Mercurial > public > mercurial-scm > hg
comparison mercurial/revset.py @ 25308:036c26b08b71
revset: add helper to build balanced addsets from chained 'or' operations
This function will be used by revset.orset() and scmutil.revrange() to reduce
the stack depth from O(n) to O(log(n)).
We've bikeshed the interface of this function, but we couldn't come to an
agreement. So we decided to attempt to make it move forward.
marmoute:
- new factory function isn't necessary for balanced addsets
- addset.__init__ can just recurse, should handle "len(subsets) == 2+"
yuja:
- want to write all "len(subsets) == 0, 1, 2, 3+" cases in the same function
- no recursion in __init__ for cosmetic reason: can't return, can't call
__init__ directly
I've changed it to a private function so that nobody would be tempted to
utilize it.
| author | Yuya Nishihara <yuya@tcha.org> |
|---|---|
| date | Sun, 24 May 2015 14:10:52 +0900 |
| parents | 4d1e56b29a91 |
| children | b333ca94403d |
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| 25307:4d1e56b29a91 | 25308:036c26b08b71 |
|---|---|
| 2942 return None | 2942 return None |
| 2943 | 2943 |
| 2944 def __repr__(self): | 2944 def __repr__(self): |
| 2945 return '<%s %r>' % (type(self).__name__, self._subset) | 2945 return '<%s %r>' % (type(self).__name__, self._subset) |
| 2946 | 2946 |
| 2947 # this function will be removed, or merged to addset or orset, when | |
| 2948 # - scmutil.revrange() can be rewritten to not combine calculated smartsets | |
| 2949 # - or addset can handle more than two sets without balanced tree | |
| 2950 def _combinesets(subsets): | |
| 2951 """Create balanced tree of addsets representing union of given sets""" | |
| 2952 if not subsets: | |
| 2953 return baseset() | |
| 2954 if len(subsets) == 1: | |
| 2955 return subsets[0] | |
| 2956 p = len(subsets) // 2 | |
| 2957 xs = _combinesets(subsets[:p]) | |
| 2958 ys = _combinesets(subsets[p:]) | |
| 2959 return addset(xs, ys) | |
| 2960 | |
| 2947 def _iterordered(ascending, iter1, iter2): | 2961 def _iterordered(ascending, iter1, iter2): |
| 2948 """produce an ordered iteration from two iterators with the same order | 2962 """produce an ordered iteration from two iterators with the same order |
| 2949 | 2963 |
| 2950 The ascending is used to indicated the iteration direction. | 2964 The ascending is used to indicated the iteration direction. |
| 2951 """ | 2965 """ |