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wireprotov2: define and implement "manifestdata" command...
wireprotov2: define and implement "manifestdata" command The added command can be used for obtaining manifest data. Given a manifest path and set of manifest nodes, data about manifests can be retrieved. Unlike changeset data, we wish to emit deltas to describe manifest revisions. So the command uses the relatively new API for building delta requests and emitting them. The code calls into deltaparent(), which I'm not very keen of. There's still work to be done in delta generation land so implementation details of storage (e.g. exactly one delta is stored/available) don't creep into higher levels. But we can worry about this later (there is already a TODO on imanifestorage tracking this). On the subject of parent deltas, the server assumes parent revisions exist on the receiving end. This is obviously wrong for shallow clone. I've added TODOs to add a mechanism to the command to allow clients to specify desired behavior. This shouldn't be too difficult to implement. Another big change is that the client must explicitly request manifest nodes to retrieve. This is a major departure from "getbundle," where the server derives relevant manifests as it iterates changesets and sends them automatically. As implemented, the client must transmit each requested node to the server. At 20 bytes per node, we're looking at 2 MB per 100,000 nodes. Plus wire encoding overhead. This isn't ideal for clients with limited upload bandwidth. I plan to address this in the future by allowing alternate mechanisms for defining the revisions to retrieve. One idea is to define a range of changeset revisions whose manifest revisions to retrieve (similar to how "changesetdata" works). We almost certainly want an API to look up an individual manifest by node. And that's where I've chosen to start with the implementation. Again, a theme of this early exchangev2 work is I want to start by building primitives for accessing raw repository data first and see how far we can get with those before we need more complexity. Differential Revision: https://phab.mercurial-scm.org/D4488

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flagprocessorext.py
136 lines | 3.7 KiB | text/x-python | PythonLexer
# coding=UTF-8
from __future__ import absolute_import
import base64
import zlib
from mercurial import (
changegroup,
exchange,
extensions,
revlog,
util,
)
# Test only: These flags are defined here only in the context of testing the
# behavior of the flag processor. The canonical way to add flags is to get in
# touch with the community and make them known in revlog.
REVIDX_NOOP = (1 << 3)
REVIDX_BASE64 = (1 << 2)
REVIDX_GZIP = (1 << 1)
REVIDX_FAIL = 1
def validatehash(self, text):
return True
def bypass(self, text):
return False
def noopdonothing(self, text):
return (text, True)
def b64encode(self, text):
return (base64.b64encode(text), False)
def b64decode(self, text):
return (base64.b64decode(text), True)
def gzipcompress(self, text):
return (zlib.compress(text), False)
def gzipdecompress(self, text):
return (zlib.decompress(text), True)
def supportedoutgoingversions(orig, repo):
versions = orig(repo)
versions.discard(b'01')
versions.discard(b'02')
versions.add(b'03')
return versions
def allsupportedversions(orig, ui):
versions = orig(ui)
versions.add(b'03')
return versions
def makewrappedfile(obj):
class wrappedfile(obj.__class__):
def addrevision(self, text, transaction, link, p1, p2,
cachedelta=None, node=None,
flags=revlog.REVIDX_DEFAULT_FLAGS):
if b'[NOOP]' in text:
flags |= REVIDX_NOOP
if b'[BASE64]' in text:
flags |= REVIDX_BASE64
if b'[GZIP]' in text:
flags |= REVIDX_GZIP
# This addrevision wrapper is meant to add a flag we will not have
# transforms registered for, ensuring we handle this error case.
if b'[FAIL]' in text:
flags |= REVIDX_FAIL
return super(wrappedfile, self).addrevision(text, transaction, link,
p1, p2,
cachedelta=cachedelta,
node=node,
flags=flags)
obj.__class__ = wrappedfile
def reposetup(ui, repo):
class wrappingflagprocessorrepo(repo.__class__):
def file(self, f):
orig = super(wrappingflagprocessorrepo, self).file(f)
makewrappedfile(orig)
return orig
repo.__class__ = wrappingflagprocessorrepo
def extsetup(ui):
# Enable changegroup3 for flags to be sent over the wire
wrapfunction = extensions.wrapfunction
wrapfunction(changegroup,
'supportedoutgoingversions',
supportedoutgoingversions)
wrapfunction(changegroup,
'allsupportedversions',
allsupportedversions)
# Teach revlog about our test flags
flags = [REVIDX_NOOP, REVIDX_BASE64, REVIDX_GZIP, REVIDX_FAIL]
revlog.REVIDX_KNOWN_FLAGS |= util.bitsfrom(flags)
revlog.REVIDX_FLAGS_ORDER.extend(flags)
# Teach exchange to use changegroup 3
for k in exchange._bundlespeccontentopts.keys():
exchange._bundlespeccontentopts[k]["cg.version"] = "03"
# Register flag processors for each extension
revlog.addflagprocessor(
REVIDX_NOOP,
(
noopdonothing,
noopdonothing,
validatehash,
)
)
revlog.addflagprocessor(
REVIDX_BASE64,
(
b64decode,
b64encode,
bypass,
),
)
revlog.addflagprocessor(
REVIDX_GZIP,
(
gzipdecompress,
gzipcompress,
bypass
)
)