view tests/flagprocessorext.py @ 37295:45b39c69fae0

wireproto: separate commands tables for version 1 and 2 commands

We can't easily reuse existing command handlers for version 2
commands because the response types will be different. e.g. many
commands return nodes encoded as hex. Our new wire protocol is
binary safe, so we'll wish to encode nodes as binary.

We /could/ teach each command handler to look at the protocol
handler and change behavior based on the version in use. However,
this would make logic a bit unwieldy over time and would make
it harder to design a unified protocol handler interface. I think
it's better to create a clean break between version 1 and version 2
of commands on the server.

What I imagine happening is we will have separate @wireprotocommand
functions for each protocol generation. Those functions will parse the
request, dispatch to a common function to process it, then generate
the response in its own, transport-specific manner.

This commit establishes a separate table for tracking version 1
commands from version 2 commands. The HTTP server pieces have been
updated to use this new table.

Most commands are marked as both version 1 and version 2, so there is
little practical impact to this change.

A side-effect of this change is we now rely on transport registration
in wireprototypes.TRANSPORTS and certain properties of the protocol
interface. So a test had to be updated to conform.

Differential Revision: https://phab.mercurial-scm.org/D2982

# coding=UTF-8

from __future__ import absolute_import

import base64
import zlib

from mercurial import (
    changegroup,
    exchange,
    extensions,
    filelog,
    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 noopaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    if b'[NOOP]' in text:
        flags |= REVIDX_NOOP
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def b64addrevision(orig, self, text, transaction, link, p1, p2,
                   cachedelta=None, node=None,
                   flags=revlog.REVIDX_DEFAULT_FLAGS):
    if b'[BASE64]' in text:
        flags |= REVIDX_BASE64
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def gzipaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    if b'[GZIP]' in text:
        flags |= REVIDX_GZIP
    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

def failaddrevision(orig, self, text, transaction, link, p1, p2,
                    cachedelta=None, node=None,
                    flags=revlog.REVIDX_DEFAULT_FLAGS):
    # 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 orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,
                node=node, flags=flags)

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"

    # Add wrappers for addrevision, responsible to set flags depending on the
    # revision data contents.
    wrapfunction(filelog.filelog, 'addrevision', noopaddrevision)
    wrapfunction(filelog.filelog, 'addrevision', b64addrevision)
    wrapfunction(filelog.filelog, 'addrevision', gzipaddrevision)
    wrapfunction(filelog.filelog, 'addrevision', failaddrevision)

    # 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
        )
    )