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Viewing changes to lib/lp/services/utils.py

  • Committer: Launchpad Patch Queue Manager
  • Date: 2011-02-08 20:34:23 UTC
  • mfrom: (12336.1.2 better-caching-iterator)
  • Revision ID: launchpad@pqm.canonical.com-20110208203423-i7ape1oqyjra35v2
[r=leonardr][no-qa] Use itertools.tee() to simplify and speed up
        CachingIterator.

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lib/lp/services/utils.py
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    'value_string',
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    ]
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from itertools import tee
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from textwrap import dedent
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import itertools
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from lazr.enum import BaseItem
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from twisted.python.util import mergeFunctionMetadata
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    def __init__(self, iterator):
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        self.iterator = iterator
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        self.data = []
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    def __iter__(self):
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        index = itertools.count()
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        while True:
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            pos = index.next()
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            try:
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                yield self.data[pos]
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            except IndexError:
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                # Defer to the iterator.
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                pass
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            else:
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                continue
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            if self.iterator is None:
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                break
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            try:
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                item = self.iterator.next()
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            except StopIteration:
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                self.iterator = None
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                break
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            self.data.append(item)
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            yield item
 
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        # Teeing an iterator previously returned by tee won't cause heat
 
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        # death. See tee_copy in itertoolsmodule.c in the Python source.
 
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        self.iterator, iterator = tee(self.iterator)
 
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        return iterator
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def decorate_with(context_factory, *args, **kwargs):