Mercurial > hg
view mercurial/dicthelpers.py @ 20713:6a1a4c212d50
revset: improve head revset performance
Previously the head() revset would iterate over every item in the subset and
check if it was a head. Since the subset is often the entire repo, this was
slow on large repos. Now we iterate over each item in the head list and check if
it's in the subset, which results in much less work.
hg log -r 'head()' on a large repo:
Before: 0.95s
After: 0.28s
author | Durham Goode <durham@fb.com> |
---|---|
date | Thu, 13 Mar 2014 13:47:21 -0700 |
parents | ed46c2b98b0d |
children |
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# dicthelpers.py - helper routines for Python dicts # # Copyright 2013 Facebook # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. def diff(d1, d2, default=None): '''Return all key-value pairs that are different between d1 and d2. This includes keys that are present in one dict but not the other, and keys whose values are different. The return value is a dict with values being pairs of values from d1 and d2 respectively, and missing values treated as default, so if a value is missing from one dict and the same as default in the other, it will not be returned.''' res = {} if d1 is d2: # same dict, so diff is empty return res for k1, v1 in d1.iteritems(): v2 = d2.get(k1, default) if v1 != v2: res[k1] = (v1, v2) for k2 in d2: if k2 not in d1: v2 = d2[k2] if v2 != default: res[k2] = (default, v2) return res def join(d1, d2, default=None): '''Return all key-value pairs from both d1 and d2. This is akin to an outer join in relational algebra. The return value is a dict with values being pairs of values from d1 and d2 respectively, and missing values represented as default.''' res = {} for k1, v1 in d1.iteritems(): if k1 in d2: res[k1] = (v1, d2[k1]) else: res[k1] = (v1, default) if d1 is d2: return res for k2 in d2: if k2 not in d1: res[k2] = (default, d2[k2]) return res