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neko_daemonizer_dante/daemonizer/_signals_common.py

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+'''
+LICENSING
+-------------------------------------------------
+
+daemoniker: Cross-platform daemonization tools.
+    Copyright (C) 2016 Muterra, Inc.
+    
+    Contributors
+    ------------
+    Nick Badger
+        badg@muterra.io | badg@nickbadger.com | nickbadger.com
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library 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
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the
+    Free Software Foundation, Inc.,
+    51 Franklin Street,
+    Fifth Floor,
+    Boston, MA  02110-1301 USA
+
+------------------------------------------------------
+'''
+
+# Global dependencies
+import os
+import sys
+import signal
+import logging
+import atexit
+import traceback
+import shutil
+
+# Intra-package dependencies
+from .utils import default_to
+
+from .exceptions import DaemonikerSignal
+
+
+# ###############################################
+# Boilerplate
+# ###############################################
+
+
+import logging
+logger = logging.getLogger(__name__)
+
+# Control * imports.
+__all__ = [
+    # 'Inquisitor',
+]
+
+
+# ###############################################
+# Library
+# ###############################################
+    
+
+IGNORE_SIGNAL = 1793
+    
+    
+def _noop(*args, **kwargs):
+    ''' Used for ignoring signals.
+    '''
+    pass
+                
+                
+def send(pid_file, signal):
+    ''' Sends the signal in signum to the pid_file. Num can be either
+    int or one of the exceptions.
+    '''
+    if isinstance(signal, DaemonikerSignal):
+        signum = signal.SIGNUM
+    elif isinstance(signal, type) and issubclass(signal, DaemonikerSignal):
+        signum = signal.SIGNUM
+    else:
+        signum = int(signal)
+    
+    with open(pid_file, 'r') as f:
+        pid = int(f.read())
+        
+    os.kill(pid, signum)
+    
+    
+def ping(pid_file):
+    ''' Returns True if the process in pid_file is available, and False
+    otherwise. Note that availability does not imply the process is
+    running, just that it recently has been. For example, recently-
+    exited processes will still return True.
+    
+    Uhhh shit, this isn't going to work well, windows converts signal 0
+    into an interrupt. Okay, punt for now.
+    '''
+    try:
+        send(pid_file, 0)
+    except OSError:
+        return False
+    else:
+        return True
+
+
+def _normalize_handler(handler, default_handler):
+    ''' Normalizes a signal handler. Converts None to the default, and
+    IGNORE_SIGNAL to noop.
+    '''
+    # None -> _default_handler
+    handler = default_to(handler, default_handler)
+    # IGNORE_SIGNAL -> _noop
+    handler = default_to(handler, _noop, comparator=IGNORE_SIGNAL)
+    
+    return handler
+        
+        
+class _SighandlerCore:
+    ''' Core, platform-independent functionality for signal handlers.
+    '''
+    @property
+    def sigint(self):
+        ''' Gets sigint.
+        '''
+        return self._sigint
+        
+    @sigint.setter
+    def sigint(self, handler):
+        ''' Normalizes and sets sigint.
+        '''
+        self._sigint = _normalize_handler(handler, self._default_handler)
+        
+    @sigint.deleter
+    def sigint(self):
+        ''' Returns the sigint handler to the default.
+        '''
+        self.sigint = None
+        
+    @property
+    def sigterm(self):
+        ''' Gets sigterm.
+        '''
+        return self._sigterm
+        
+    @sigterm.setter
+    def sigterm(self, handler):
+        ''' Normalizes and sets sigterm.
+        '''
+        self._sigterm = _normalize_handler(handler, self._default_handler)
+        
+    @sigterm.deleter
+    def sigterm(self):
+        ''' Returns the sigterm handler to the default.
+        '''
+        self.sigterm = None
+        
+    @property
+    def sigabrt(self):
+        ''' Gets sigabrt.
+        '''
+        return self._sigabrt
+        
+    @sigabrt.setter
+    def sigabrt(self, handler):
+        ''' Normalizes and sets sigabrt.
+        '''
+        self._sigabrt = _normalize_handler(handler, self._default_handler)
+        
+    @sigabrt.deleter
+    def sigabrt(self):
+        ''' Returns the sigabrt handler to the default.
+        '''
+        self.sigabrt = None