view hgext/largefiles/wirestore.py @ 28196:87de4a22e8c2

chg: hold a lock file before connected to server

This is a part of the one server per config series. In multiple-server setup,
multiple clients may try to start different servers (on demand) at the same
time. The old lock will not guarantee a client to connect to the server it
just started, and is not crash friendly.

This patch addressed above issues by using flock and does not release the lock
until the client actually connects to the server or times out.

# Copyright 2010-2011 Fog Creek Software
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''largefile store working over Mercurial's wire protocol'''

import lfutil
import remotestore

class wirestore(remotestore.remotestore):
    def __init__(self, ui, repo, remote):
        cap = remote.capable('largefiles')
        if not cap:
            raise lfutil.storeprotonotcapable([])
        storetypes = cap.split(',')
        if 'serve' not in storetypes:
            raise lfutil.storeprotonotcapable(storetypes)
        self.remote = remote
        super(wirestore, self).__init__(ui, repo, remote.url())

    def _put(self, hash, fd):
        return self.remote.putlfile(hash, fd)

    def _get(self, hash):
        return self.remote.getlfile(hash)

    def _stat(self, hashes):
        '''For each hash, return 0 if it is available, other values if not.
        It is usually 2 if the largefile is missing, but might be 1 the server
        has a corrupted copy.'''
        batch = self.remote.batch()
        futures = {}
        for hash in hashes:
            futures[hash] = batch.statlfile(hash)
        batch.submit()
        retval = {}
        for hash in hashes:
            retval[hash] = futures[hash].value
        return retval