# watchmanclient.py - Watchman client for the fsmonitor extension

#

# Copyright 2013-2016 Facebook, 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

import getpass

from mercurial import (

    encoding,

    util,

)

from mercurial.utils import (

    procutil,

    stringutil,

)

from . import pywatchman

class Unavailable(Exception):

    def __init__(self, msg, warn=True, invalidate=False):

        self.msg = msg

        self.warn = warn

        if self.msg == b'timed out waiting for response':

            self.warn = False

        self.invalidate = invalidate

    def __bytes__(self):

        if self.warn:

            return b'warning: Watchman unavailable: %s' % self.msg

        else:

            return b'Watchman unavailable: %s' % self.msg

    __str__ = encoding.strmethod(__bytes__)

class WatchmanNoRoot(Unavailable):

    def __init__(self, root, msg):

        self.root = root

        super(WatchmanNoRoot, self).__init__(msg)

class client(object):

    def __init__(self, ui, root, timeout=1.0):

        err = None

        if not self._user:

            err = b"couldn't get user"

            warn = True

        if self._user in ui.configlist(b'fsmonitor', b'blacklistusers'):

            err = b'user %s in blacklist' % self._user

            warn = False

        if err:

            raise Unavailable(err, warn)

        self._timeout = timeout

        self._watchmanclient = None

        self._root = root

        self._ui = ui

        self._firsttime = True

    def settimeout(self, timeout):

        self._timeout = timeout

        if self._watchmanclient is not None:

            self._watchmanclient.setTimeout(timeout)

    def getcurrentclock(self):

        result = self.command(b'clock')

        if not util.safehasattr(result, 'clock'):

            raise Unavailable(

                b'clock result is missing clock value', invalidate=True

            )

        return result.clock

    def clearconnection(self):

        self._watchmanclient = None

    def available(self):

        return self._watchmanclient is not None or self._firsttime

    @util.propertycache

    def _user(self):

        try:

            return getpass.getuser()

        except KeyError:

            # couldn't figure out our user

            return None

    def _command(self, *args):

        watchmanargs = (args[0], self._root) + args[1:]

        try:

            if self._watchmanclient is None:

                self._firsttime = False

                watchman_exe = self._ui.configpath(

                    b'fsmonitor', b'watchman_exe'

                )

                self._watchmanclient = pywatchman.client(

                    timeout=self._timeout,

                    useImmutableBser=True,

                    binpath=procutil.tonativestr(watchman_exe),

                )

            return self._watchmanclient.query(*watchmanargs)

        except pywatchman.CommandError as ex:

            if 'unable to resolve root' in ex.msg:

                raise WatchmanNoRoot(

                    self._root, stringutil.forcebytestr(ex.msg)

                )

            raise Unavailable(stringutil.forcebytestr(ex.msg))

        except pywatchman.WatchmanError as ex:

            raise Unavailable(stringutil.forcebytestr(ex))

    def command(self, *args):

        try:

            try:

                return self._command(*args)

            except WatchmanNoRoot:

                # this 'watch' command can also raise a WatchmanNoRoot if

                # watchman refuses to accept this root

                self._command(b'watch')

                return self._command(*args)

        except Unavailable:

            # this is in an outer scope to catch Unavailable form any of the

            # above _command calls

            self._watchmanclient = None

            raise