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Move crash handling to the application level and simplify class structure....
Move crash handling to the application level and simplify class structure. Starting to try to take real advantage of the refactoring, to have generic crash handling. This also lets us initialize the app without needing all the self.attempt() wrappers, since now there's a good system-wide crash handler at the app level (not inside the shell instance). I didn't yet remove the attempt() method because we may have occasional uses for it (we still do, but in one place only). I also removed some extra class layers that weren't quite needed. Creating classes solely for the purpose of passing parameters makes the code (IMO) harder to understand, I kept getting lost in parts of the class hierarchy. I think these changes provide the same flexibility but with easier to follow code (less things to remember, basically). What I tried to do was to use argument passing instead of inheritance for all cases I saw where the inheritance wasn't really adding new functionality. In some cases, this actually allowed me to remove methods that were effectively duplicated in the subclasses.

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asyncfrontendbase.py
82 lines | 2.8 KiB | text/x-python | PythonLexer
"""
Base front end class for all async frontends.
"""
__docformat__ = "restructuredtext en"
# Tell nose to skip this module
__test__ = {}
#-------------------------------------------------------------------------------
# Copyright (C) 2008 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-------------------------------------------------------------------------------
#-------------------------------------------------------------------------------
# Imports
#-------------------------------------------------------------------------------
# Third-party
from twisted.python.failure import Failure
from zope.interface import implements, classProvides
# From IPython
from IPython.external import guid
from IPython.frontend.frontendbase import (FrontEndBase, IFrontEnd,
IFrontEndFactory)
from IPython.kernel.core.history import FrontEndHistory
from IPython.kernel.engineservice import IEngineCore
#-----------------------------------------------------------------------------
# Classes and functions
#-----------------------------------------------------------------------------
class AsyncFrontEndBase(FrontEndBase):
"""
Overrides FrontEndBase to wrap execute in a deferred result.
All callbacks are made as callbacks on the deferred result.
"""
implements(IFrontEnd)
classProvides(IFrontEndFactory)
def __init__(self, engine=None, history=None):
assert(engine==None or IEngineCore.providedBy(engine))
self.engine = IEngineCore(engine)
if history is None:
self.history = FrontEndHistory(input_cache=[''])
else:
self.history = history
def execute(self, block, blockID=None):
"""Execute the block and return the deferred result.
Parameters:
block : {str, AST}
blockID : any
Caller may provide an ID to identify this block.
result['blockID'] := blockID
Result:
Deferred result of self.interpreter.execute
"""
if(not self.is_complete(block)):
return Failure(Exception("Block is not compilable"))
if(blockID == None):
blockID = guid.generate()
d = self.engine.execute(block)
d.addCallback(self._add_history, block=block)
d.addCallbacks(self._add_block_id_for_result,
errback=self._add_block_id_for_failure,
callbackArgs=(blockID,),
errbackArgs=(blockID,))
d.addBoth(self.update_cell_prompt, blockID=blockID)
d.addCallbacks(self.render_result,
errback=self.render_error)
return d