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neko_daemonizer_dante/daemonizer/exceptions.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
+
+------------------------------------------------------
+'''
+
+import signal
+
+# Control * imports.
+__all__ = [
+    # Base class for all of the above
+    'DaemonikerException',
+    # These are daemonization/sighandling errors and exceptions
+    'SignalError',
+    # These are actual signals
+    'DaemonikerSignal',
+    'SIGABRT',
+    'SIGINT',
+    'SIGTERM',
+]
+
+
+class DaemonikerException(Exception):
+    ''' This is suclassed for all exceptions and warnings, so that code
+    using daemoniker as an import can successfully catch all daemoniker
+    exceptions with a single except.
+    '''
+    pass
+
+
+# ###############################################
+# Signal handling errors and exceptions
+# ###############################################
+
+
+class SignalError(DaemonikerException, RuntimeError):
+    ''' This exception (or a subclass thereof) is raised for all issues
+    related to signal handling.
+    '''
+    pass
+
+
+# ###############################################
+# Signals themselves
+# ###############################################
+    
+    
+class _SignalMeta(type):
+    def __int__(self):
+        return self.SIGNUM
+
+
+class DaemonikerSignal(BaseException, metaclass=_SignalMeta):
+    ''' Subclasses of this exception are raised by all of the default
+    signal handlers defined using SignalHandlers.
+    
+    This subclasses BaseException because, when unhandled, it should
+    always be a system-exiting exception. That being said, it should not
+    subclass SystemExit, because that's a whole different can of worms.
+    '''
+    SIGNUM = -1
+    
+    def __int__(self):
+        return self.SIGNUM
+        
+        
+ReceivedSignal = DaemonikerSignal
+
+
+class SIGABRT(DaemonikerSignal):
+    ''' Raised upon receipt of SIGABRT.
+    '''
+    SIGNUM = int(signal.SIGABRT)
+
+
+class SIGINT(DaemonikerSignal):
+    ''' Raised upon receipt of SIGINT, CTRL_C_EVENT, CTRL_BREAK_EVENT.
+    '''
+    SIGNUM = int(signal.SIGINT)
+
+
+class SIGTERM(DaemonikerSignal):
+    ''' Raised upon receipt of SIGTERM.
+    '''
+    SIGNUM = int(signal.SIGTERM)