sparse-revlog: new requirement enabled with format.sparse-revlog
The meaning of the new 'sparse-revlog' requirement is that the revlogs are
allowed to contain wider delta chains with larger holes between the interesting
chunks. These sparse delta chains should be read in several chunks to avoid a
potential explosion of memory usage.
Former version won't know how to read a delta chain in several chunks. They
would keep reading them in a single read, and therefore would be subject to the
potential memory explosion. Hence this new requirement: only versions having
support of sparse-revlog reading should be allowed to read such a revlog.
Implementation of this new algorithm and tools to enable or disable the
requirement will follow in the next changesets.
# 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'''
from __future__ import absolute_import
from . import (
lfutil,
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.'''
with self.remote.commandexecutor() as e:
fs = []
for hash in hashes:
fs.append((hash, e.callcommand('statlfile', {
'sha': hash,
})))
return {hash: f.result() for hash, f in fs}