comparison mercurial/wireproto.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

37294:27527d8cff5c

    """
    return repo.filtered('served')

def dispatch(repo, proto, command):
    repo = getdispatchrepo(repo, proto, command)
    func, spec = commands[command]
    args = proto.getargs(spec)
    return func(repo, proto, *args)

def options(cmd, keys, others):
    opts = {}

# available on. For use with @wireprotocommand.
POLICY_ALL = 'all'
POLICY_V1_ONLY = 'v1-only'
POLICY_V2_ONLY = 'v2-only'

commands = commanddict()

def wireprotocommand(name, args='', transportpolicy=POLICY_ALL,
                     permission='push'):
    """Decorator to declare a wire protocol command.

    because otherwise commands not declaring their permissions could modify
    a repository that is supposed to be read-only.
    """
    if transportpolicy == POLICY_ALL:
        transports = set(wireprototypes.TRANSPORTS)
    elif transportpolicy == POLICY_V1_ONLY:
        transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                      if v['version'] == 1}
    elif transportpolicy == POLICY_V2_ONLY:
        transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                      if v['version'] == 2}
    else:
        raise error.ProgrammingError('invalid transport policy value: %s' %
                                     transportpolicy)

    # Because SSHv2 is a mirror of SSHv1, we allow "batch" commands through to

        raise error.ProgrammingError('invalid wire protocol permission; '
                                     'got %s; expected "push" or "pull"' %
                                     permission)

    def register(func):
        commands[name] = commandentry(func, args=args, transports=transports,
                                      permission=permission)
        return func
    return register

# TODO define a more appropriate permissions type to use for this.
@wireprotocommand('batch', 'cmds *', permission='pull',

37295:45b39c69fae0

    """
    return repo.filtered('served')

def dispatch(repo, proto, command):
    repo = getdispatchrepo(repo, proto, command)

    transportversion = wireprototypes.TRANSPORTS[proto.name]['version']
    commandtable = commandsv2 if transportversion == 2 else commands
    func, spec = commandtable[command]

    args = proto.getargs(spec)
    return func(repo, proto, *args)

def options(cmd, keys, others):
    opts = {}

# available on. For use with @wireprotocommand.
POLICY_ALL = 'all'
POLICY_V1_ONLY = 'v1-only'
POLICY_V2_ONLY = 'v2-only'

# For version 1 transports.
commands = commanddict()

# For version 2 transports.
commandsv2 = commanddict()

def wireprotocommand(name, args='', transportpolicy=POLICY_ALL,
                     permission='push'):
    """Decorator to declare a wire protocol command.

    because otherwise commands not declaring their permissions could modify
    a repository that is supposed to be read-only.
    """
    if transportpolicy == POLICY_ALL:
        transports = set(wireprototypes.TRANSPORTS)
        transportversions = {1, 2}
    elif transportpolicy == POLICY_V1_ONLY:
        transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                      if v['version'] == 1}
        transportversions = {1}
    elif transportpolicy == POLICY_V2_ONLY:
        transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                      if v['version'] == 2}
        transportversions = {2}
    else:
        raise error.ProgrammingError('invalid transport policy value: %s' %
                                     transportpolicy)

    # Because SSHv2 is a mirror of SSHv1, we allow "batch" commands through to

        raise error.ProgrammingError('invalid wire protocol permission; '
                                     'got %s; expected "push" or "pull"' %
                                     permission)

    def register(func):
        if 1 in transportversions:
            if name in commands:
                raise error.ProgrammingError('%s command already registered '
                                             'for version 1' % name)
            commands[name] = commandentry(func, args=args,
                                          transports=transports,
                                          permission=permission)
        if 2 in transportversions:
            if name in commandsv2:
                raise error.ProgrammingError('%s command already registered '
                                             'for version 2' % name)
            commandsv2[name] = commandentry(func, args=args,
                                            transports=transports,
                                            permission=permission)

        return func
    return register

# TODO define a more appropriate permissions type to use for this.
@wireprotocommand('batch', 'cmds *', permission='pull',