branchmap: add a cache validation cache, avoid expensive re-hash on every use
In a pathological `hg log` case, we end up executing the branchmap validity
checking twice per commit displayed. Or maybe we always do, and I just noticed
because it's really slow in this repo for some reason.
Before:
```
Time (mean ± σ): 9.816 s ± 0.071 s [User: 9.435 s, System: 0.392 s]
Range (min … max): 9.709 s … 9.920 s
```
After:
```
Time (mean ± σ): 8.671 s ± 0.078 s [User: 8.309 s, System: 0.392 s]
Range (min … max): 8.594 s … 8.816 s
```
Differential Revision: https://phab.mercurial-scm.org/D9023
# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import binascii
# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
# Adapt to Python 3 API changes. If this ends up showing up in
# profiles, we can use this version only on Python 3, and forward
# binascii.unhexlify like we used to on Python 2.
def bin(s):
try:
return binascii.unhexlify(s)
except binascii.Error as e:
raise TypeError(e)
nullrev = -1
# In hex, this is '0000000000000000000000000000000000000000'
nullid = b"\0" * 20
nullhex = hex(nullid)
# Phony node value to stand-in for new files in some uses of
# manifests.
# In hex, this is '2121212121212121212121212121212121212121'
newnodeid = b'!!!!!!!!!!!!!!!!!!!!'
# In hex, this is '3030303030303030303030303030306164646564'
addednodeid = b'000000000000000added'
# In hex, this is '3030303030303030303030306d6f646966696564'
modifiednodeid = b'000000000000modified'
wdirfilenodeids = {newnodeid, addednodeid, modifiednodeid}
# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7FFFFFFF
# In hex, this is 'ffffffffffffffffffffffffffffffffffffffff'
wdirid = b"\xff" * 20
wdirhex = hex(wdirid)
def short(node):
return hex(node[:6])