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  • Committer: Robert Collins
  • Date: 2009-12-16 22:29:31 UTC
  • mto: This revision was merged to the branch mainline in revision 4920.
  • Revision ID: robertc@robertcollins.net-20091216222931-wbbn5ey4mwmpatwd
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bzrlib/cleanup.py
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# Copyright (C) 2009, 2010 Canonical Ltd
 
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# Copyright (C) 2009 Canonical Ltd
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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If you want to be certain that the first, and only the first, error is raised,
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then use::
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    operation = OperationWithCleanups(do_something)
 
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    operation = OperationWithCleanups(lambda operation: do_something())
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    operation.add_cleanup(cleanup_something)
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    operation.run_simple()
 
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    operation.run()
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This is more inconvenient (because you need to make every try block a
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function), but will ensure that the first error encountered is the one raised,
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        _run_cleanup(func, *args, **kwargs)
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class ObjectWithCleanups(object):
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    """A mixin for objects that hold a cleanup list.
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    Subclass or client code can call add_cleanup and then later `cleanup_now`.
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    """
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    def __init__(self):
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        self.cleanups = deque()
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    def add_cleanup(self, cleanup_func, *args, **kwargs):
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        """Add a cleanup to run.
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        Cleanups may be added at any time.  
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        Cleanups will be executed in LIFO order.
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        """
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        self.cleanups.appendleft((cleanup_func, args, kwargs))
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    def cleanup_now(self):
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        _run_cleanups(self.cleanups)
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        self.cleanups.clear()
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class OperationWithCleanups(ObjectWithCleanups):
 
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class OperationWithCleanups(object):
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    """A way to run some code with a dynamic cleanup list.
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    This provides a way to add cleanups while the function-with-cleanups is
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    where `some_func` is::
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        def some_func(operation, args, ...):
 
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        def some_func(operation, args, ...)
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            do_something()
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            operation.add_cleanup(something)
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            # etc
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    Note that the first argument passed to `some_func` will be the
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    OperationWithCleanups object.  To invoke `some_func` without that, use
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    `run_simple` instead of `run`.
 
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    OperationWithCleanups object.
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    """
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    def __init__(self, func):
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        super(OperationWithCleanups, self).__init__()
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        self.func = func
 
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        self.cleanups = deque()
 
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    def add_cleanup(self, cleanup_func, *args, **kwargs):
 
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        """Add a cleanup to run.
 
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        Cleanups may be added at any time before or during the execution of
 
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        self.func.  Cleanups will be executed in LIFO order.
 
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        """
 
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        self.cleanups.appendleft((cleanup_func, args, kwargs))
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    def run(self, *args, **kwargs):
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        return _do_with_cleanups(
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            self.cleanups, self.func, self, *args, **kwargs)
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    def run_simple(self, *args, **kwargs):
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        return _do_with_cleanups(
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            self.cleanups, self.func, *args, **kwargs)
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def _do_with_cleanups(cleanup_funcs, func, *args, **kwargs):
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    """Run `func`, then call all the cleanup_funcs.
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                # but don't propagate them.
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                _run_cleanup(cleanup, *c_args, **kwargs)
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        if exc_info is not None:
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            try:
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                raise exc_info[0], exc_info[1], exc_info[2]
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            finally:
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                del exc_info
 
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            raise exc_info[0], exc_info[1], exc_info[2]
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        # No error, so we can return the result
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        return result
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