# sshpeer.py - ssh repository proxy class for mercurial

#

# Copyright 2005, 2006 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 re

from .i18n import _

from . import (

    error,

    util,

    wireproto,

)

class remotelock(object):

    def __init__(self, repo):

        self.repo = repo

    def release(self):

        self.repo.unlock()

        self.repo = None

    def __enter__(self):

        return self

    def __exit__(self, exc_type, exc_val, exc_tb):

        if self.repo:

            self.release()

    def __del__(self):

        if self.repo:

            self.release()

def _serverquote(s):

    if not s:

        return s

    '''quote a string for the remote shell ... which we assume is sh'''

    if re.match('[a-zA-Z0-9@%_+=:,./-]*$', s):

        return s

    return "'%s'" % s.replace("'", "'\\''")

def _forwardoutput(ui, pipe):

    """display all data currently available on pipe as remote output.

    This is non blocking."""

    s = util.readpipe(pipe)

    if s:

        for l in s.splitlines():

            ui.status(_("remote: "), l, '\n')

class doublepipe(object):

    """Operate a side-channel pipe in addition of a main one

    The side-channel pipe contains server output to be forwarded to the user

    input. The double pipe will behave as the "main" pipe, but will ensure the

    content of the "side" pipe is properly processed while we wait for blocking

    call on the "main" pipe.

    If large amounts of data are read from "main", the forward will cease after

    the first bytes start to appear. This simplifies the implementation

    without affecting actual output of sshpeer too much as we rarely issue

    large read for data not yet emitted by the server.

    The main pipe is expected to be a 'bufferedinputpipe' from the util module

    that handle all the os specific bites. This class lives in this module

    because it focus on behavior specific to the ssh protocol."""

    def __init__(self, ui, main, side):

        self._ui = ui

        self._main = main

        self._side = side

    def _wait(self):

        """wait until some data are available on main or side

        return a pair of boolean (ismainready, issideready)

        (This will only wait for data if the setup is supported by `util.poll`)

        """

        if getattr(self._main, 'hasbuffer', False): # getattr for classic pipe

            return (True, True) # main has data, assume side is worth poking at.

        fds = [self._main.fileno(), self._side.fileno()]

        try:

            act = util.poll(fds)

        except NotImplementedError:

            # non supported yet case, assume all have data.

            act = fds

        return (self._main.fileno() in act, self._side.fileno() in act)

    def write(self, data):

        return self._call('write', data)

    def read(self, size):

        return self._call('read', size)

    def readline(self):

        return self._call('readline')

    def _call(self, methname, data=None):

        """call <methname> on "main", forward output of "side" while blocking

        """

        # data can be '' or 0

        if (data is not None and not data) or self._main.closed:

            _forwardoutput(self._ui, self._side)

            return ''

        while True:

            mainready, sideready = self._wait()

            if sideready:

                _forwardoutput(self._ui, self._side)

            if mainready:

                meth = getattr(self._main, methname)

                if data is None:

                    return meth()

                else:

                    return meth(data)

    def close(self):

        return self._main.close()

    def flush(self):

        return self._main.flush()

class sshpeer(wireproto.wirepeer):

    def __init__(self, ui, path, create=False):

        self._url = path

        self.ui = ui

        self.pipeo = self.pipei = self.pipee = None

        u = util.url(path, parsequery=False, parsefragment=False)

        if u.scheme != 'ssh' or not u.host or u.path is None:

            self._abort(error.RepoError(_("couldn't parse location %s") % path))

        self.user = u.user

        if u.passwd is not None:

            self._abort(error.RepoError(_("password in URL not supported")))

        self.host = u.host

        self.port = u.port

        self.path = u.path or "."

        sshcmd = self.ui.config("ui", "ssh", "ssh")

        remotecmd = self.ui.config("ui", "remotecmd", "hg")

        args = util.sshargs(sshcmd,

                            _serverquote(self.host),

                            _serverquote(self.user),

                            _serverquote(self.port))

        if create:

            cmd = '%s %s %s' % (sshcmd, args,

                util.shellquote("%s init %s" %

                    (_serverquote(remotecmd), _serverquote(self.path))))

            ui.debug('running %s\n' % cmd)

            res = ui.system(cmd)

            if res != 0:

                self._abort(error.RepoError(_("could not create remote repo")))

        self._validaterepo(sshcmd, args, remotecmd)

    def url(self):

        return self._url

    def _validaterepo(self, sshcmd, args, remotecmd):

        # cleanup up previous run

        self.cleanup()

        cmd = '%s %s %s' % (sshcmd, args,

            util.shellquote("%s -R %s serve --stdio" %

                (_serverquote(remotecmd), _serverquote(self.path))))

        self.ui.debug('running %s\n' % cmd)

        cmd = util.quotecommand(cmd)

        # while self.subprocess isn't used, having it allows the subprocess to

        # to clean up correctly later

        #

        # no buffer allow the use of 'select'

        # feel free to remove buffering and select usage when we ultimately

        # move to threading.

        sub = util.popen4(cmd, bufsize=0)

        self.pipeo, self.pipei, self.pipee, self.subprocess = sub

        self.pipei = util.bufferedinputpipe(self.pipei)

        self.pipei = doublepipe(self.ui, self.pipei, self.pipee)

        self.pipeo = doublepipe(self.ui, self.pipeo, self.pipee)

        # skip any noise generated by remote shell

        self._callstream("hello")

        r = self._callstream("between", pairs=("%s-%s" % ("0"*40, "0"*40)))

        lines = ["", "dummy"]

        max_noise = 500

        while lines[-1] and max_noise:

            l = r.readline()

            self.readerr()

            if lines[-1] == "1\n" and l == "\n":

                break

            if l:

                self.ui.debug("remote: ", l)

            lines.append(l)

            max_noise -= 1

        else:

            self._abort(error.RepoError(_('no suitable response from '

                                          'remote hg')))

        self._caps = set()

        for l in reversed(lines):

            if l.startswith("capabilities:"):

                self._caps.update(l[:-1].split(":")[1].split())

                break

    def _capabilities(self):

        return self._caps

    def readerr(self):

        _forwardoutput(self.ui, self.pipee)

    def _abort(self, exception):

        self.cleanup()

        raise exception

    def cleanup(self):

        if self.pipeo is None:

            return

        self.pipeo.close()

        self.pipei.close()

        try:

            # read the error descriptor until EOF

            for l in self.pipee:

                self.ui.status(_("remote: "), l)

        except (IOError, ValueError):

            pass

        self.pipee.close()

    __del__ = cleanup

    def _callstream(self, cmd, **args):

        self.ui.debug("sending %s command\n" % cmd)

        self.pipeo.write("%s\n" % cmd)

        _func, names = wireproto.commands[cmd]

        keys = names.split()

        wireargs = {}

        for k in keys:

            if k == '*':

                wireargs['*'] = args

                break

            else:

                wireargs[k] = args[k]

                del args[k]

        for k, v in sorted(wireargs.iteritems()):

            self.pipeo.write("%s %d\n" % (k, len(v)))

            if isinstance(v, dict):

                for dk, dv in v.iteritems():

                    self.pipeo.write("%s %d\n" % (dk, len(dv)))

                    self.pipeo.write(dv)

            else:

                self.pipeo.write(v)

        self.pipeo.flush()

        return self.pipei

    def _callcompressable(self, cmd, **args):

        return self._callstream(cmd, **args)

    def _call(self, cmd, **args):

        self._callstream(cmd, **args)

        return self._recv()

    def _callpush(self, cmd, fp, **args):

        r = self._call(cmd, **args)

        if r:

            return '', r

        while True:

            d = fp.read(4096)

            if not d:

                break

            self._send(d)

        self._send("", flush=True)

        r = self._recv()

        if r:

            return '', r

        return self._recv(), ''

    def _calltwowaystream(self, cmd, fp, **args):

        r = self._call(cmd, **args)

        if r:

            # XXX needs to be made better

            raise error.Abort('unexpected remote reply: %s' % r)

        while True:

            d = fp.read(4096)

            if not d:

                break

            self._send(d)

        self._send("", flush=True)

        return self.pipei

        l = self.pipei.readline()

        if l == '\n':

            self.readerr()

            msg = _('check previous remote output')

            self._abort(error.OutOfBandError(hint=msg))

        self.readerr()

        try:

        except ValueError:

            self._abort(error.ResponseError(_("unexpected response:"), l))

    def _send(self, data, flush=False):

        self.pipeo.write("%d\n" % len(data))

        if data:

            self.pipeo.write(data)

        if flush:

            self.pipeo.flush()

        self.readerr()

    def lock(self):

        self._call("lock")

        return remotelock(self)

    def unlock(self):

        self._call("unlock")

    def addchangegroup(self, cg, source, url, lock=None):

        '''Send a changegroup to the remote server.  Return an integer

        similar to unbundle(). DEPRECATED, since it requires locking the

        remote.'''

        d = self._call("addchangegroup")

        if d:

            self._abort(error.RepoError(_("push refused: %s") % d))

        while True:

            d = cg.read(4096)

            if not d:

                break

            self.pipeo.write(d)

            self.readerr()

        self.pipeo.flush()