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

branchmap: avoid ancestor computations in absence of non-continous branches...

branchmap: avoid ancestor computations in absence of non-continous branches The branchhead computation is one of the more heavy operations for bigger repositories as it has to scan all changesets and potentially involves the expensive computation of the ancestor sets. Redo the computation to handle the common cases directly and use tighter conditions for when the ancestor scan is necessary. Most importantly, avoid it completely if the non-continous branches are processed in one update as seen in the initial computation after a clone. For the Mercurial repository, it gives a small 2-3% performance boost. For the NetBSD test repository, it cuts the time in half. Differential Revision: https://phab.mercurial-scm.org/D9631

Augie Fackler - - Load All Authors

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      # txnutil.py - transaction related utilities

      #

      #  Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others

      #

      # 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 errno

      from . import encoding

      def mayhavepending(root):

          """return whether 'root' may have pending changes, which are

          visible to this process.

          """

          return root == encoding.environ.get(b'HG_PENDING')

      def trypending(root, vfs, filename, **kwargs):

          """Open  file to be read according to HG_PENDING environment variable

          This opens '.pending' of specified 'filename' only when HG_PENDING

          is equal to 'root'.

          This returns '(fp, is_pending_opened)' tuple.

          """

          if mayhavepending(root):

              try:

                  return (vfs(b'%s.pending' % filename, **kwargs), True)

              except IOError as inst:

                  if inst.errno != errno.ENOENT:

                      raise

          return (vfs(filename, **kwargs), False)

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				# txnutil.py - transaction related utilities
				#
				# Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others
				#
				# 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 errno

				from . import encoding


				def mayhavepending(root):
				"""return whether 'root' may have pending changes, which are
				visible to this process.
				"""
				return root == encoding.environ.get(b'HG_PENDING')


				def trypending(root, vfs, filename, **kwargs):
				"""Open file to be read according to HG_PENDING environment variable

				This opens '.pending' of specified 'filename' only when HG_PENDING
				is equal to 'root'.

				This returns '(fp, is_pending_opened)' tuple.
				"""
				if mayhavepending(root):
				try:
				return (vfs(b'%s.pending' % filename, **kwargs), True)
				except IOError as inst:
				if inst.errno != errno.ENOENT:
				raise
				return (vfs(filename, **kwargs), False)