view hgext/narrow/narrowcopies.py @ 39814:d059cb669632

wireprotov2: allow multiple fields to follow revision maps

The *data wire protocol commands emit a series of CBOR values.
Because revision/delta data may be large, their data is emitted
outside the map as a top-level bytestring value.

Before this commit, we'd emit a single optional bytestring
value after the revision descriptor map. This got the job done.
But it was limiting in that we could only send a single field.
And, it required the consumer to know that the presence of a
key in the map implied the existence of a following bytestring
value.

This commit changes the encoding strategy so top-level bytestring
values in the stream are explicitly denoted in a "fieldsfollowing"
key. This key contains an array defining what fields that follow
and the expected size of each field.

By defining things this way, we can easily send N bytestring
values without any ambiguity about their order. In addition,
clients only need to know how to parse ``fieldsfollowing`` to
know if extra values are present.

Because this breaks backwards compatibility, we've bumped the version
number of the wire protocol version 2 API endpoint.

Differential Revision: https://phab.mercurial-scm.org/D4620

# narrowcopies.py - extensions to mercurial copies module to support narrow
# clones
#
# Copyright 2017 Google, Inc.
#
# 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 mercurial import (
    copies,
    extensions,
)

def setup(repo):
    def _computeforwardmissing(orig, a, b, match=None):
        missing = orig(a, b, match)
        narrowmatch = repo.narrowmatch()
        if narrowmatch.always():
            return missing
        missing = [f for f in missing if narrowmatch(f)]
        return missing

    def _checkcopies(orig, srcctx, dstctx, f, base, tca, remotebase, limit,
                     data):
        narrowmatch = repo.narrowmatch()
        if not narrowmatch(f):
            return
        orig(srcctx, dstctx, f, base, tca, remotebase, limit, data)

    extensions.wrapfunction(copies, '_computeforwardmissing',
                            _computeforwardmissing)
    extensions.wrapfunction(copies, '_checkcopies', _checkcopies)