[user/henk/code/inspircd.git] / src / modules / m_spanningtree / fjoin.cpp

/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2009-2010 Daniel De Graaf <danieldg@inspircd.org>
 *   Copyright (C) 2008 Robin Burchell <robin+git@viroteck.net>
 *   Copyright (C) 2008 Dennis Friis <peavey@inspircd.org>
 *   Copyright (C) 2008 Craig Edwards <craigedwards@brainbox.cc>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "inspircd.h"
#include "commands.h"
#include "treeserver.h"
#include "treesocket.h"

/** FJOIN, almost identical to TS6 SJOIN, except for nicklist handling. */
CmdResult CommandFJoin::Handle(User* srcuser, std::vector<std::string>& params)
{
        /* 1.1+ FJOIN works as follows:
         *
         * Each FJOIN is sent along with a timestamp, and the side with the lowest
         * timestamp 'wins'. From this point on we will refer to this side as the
         * winner. The side with the higher timestamp loses, from this point on we
         * will call this side the loser or losing side. This should be familiar to
         * anyone who's dealt with dreamforge or TS6 before.
         *
         * When two sides of a split heal and this occurs, the following things
         * will happen:
         *
         * If the timestamps are exactly equal, both sides merge their privilages
         * and users, as in InspIRCd 1.0 and ircd2.8. The channels have not been
         * re-created during a split, this is safe to do.
         *
         * If the timestamps are NOT equal, the losing side removes all of its
         * modes from the channel, before introducing new users into the channel
         * which are listed in the FJOIN command's parameters. The losing side then
         * LOWERS its timestamp value of the channel to match that of the winning
         * side, and the modes of the users of the winning side are merged in with
         * the losing side.
         *
         * The winning side on the other hand will ignore all user modes from the
         * losing side, so only its own modes get applied. Life is simple for those
         * who succeed at internets. :-)
         *
         * Syntax:
         * :<sid> FJOIN <chan> <TS> <modes> :[<member> [<member> ...]]
         * The last parameter is a list consisting of zero or more channel members
         * (permanent channels may have zero users). Each entry on the list is in the
         * following format:
         * [[<modes>,]<uuid>[:<membid>]
         * <modes> is a concatenation of the mode letters the user has on the channel
         * (e.g.: "ov" if the user is opped and voiced). The order of the mode letters
         * are not important but if a server ecounters an unknown mode letter, it will
         * drop the link to avoid desync.
         *
         * InspIRCd 2.0 and older required a comma before the uuid even if the user
         * had no prefix modes on the channel, InspIRCd 2.2 and later does not require
         * a comma in this case anymore.
         *
         * <membid> is a positive integer representing the id of the membership.
         * If not present (in FJOINs coming from pre-1205 servers), 0 is assumed.
         *
         */

        time_t TS = ServerCommand::ExtractTS(params[1]);

        const std::string& channel = params[0];
        Channel* chan = ServerInstance->FindChan(channel);
        bool apply_other_sides_modes = true;

        if (!chan)
        {
                chan = new Channel(channel, TS);
        }
        else
        {
                time_t ourTS = chan->age;
                if (TS != ourTS)
                {
                        ServerInstance->SNO->WriteToSnoMask('d', "Merge FJOIN received for %s, ourTS: %lu, TS: %lu, difference: %lu",
                                chan->name.c_str(), (unsigned long)ourTS, (unsigned long)TS, (unsigned long)(ourTS - TS));
                        /* If our TS is less than theirs, we dont accept their modes */
                        if (ourTS < TS)
                        {
                                apply_other_sides_modes = false;
                        }
                        else if (ourTS > TS)
                        {
                                // Our TS is greater than theirs, remove all modes, extensions, etc. from the channel
                                LowerTS(chan, TS, channel);

                                // XXX: If the channel does not exist in the chan hash at this point, create it so the remote modes can be applied on it.
                                // This happens to 0-user permanent channels on the losing side, because those are removed (from the chan hash, then
                                // deleted later) as soon as the permchan mode is removed from them.
                                if (ServerInstance->FindChan(channel) == NULL)
                                {
                                        chan = new Channel(channel, TS);
                                }
                        }
                }
        }

        /* First up, apply their channel modes if they won the TS war */
        Modes::ChangeList modechangelist;
        if (apply_other_sides_modes)
        {
                std::vector<std::string>::const_iterator paramit = params.begin() + 3;
                const std::vector<std::string>::const_iterator lastparamit = ((params.size() > 3) ? (params.end() - 1) : params.end());
                for (std::string::const_iterator i = params[2].begin(); i != params[2].end(); ++i)
                {
                        ModeHandler* mh = ServerInstance->Modes->FindMode(*i, MODETYPE_CHANNEL);
                        if (!mh)
                                continue;

                        std::string modeparam;
                        if ((paramit != lastparamit) && (mh->GetNumParams(true)))
                        {
                                modeparam = *paramit;
                                ++paramit;
                        }

                        modechangelist.push_add(mh, modeparam);
                }

                ServerInstance->Modes->Process(srcuser, chan, NULL, modechangelist, ModeParser::MODE_LOCALONLY | ModeParser::MODE_MERGE);
                // Reuse for prefix modes
                modechangelist.clear();
        }

        TreeServer* const sourceserver = TreeServer::Get(srcuser);

        /* Now, process every 'modes,uuid' pair */
        irc::tokenstream users(params.back());
        std::string item;
        Modes::ChangeList* modechangelistptr = (apply_other_sides_modes ? &modechangelist : NULL);
        while (users.GetToken(item))
        {
                ProcessModeUUIDPair(item, sourceserver, chan, modechangelistptr);
        }

        // Set prefix modes on their users if we lost the FJOIN or had equal TS
        if (apply_other_sides_modes)
                ServerInstance->Modes->Process(srcuser, chan, NULL, modechangelist, ModeParser::MODE_LOCALONLY);

        return CMD_SUCCESS;
}

void CommandFJoin::ProcessModeUUIDPair(const std::string& item, TreeServer* sourceserver, Channel* chan, Modes::ChangeList* modechangelist)
{
        std::string::size_type comma = item.find(',');

        // Comma not required anymore if the user has no modes
        const std::string::size_type ubegin = (comma == std::string::npos ? 0 : comma+1);
        std::string uuid(item, ubegin, UIDGenerator::UUID_LENGTH);
        User* who = ServerInstance->FindUUID(uuid);
        if (!who)
        {
                // Probably KILLed, ignore
                return;
        }

        TreeSocket* src_socket = sourceserver->GetSocket();
        /* Check that the user's 'direction' is correct */
        TreeServer* route_back_again = TreeServer::Get(who);
        if (route_back_again->GetSocket() != src_socket)
        {
                return;
        }

        /* Check if the user received at least one mode */
        if ((modechangelist) && (comma > 0) && (comma != std::string::npos))
        {
                /* Iterate through the modes and see if they are valid here, if so, apply */
                std::string::const_iterator commait = item.begin()+comma;
                for (std::string::const_iterator i = item.begin(); i != commait; ++i)
                {
                        ModeHandler* mh = ServerInstance->Modes->FindMode(*i, MODETYPE_CHANNEL);
                        if (!mh)
                                throw ProtocolException("Unrecognised mode '" + std::string(1, *i) + "'");

                        /* Add any modes this user had to the mode stack */
                        modechangelist->push_add(mh, who->nick);
                }
        }

        Membership* memb = chan->ForceJoin(who, NULL, sourceserver->IsBursting());
        if (!memb)
                return;

        // Assign the id to the new Membership
        Membership::Id membid = 0;
        const std::string::size_type colon = item.rfind(':');
        if (colon != std::string::npos)
                membid = Membership::IdFromString(item.substr(colon+1));
        memb->id = membid;
}

void CommandFJoin::RemoveStatus(Channel* c)
{
        Modes::ChangeList changelist;

        const ModeParser::ModeHandlerMap& mhs = ServerInstance->Modes->GetModes(MODETYPE_CHANNEL);
        for (ModeParser::ModeHandlerMap::const_iterator i = mhs.begin(); i != mhs.end(); ++i)
        {
                ModeHandler* mh = i->second;

                /* Passing a pointer to a modestacker here causes the mode to be put onto the mode stack,
                 * rather than applied immediately. Module unloads require this to be done immediately,
                 * for this function we require tidyness instead. Fixes bug #493
                 */
                mh->RemoveMode(c, changelist);
        }

        ServerInstance->Modes->Process(ServerInstance->FakeClient, c, NULL, changelist, ModeParser::MODE_LOCALONLY);
}

void CommandFJoin::LowerTS(Channel* chan, time_t TS, const std::string& newname)
{
        if (Utils->AnnounceTSChange)
                chan->WriteChannelWithServ(ServerInstance->Config->ServerName, "NOTICE %s :TS for %s changed from %lu to %lu", chan->name.c_str(), newname.c_str(), (unsigned long) chan->age, (unsigned long) TS);

        // While the name is equal in case-insensitive compare, it might differ in case; use the remote version
        chan->name = newname;
        chan->age = TS;

        // Remove all pending invites
        chan->ClearInvites();

        // Clear all modes
        CommandFJoin::RemoveStatus(chan);

        // Unset all extensions
        chan->FreeAllExtItems();

        // Clear the topic, if it isn't empty then send a topic change message to local users
        if (!chan->topic.empty())
        {
                chan->topic.clear();
                chan->WriteChannelWithServ(ServerInstance->Config->ServerName, "TOPIC %s :", chan->name.c_str());
        }
        chan->setby.clear();
        chan->topicset = 0;
}

CommandFJoin::Builder::Builder(Channel* chan)
        : CmdBuilder("FJOIN")
{
        push(chan->name).push_int(chan->age).push_raw(" +");
        pos = str().size();
        push_raw(chan->ChanModes(true)).push_raw(" :");
}

void CommandFJoin::Builder::add(Membership* memb)
{
        push_raw(memb->modes).push_raw(',').push_raw(memb->user->uuid);
        push_raw(':').push_raw_int(memb->id);
        push_raw(' ');
}

bool CommandFJoin::Builder::has_room(Membership* memb) const
{
        return ((str().size() + memb->modes.size() + UIDGenerator::UUID_LENGTH + 2 + membid_max_digits + 1) <= maxline);
}

void CommandFJoin::Builder::clear()
{
        content.erase(pos);
        push_raw(" :");
}

const std::string& CommandFJoin::Builder::finalize()
{
        if (*content.rbegin() == ' ')
                content.erase(content.size()-1);
        return str();
}