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# Copyright (c) 2009, 2010 hut <hut@lavabit.com>
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""
This module is an abstract layer over subprocess.Popen
It gives you highlevel control about how processes are run.
Example:
run = Runner(logfunc=print)
run('sleep 2', wait=True) # waits until the process exists
run(['ls', '--help'], flags='p') # pipes output to pager
run() # prints an error message
List of allowed flags:
s: silent mode. output will be discarded.
d: detach the process.
p: redirect output to the pager
(An uppercase key ensures that a certain flag will not be used.)
"""
import os
import sys
from subprocess import Popen, PIPE
from ranger.ext.waitpid_no_intr import waitpid_no_intr
ALLOWED_FLAGS = 'sdpSDP'
devnull = open(os.devnull, 'a')
class Context(object):
"""
A context object contains data on how to run a process.
The attributes are:
action -- a string with a command or a list of arguments for
the Popen call.
app -- the name of the app function. ("vim" for app_vim.)
app is used to get an action if the user didn't specify one.
mode -- a number, mainly used in determining the action in app_xyz()
flags -- a string with flags which change the way programs are run
files -- a list containing files, mainly used in app_xyz
file -- an arbitrary file from that list (or None)
fm -- the filemanager instance
wait -- boolean, wait for the end or execute programs in parallel?
popen_kws -- keyword arguments which are directly passed to Popen
"""
def __init__(self, **keywords):
self.__dict__ = keywords
@property
def filepaths(self):
try:
return [f.path for f in self.files]
except:
return []
def __iter__(self):
"""Iterate over file paths"""
for item in self.filepaths:
yield item
def squash_flags(self):
"""Remove duplicates and lowercase counterparts of uppercase flags"""
for flag in self.flags:
if ord(flag) <= 90:
bad = flag + flag.lower()
self.flags = ''.join(c for c in self.flags if c not in bad)
class Runner(object):
def __init__(self, ui=None, logfunc=None, apps=None):
self.ui = ui
self.logfunc = logfunc
self.apps = apps
def _log(self, text):
try:
self.logfunc(text)
except TypeError:
pass
return False
def _activate_ui(self, boolean):
if self.ui is not None:
if boolean:
try: self.ui.initialize()
except: self._log("Failed to initialize UI")
else:
try: self.ui.suspend()
except: self._log("Failed to suspend UI")
def __call__(self, action=None, try_app_first=False,
app='default', files=None, mode=0,
flags='', wait=True, **popen_kws):
"""
Run the application in the way specified by the options.
Returns False if nothing can be done, None if there was an error,
otherwise the process object returned by Popen().
This function tries to find an action if none is defined.
"""
# Find an action if none was supplied by
# creating a Context object and passing it to
# an Application object.
context = Context(app=app, files=files, mode=mode,
flags=flags, wait=wait, popen_kws=popen_kws,
file=files and files[0] or None)
if self.apps:
if try_app_first and action is not None:
test = self.apps.apply(app, context)
if test:
action = test
if action is None:
action = self.apps.apply(app, context)
if action is None:
return self._log("No action found!")
if action is None:
return self._log("No way of determining the action!")
# Preconditions
context.squash_flags()
popen_kws = context.popen_kws # shortcut
toggle_ui = True
pipe_output = False
popen_kws['args'] = action
if 'shell' not in popen_kws:
popen_kws['shell'] = isinstance(action, str)
if 'stdout' not in popen_kws:
popen_kws['stdout'] = sys.stdout
if 'stderr' not in popen_kws:
popen_kws['stderr'] = sys.stderr
# Evaluate the flags to determine keywords
# for Popen() and other variables
if 'p' in context.flags:
popen_kws['stdout'] = PIPE
popen_kws['stderr'] = PIPE
toggle_ui = False
pipe_output = True
context.wait = False
if 's' in context.flags or 'd' in context.flags:
for key in ('stdout', 'stderr', 'stdin'):
popen_kws[key] = devnull
if 'd' in context.flags:
toggle_ui = False
context.wait = False
# Finally, run it
if toggle_ui:
self._activate_ui(False)
try:
process = None
try:
process = Popen(**popen_kws)
except:
self._log("Failed to run: " + str(action))
else:
if context.wait:
waitpid_no_intr(process.pid)
finally:
if toggle_ui:
self._activate_ui(True)
if pipe_output and process:
return self(action='less', app='pager', try_app_first=True,
stdin=process.stdout)
return process
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