D4724: wireprotov2server: port to emitrevisions()
indygreg (Gregory Szorc)
phabricator at mercurial-scm.org
Mon Sep 24 17:15:53 UTC 2018
indygreg created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.
REVISION SUMMARY
We now have a proper storage API to request data on multiple
revisions. We can drop it into wire protocol version 2 with
minimal effort.
The new API handles pretty much everything we were doing manually to
build up the delta request. So we were able to delete a lot of code.
As a bonus, wireprotov2 code is no longer accessing some low-level
storage APIs. This includes the assumption that a node has an
associated numeric revision number! This should make it drastically
simpler to implement a server that doesn't have the concept of
revision numbers.
REPOSITORY
rHG Mercurial
REVISION DETAIL
https://phab.mercurial-scm.org/D4724
AFFECTED FILES
mercurial/wireprotov2server.py
CHANGE DETAILS
diff --git a/mercurial/wireprotov2server.py b/mercurial/wireprotov2server.py
--- a/mercurial/wireprotov2server.py
+++ b/mercurial/wireprotov2server.py
@@ -12,11 +12,8 @@
from .node import (
hex,
nullid,
- nullrev,
)
from . import (
- changegroup,
- dagop,
discovery,
encoding,
error,
@@ -461,86 +458,6 @@
return proto.addcapabilities(repo, caps)
-def builddeltarequests(store, nodes, haveparents):
- """Build a series of revision delta requests against a backend store.
-
- Returns a list of revision numbers in the order they should be sent
- and a list of ``irevisiondeltarequest`` instances to be made against
- the backend store.
- """
- # We sort and send nodes in DAG order because this is optimal for
- # storage emission.
- # TODO we may want a better storage API here - one where we can throw
- # a list of nodes and delta preconditions over a figurative wall and
- # have the storage backend figure it out for us.
- revs = dagop.linearize({store.rev(n) for n in nodes}, store.parentrevs)
-
- requests = []
- seenrevs = set()
-
- for rev in revs:
- node = store.node(rev)
- parentnodes = store.parents(node)
- parentrevs = [store.rev(n) for n in parentnodes]
- deltabaserev = store.deltaparent(rev)
- deltabasenode = store.node(deltabaserev)
-
- # The choice of whether to send a fulltext revision or a delta and
- # what delta to send is governed by a few factors.
- #
- # To send a delta, we need to ensure the receiver is capable of
- # decoding it. And that requires the receiver to have the base
- # revision the delta is against.
- #
- # We can only guarantee the receiver has the base revision if
- # a) we've already sent the revision as part of this group
- # b) the receiver has indicated they already have the revision.
- # And the mechanism for "b" is the client indicating they have
- # parent revisions. So this means we can only send the delta if
- # it is sent before or it is against a delta and the receiver says
- # they have a parent.
-
- # We can send storage delta if it is against a revision we've sent
- # in this group.
- if deltabaserev != nullrev and deltabaserev in seenrevs:
- basenode = deltabasenode
-
- # We can send storage delta if it is against a parent revision and
- # the receiver indicates they have the parents.
- elif (deltabaserev != nullrev and deltabaserev in parentrevs
- and haveparents):
- basenode = deltabasenode
-
- # Otherwise the storage delta isn't appropriate. Fall back to
- # using another delta, if possible.
-
- # Use p1 if we've emitted it or receiver says they have it.
- elif parentrevs[0] != nullrev and (
- parentrevs[0] in seenrevs or haveparents):
- basenode = parentnodes[0]
-
- # Use p2 if we've emitted it or receiver says they have it.
- elif parentrevs[1] != nullrev and (
- parentrevs[1] in seenrevs or haveparents):
- basenode = parentnodes[1]
-
- # Nothing appropriate to delta against. Send the full revision.
- else:
- basenode = nullid
-
- requests.append(changegroup.revisiondeltarequest(
- node=node,
- p1node=parentnodes[0],
- p2node=parentnodes[1],
- # Receiver deals with linknode resolution.
- linknode=nullid,
- basenode=basenode,
- ))
-
- seenrevs.add(rev)
-
- return revs, requests
-
def wireprotocommand(name, args=None, permission='push'):
"""Decorator to declare a wire protocol command.
@@ -858,47 +775,33 @@
raise error.WireprotoCommandError('unknown file node: %s',
(hex(node),))
- revs, requests = builddeltarequests(store, nodes, haveparents)
+ revisions = store.emitrevisions(nodes,
+ revisiondata=b'revision' in fields,
+ assumehaveparentrevisions=haveparents)
yield {
- b'totalitems': len(revs),
+ b'totalitems': len(nodes),
}
- if b'revision' in fields:
- deltas = store.emitrevisiondeltas(requests)
- else:
- deltas = None
-
- for rev in revs:
- node = store.node(rev)
-
- if deltas is not None:
- delta = next(deltas)
- else:
- delta = None
-
+ for revision in revisions:
d = {
- b'node': node,
+ b'node': revision.node,
}
if b'parents' in fields:
- d[b'parents'] = store.parents(node)
+ d[b'parents'] = [revision.p1node, revision.p2node]
followingmeta = []
followingdata = []
if b'revision' in fields:
- assert delta is not None
- assert delta.flags == 0
- assert d[b'node'] == delta.node
-
- if delta.revision is not None:
- followingmeta.append((b'revision', len(delta.revision)))
- followingdata.append(delta.revision)
+ if revision.revision is not None:
+ followingmeta.append((b'revision', len(revision.revision)))
+ followingdata.append(revision.revision)
else:
- d[b'deltabasenode'] = delta.basenode
- followingmeta.append((b'delta', len(delta.delta)))
- followingdata.append(delta.delta)
+ d[b'deltabasenode'] = revision.basenode
+ followingmeta.append((b'delta', len(revision.delta)))
+ followingdata.append(revision.delta)
if followingmeta:
d[b'fieldsfollowing'] = followingmeta
@@ -908,13 +811,6 @@
for extra in followingdata:
yield extra
- if deltas is not None:
- try:
- next(deltas)
- raise error.ProgrammingError('should not have more deltas')
- except GeneratorExit:
- pass
-
@wireprotocommand(
'heads',
args={
@@ -1017,47 +913,33 @@
raise error.WireprotoCommandError(
'unknown node: %s', (node,))
- revs, requests = builddeltarequests(store, nodes, haveparents)
+ revisions = store.emitrevisions(nodes,
+ revisiondata=b'revision' in fields,
+ assumehaveparentrevisions=haveparents)
yield {
- b'totalitems': len(revs),
+ b'totalitems': len(nodes),
}
- if b'revision' in fields:
- deltas = store.emitrevisiondeltas(requests)
- else:
- deltas = None
-
- for rev in revs:
- node = store.node(rev)
-
- if deltas is not None:
- delta = next(deltas)
- else:
- delta = None
-
+ for revision in revisions:
d = {
- b'node': node,
+ b'node': revision.node,
}
if b'parents' in fields:
- d[b'parents'] = store.parents(node)
+ d[b'parents'] = [revision.p1node, revision.p2node]
followingmeta = []
followingdata = []
if b'revision' in fields:
- assert delta is not None
- assert delta.flags == 0
- assert d[b'node'] == delta.node
-
- if delta.revision is not None:
- followingmeta.append((b'revision', len(delta.revision)))
- followingdata.append(delta.revision)
+ if revision.revision is not None:
+ followingmeta.append((b'revision', len(revision.revision)))
+ followingdata.append(revision.revision)
else:
- d[b'deltabasenode'] = delta.basenode
- followingmeta.append((b'delta', len(delta.delta)))
- followingdata.append(delta.delta)
+ d[b'deltabasenode'] = revision.basenode
+ followingmeta.append((b'delta', len(revision.delta)))
+ followingdata.append(revision.delta)
if followingmeta:
d[b'fieldsfollowing'] = followingmeta
@@ -1067,13 +949,6 @@
for extra in followingdata:
yield extra
- if deltas is not None:
- try:
- next(deltas)
- raise error.ProgrammingError('should not have more deltas')
- except GeneratorExit:
- pass
-
@wireprotocommand(
'pushkey',
args={
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