view hgext/largefiles/localstore.py @ 24992:7df090c9c9fe

localrepo: use changelog.hasnode instead of self.__contains__

Before this patch, releasing the store lock implies the actions below, when
the transaction is aborted:

  1. "commithook()" scheduled in "localrepository.commit()" is invoked
  2. "changectx.__init__()" is invoked via "self.__contains__()"
  3. specified ID is examined against "repo.dirstate.p1()"
  4. validation function is invoked in "dirstate.p1()"

In subsequent patches, "dirstate.invalidate()" invocations for
discarding changes are replaced with "dirstateguard", but discarding
changes by "dirstateguard" is executed after releasing the store lock:
resources are acquired in "wlock => dirstateguard => store lock" order,
and are released in reverse order.

This may cause that "dirstate.p1()" still refers to the changeset to be
rolled-back at (4) above: pushing multiple patches by "hg qpush" is
a typical case.

When releasing the store lock, such changesets are:

  - not contained in "repo.changelog", if it is reloaded from
    ".hg/00changelog.i", as that file was already truncated by
    "transaction.abort()"

  - still contained in it, otherwise
    (this "dirty read" problem is discussed in "Transaction Plan"
     http://mercurial.selenic.com/wiki/TransactionPlan)

Validation function shows "unknown working parent" warning in the
former case, but reloading "repo.changelog" depends on the timestamp
of ".hg/00changelog.i". This causes occasional test failures.

In the case of scheduled "commithook()", it just wants to examine
whether "node ID" of committed changeset is still valid or not. Other
examinations implied in "changectx.__init__()" are meaningless.

To avoid showing the "unknown working parent" warning irregularly, this
patch uses "changelog.hasnode()" instead of "node in self" to examine
existence of committed changeset.

# Copyright 2009-2010 Gregory P. Ward
# Copyright 2009-2010 Intelerad Medical Systems Incorporated
# Copyright 2010-2011 Fog Creek Software
# Copyright 2010-2011 Unity Technologies
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''store class for local filesystem'''

from mercurial.i18n import _

import lfutil
import basestore

class localstore(basestore.basestore):
    '''localstore first attempts to grab files out of the store in the remote
    Mercurial repository.  Failing that, it attempts to grab the files from
    the user cache.'''

    def __init__(self, ui, repo, remote):
        self.remote = remote.local()
        super(localstore, self).__init__(ui, repo, self.remote.url())

    def put(self, source, hash):
        if lfutil.instore(self.remote, hash):
            return
        lfutil.link(source, lfutil.storepath(self.remote, hash))

    def exists(self, hashes):
        retval = {}
        for hash in hashes:
            retval[hash] = lfutil.instore(self.remote, hash)
        return retval


    def _getfile(self, tmpfile, filename, hash):
        path = lfutil.findfile(self.remote, hash)
        if not path:
            raise basestore.StoreError(filename, hash, self.url,
                _("can't get file locally"))
        fd = open(path, 'rb')
        try:
            return lfutil.copyandhash(fd, tmpfile)
        finally:
            fd.close()

    def _verifyfile(self, cctx, cset, contents, standin, verified):
        filename = lfutil.splitstandin(standin)
        if not filename:
            return False
        fctx = cctx[standin]
        key = (filename, fctx.filenode())
        if key in verified:
            return False

        expecthash = fctx.data()[0:40]
        storepath, exists = lfutil.findstorepath(self.remote, expecthash)
        verified.add(key)
        if not exists:
            self.ui.warn(
                _('changeset %s: %s references missing %s\n')
                % (cset, filename, storepath))
            return True                 # failed

        if contents:
            actualhash = lfutil.hashfile(storepath)
            if actualhash != expecthash:
                self.ui.warn(
                    _('changeset %s: %s references corrupted %s\n')
                    % (cset, filename, storepath))
                return True             # failed
        return False