###
# Copyright (c) 2002-2004, Jeremiah Fincher
# Copyright (c) 2010, James McCoy
# All rights reserved.
#
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# modification, are permitted provided that the following conditions are met:
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#   * Redistributions of source code must retain the above copyright notice,
#     this list of conditions, and the following disclaimer.
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#     documentation and/or other materials provided with the distribution.
#   * Neither the name of the author of this software nor the name of
#     contributors to this software may be used to endorse or promote products
#     derived from this software without specific prior written consent.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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###

"""
Contains simple socket drivers.  Asyncore bugged (haha, pun!) me.
"""

from __future__ import division

import sys
import time
import select
import socket
import supybot.log as log
import supybot.conf as conf
import supybot.utils as utils
import supybot.world as world
import supybot.drivers as drivers
import supybot.schedule as schedule
from itertools import imap
try:
    import ssl
    SSLError = ssl.SSLError
except:
    drivers.log.debug('ssl module is not available, '
                      'cannot connect to SSL servers.')
    class SSLError(Exception):
        pass


class SocketDriver(drivers.IrcDriver, drivers.ServersMixin):
    _instances = []
    _selecting = [False] # We want it to be mutable.
    def __init__(self, irc):
        self._instances.append(self)
        self.irc = irc
        drivers.IrcDriver.__init__(self, irc)
        drivers.ServersMixin.__init__(self, irc)
        self.conn = None
        self.servers = ()
        self.eagains = 0
        self.inbuffer = b''
        self.outbuffer = ''
        self.zombie = False
        self.connected = False
        self.writeCheckTime = None
        self.nextReconnectTime = None
        self.resetDelay()
        if self.networkGroup.get('ssl').value and not globals().has_key('ssl'):
            drivers.log.error('The Socket driver can not connect to SSL '
                              'servers for your Python version.  Try the '
                              'Twisted driver instead, or install a Python'
                              'version that supports SSL (2.6 and greater).')
        else:
            self.connect()

    def getDelay(self):
        ret = self.currentDelay
        self.currentDelay = min(self.currentDelay * 2,
                                conf.supybot.drivers.maxReconnectWait())
        return ret

    def resetDelay(self):
        self.currentDelay = 10.0

    def _getNextServer(self):
        oldServer = getattr(self, 'currentServer', None)
        server = drivers.ServersMixin._getNextServer(self)
        if self.currentServer != oldServer:
            self.resetDelay()
        return server

    def _handleSocketError(self, e):
        # (11, 'Resource temporarily unavailable') raised if connect
        # hasn't finished yet.  We'll keep track of how many we get.
        if e.args[0] != 11 or self.eagains > 120:
            drivers.log.disconnect(self.currentServer, e)
            if self in self._instances:
                self._instances.remove(self)
            try:
                self.conn.close()
            except:
                pass
            self.connected = False
            self.scheduleReconnect()
        else:
            log.debug('Got EAGAIN, current count: %s.', self.eagains)
            self.eagains += 1

    def _sendIfMsgs(self):
        if not self.zombie:
            msgs = [self.irc.takeMsg()]
            while msgs[-1] is not None:
                msgs.append(self.irc.takeMsg())
            del msgs[-1]
            self.outbuffer += ''.join(imap(str, msgs))
        if self.outbuffer:
            try:
                if sys.version_info[0] < 3:
                    sent = self.conn.send(self.outbuffer)
                else:
                    sent = self.conn.send(self.outbuffer.encode())
                self.outbuffer = self.outbuffer[sent:]
                self.eagains = 0
            except socket.error, e:
                self._handleSocketError(e)
        if self.zombie and not self.outbuffer:
            self._reallyDie()

    @classmethod
    def _select(cls):
        if cls._selecting[0]:
            return
        try:
            cls._selecting[0] = True
            for inst in cls._instances:
                # Do not use a list comprehension here, we have to edit the list
                # and not to reassign it.
                if (sys.version_info[0] == 3 and inst.conn._closed) or \
                        (sys.version_info[0] == 2 and
                            inst.conn._sock.__class__ is socket._closedsocket):
                    cls._instances.remove(inst)
            if not cls._instances:
                return
            rlist, wlist, xlist = select.select([x.conn for x in cls._instances],
                    [], [], conf.supybot.drivers.poll())
            for instance in cls._instances:
                if instance.conn in rlist:
                    instance._read()
        finally:
            cls._selecting[0] = False
        for instance in cls._instances:
            if instance.irc and not instance.irc.zombie:
                instance._sendIfMsgs()


    def run(self):
        now = time.time()
        if self.nextReconnectTime is not None and now > self.nextReconnectTime:
            self.reconnect()
        elif self.writeCheckTime is not None and now > self.writeCheckTime:
            self._checkAndWriteOrReconnect()
        if not self.connected:
            # We sleep here because otherwise, if we're the only driver, we'll
            # spin at 100% CPU while we're disconnected.
            time.sleep(conf.supybot.drivers.poll())
            return
        self._sendIfMsgs()
        self._select()

    def _read(self):
        """Called by _select() when we can read data."""
        try:
            self.inbuffer += self.conn.recv(1024)
            self.eagains = 0 # If we successfully recv'ed, we can reset this.
            lines = self.inbuffer.split(b'\n')
            self.inbuffer = lines.pop()
            for line in lines:
                if sys.version_info[0] >= 3:
                    line = line.decode(errors='replace')
                msg = drivers.parseMsg(line)
                if msg is not None:
                    self.irc.feedMsg(msg)
        except socket.timeout:
            pass
        except SSLError, e:
            if e.args[0] == 'The read operation timed out':
                pass
            else:
                self._handleSocketError(e)
                return
        except socket.error, e:
            self._handleSocketError(e)
            return
        if not self.irc.zombie:
            self._sendIfMsgs()

    def connect(self, **kwargs):
        self.reconnect(reset=False, **kwargs)

    def reconnect(self, reset=True):
        self.nextReconnectTime = None
        if self.connected:
            drivers.log.reconnect(self.irc.network)
            if self in self._instances:
                self._instances.remove(self)
            self.conn.shutdown(socket.SHUT_RDWR)
            self.conn.close()
            self.connected = False
        if reset:
            drivers.log.debug('Resetting %s.', self.irc)
            self.irc.reset()
        else:
            drivers.log.debug('Not resetting %s.', self.irc)
        server = self._getNextServer()
        drivers.log.connect(self.currentServer)
        try:
            socks_proxy = getattr(conf.supybot.networks, self.irc.network) \
                    .socksproxy()
            try:
                if socks_proxy:
                    import socks
            except ImportError:
                log.error('Cannot use socks proxy (SocksiPy not installed), '
                        'using direct connection instead.')
                socks_proxy = ''
            self.conn = utils.net.getSocket(server[0], socks_proxy)
            vhost = conf.supybot.protocols.irc.vhost()
            self.conn.bind((vhost, 0))
        except socket.error, e:
            drivers.log.connectError(self.currentServer, e)
            self.scheduleReconnect()
            return
        # We allow more time for the connect here, since it might take longer.
        # At least 10 seconds.
        self.conn.settimeout(max(10, conf.supybot.drivers.poll()*10))
        try:
            self.conn.connect(server)
            def setTimeout():
                self.conn.settimeout(conf.supybot.drivers.poll())
            conf.supybot.drivers.poll.addCallback(setTimeout)
            setTimeout()
            if getattr(conf.supybot.networks, self.irc.network).ssl():
                assert globals().has_key('ssl')
                self.conn = ssl.wrap_socket(self.conn)
            self.connected = True
            self.resetDelay()
        except socket.error, e:
            if e.args[0] == 115:
                now = time.time()
                when = now + 60
                whenS = log.timestamp(when)
                drivers.log.debug('Connection in progress, scheduling '
                                  'connectedness check for %s', whenS)
                self.writeCheckTime = when
            else:
                drivers.log.connectError(self.currentServer, e)
                self.scheduleReconnect()
            return
        self._instances.append(self)

    def _checkAndWriteOrReconnect(self):
        self.writeCheckTime = None
        drivers.log.debug('Checking whether we are connected.')
        (_, w, _) = select.select([], [self.conn], [], 0)
        if w:
            drivers.log.debug('Socket is writable, it might be connected.')
            self.connected = True
            self.resetDelay()
        else:
            drivers.log.connectError(self.currentServer, 'Timed out')
            self.reconnect()

    def scheduleReconnect(self):
        when = time.time() + self.getDelay()
        if not world.dying:
            drivers.log.reconnect(self.irc.network, when)
        if self.nextReconnectTime:
            drivers.log.error('Updating next reconnect time when one is '
                              'already present.  This is a bug; please '
                              'report it, with an explanation of what caused '
                              'this to happen.')
        self.nextReconnectTime = when

    def die(self):
        if self in self._instances:
            self._instances.remove(self)
        self.zombie = True
        if self.nextReconnectTime is not None:
            self.nextReconnectTime = None
        if self.writeCheckTime is not None:
            self.writeCheckTime = None
        drivers.log.die(self.irc)

    def _reallyDie(self):
        if self.conn is not None:
            self.conn.shutdown(socket.SHUT_RDWR)
            self.conn.close()
        drivers.IrcDriver.die(self)
        # self.irc.die() Kill off the ircs yourself, jerk!

    def name(self):
        return '%s(%s)' % (self.__class__.__name__, self.irc)


Driver = SocketDriver

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