branchcache: skip entries that are topological heads in the on disk file
In the majority of cases, topological heads are also branch heads. We have
efficient way to get the topological heads and efficient way to retrieve
their branch information. So there is little value in putting them in the branch
cache file explicitly. On the contrary, writing them explicitly tend to create
very large cache file that are inefficient to read and update.
So the branch cache v3 format is no longer including them. This changeset focus
on the format aspect and have no focus on the performance aspect. We will cover
that later.
# 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 . import (
lfutil,
remotestore,
)
class wirestore(remotestore.remotestore):
def __init__(self, ui, repo, remote):
cap = remote.capable(b'largefiles')
if not cap:
raise lfutil.storeprotonotcapable([])
storetypes = cap.split(b',')
if b'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(
b'statlfile',
{
b'sha': hash,
},
),
)
)
return {hash: f.result() for hash, f in fs}