rust-nodemap: accounting for dead blocks
By the very append-only nature of the `NodeTree`, inserting
new blocks has the effect of making some of the older ones
useless as they become unreachable.
Therefore some automatic housekeeping will need to be provided.
This is standard procedure in the word of databases, under names
such as "repack" or "vacuum".
The new `masked_readonly_blocks()` will provide callers with
useful information to decide if the nodetree is ripe for
repacking, but all the `NodeTree` can provide is how many
blocks have been masked in the currently mutable part. Analysing
the readonly part would be way too long to do it for each
transaction and defeat the whole purpose of nodemap persistence.
Serializing callers (from the Python layer) will get this figure
before each extraction and maintain an aggregate counter of
unreachable blocks separately.
Note: at this point, the most efficient repacking is just to restart
afresh with a full rescan.
Differential Revision: https://phab.mercurial-scm.org/D8097
# scmutil.py - Mercurial core utility functions
#
# Copyright Matt Mackall <mpm@selenic.com> and other
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
from . import repoview
def cachetocopy(srcrepo):
"""return the list of cache file valuable to copy during a clone"""
# In local clones we're copying all nodes, not just served
# ones. Therefore copy all branch caches over.
cachefiles = [b'branch2']
cachefiles += [b'branch2-%s' % f for f in repoview.filtertable]
cachefiles += [b'rbc-names-v1', b'rbc-revs-v1']
cachefiles += [b'tags2']
cachefiles += [b'tags2-%s' % f for f in repoview.filtertable]
cachefiles += [b'hgtagsfnodes1']
return cachefiles