[PATCH 2 of 2] pager: don't run pager if nothing is written to stdout/stderr
Brodie Rao
brodie at bitheap.org
Sun Sep 19 10:59:08 CDT 2010
# HG changeset patch
# User Brodie Rao <brodie at bitheap.org>
# Date 1284911508 18000
# Node ID 5011b82fb81a1960b928216ccea2abe580fb61d1
# Parent 3ee6c8c332b6498af760708d1f7eb139c5f10edf
pager: don't run pager if nothing is written to stdout/stderr
This decides when to run the pager based on the first call to
ui.write() and ui.write_err(). This has the side effect of not the
output of subprocesses that write output before hg does.
diff --git a/hgext/pager.py b/hgext/pager.py
--- a/hgext/pager.py
+++ b/hgext/pager.py
@@ -22,6 +22,12 @@ To set the pager that should be used, se
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.
+By default, the pager is only executed if a command has output. To
+force the pager to run even if a command prints nothing, set::
+
+ [pager]
+ force = True
+
If you notice "BROKEN PIPE" error messages, you can disable them by
setting::
@@ -57,7 +63,7 @@ import sys, os, signal, shlex, errno
from mercurial import commands, dispatch, util, extensions
from mercurial.i18n import _
-def _runpager(p):
+def _runpager(p, sigpipe=False):
if not hasattr(os, 'fork'):
sys.stderr = sys.stdout = util.popen(p, 'wb')
return
@@ -68,6 +74,8 @@ def _runpager(p):
os.dup2(fdout, sys.stdout.fileno())
os.dup2(fdout, sys.stderr.fileno())
os.close(fdout)
+ if sigpipe:
+ signal.signal(signal.SIGPIPE, signal.SIG_DFL)
return
os.dup2(fdin, sys.stdin.fileno())
os.close(fdin)
@@ -86,6 +94,23 @@ def uisetup(ui):
if ui.plain():
return
+ class pagerui(ui.__class__):
+ _pager = None
+ _pagerstarted = False
+
+ def write(self, *args, **opts):
+ if self._pager and not self._pagerstarted:
+ self._pagerstarted = True
+ self._pager()
+ return super(pagerui, self).write(*args, **opts)
+
+ def write_err(self, *args, **opts):
+ if self._pager and not self._pagerstarted:
+ self._pagerstarted = True
+ self._pager()
+ return super(pagerui, self).write(*args, **opts)
+ ui.__class__ = pagerui
+
def pagecmd(orig, 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:
@@ -97,9 +122,11 @@ def uisetup(ui):
(cmd not in ui.configlist('pager', 'ignore') and not attend))):
ui.setconfig('ui', 'formatted', ui.formatted())
ui.setconfig('ui', 'interactive', False)
- _runpager(p)
- if ui.configbool('pager', 'quiet'):
- signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+ sigpipe = ui.configbool('pager', 'quiet')
+ if ui.configbool('pager', 'force'):
+ _runpager(p, sigpipe)
+ else:
+ ui._pager = lambda: _runpager(p, sigpipe)
return orig(ui, options, cmd, cmdfunc)
extensions.wrapfunction(dispatch, '_runcommand', pagecmd)
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