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| -rw-r--r-- | ranger/runner.py | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/ranger/runner.py b/ranger/runner.py new file mode 100644 index 00000000..c5d5a78c --- /dev/null +++ b/ranger/runner.py @@ -0,0 +1,175 @@ +# 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.shell_escape import shell_escape +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. + """ + + def __init__(self, **keywords): + self.__dict__ = keywords + + @property + def filepaths(self): + if hasattr(self, files): + return [f.path for f in self.files] + return [] + + def __iter__(self): + """Iterate over file paths""" + return iter(self.filepaths) + + 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) + + 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 |