Mercurial > hg
view mercurial/treediscovery.py @ 39017:ef3d3a2f9aa5
changegroup: refactor delta parent code
We had recently abstracted the delta parent functions to
facilitate extracting code from cgpacker. Now that we're in
a better place, it is time to revisit the design.
Changegroup version 1 requires that the previous node be used as the
delta parent. Later versions allow any available node to be used
as the base.
In the case where an arbitrary parent can be used, the choice of
a delta parent is best left in the hands of the storage backend.
So it makes sense for the delta parent selection to be hidden
away in the storage layer. This means deferring the choice of the
delta parent selection function to as close to delta generation
time as possible.
This commit moves the delta selection logic to essentially just
before delta generation. However, because changegroup version 1
limits what we can do, we have retained the ability to force a
delta against the previous revision.
As part of this, I realized that the ellipsis parent function was
unused! That's because ellipsis mode always sends full revisions
and not deltas.
Differential Revision: https://phab.mercurial-scm.org/D4214
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 08 Aug 2018 20:17:48 -0700 |
parents | e7aa113b14f7 |
children | 2372284d9457 |
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# discovery.py - protocol changeset discovery functions # # Copyright 2010 Matt Mackall <mpm@selenic.com> # # 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 import collections from .i18n import _ from .node import ( nullid, short, ) from . import ( error, pycompat, ) def findcommonincoming(repo, remote, heads=None, force=False): """Return a tuple (common, fetch, heads) used to identify the common subset of nodes between repo and remote. "common" is a list of (at least) the heads of the common subset. "fetch" is a list of roots of the nodes that would be incoming, to be supplied to changegroupsubset. "heads" is either the supplied heads, or else the remote's heads. """ knownnode = repo.changelog.hasnode search = [] fetch = set() seen = set() seenbranch = set() base = set() if not heads: with remote.commandexecutor() as e: heads = e.callcommand('heads', {}).result() if repo.changelog.tip() == nullid: base.add(nullid) if heads != [nullid]: return [nullid], [nullid], list(heads) return [nullid], [], heads # assume we're closer to the tip than the root # and start by examining the heads repo.ui.status(_("searching for changes\n")) unknown = [] for h in heads: if not knownnode(h): unknown.append(h) else: base.add(h) if not unknown: return list(base), [], list(heads) req = set(unknown) reqcnt = 0 progress = repo.ui.makeprogress(_('searching'), unit=_('queries')) # search through remote branches # a 'branch' here is a linear segment of history, with four parts: # head, root, first parent, second parent # (a branch always has two parents (or none) by definition) with remote.commandexecutor() as e: branches = e.callcommand('branches', {'nodes': unknown}).result() unknown = collections.deque(branches) while unknown: r = [] while unknown: n = unknown.popleft() if n[0] in seen: continue repo.ui.debug("examining %s:%s\n" % (short(n[0]), short(n[1]))) if n[0] == nullid: # found the end of the branch pass elif n in seenbranch: repo.ui.debug("branch already found\n") continue elif n[1] and knownnode(n[1]): # do we know the base? repo.ui.debug("found incomplete branch %s:%s\n" % (short(n[0]), short(n[1]))) search.append(n[0:2]) # schedule branch range for scanning seenbranch.add(n) else: if n[1] not in seen and n[1] not in fetch: if knownnode(n[2]) and knownnode(n[3]): repo.ui.debug("found new changeset %s\n" % short(n[1])) fetch.add(n[1]) # earliest unknown for p in n[2:4]: if knownnode(p): base.add(p) # latest known for p in n[2:4]: if p not in req and not knownnode(p): r.append(p) req.add(p) seen.add(n[0]) if r: reqcnt += 1 progress.increment() repo.ui.debug("request %d: %s\n" % (reqcnt, " ".join(map(short, r)))) for p in pycompat.xrange(0, len(r), 10): with remote.commandexecutor() as e: branches = e.callcommand('branches', { 'nodes': r[p:p + 10], }).result() for b in branches: repo.ui.debug("received %s:%s\n" % (short(b[0]), short(b[1]))) unknown.append(b) # do binary search on the branches we found while search: newsearch = [] reqcnt += 1 progress.increment() with remote.commandexecutor() as e: between = e.callcommand('between', {'pairs': search}).result() for n, l in zip(search, between): l.append(n[1]) p = n[0] f = 1 for i in l: repo.ui.debug("narrowing %d:%d %s\n" % (f, len(l), short(i))) if knownnode(i): if f <= 2: repo.ui.debug("found new branch changeset %s\n" % short(p)) fetch.add(p) base.add(i) else: repo.ui.debug("narrowed branch search to %s:%s\n" % (short(p), short(i))) newsearch.append((p, i)) break p, f = i, f * 2 search = newsearch # sanity check our fetch list for f in fetch: if knownnode(f): raise error.RepoError(_("already have changeset ") + short(f[:4])) base = list(base) if base == [nullid]: if force: repo.ui.warn(_("warning: repository is unrelated\n")) else: raise error.Abort(_("repository is unrelated")) repo.ui.debug("found new changesets starting at " + " ".join([short(f) for f in fetch]) + "\n") progress.complete() repo.ui.debug("%d total queries\n" % reqcnt) return base, list(fetch), heads