bundle2: implement consume() API on unbundlepart
We want bundle parts to not be seekable by default. That means
eliminating the generic seek() method.
A common pattern in bundle2.py is to seek to the end of the part
data. This is mainly used by the part iteration code to ensure
the underlying stream is advanced to the next bundle part.
In this commit, we establish a dedicated API for consuming a
bundle2 part data. We switch users of seek() to it.
The old implementation of seek(0, os.SEEK_END) would effectively
call self.read(). The new implementation calls self.read(32768)
in a loop. The old implementation would therefore assemble a
buffer to hold all remaining data being seeked over. For seeking
over large bundle parts, this would involve a large allocation and
a lot of overhead to collect intermediate data! This overhead can
be seen in the results for `hg perfbundleread`:
! bundle2 iterparts()
! wall 10.891305 comb 10.820000 user 7.990000 sys 2.830000 (best of 3)
! wall 8.070791 comb 8.060000 user 7.180000 sys 0.880000 (best of 3)
! bundle2 part seek()
! wall 12.991478 comb 10.390000 user 7.720000 sys 2.670000 (best of 3)
! wall 10.370142 comb 10.350000 user 7.430000 sys 2.920000 (best of 3)
Of course, skipping over large payload data isn't likely very common.
So I doubt the performance wins will be observed in the wild.
Differential Revision: https://phab.mercurial-scm.org/D1388
# Copyright 2006, 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.
'''share a common history between several working directories
Automatic Pooled Storage for Clones
-----------------------------------
When this extension is active, :hg:`clone` can be configured to
automatically share/pool storage across multiple clones. This
mode effectively converts :hg:`clone` to :hg:`clone` + :hg:`share`.
The benefit of using this mode is the automatic management of
store paths and intelligent pooling of related repositories.
The following ``share.`` config options influence this feature:
``share.pool``
Filesystem path where shared repository data will be stored. When
defined, :hg:`clone` will automatically use shared repository
storage instead of creating a store inside each clone.
``share.poolnaming``
How directory names in ``share.pool`` are constructed.
"identity" means the name is derived from the first changeset in the
repository. In this mode, different remotes share storage if their
root/initial changeset is identical. In this mode, the local shared
repository is an aggregate of all encountered remote repositories.
"remote" means the name is derived from the source repository's
path or URL. In this mode, storage is only shared if the path or URL
requested in the :hg:`clone` command matches exactly to a repository
that was cloned before.
The default naming mode is "identity".
'''
from __future__ import absolute_import
import errno
from mercurial.i18n import _
from mercurial import (
bookmarks,
commands,
error,
extensions,
hg,
registrar,
txnutil,
util,
)
repository = hg.repository
parseurl = hg.parseurl
cmdtable = {}
command = registrar.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'
@command('share',
[('U', 'noupdate', None, _('do not create a working directory')),
('B', 'bookmarks', None, _('also share bookmarks')),
('', 'relative', None, _('point to source using a relative path '
'(EXPERIMENTAL)')),
],
_('[-U] [-B] SOURCE [DEST]'),
norepo=True)
def share(ui, source, dest=None, noupdate=False, bookmarks=False,
relative=False):
"""create a new shared repository
Initialize a new repository and working directory that shares its
history (and optionally bookmarks) with another repository.
.. note::
using rollback or extensions that destroy/modify history (mq,
rebase, etc.) can cause considerable confusion with shared
clones. In particular, if two shared clones are both updated to
the same changeset, and one of them destroys that changeset
with rollback, the other clone will suddenly stop working: all
operations will fail with "abort: working directory has unknown
parent". The only known workaround is to use debugsetparents on
the broken clone to reset it to a changeset that still exists.
"""
hg.share(ui, source, dest=dest, update=not noupdate,
bookmarks=bookmarks, relative=relative)
return 0
@command('unshare', [], '')
def unshare(ui, repo):
"""convert a shared repository to a normal one
Copy the store data to the repo and remove the sharedpath data.
"""
if not repo.shared():
raise error.Abort(_("this is not a shared repo"))
hg.unshare(ui, repo)
# Wrap clone command to pass auto share options.
def clone(orig, ui, source, *args, **opts):
pool = ui.config('share', 'pool')
if pool:
pool = util.expandpath(pool)
opts[r'shareopts'] = {
'pool': pool,
'mode': ui.config('share', 'poolnaming'),
}
return orig(ui, source, *args, **opts)
def extsetup(ui):
extensions.wrapfunction(bookmarks, '_getbkfile', getbkfile)
extensions.wrapfunction(bookmarks.bmstore, '_recordchange', recordchange)
extensions.wrapfunction(bookmarks.bmstore, '_writerepo', writerepo)
extensions.wrapcommand(commands.table, 'clone', clone)
def _hassharedbookmarks(repo):
"""Returns whether this repo has shared bookmarks"""
try:
shared = repo.vfs.read('shared').splitlines()
except IOError as inst:
if inst.errno != errno.ENOENT:
raise
return False
return hg.sharedbookmarks in shared
def _getsrcrepo(repo):
"""
Returns the source repository object for a given shared repository.
If repo is not a shared repository, return None.
"""
if repo.sharedpath == repo.path:
return None
if util.safehasattr(repo, 'srcrepo') and repo.srcrepo:
return repo.srcrepo
# the sharedpath always ends in the .hg; we want the path to the repo
source = repo.vfs.split(repo.sharedpath)[0]
srcurl, branches = parseurl(source)
srcrepo = repository(repo.ui, srcurl)
repo.srcrepo = srcrepo
return srcrepo
def getbkfile(orig, repo):
if _hassharedbookmarks(repo):
srcrepo = _getsrcrepo(repo)
if srcrepo is not None:
# just orig(srcrepo) doesn't work as expected, because
# HG_PENDING refers repo.root.
try:
fp, pending = txnutil.trypending(repo.root, repo.vfs,
'bookmarks')
if pending:
# only in this case, bookmark information in repo
# is up-to-date.
return fp
fp.close()
except IOError as inst:
if inst.errno != errno.ENOENT:
raise
# otherwise, we should read bookmarks from srcrepo,
# because .hg/bookmarks in srcrepo might be already
# changed via another sharing repo
repo = srcrepo
# TODO: Pending changes in repo are still invisible in
# srcrepo, because bookmarks.pending is written only into repo.
# See also https://www.mercurial-scm.org/wiki/SharedRepository
return orig(repo)
def recordchange(orig, self, tr):
# Continue with write to local bookmarks file as usual
orig(self, tr)
if _hassharedbookmarks(self._repo):
srcrepo = _getsrcrepo(self._repo)
if srcrepo is not None:
category = 'share-bookmarks'
tr.addpostclose(category, lambda tr: self._writerepo(srcrepo))
def writerepo(orig, self, repo):
# First write local bookmarks file in case we ever unshare
orig(self, repo)
if _hassharedbookmarks(self._repo):
srcrepo = _getsrcrepo(self._repo)
if srcrepo is not None:
orig(self, srcrepo)