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annotate mercurial/node.py @ 30370:0298a07f64d9

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dirstate: change placeholder hash length to 20 bytes Previously the new-node placeholder hash for manifests generated from the dirstate was a 21byte long string of "!" characters. Normal hashes are only 20 bytes long. This makes it complicated to implement more efficient manifest implementations which rely on the hashes being fixed length. Let's change this hash to just be 20 bytes long, and rely on the astronomical improbability of an actual hash being 20 "!" bytes in a row (just like we rely on no hash ever being the nullid). A future diff will do this for added and modified dirstate markers as well, so we're putting the new newnodeid in node.py so there's a common place for these placeholders.
author Durham Goode <durham@fb.com>
date Thu, 10 Nov 2016 02:17:22 -0800
parents a3f3fdac8433
children 1070df141718
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Martin Geisler <mg@lazybytes.net>
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1 # node.py - basic nodeid manipulation for mercurial
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Martin Geisler <mg@lazybytes.net>
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2 #
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Martin Geisler <mg@lazybytes.net>
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3 # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com>
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Martin Geisler <mg@lazybytes.net>
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4 #
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Martin Geisler <mg@lazybytes.net>
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5 # This software may be used and distributed according to the terms of the
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Matt Mackall <mpm@selenic.com>
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6 # GNU General Public License version 2 or any later version.
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Gregory Szorc <gregory.szorc@gmail.com>
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8 from __future__ import absolute_import
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9
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Matt Mackall <mpm@selenic.com>
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10 import binascii
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Siddharth Agarwal <sid0@fb.com>
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12 # This ugly style has a noticeable effect in manifest parsing
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Siddharth Agarwal <sid0@fb.com>
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13 hex = binascii.hexlify
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14 bin = binascii.unhexlify
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15
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3b4e00cba57a Define and use nullrev (revision of nullid) instead of -1.
Thomas Arendsen Hein <thomas@intevation.de>
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16 nullrev = -1
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Gregory Szorc <gregory.szorc@gmail.com>
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17 nullid = b"\0" * 20
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18 nullhex = hex(nullid)
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0298a07f64d9 dirstate: change placeholder hash length to 20 bytes
Durham Goode <durham@fb.com>
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20 # Phony node value to stand-in for new files in some uses of
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Durham Goode <durham@fb.com>
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21 # manifests.
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22 newnodeid = '!' * 20
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23
0298a07f64d9 dirstate: change placeholder hash length to 20 bytes
Durham Goode <durham@fb.com>
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24 wdirnodes = set((newnodeid,))
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25
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Yuya Nishihara <yuya@tcha.org>
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26 # pseudo identifiers for working directory
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Yuya Nishihara <yuya@tcha.org>
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27 # (they are experimental, so don't add too many dependencies on them)
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28 wdirrev = 0x7fffffff
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29 wdirid = b"\xff" * 20
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30
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31 def short(node):
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32 return hex(node[:6])