view hgext/largefiles/remotestore.py @ 41755:a4358f7345b4

context: introduce p[12]copies() methods and debugp[12]copies commands

As mentioned earlier, I'm working on support for storing copy metadata
in the changeset instead of in the filelog.

In order to transition a repo from storing metadata in filelogs to
storing it in the changeset, I'm going to provide a config option for
reading the metadata from the changeset, but falling back to getting
it from the filelog if it's not in the changeset. In this compatiblity
mode, the changeset-optmized algorithms will be used. We will then
need to convert the filelog copy metadata to look like that provided
by changeset copy metadata. This patch introduces methods that do just
that.

By having these methods here, we can start writing changeset-optimized
algorithms that should work already before we add any support for
storing the metadata in the changesets.

This commit also includes new debugp[12]copies commands and exercises
them in test-copies.t.

Differential Revision: https://phab.mercurial-scm.org/D5990

# 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.

'''remote largefile store; the base class for wirestore'''
from __future__ import absolute_import

from mercurial.i18n import _

from mercurial import (
    error,
    util,
)

from mercurial.utils import (
    stringutil,
)

from . import (
    basestore,
    lfutil,
    localstore,
)

urlerr = util.urlerr
urlreq = util.urlreq

class remotestore(basestore.basestore):
    '''a largefile store accessed over a network'''
    def __init__(self, ui, repo, url):
        super(remotestore, self).__init__(ui, repo, url)
        self._lstore = None
        if repo is not None:
            self._lstore = localstore.localstore(self.ui, self.repo, self.repo)

    def put(self, source, hash):
        if self.sendfile(source, hash):
            raise error.Abort(
                _('remotestore: could not put %s to remote store %s')
                % (source, util.hidepassword(self.url)))
        self.ui.debug(
            _('remotestore: put %s to remote store %s\n')
            % (source, util.hidepassword(self.url)))

    def exists(self, hashes):
        return dict((h, s == 0) for (h, s) in # dict-from-generator
                    self._stat(hashes).iteritems())

    def sendfile(self, filename, hash):
        self.ui.debug('remotestore: sendfile(%s, %s)\n' % (filename, hash))
        try:
            with lfutil.httpsendfile(self.ui, filename) as fd:
                return self._put(hash, fd)
        except IOError as e:
            raise error.Abort(
                _('remotestore: could not open file %s: %s')
                % (filename, stringutil.forcebytestr(e)))

    def _getfile(self, tmpfile, filename, hash):
        try:
            chunks = self._get(hash)
        except urlerr.httperror as e:
            # 401s get converted to error.Aborts; everything else is fine being
            # turned into a StoreError
            raise basestore.StoreError(filename, hash, self.url,
                                       stringutil.forcebytestr(e))
        except urlerr.urlerror as e:
            # This usually indicates a connection problem, so don't
            # keep trying with the other files... they will probably
            # all fail too.
            raise error.Abort('%s: %s' %
                             (util.hidepassword(self.url), e.reason))
        except IOError as e:
            raise basestore.StoreError(filename, hash, self.url,
                                       stringutil.forcebytestr(e))

        return lfutil.copyandhash(chunks, tmpfile)

    def _hashesavailablelocally(self, hashes):
        existslocallymap = self._lstore.exists(hashes)
        localhashes = [hash for hash in hashes if existslocallymap[hash]]
        return localhashes

    def _verifyfiles(self, contents, filestocheck):
        failed = False
        expectedhashes = [expectedhash
                          for cset, filename, expectedhash in filestocheck]
        localhashes = self._hashesavailablelocally(expectedhashes)
        stats = self._stat([expectedhash for expectedhash in expectedhashes
                            if expectedhash not in localhashes])

        for cset, filename, expectedhash in filestocheck:
            if expectedhash in localhashes:
                filetocheck = (cset, filename, expectedhash)
                verifyresult = self._lstore._verifyfiles(contents,
                                                         [filetocheck])
                if verifyresult:
                    failed = True
            else:
                stat = stats[expectedhash]
                if stat:
                    if stat == 1:
                        self.ui.warn(
                            _('changeset %s: %s: contents differ\n')
                            % (cset, filename))
                        failed = True
                    elif stat == 2:
                        self.ui.warn(
                            _('changeset %s: %s missing\n')
                            % (cset, filename))
                        failed = True
                    else:
                        raise RuntimeError('verify failed: unexpected response '
                                           'from statlfile (%r)' % stat)
        return failed

    def _put(self, hash, fd):
        '''Put file with the given hash in the remote store.'''
        raise NotImplementedError('abstract method')

    def _get(self, hash):
        '''Get a iterator for content with the given hash.'''
        raise NotImplementedError('abstract method')

    def _stat(self, hashes):
        '''Get information about availability of files specified by
        hashes in the remote store. Return dictionary mapping hashes
        to return code where 0 means that file is available, other
        values if not.'''
        raise NotImplementedError('abstract method')