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# This file is part of ranger, the console file manager.
# License: GNU GPL version 3, see the file "AUTHORS" for details.
"""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.
f: fork the process.
p: redirect output to the pager
c: run only the current file (not handled here)
w: wait for enter-press afterwards
r: run application with root privilege (requires sudo)
t: run application in a new terminal window
(An uppercase key negates the respective lower case flag)
"""
from __future__ import (absolute_import, division, print_function)
import logging
import os
import sys
from subprocess import Popen, PIPE, STDOUT
from ranger.ext.get_executables import get_executables, get_term
from ranger.ext.popen_forked import Popen_forked
LOG = logging.getLogger(__name__)
# TODO: Remove unused parts of runner.py
# ALLOWED_FLAGS = 'sdpwcrtSDPWCRT'
ALLOWED_FLAGS = 'cfrtCFRT'
def press_enter():
"""Wait for an ENTER-press"""
sys.stdout.write("Press ENTER to continue")
try:
waitfnc = raw_input
except NameError:
# "raw_input" not available in python3
waitfnc = input
waitfnc()
class Context(object): # pylint: disable=too-many-instance-attributes
"""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__( # pylint: disable=redefined-builtin,too-many-arguments
self, action=None, app=None, mode=None, flags=None,
files=None, file=None, fm=None, wait=None, popen_kws=None):
self.action = action
self.app = app
self.mode = mode
self.flags = flags
self.files = files
self.file = file
self.fm = fm
self.wait = wait
self.popen_kws = popen_kws
@property
def filepaths(self):
try:
return [f.path for f in self.files]
except AttributeError:
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): # pylint: disable=too-few-public-methods
def __init__(self, ui=None, logfunc=None, fm=None):
self.ui = ui
self.fm = fm
self.logfunc = logfunc
self.zombies = set()
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 Exception as ex: # pylint: disable=broad-except
self._log("Failed to initialize UI")
LOG.exception(ex)
else:
try:
self.ui.suspend()
except Exception as ex: # pylint: disable=broad-except
self._log("Failed to suspend UI")
LOG.exception(ex)
def __call__(
# pylint: disable=too-many-branches,too-many-statements
# pylint: disable=too-many-arguments,too-many-locals
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, fm=self.fm,
flags=flags, wait=wait, popen_kws=popen_kws,
file=files and files[0] or None)
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
wait_for_enter = False
devnull = None
if 'shell' not in popen_kws:
popen_kws['shell'] = isinstance(action, str)
# Set default shell for Popen
if popen_kws['shell']:
# This doesn't work with fish, see #300
if 'fish' not in os.environ['SHELL']:
popen_kws['executable'] = os.environ['SHELL']
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'] = STDOUT
toggle_ui = False
pipe_output = True
context.wait = False
if 's' in context.flags:
devnull_writable = open(os.devnull, 'w')
devnull_readable = open(os.devnull, 'r')
for key in ('stdout', 'stderr'):
popen_kws[key] = devnull_writable
toggle_ui = False
popen_kws['stdin'] = devnull_readable
if 'f' in context.flags:
toggle_ui = False
context.wait = False
if 'w' in context.flags:
if not pipe_output and context.wait: # <-- sanity check
wait_for_enter = True
if 'r' in context.flags:
# TODO: make 'r' flag work with pipes
if 'sudo' not in get_executables():
return self._log("Can not run with 'r' flag, sudo is not installed!")
f_flag = ('f' in context.flags)
if isinstance(action, str):
action = 'sudo ' + (f_flag and '-b ' or '') + action
else:
action = ['sudo'] + (f_flag and ['-b'] or []) + action
toggle_ui = True
context.wait = True
if 't' in context.flags:
if 'DISPLAY' not in os.environ:
return self._log("Can not run with 't' flag, no display found!")
term = get_term()
if isinstance(action, str):
action = term + ' -e ' + action
else:
action = [term, '-e'] + action
toggle_ui = False
context.wait = False
popen_kws['args'] = action
# Finally, run it
if toggle_ui:
self._activate_ui(False)
try:
error = None
process = None
self.fm.signal_emit('runner.execute.before',
popen_kws=popen_kws, context=context)
try:
if 'f' in context.flags and 'r' not in context.flags:
# This can fail and return False if os.fork() is not
# supported, but we assume it is, since curses is used.
Popen_forked(**popen_kws)
else:
process = Popen(**popen_kws)
except OSError as ex:
error = ex
self._log("Failed to run: %s\n%s" % (str(action), str(ex)))
else:
if context.wait:
process.wait()
elif process:
self.zombies.add(process)
if wait_for_enter:
press_enter()
finally:
self.fm.signal_emit('runner.execute.after',
popen_kws=popen_kws, context=context, error=error)
if devnull:
devnull.close()
if toggle_ui:
self._activate_ui(True)
if pipe_output and process:
return self(action='sensible-pager', app='pager', # pylint: disable=lost-exception
try_app_first=True, stdin=process.stdout)
return process # pylint: disable=lost-exception
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