# wireproto.py - generic wire protocol support functions

#

# Copyright 2005-2010 Matt Mackall <mpm@selenic.com>

#

# 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

import os

import tempfile

from .i18n import _

from .node import (

    hex,

    nullid,

)

from . import (

    bundle2,

    changegroup as changegroupmod,

    discovery,

    encoding,

    error,

    exchange,

    pushkey as pushkeymod,

    pycompat,

    streamclone,

    util,

    wireprototypes,

)

from .utils import (

    procutil,

    stringutil,

)

urlerr = util.urlerr

urlreq = util.urlreq

bundle2requiredmain = _('incompatible Mercurial client; bundle2 required')

bundle2requiredhint = _('see https://www.mercurial-scm.org/wiki/'

                        'IncompatibleClient')

bundle2required = '%s\n(%s)\n' % (bundle2requiredmain, bundle2requiredhint)

def clientcompressionsupport(proto):

    """Returns a list of compression methods supported by the client.

    Returns a list of the compression methods supported by the client

    according to the protocol capabilities. If no such capability has

    been announced, fallback to the default of zlib and uncompressed.

    """

    for cap in proto.getprotocaps():

        if cap.startswith('comp='):

            return cap[5:].split(',')

    return ['zlib', 'none']

# wire protocol command can either return a string or one of these classes.

def getdispatchrepo(repo, proto, command):

    """Obtain the repo used for processing wire protocol commands.

    The intent of this function is to serve as a monkeypatch point for

    extensions that need commands to operate on different repo views under

    specialized circumstances.

    """

    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)

    # Version 1 protocols define arguments as a list. Version 2 uses a dict.

    if isinstance(args, list):

        return func(repo, proto, *args)

    elif isinstance(args, dict):

        return func(repo, proto, **args)

    else:

        raise error.ProgrammingError('unexpected type returned from '

                                     'proto.getargs(): %s' % type(args))

def options(cmd, keys, others):

    opts = {}

    for k in keys:

        if k in others:

            opts[k] = others[k]

            del others[k]

    if others:

        procutil.stderr.write("warning: %s ignored unexpected arguments %s\n"

                              % (cmd, ",".join(others)))

    return opts

def bundle1allowed(repo, action):

    """Whether a bundle1 operation is allowed from the server.

    Priority is:

    1. server.bundle1gd.<action> (if generaldelta active)

    2. server.bundle1.<action>

    3. server.bundle1gd (if generaldelta active)

    4. server.bundle1

    """

    ui = repo.ui

    gd = 'generaldelta' in repo.requirements

    if gd:

        v = ui.configbool('server', 'bundle1gd.%s' % action)

        if v is not None:

            return v

    v = ui.configbool('server', 'bundle1.%s' % action)

    if v is not None:

        return v

    if gd:

        v = ui.configbool('server', 'bundle1gd')

        if v is not None:

            return v

    return ui.configbool('server', 'bundle1')

def supportedcompengines(ui, role):

    """Obtain the list of supported compression engines for a request."""

    assert role in (util.CLIENTROLE, util.SERVERROLE)

    compengines = util.compengines.supportedwireengines(role)

    # Allow config to override default list and ordering.

    if role == util.SERVERROLE:

        configengines = ui.configlist('server', 'compressionengines')

        config = 'server.compressionengines'

    else:

        # This is currently implemented mainly to facilitate testing. In most

        # cases, the server should be in charge of choosing a compression engine

        # because a server has the most to lose from a sub-optimal choice. (e.g.

        # CPU DoS due to an expensive engine or a network DoS due to poor

        # compression ratio).

        configengines = ui.configlist('experimental',

                                      'clientcompressionengines')

        config = 'experimental.clientcompressionengines'

    # No explicit config. Filter out the ones that aren't supposed to be

    # advertised and return default ordering.

    if not configengines:

        attr = 'serverpriority' if role == util.SERVERROLE else 'clientpriority'

        return [e for e in compengines

                if getattr(e.wireprotosupport(), attr) > 0]

    # If compression engines are listed in the config, assume there is a good

    # reason for it (like server operators wanting to achieve specific

    # performance characteristics). So fail fast if the config references

    # unusable compression engines.

    validnames = set(e.name() for e in compengines)

    invalidnames = set(e for e in configengines if e not in validnames)

    if invalidnames:

        raise error.Abort(_('invalid compression engine defined in %s: %s') %

                          (config, ', '.join(sorted(invalidnames))))

    compengines = [e for e in compengines if e.name() in configengines]

    compengines = sorted(compengines,

                         key=lambda e: configengines.index(e.name()))

    if not compengines:

        raise error.Abort(_('%s config option does not specify any known '

                            'compression engines') % config,

                          hint=_('usable compression engines: %s') %

                          ', '.sorted(validnames))

    return compengines

class commandentry(object):

    """Represents a declared wire protocol command."""

    def __init__(self, func, args='', transports=None,

                 permission='push'):

        self.func = func

        self.args = args

        self.transports = transports or set()

        self.permission = permission

    def _merge(self, func, args):

        """Merge this instance with an incoming 2-tuple.

        This is called when a caller using the old 2-tuple API attempts

        to replace an instance. The incoming values are merged with

        data not captured by the 2-tuple and a new instance containing

        the union of the two objects is returned.

        """

        return commandentry(func, args=args, transports=set(self.transports),

                            permission=self.permission)

    # Old code treats instances as 2-tuples. So expose that interface.

    def __iter__(self):

        yield self.func

        yield self.args

    def __getitem__(self, i):

        if i == 0:

            return self.func

        elif i == 1:

            return self.args

        else:

            raise IndexError('can only access elements 0 and 1')

class commanddict(dict):

    """Container for registered wire protocol commands.

    It behaves like a dict. But __setitem__ is overwritten to allow silent

    coercion of values from 2-tuples for API compatibility.

    """

    def __setitem__(self, k, v):

        if isinstance(v, commandentry):

            pass

        # Cast 2-tuples to commandentry instances.

        elif isinstance(v, tuple):

            if len(v) != 2:

                raise ValueError('command tuples must have exactly 2 elements')

            # It is common for extensions to wrap wire protocol commands via

            # e.g. ``wireproto.commands[x] = (newfn, args)``. Because callers

            # doing this aren't aware of the new API that uses objects to store

            # command entries, we automatically merge old state with new.

            if k in self:

                v = self[k]._merge(v[0], v[1])

            else:

                # Use default values from @wireprotocommand.

                v = commandentry(v[0], args=v[1],

                                 transports=set(wireprototypes.TRANSPORTS),

                                 permission='push')

        else:

            raise ValueError('command entries must be commandentry instances '

                             'or 2-tuples')

        return super(commanddict, self).__setitem__(k, v)

    def commandavailable(self, command, proto):

        """Determine if a command is available for the requested protocol."""

        assert proto.name in wireprototypes.TRANSPORTS

        entry = self.get(command)

        if not entry:

            return False

        if proto.name not in entry.transports:

            return False

        return True

# For version 1 transports.

commands = commanddict()

# For version 2 transports.

commandsv2 = commanddict()

    """Decorator to declare a wire protocol command.

    ``name`` is the name of the wire protocol command being provided.

    ``args`` defines the named arguments accepted by the command. It is

    ``permission`` defines the permission type needed to run this command.

    Can be ``push`` or ``pull``. These roughly map to read-write and read-only,

    respectively. Default is to assume command requires ``push`` permissions

    because otherwise commands not declaring their permissions could modify

    a repository that is supposed to be read-only.

    """

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

    # SSHv2.

    # TODO undo this hack when SSH is using the unified frame protocol.

    if name == b'batch':

        transports.add(wireprototypes.SSHV2)

    if permission not in ('push', 'pull'):

        raise error.ProgrammingError('invalid wire protocol permission; '

                                     'got %s; expected "push" or "pull"' %

                                     permission)

    def register(func):

        return func

    return register

# TODO define a more appropriate permissions type to use for this.

@wireprotocommand('batch', 'cmds *', permission='pull')

def batch(repo, proto, cmds, others):

    unescapearg = wireprototypes.unescapebatcharg

    repo = repo.filtered("served")

    res = []

    for pair in cmds.split(';'):

        op, args = pair.split(' ', 1)

        vals = {}

        for a in args.split(','):

            if a:

                n, v = a.split('=')

                vals[unescapearg(n)] = unescapearg(v)

        func, spec = commands[op]

        # Validate that client has permissions to perform this command.

        perm = commands[op].permission

        assert perm in ('push', 'pull')

        proto.checkperm(perm)

        if spec:

            keys = spec.split()

            data = {}

            for k in keys:

                if k == '*':

                    star = {}

                    for key in vals.keys():

                        if key not in keys:

                            star[key] = vals[key]

                    data['*'] = star

                else:

                    data[k] = vals[k]

            result = func(repo, proto, *[data[k] for k in keys])

        else:

            result = func(repo, proto)

        if isinstance(result, wireprototypes.ooberror):

            return result

        # For now, all batchable commands must return bytesresponse or

        # raw bytes (for backwards compatibility).

        assert isinstance(result, (wireprototypes.bytesresponse, bytes))

        if isinstance(result, wireprototypes.bytesresponse):

            result = result.data

        res.append(wireprototypes.escapebatcharg(result))

    return wireprototypes.bytesresponse(';'.join(res))

@wireprotocommand('between', 'pairs', permission='pull')

def between(repo, proto, pairs):

    pairs = [wireprototypes.decodelist(p, '-') for p in pairs.split(" ")]

    r = []

    for b in repo.between(pairs):

        r.append(wireprototypes.encodelist(b) + "\n")

    return wireprototypes.bytesresponse(''.join(r))

@wireprotocommand('branchmap', permission='pull')

def branchmap(repo, proto):

    branchmap = repo.branchmap()

    heads = []

    for branch, nodes in branchmap.iteritems():

        branchname = urlreq.quote(encoding.fromlocal(branch))

        branchnodes = wireprototypes.encodelist(nodes)

        heads.append('%s %s' % (branchname, branchnodes))

    return wireprototypes.bytesresponse('\n'.join(heads))

@wireprotocommand('branches', 'nodes', permission='pull')

def branches(repo, proto, nodes):

    nodes = wireprototypes.decodelist(nodes)

    r = []

    for b in repo.branches(nodes):

        r.append(wireprototypes.encodelist(b) + "\n")

    return wireprototypes.bytesresponse(''.join(r))

@wireprotocommand('clonebundles', '', permission='pull')

def clonebundles(repo, proto):