upstream/mercurial-mirror Files · mercurial/node.py

changegroup: store old heads as a set...

changegroup: store old heads as a set Previously, the "oldheads" variable was a list. On a repository at Mozilla with 46,492 heads, profiling revealed that list membership testing was dominating execution time of applying small changegroups. This patch converts the list of old heads to a set. This makes membership testing significantly faster. On the aforementioned repository with 46,492 heads: $ hg unbundle <file with 1 changeset> before: 18.535s wall after: 1.303s Consumers of this variable only check for truthiness (`if oldheads`), length (`len(oldheads)`), and (most importantly) item membership (`h not in oldheads` - which occurs twice). So, the change to a set should be safe and suitable for stable. The practical effect of this change is that changegroup application and related operations (like `hg push`) no longer exhibit an O(n^2) CPU explosion as the number of heads grows.

Durham Goode - - Load All Authors

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      # 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

      bin = binascii.unhexlify

      nullrev = -1

      nullid = b"\0" * 20

      nullhex = hex(nullid)

      # Phony node value to stand-in for new files in some uses of

      # manifests.

      newnodeid = '!' * 20

      addednodeid = ('0' * 15) + 'added'

      modifiednodeid = ('0' * 12) + 'modified'

      wdirnodes = set((newnodeid, addednodeid, modifiednodeid))

      # pseudo identifiers for working directory

      # (they are experimental, so don't add too many dependencies on them)

      wdirrev = 0x7fffffff

      wdirid = b"\xff" * 20

      def short(node):

          return hex(node[:6])

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				# 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
				bin = binascii.unhexlify

				nullrev = -1
				nullid = b"\0" * 20
				nullhex = hex(nullid)

				# Phony node value to stand-in for new files in some uses of
				# manifests.
				newnodeid = '!' * 20
				addednodeid = ('0' * 15) + 'added'
				modifiednodeid = ('0' * 12) + 'modified'

				wdirnodes = set((newnodeid, addednodeid, modifiednodeid))

				# pseudo identifiers for working directory
				# (they are experimental, so don't add too many dependencies on them)
				wdirrev = 0x7fffffff
				wdirid = b"\xff" * 20

				def short(node):
				return hex(node[:6])