gstreamer/debug-viewer/GstDebugViewer/Common/Main.py

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# -*- coding: utf-8; mode: python; -*-
#
# GStreamer Development Utilities
#
# Copyright (C) 2007 René Stadler <mail@renestadler.de>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 3 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# this program. If not, see <http://www.gnu.org/licenses/>.
"""GStreamer Development Utilities Common Main module."""
import sys
import os
import traceback
from operator import attrgetter
import logging
import locale
import gettext
from gettext import gettext as _, ngettext
import gi
from gi.repository import GLib
from gi.repository import GObject
from gi.repository import Gtk
class ExceptionHandler (object):
exc_types = (Exception,)
priority = 50
inherit_fork = True
_handling_exception = False
def __call__(self, exc_type, exc_value, exc_traceback):
raise NotImplementedError(
"derived classes need to override this method")
class DefaultExceptionHandler (ExceptionHandler):
exc_types = (BaseException,)
priority = 0
inherit_fork = True
def __init__(self, excepthook):
ExceptionHandler.__init__(self)
self.excepthook = excepthook
def __call__(self, *exc_info):
return self.excepthook(*exc_info)
class ExitOnInterruptExceptionHandler (ExceptionHandler):
exc_types = (KeyboardInterrupt,)
priority = 100
inherit_fork = False
exit_status = 2
def __call__(self, *args):
print("Interrupt caught, exiting.", file=sys.stderr)
sys.exit(self.exit_status)
class MainLoopWrapper (ExceptionHandler):
priority = 95
inherit_fork = False
def __init__(self, enter, exit):
ExceptionHandler.__init__(self)
self.exc_info = (None,) * 3
self.enter = enter
self.exit = exit
def __call__(self, *exc_info):
self.exc_info = exc_info
self.exit()
def run(self):
ExceptHookManager.register_handler(self)
try:
self.enter()
finally:
ExceptHookManager.unregister_handler(self)
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if self.exc_info != (None,) * 3:
# Re-raise unhandled exception that occured while running the loop.
exc_type, exc_value, exc_tb = self.exc_info
raise exc_value
class ExceptHookManagerClass (object):
def __init__(self):
self._in_forked_child = False
self.handlers = []
def setup(self):
if sys.excepthook == self.__excepthook:
raise ValueError("already set up")
hook = sys.excepthook
self.__instrument_excepthook()
self.__instrument_fork()
self.register_handler(DefaultExceptionHandler(hook))
def shutdown(self):
if sys.excepthook != self.__excepthook:
raise ValueError("not set up")
self.__restore_excepthook()
self.__restore_fork()
def __instrument_excepthook(self):
hook = sys.excepthook
self._original_excepthook = hook
sys.excepthook = self.__excepthook
def __restore_excepthook(self):
sys.excepthook = self._original_excepthook
def __instrument_fork(self):
try:
fork = os.fork
except AttributeError:
# System has no fork() system call.
self._original_fork = None
else:
self._original_fork = fork
os.fork = self.__fork
def __restore_fork(self):
if not hasattr(os, "fork"):
return
os.fork = self._original_fork
def entered_forked_child(self):
self._in_forked_child = True
for handler in tuple(self.handlers):
if not handler.inherit_fork:
self.handlers.remove(handler)
def register_handler(self, handler):
if self._in_forked_child and not handler.inherit_fork:
return
self.handlers.append(handler)
def unregister_handler(self, handler):
self.handlers.remove(handler)
def __fork(self):
pid = self._original_fork()
if pid == 0:
# Child process.
self.entered_forked_child()
return pid
def __excepthook(self, exc_type, exc_value, exc_traceback):
for handler in sorted(self.handlers,
key=attrgetter("priority"),
reverse=True):
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if handler._handling_exception:
continue
for type_ in handler.exc_types:
if issubclass(exc_type, type_):
break
else:
continue
handler._handling_exception = True
handler(exc_type, exc_value, exc_traceback)
# Not using try...finally on purpose here. If the handler itself
# fails with an exception, this prevents recursing into it again.
handler._handling_exception = False
return
else:
from warnings import warn
warn("ExceptHookManager: unhandled %r" % (exc_value,),
RuntimeWarning,
stacklevel=2)
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ExceptHookManager = ExceptHookManagerClass()
class PathsBase (object):
data_dir = None
icon_dir = None
locale_dir = None
@classmethod
def setup_installed(cls, data_prefix):
"""Set up paths for running from a regular installation."""
pass
@classmethod
def setup_uninstalled(cls, source_dir):
"""Set up paths for running 'uninstalled' (i.e. directly from the
source dist)."""
pass
@classmethod
def ensure_setup(cls):
"""If paths are still not set up, try to set from a fallback."""
if cls.data_dir is None:
source_dir = os.path.dirname(
os.path.dirname(os.path.abspath(__file__)))
cls.setup_uninstalled(source_dir)
def __new__(cls):
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raise RuntimeError("do not create instances of this class -- "
"use the class object directly")
class PathsProgramBase (PathsBase):
program_name = None
@classmethod
def setup_installed(cls, data_prefix):
if cls.program_name is None:
raise NotImplementedError(
"derived classes need to set program_name attribute")
cls.data_dir = os.path.join(data_prefix, cls.program_name)
cls.icon_dir = os.path.join(data_prefix, "icons")
cls.locale_dir = os.path.join(data_prefix, "locale")
@classmethod
def setup_uninstalled(cls, source_dir):
"""Set up paths for running 'uninstalled' (i.e. directly from the
source dist)."""
# This is essential: The GUI module needs to find the .glade file.
cls.data_dir = os.path.join(source_dir, "data")
# The locale data might be missing if "setup.py build" wasn't run.
cls.locale_dir = os.path.join(source_dir, "build", "mo")
# Not setting icon_dir. It is not useful since we don't employ the
# needed directory structure in the source dist.
def _init_excepthooks():
ExceptHookManager.setup()
ExceptHookManager.register_handler(ExitOnInterruptExceptionHandler())
def _init_paths(paths):
paths.ensure_setup()
def _init_locale(gettext_domain=None):
if Paths.locale_dir and gettext_domain is not None:
try:
locale.setlocale(locale.LC_ALL, "")
except locale.Error as exc:
from warnings import warn
warn("locale error: %s" % (exc,),
RuntimeWarning,
stacklevel=2)
Paths.locale_dir = None
else:
gettext.bindtextdomain(gettext_domain, Paths.locale_dir)
gettext.textdomain(gettext_domain)
gettext.bind_textdomain_codeset(gettext_domain, "UTF-8")
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def _init_logging(level):
if level == "none":
return
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mapping = {"debug": logging.DEBUG,
"info": logging.INFO,
"warning": logging.WARNING,
"error": logging.ERROR,
"critical": logging.CRITICAL}
logging.basicConfig(level=mapping[level],
format='%(asctime)s.%(msecs)03d %(levelname)8s %(name)20s: %(message)s',
datefmt='%H:%M:%S')
logger = logging.getLogger("main")
logger.debug("logging at level %s", logging.getLevelName(level))
logger.info("using Python %i.%i.%i %s %i", *sys.version_info)
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def _init_log_option(parser):
choices = ["none", "debug", "info", "warning", "error", "critical"]
parser.add_option("--log-level", "-l",
type="choice",
choices=choices,
action="store",
dest="log_level",
default="none",
help=_("Enable logging, possible values: ") + ", ".join(choices))
return parser
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def main(main_function, option_parser, gettext_domain=None, paths=None):
# FIXME:
global Paths
Paths = paths
_init_excepthooks()
_init_paths(paths)
_init_locale(gettext_domain)
parser = _init_log_option(option_parser)
options, args = option_parser.parse_args()
_init_logging(options.log_level)
try:
main_function(args)
finally:
logging.shutdown()