug in popularly
# available versions of 'less', a better 'more'.
#
a, b, c = select.select([0], [], [0])
os.environ['LESS'] = 'FRSX'
try:
os.execvp(pager, [pager])
except OSError, e:
os.execv('/bin/sh', ['sh', '-c', pager])