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# Copyright (c) 2005-2007 Forest Bond.
# This file is part of the sclapp software package.
#
# sclapp is free software; you can redistribute it and/or modify it under the
# terms of the GNU General Public License version 2 as published by the Free
# Software Foundation.
#
# A copy of the license has been included in the COPYING file.
import sys, os, signal, errno
from sclapp.exceptions import CriticalError
import sclapp.signals
from sclapp.util import DelegateWrapper
_protected_output_enabled = False
class _FileWrapper(DelegateWrapper):
buffer = [ ]
def __init__(self, wrapped_obj):
self.wrapped_obj = wrapped_obj
def write(self, message):
pass
def flush(self):
pass
def signalOutput(self):
pass
def restoreOutput(self):
pass
def disableOutput(self):
self.__class__ = _NullFileWrapper
class _NullFileWrapper(_FileWrapper):
def disableOutput(self):
pass
class _SafeFileWrapper(_FileWrapper):
def write(self, message):
try:
self.wrapped_obj.write(message)
self.wrapped_obj.flush()
except IOError, e:
if e.errno != errno.EPIPE:
raise
if hasattr(signal, 'SIGPIPE') and (
signal.SIGPIPE in sclapp.signals.getExitSignals()):
# We want to disable output for stdout, stderr if they are
# triggering IOError EPIPE exceptions, but we need to wait
# until a SIGPIPE signal is caught on POSIX systems.
if signal.SIGPIPE in sclapp.signals.getCaughtSignals():
self.disableOutput()
# The IOError we just caught may have interrupted handling of
# an ExitSignalError. If so, we should re-raise it to ensure
# proper handling of that exception.
if sclapp.signals._exit_signal_exception is not None:
raise sclapp.signals._exit_signal_exception
else:
self.disableOutput()
raise CriticalError, (e.errno, unicode(e))
def signalOutput(self):
self.__class__ = _SignalFileWrapper
class _SignalFileWrapper(_FileWrapper):
def write(self, message):
self.buffer.append(message)
self.flush()
def restoreOutput(self):
self.__class__ = _SafeFileWrapper
while len(self.buffer) > 0:
self.write(self.buffer.pop())
def flush(self):
if sclapp.signals._handling_signal is None:
self.restoreOutput()
def _protectOutput():
global _protected_output_enabled
sys.stdout = _SafeFileWrapper(sys.stdout)
sys.stderr = _SafeFileWrapper(sys.stderr)
_protected_output_enabled = True
def protectOutput():
if not _protected_output_enabled:
return _protectOutput()
def _unprotectOutput():
global _protected_output_enabled
sys.stdout = sys.stdout.wrapped_obj
sys.stderr = sys.stderr.wrapped_obj
_protected_output_enabled = False
def unprotectOutput():
if _protected_output_enabled:
_unprotectOutput()
def _signalOutput():
sys.stdout.signalOutput()
sys.stderr.signalOutput()
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