upstream/mercurial-mirror Files · mercurial/dirstateguard.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.

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      # dirstateguard.py - class to allow restoring dirstate after failure

      #

      # Copyright 2005-2007 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

      from .i18n import _

      from . import (

          error,

      )

      class dirstateguard(object):

          '''Restore dirstate at unexpected failure.

          At the construction, this class does:

          - write current ``repo.dirstate`` out, and

          - save ``.hg/dirstate`` into the backup file

          This restores ``.hg/dirstate`` from backup file, if ``release()``

          is invoked before ``close()``.

          This just removes the backup file at ``close()`` before ``release()``.

          '''

          def __init__(self, repo, name):

              self._repo = repo

              self._active = False

              self._closed = False

              self._suffix = '.backup.%s.%d' % (name, id(self))

              repo.dirstate.savebackup(repo.currenttransaction(), self._suffix)

              self._active = True

          def __del__(self):

              if self._active: # still active

                  # this may occur, even if this class is used correctly:

                  # for example, releasing other resources like transaction

                  # may raise exception before ``dirstateguard.release`` in

                  # ``release(tr, ....)``.

                  self._abort()

          def close(self):

              if not self._active: # already inactivated

                  msg = (_("can't close already inactivated backup: dirstate%s")

                         % self._suffix)

                  raise error.Abort(msg)

              self._repo.dirstate.clearbackup(self._repo.currenttransaction(),

                                               self._suffix)

              self._active = False

              self._closed = True

          def _abort(self):

              self._repo.dirstate.restorebackup(self._repo.currenttransaction(),

                                                 self._suffix)

              self._active = False

          def release(self):

              if not self._closed:

                  if not self._active: # already inactivated

                      msg = (_("can't release already inactivated backup:"

                               " dirstate%s")

                             % self._suffix)

                      raise error.Abort(msg)

                  self._abort()

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				# dirstateguard.py - class to allow restoring dirstate after failure
				#
				# Copyright 2005-2007 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

				from .i18n import _

				from . import (
				error,
				)

				class dirstateguard(object):
				'''Restore dirstate at unexpected failure.

				At the construction, this class does:

				- write current ``repo.dirstate`` out, and
				- save ``.hg/dirstate`` into the backup file

				This restores ``.hg/dirstate`` from backup file, if ``release()``
				is invoked before ``close()``.

				This just removes the backup file at ``close()`` before ``release()``.
				'''

				def __init__(self, repo, name):
				self._repo = repo
				self._active = False
				self._closed = False
				self._suffix = '.backup.%s.%d' % (name, id(self))
				repo.dirstate.savebackup(repo.currenttransaction(), self._suffix)
				self._active = True

				def __del__(self):
				if self._active: # still active
				# this may occur, even if this class is used correctly:
				# for example, releasing other resources like transaction
				# may raise exception before ``dirstateguard.release`` in
				# ``release(tr, ....)``.
				self._abort()

				def close(self):
				if not self._active: # already inactivated
				msg = (_("can't close already inactivated backup: dirstate%s")
				% self._suffix)
				raise error.Abort(msg)

				self._repo.dirstate.clearbackup(self._repo.currenttransaction(),
				self._suffix)
				self._active = False
				self._closed = True

				def _abort(self):
				self._repo.dirstate.restorebackup(self._repo.currenttransaction(),
				self._suffix)
				self._active = False

				def release(self):
				if not self._closed:
				if not self._active: # already inactivated
				msg = (_("can't release already inactivated backup:"
				" dirstate%s")
				% self._suffix)
				raise error.Abort(msg)
				self._abort()