Mercurial > public > mercurial-scm > hg-stable
diff mercurial/util.py @ 39581:2dcc68c7d25b
util: ability to change capacity when copying lrucachedict
This will allow us to easily replace an lrucachedict with one
with a higher or lower capacity as consumers deem necessary.
IMO it is easier to just create a new cache instance than to
muck with the capacity of an existing cache. Mutating an existing
cache's capacity feels more prone to bugs.
Differential Revision: https://phab.mercurial-scm.org/D4500
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Thu, 06 Sep 2018 11:40:20 -0700 |
| parents | 5d75a3c16193 |
| children | bd9d3a89f07b |
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--- a/mercurial/util.py Thu Sep 06 11:37:27 2018 -0700 +++ b/mercurial/util.py Thu Sep 06 11:40:20 2018 -0700 @@ -1311,8 +1311,19 @@ self._cache.clear() - def copy(self): - result = lrucachedict(self.capacity) + def copy(self, capacity=None): + """Create a new cache as a copy of the current one. + + By default, the new cache has the same capacity as the existing one. + But, the cache capacity can be changed as part of performing the + copy. + + Items in the copy have an insertion/access order matching this + instance. + """ + + capacity = capacity or self.capacity + result = lrucachedict(capacity) # We copy entries by iterating in oldest-to-newest order so the copy # has the correct ordering. @@ -1322,6 +1333,8 @@ while n.key is _notset and n is not self._head: n = n.prev + # We could potentially skip the first N items when decreasing capacity. + # But let's keep it simple unless it is a performance problem. for i in range(len(self._cache)): result[n.key] = n.value n = n.prev