mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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324 lines
8.2 KiB
Python
324 lines
8.2 KiB
Python
# -*- coding: utf-8; mode: python; -*-
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#
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# GStreamer Inspector - Multimedia system plugin introspection
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#
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# Copyright (C) 2007 René Stadler <mail@renestadler.de>
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#
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# This program is free software; you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by the Free
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# Software Foundation; either version 3 of the License, or (at your option)
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# any later version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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# more details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, see <http://www.gnu.org/licenses/>.
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"""Misc utilities."""
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import os
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import logging
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import subprocess as _subprocess
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class SingletonMeta (type):
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def __init__ (cls, name, bases, dict_):
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from weakref import WeakValueDictionary
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super (SingletonMeta, cls).__init__ (name, bases, dict_)
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cls._singleton_instances = WeakValueDictionary ()
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def __call__ (cls, *a, **kw):
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kw_key = tuple (sorted (kw.iteritems ()))
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try:
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obj = cls._singleton_instances[a + kw_key]
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except KeyError:
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obj = super (SingletonMeta, cls).__call__ (*a, **kw)
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cls._singleton_instances[a + kw_key] = obj
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return obj
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def gettext_cache ():
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"""Return a callable object that operates like gettext.gettext, but is much
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faster when a string is looked up more than once. This is very useful in
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loops, where calling gettext.gettext can quickly become a major performance
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bottleneck."""
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from gettext import gettext
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d = {}
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def gettext_cache_access (s):
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if not s in d:
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d[s] = gettext (s)
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return d[s]
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return gettext_cache_access
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class ClassProperty (property):
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"Like the property class, but also invokes the getter for class access."
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def __init__ (self, fget = None, fset = None, fdel = None, doc = None):
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property.__init__ (self, fget, fset, fdel, doc)
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self.__fget = fget
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def __get__ (self, obj, obj_class = None):
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ret = property.__get__ (self, obj, obj_class)
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if ret == self:
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return self.__fget (None)
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else:
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return ret
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class _XDGClass (object):
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"""Partial implementation of the XDG Base Directory specification v0.6.
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http://standards.freedesktop.org/basedir-spec/basedir-spec-0.6.html"""
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def __init__ (self):
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self._add_base_dir ("DATA_HOME", "~/.local/share")
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self._add_base_dir ("CONFIG_HOME", "~/.config")
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self._add_base_dir ("CACHE_HOME", "~/.cache")
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def _add_base_dir (self, name, default):
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dir = os.environ.get ("XDG_%s" % (name,))
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if not dir:
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dir = os.path.expanduser (os.path.join (*default.split ("/")))
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setattr (self, name, dir)
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XDG = _XDGClass ()
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class SaveWriteFile (object):
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def __init__ (self, filename, mode = "wt"):
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from tempfile import mkstemp
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self.logger = logging.getLogger ("tempfile")
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dir = os.path.dirname (filename)
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base_name = os.path.basename (filename)
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temp_prefix = "%s-tmp" % (base_name,)
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if dir:
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# Destination dir differs from current directory, ensure that it
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# exists:
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try:
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os.makedirs (dir)
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except OSError:
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pass
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self.clean_stale (dir, temp_prefix)
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fd, temp_name = mkstemp (dir = dir, prefix = temp_prefix)
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self.target_name = filename
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self.temp_name = temp_name
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self.real_file = os.fdopen (fd, mode)
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def __enter__ (self):
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return self
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def __exit__ (self, *exc_args):
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if exc_args == (None, None, None,):
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self.close ()
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else:
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self.discard ()
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def __del__ (self):
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try:
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self.discard ()
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except AttributeError:
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# If __init__ failed, self has no real_file attribute.
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pass
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def __close_real (self):
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if self.real_file:
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self.real_file.close ()
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self.real_file = None
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def clean_stale (self, dir, temp_prefix):
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from time import time
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from glob import glob
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now = time ()
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pattern = os.path.join (dir, "%s*" % (temp_prefix,))
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for temp_filename in glob (pattern):
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mtime = os.stat (temp_filename).st_mtime
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if now - mtime > 3600:
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self.logger.info ("deleting stale temporary file %s",
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temp_filename)
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try:
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os.unlink (temp_filename)
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except EnvironmentError, exc:
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self.logger.warning ("deleting stale temporary file "
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"failed: %s", exc)
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def tell (self, *a, **kw):
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return self.real_file.tell (*a, **kw)
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def write (self, *a, **kw):
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return self.real_file.write (*a, **kw)
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def close (self):
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self.__close_real ()
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if self.temp_name:
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try:
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os.rename (self.temp_name, self.target_name)
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except OSError, exc:
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import errno
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if exc.errno == errno.EEXIST:
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# We are probably on windows.
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os.unlink (self.target_name)
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os.rename (self.temp_name, self.target_name)
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self.temp_name = None
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def discard (self):
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self.__close_real ()
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if self.temp_name:
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try:
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os.unlink (self.temp_name)
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except EnvironmentError, exc:
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self.logger.warning ("deleting temporary file failed: %s", exc)
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self.temp_name = None
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class TeeWriteFile (object):
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# TODO Py2.5: Add context manager methods.
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def __init__ (self, *file_objects):
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self.files = list (file_objects)
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def close (self):
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for file in self.files:
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file.close ()
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def flush (self):
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for file in self.files:
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file.flush ()
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def write (self, string):
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for file in self.files:
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file.write (string)
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def writelines (self, lines):
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for file in self.files:
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file.writelines (lines)
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class FixedPopen (_subprocess.Popen):
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def __init__ (self, args, **kw):
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# Unconditionally specify all descriptors as redirected, to
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# work around Python bug #1358527 (which is triggered for
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# console-less applications on Windows).
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close = []
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for name in ("stdin", "stdout", "stderr",):
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target = kw.get (name)
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if not target:
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kw[name] = _subprocess.PIPE
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close.append (name)
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_subprocess.Popen.__init__ (self, args, **kw)
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for name in close:
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fp = getattr (self, name)
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fp.close ()
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setattr (self, name, None)
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class DevhelpError (EnvironmentError):
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pass
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class DevhelpUnavailableError (DevhelpError):
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pass
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class DevhelpClient (object):
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def available (self):
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try:
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self.version ()
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except DevhelpUnavailableError:
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return False
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else:
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return True
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def version (self):
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return self._invoke ("--version")
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def search (self, entry):
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self._invoke_no_interact ("-s", entry)
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def _check_os_error (self, exc):
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import errno
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if exc.errno == errno.ENOENT:
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raise DevhelpUnavailableError ()
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def _invoke (self, *args):
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from subprocess import PIPE
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try:
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proc = FixedPopen (("devhelp",) + args,
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stdout = PIPE)
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except OSError, exc:
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self._check_os_error (exc)
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raise
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out, err = proc.communicate ()
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if proc.returncode is not None and proc.returncode != 0:
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raise DevhelpError ("devhelp exited with status %i"
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% (proc.returncode,))
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return out
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def _invoke_no_interact (self, *args):
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from subprocess import PIPE
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try:
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proc = FixedPopen (("devhelp",) + args)
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except OSError, exc:
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self._check_os_error (exc)
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raise
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