git-repo/pager.py
Shawn O. Pearce 8f82a4f828 Don't start the pager if stdout is a pipe
The repo script often uses a pager by default and will produce
control characters (coloring) to standard output when using the
pager, even if the output is redirected to another pipe or script.
This is because the pager setup checked for the terminal presence
on FD 0, and in case of redirection FD 0 is still attached to
the terminal.

Instead require that both FD 0 and FD 1 are connected to the terminal
in order to start the pager.

Bug: REPO-19, b.android.com/2004
Signed-off-by: Shawn O. Pearce <sop@google.com>
2009-04-01 07:24:22 -07:00

85 lines
2.0 KiB
Python
Executable File

#
# 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
os.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])