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  • Committer: John Arbash Meinel
  • Date: 2006-08-16 22:05:26 UTC
  • mto: This revision was merged to the branch mainline in revision 1942.
  • Revision ID: john@arbash-meinel.com-20060816220526-9e9e34ad909f252d
Document why we use try/except rather than if None

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bzrlib/cache_utf8.py
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           _uni_to_utf8=_unicode_to_utf8_map,
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           _utf8_to_uni=_utf8_to_unicode_map):
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    """Take this unicode revision id, and get a unicode version"""
 
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    # If the key is in the cache try/KeyError is 50% faster than
 
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    # val = dict.get(key), if val is None:
 
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    # On jam's machine the difference is 
 
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    # try/KeyError:  900ms 
 
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    #      if None: 1250ms 
 
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    # Since these are primarily used when iterating over a knit entry
 
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    # *most* of the time the key will already be in the cache, so use the
 
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    # fast path
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    try:
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        return _uni_to_utf8[unicode_str]
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    except KeyError: