source: irc_channel.c @ 7821ee8

  /********************************************************************\
  * BitlBee -- An IRC to other IM-networks gateway                     *
  *                                                                    *
  * Copyright 2002-2013 Wilmer van der Gaast and others                *
  \********************************************************************/

/* The IRC-based UI - Representing (virtual) channels.                  */

/*
  This program 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; either version 2 of the License, or
  (at your option) any later version.

  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 with
  the Debian GNU/Linux distribution in /usr/share/common-licenses/GPL;
  if not, write to the Free Software Foundation, Inc., 51 Franklin St.,
  Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "bitlbee.h"

static char *set_eval_channel_type( set_t *set, char *value );
static gint irc_channel_user_cmp( gconstpointer a_, gconstpointer b_ );
static const struct irc_channel_funcs control_channel_funcs;

extern const struct irc_channel_funcs irc_channel_im_chat_funcs;

irc_channel_t *irc_channel_new( irc_t *irc, const char *name )
{
        irc_channel_t *ic;
        set_t *s;
        
        if( !irc_channel_name_ok( name ) || irc_channel_by_name( irc, name ) )
                return NULL;
        
        ic = g_new0( irc_channel_t, 1 );
        ic->irc = irc;
        ic->name = g_strdup( name );
        strcpy( ic->mode, CMODE );
        
        irc_channel_add_user( ic, irc->root );
        
        irc->channels = g_slist_append( irc->channels, ic );
        
        set_add( &ic->set, "auto_join", "false", set_eval_bool, ic );
        
        s = set_add( &ic->set, "type", "control", set_eval_channel_type, ic );
        s->flags |= SET_NOSAVE;    /* Layer violation (XML format detail) */
        
        if( name[0] == '&' )
                set_setstr( &ic->set, "type", "control" );
        else /* if( name[0] == '#' ) */
                set_setstr( &ic->set, "type", "chat" );
        
        return ic;
}

irc_channel_t *irc_channel_by_name( irc_t *irc, const char *name )
{
        GSList *l;
        
        for( l = irc->channels; l; l = l->next )
        {
                irc_channel_t *ic = l->data;
                
                if( irc_channel_name_cmp( name, ic->name ) == 0 )
                        return ic;
        }
        
        return NULL;
}

irc_channel_t *irc_channel_get( irc_t *irc, char *id )
{
        irc_channel_t *ic, *ret = NULL;
        GSList *l;
        int nr;
        
        if( sscanf( id, "%d", &nr ) == 1 && nr < 1000 )
        {
                for( l = irc->channels; l; l = l->next )
                {
                        ic = l->data;
                        if( ( nr-- ) == 0 ) 
                                return ic;
                }
                
                return NULL;
        }
        
        /* Exact match first: Partial match only sucks if there's a channel
           #aa and #aabb */
        if( ( ret = irc_channel_by_name( irc, id ) ) )
                return ret;
        
        for( l = irc->channels; l; l = l->next )
        {
                ic = l->data;
                
                if( strstr( ic->name, id ) )
                {
                        /* Make sure it's a unique match. */
                        if( !ret )
                                ret = ic;
                        else
                                return NULL;
                }
        }
        
        return ret;
}

int irc_channel_free( irc_channel_t *ic )
{
        irc_t *irc;
        GSList *l;
        
        if( ic == NULL )
                return 0;
        irc = ic->irc;
        
        if( ic->flags & IRC_CHANNEL_JOINED )
                irc_channel_del_user( ic, irc->user, IRC_CDU_KICK, "Cleaning up channel" );
        
        if( ic->f->_free )
                ic->f->_free( ic );
        
        while( ic->set )
                set_del( &ic->set, ic->set->key );
        
        irc->channels = g_slist_remove( irc->channels, ic );
        while( ic->users )
        {
                g_free( ic->users->data );
                ic->users = g_slist_remove( ic->users, ic->users->data );
        }
        
        for( l = irc->users; l; l = l->next )
        {
                irc_user_t *iu = l->data;
                
                if( iu->last_channel == ic )
                        iu->last_channel = irc->default_channel;
        }
        
        if( ic->pastebuf_timer ) b_event_remove( ic->pastebuf_timer );
        
        g_free( ic->name );
        g_free( ic->topic );
        g_free( ic->topic_who );
        g_free( ic );
        
        return 1;
}

struct irc_channel_free_data
{
        irc_t *irc;
        irc_channel_t *ic;
        char *name;
};

static gboolean irc_channel_free_callback( gpointer data, gint fd, b_input_condition cond )
{
        struct irc_channel_free_data *d = data;
        
        if( g_slist_find( irc_connection_list, d->irc ) &&
            irc_channel_by_name( d->irc, d->name ) == d->ic &&
            !( d->ic->flags & IRC_CHANNEL_JOINED ) )
                irc_channel_free( d->ic );

        g_free( d->name );
        g_free( d );
        return FALSE;
}

/* Free the channel, but via the event loop, so after finishing whatever event
   we're currently handling. */
void irc_channel_free_soon( irc_channel_t *ic )
{
        struct irc_channel_free_data *d = g_new0( struct irc_channel_free_data, 1 );
        
        d->irc = ic->irc;
        d->ic = ic;
        d->name = g_strdup( ic->name );
        
        b_timeout_add( 0, irc_channel_free_callback, d );
}

static char *set_eval_channel_type( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        const struct irc_channel_funcs *new;
        
        if( strcmp( value, "control" ) == 0 )
                new = &control_channel_funcs;
        else if( ic != ic->irc->default_channel && strcmp( value, "chat" ) == 0 )
                new = &irc_channel_im_chat_funcs;
        else
                return SET_INVALID;
        
        /* TODO: Return values. */
        if( ic->f && ic->f->_free )
                ic->f->_free( ic );
        
        ic->f = new;
        
        if( ic->f && ic->f->_init )
                ic->f->_init( ic );
        
        return value;
}

int irc_channel_add_user( irc_channel_t *ic, irc_user_t *iu )
{
        irc_channel_user_t *icu;
        
        if( irc_channel_has_user( ic, iu ) )
                return 0;
        
        icu = g_new0( irc_channel_user_t, 1 );
        icu->iu = iu;
        
        ic->users = g_slist_insert_sorted( ic->users, icu, irc_channel_user_cmp );
        
        irc_channel_update_ops( ic, set_getstr( &ic->irc->b->set, "ops" ) );
        
        if( iu == ic->irc->user || ic->flags & IRC_CHANNEL_JOINED )
        {
                ic->flags |= IRC_CHANNEL_JOINED;
                irc_send_join( ic, iu );
        }
        
        return 1;
}

int irc_channel_del_user( irc_channel_t *ic, irc_user_t *iu, irc_channel_del_user_type_t type, const char *msg )
{
        irc_channel_user_t *icu;
        
        if( !( icu = irc_channel_has_user( ic, iu ) ) )
                return 0;
        
        ic->users = g_slist_remove( ic->users, icu );
        g_free( icu );
        
        if( !( ic->flags & IRC_CHANNEL_JOINED ) || type == IRC_CDU_SILENT ) {}
                /* Do nothing. The caller should promise it won't screw
                   up state of the IRC client. :-) */
        else if( type == IRC_CDU_PART )
                irc_send_part( ic, iu, msg );
        else if( type == IRC_CDU_KICK )
                irc_send_kick( ic, iu, ic->irc->root, msg );
        
        if( iu == ic->irc->user )
        {
                ic->flags &= ~IRC_CHANNEL_JOINED;
                
                if( ic->irc->status & USTATUS_SHUTDOWN )
                {
                        /* Don't do anything fancy when we're shutting down anyway. */
                }
                else if( ic->flags & IRC_CHANNEL_TEMP )
                {
                        irc_channel_free_soon( ic );
                }
                else
                {
                        /* Flush userlist now. The user won't see it anyway. */
                        while( ic->users )
                        {
                                g_free( ic->users->data );
                                ic->users = g_slist_remove( ic->users, ic->users->data );
                        }
                        irc_channel_add_user( ic, ic->irc->root );
                }
        }
        
        return 1;
}

irc_channel_user_t *irc_channel_has_user( irc_channel_t *ic, irc_user_t *iu )
{
        GSList *l;
        
        for( l = ic->users; l; l = l->next )
        {
                irc_channel_user_t *icu = l->data;
                
                if( icu->iu == iu )
                        return icu;
        }
        
        return NULL;
}

/* Find a channel we're currently in, that currently has iu in it. */
struct irc_channel *irc_channel_with_user( irc_t *irc, irc_user_t *iu )
{
        GSList *l;
        
        for( l = irc->channels; l; l = l->next )
        {
                irc_channel_t *ic = l->data;
                
                if( strcmp( set_getstr( &ic->set, "type" ), "control" ) != 0 )
                        continue;
                
                if( ( ic->flags & IRC_CHANNEL_JOINED ) &&
                    irc_channel_has_user( ic, iu ) )
                        return ic;
        }
        
        /* If there was no match, try once more but just see if the user
           *would* be in the channel, i.e. if s/he were online. */
        if( iu->bu == NULL )
                return NULL;
        
        for( l = irc->channels; l; l = l->next )
        {
                irc_channel_t *ic = l->data;
                
                if( strcmp( set_getstr( &ic->set, "type" ), "control" ) != 0 )
                        continue;
                
                if( ( ic->flags & IRC_CHANNEL_JOINED ) &&
                    irc_channel_wants_user( ic, iu ) )
                        return ic;
        }
        
        return NULL;
}

int irc_channel_set_topic( irc_channel_t *ic, const char *topic, const irc_user_t *iu )
{
        g_free( ic->topic );
        ic->topic = g_strdup( topic );
        
        g_free( ic->topic_who );
        if( iu )
                ic->topic_who = g_strdup_printf( "%s!%s@%s", iu->nick, iu->user, iu->host );
        else
                ic->topic_who = NULL;
        
        ic->topic_time = time( NULL );
        
        if( ic->flags & IRC_CHANNEL_JOINED )
                irc_send_topic( ic, TRUE );
        
        return 1;
}

void irc_channel_user_set_mode( irc_channel_t *ic, irc_user_t *iu, irc_channel_user_flags_t flags )
{
        irc_channel_user_t *icu = irc_channel_has_user( ic, iu );
        
        if( !icu || icu->flags == flags )
                return;
        
        if( ic->flags & IRC_CHANNEL_JOINED )
                irc_send_channel_user_mode_diff( ic, iu, icu->flags, flags );
        
        icu->flags = flags;
}

void irc_channel_set_mode( irc_channel_t *ic, const char *s )
{
        irc_t *irc = ic->irc;
        char m[128], st = 1;
        const char *t;
        int i;
        char changes[512], *p, st2 = 2;
        
        memset( m, 0, sizeof( m ) );
        
        for( t = ic->mode; *t; t ++ )
                if( *t < sizeof( m ) )
                        m[(int)*t] = 1;
        
        p = changes;
        for( t = s; *t; t ++ )
        {
                if( *t == '+' || *t == '-' )
                        st = *t == '+';
                else if( strchr( CMODES, *t ) )
                {
                        if( m[(int)*t] != st)
                        {
                                if( st != st2 )
                                        st2 = st, *p++ = st ? '+' : '-';
                                *p++ = *t;
                        }
                        m[(int)*t] = st;
                }
        }
        *p = '\0';
        
        memset( ic->mode, 0, sizeof( ic->mode ) );
        
        for( i = 'A'; i <= 'z' && strlen( ic->mode ) < ( sizeof( ic->mode ) - 1 ); i ++ )
                if( m[i] )
                        ic->mode[strlen(ic->mode)] = i;
        
        if( *changes && ( ic->flags & IRC_CHANNEL_JOINED ) )
                irc_write( irc, ":%s!%s@%s MODE %s :%s", irc->root->nick,
                           irc->root->user, irc->root->host, ic->name,
                           changes );
}

void irc_channel_auto_joins( irc_t *irc, account_t *acc )
{
        GSList *l;
        
        for( l = irc->channels; l; l = l->next )
        {
                irc_channel_t *ic = l->data;
                gboolean aj = set_getbool( &ic->set, "auto_join" );
                char *type;
                
                if( acc &&
                    ( type = set_getstr( &ic->set, "chat_type" ) ) &&
                    strcmp( type, "room" ) == 0 )
                {
                        /* Bit of an ugly special case: Handle chatrooms here, we
                           can only auto-join them if their account is online. */
                        char *acc_s;
                        
                        if( !aj || ( ic->flags & IRC_CHANNEL_JOINED ) )
                                /* Only continue if this one's marked as auto_join
                                   or if we're in it already. (Possible if the
                                   client auto-rejoined it before identyfing.) */
                                continue;
                        else if( !( acc_s = set_getstr( &ic->set, "account" ) ) )
                                continue;
                        else if( account_get( irc->b, acc_s ) != acc )
                                continue;
                        else if( acc->ic == NULL || !( acc->ic->flags & OPT_LOGGED_IN ) )
                                continue;
                        else
                                ic->f->join( ic );
                }
                else if( aj )
                {
                        irc_channel_add_user( ic, irc->user );
                }
        }
}

void irc_channel_printf( irc_channel_t *ic, char *format, ... )
{
        va_list params;
        char *text;
        
        va_start( params, format );
        text = g_strdup_vprintf( format, params );
        va_end( params );
        
        irc_send_msg( ic->irc->root, "PRIVMSG", ic->name, text, NULL );
        g_free( text );
}

gboolean irc_channel_name_ok( const char *name_ )
{
        const unsigned char *name = (unsigned char*) name_;
        int i;
        
        if( name_[0] == '\0' )
                return FALSE;
        
        /* Check if the first character is in CTYPES (#&) */
        if( strchr( CTYPES, name_[0] ) == NULL )
                return FALSE;
        
        /* RFC 1459 keeps amazing me: While only a "few" chars are allowed
           in nicknames, channel names can be pretty much anything as long
           as they start with # or &. I'll be a little bit more strict and
           disallow all non-printable characters. */
        for( i = 1; name[i]; i ++ )
                if( name[i] <= ' ' || name[i] == ',' )
                        return FALSE;
        
        return TRUE;
}

void irc_channel_name_strip( char *name )
{
        int i, j;
        
        for( i = j = 0; name[i]; i ++ )
                if( name[i] > ' ' && name[i] != ',' )
                        name[j++] = name[i];
        
        name[j] = '\0';
}

int irc_channel_name_cmp( const char *a_, const char *b_ )
{
        static unsigned char case_map[256];
        const unsigned char *a = (unsigned char*) a_, *b = (unsigned char*) b_;
        int i;
        
        if( case_map['A'] == '\0' )
        {
                for( i = 33; i < 256; i ++ )
                        if( i != ',' )
                                case_map[i] = i;
                
                for( i = 0; i < 26; i ++ )
                        case_map['A'+i] = 'a' + i;
                
                case_map['['] = '{';
                case_map[']'] = '}';
                case_map['~'] = '`';
                case_map['\\'] = '|';
        }
        
        if( !irc_channel_name_ok( a_ ) || !irc_channel_name_ok( b_ ) )
                return -1;
        
        for( i = 0; a[i] && b[i] && case_map[a[i]] && case_map[b[i]]; i ++ )
        {
                if( case_map[a[i]] == case_map[b[i]] )
                        continue;
                else
                        return case_map[a[i]] - case_map[b[i]];
        }
        
        return case_map[a[i]] - case_map[b[i]];
}

static gint irc_channel_user_cmp( gconstpointer a_, gconstpointer b_ )
{
        const irc_channel_user_t *a = a_, *b = b_;
        
        return irc_user_cmp( a->iu, b->iu );
}

void irc_channel_update_ops( irc_channel_t *ic, char *value )
{
        irc_channel_user_set_mode( ic, ic->irc->root,
                ( strcmp( value, "both" ) == 0 ||
                  strcmp( value, "root" ) == 0 ) ? IRC_CHANNEL_USER_OP : 0 );
        irc_channel_user_set_mode( ic, ic->irc->user,
                ( strcmp( value, "both" ) == 0 ||
                  strcmp( value, "user" ) == 0 ) ? IRC_CHANNEL_USER_OP : 0 );
}

char *set_eval_irc_channel_ops( set_t *set, char *value )
{
        irc_t *irc = set->data;
        GSList *l;
        
        if( strcmp( value, "both" ) != 0 && strcmp( value, "none" ) != 0 && 
            strcmp( value, "user" ) != 0 && strcmp( value, "root" ) != 0 )
                return SET_INVALID;
        
        for( l = irc->channels; l; l = l->next )
                irc_channel_update_ops( l->data, value );
        
        return value;
}

/* Channel-type dependent functions, for control channels: */
static gboolean control_channel_privmsg( irc_channel_t *ic, const char *msg )
{
        irc_t *irc = ic->irc;
        irc_user_t *iu;
        const char *s;
        
        /* Scan for non-whitespace chars followed by a colon: */
        for( s = msg; *s && !g_ascii_isspace( *s ) && *s != ':' && *s != ','; s ++ ) {}
        
        if( *s == ':' || *s == ',' )
        {
                char to[s-msg+1];
                
                memset( to, 0, sizeof( to ) );
                strncpy( to, msg, s - msg );
                while( *(++s) && g_ascii_isspace( *s ) ) {}
                msg = s;
                
                if( !( iu = irc_user_by_name( irc, to ) ) )
                        irc_channel_printf( ic, "User does not exist: %s", to );
                else
                        ic->last_target = iu;
        }
        else if( g_strcasecmp( set_getstr( &irc->b->set, "default_target" ), "last" ) == 0 &&
                 ic->last_target && g_slist_find( irc->users, ic->last_target ) )
                iu = ic->last_target;
        else
                iu = irc->root;
        
        if( iu && iu->f->privmsg )
        {
                iu->last_channel = ic;
                iu->f->privmsg( iu, msg );
        }
        
        return TRUE;
}

static gboolean control_channel_invite( irc_channel_t *ic, irc_user_t *iu )
{
        struct irc_control_channel *icc = ic->data;
        bee_user_t *bu = iu->bu;
        
        if( bu == NULL )
                return FALSE;
        
        if( icc->type != IRC_CC_TYPE_GROUP )
        {
                irc_send_num( ic->irc, 482, "%s :Invitations are only possible to fill_by=group channels", ic->name );
                return FALSE;
        }
        
        bu->ic->acc->prpl->add_buddy( bu->ic, bu->handle,
                                      icc->group ? icc->group->name : NULL );
        
        return TRUE;
}

static void control_channel_kick( irc_channel_t *ic, irc_user_t *iu, const char *msg )
{
        struct irc_control_channel *icc = ic->data;
        bee_user_t *bu = iu->bu;
        
        if( bu == NULL )
                return;
        
        if( icc->type != IRC_CC_TYPE_GROUP )
        {
                irc_send_num( ic->irc, 482, "%s :Kicks are only possible to fill_by=group channels", ic->name );
                return;
        }
        
        bu->ic->acc->prpl->remove_buddy( bu->ic, bu->handle,
                                         icc->group ? icc->group->name : NULL );
}

static char *set_eval_by_account( set_t *set, char *value );
static char *set_eval_fill_by( set_t *set, char *value );
static char *set_eval_by_group( set_t *set, char *value );
static char *set_eval_by_protocol( set_t *set, char *value );
static char *set_eval_show_users( set_t *set, char *value );

static gboolean control_channel_init( irc_channel_t *ic )
{
        struct irc_control_channel *icc;
        
        set_add( &ic->set, "account", NULL, set_eval_by_account, ic );
        set_add( &ic->set, "fill_by", "all", set_eval_fill_by, ic );
        set_add( &ic->set, "group", NULL, set_eval_by_group, ic );
        set_add( &ic->set, "protocol", NULL, set_eval_by_protocol, ic );
        
        /* When changing the default, also change it below. */
        set_add( &ic->set, "show_users", "online+,special%,away", set_eval_show_users, ic );
        
        ic->data = icc = g_new0( struct irc_control_channel, 1 );
        icc->type = IRC_CC_TYPE_DEFAULT;
        
        /* Have to run the evaluator to initialize icc->modes. */
        set_setstr( &ic->set, "show_users", "online+,special%,away" );
        
        /* For scripts that care. */
        irc_channel_set_mode( ic, "+C" );
        
        return TRUE;
}

static gboolean control_channel_join( irc_channel_t *ic )
{
        bee_irc_channel_update( ic->irc, ic, NULL );
        
        return TRUE;
}

static char *set_eval_by_account( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        struct irc_control_channel *icc = ic->data;
        account_t *acc;
        
        if( !( acc = account_get( ic->irc->b, value ) ) )
                return SET_INVALID;
        
        icc->account = acc;
        if( ( icc->type & IRC_CC_TYPE_MASK ) == IRC_CC_TYPE_ACCOUNT )
                bee_irc_channel_update( ic->irc, ic, NULL );
        
        return g_strdup( acc->tag );
}

static char *set_eval_fill_by( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        struct irc_control_channel *icc = ic->data;
        char *s;
        
        icc->type &= ~( IRC_CC_TYPE_MASK | IRC_CC_TYPE_INVERT );
        
        s = value;
        if( s[0] == '!' )
        {
                icc->type |= IRC_CC_TYPE_INVERT;
                s ++;
        }
        
        if( strcmp( s, "all" ) == 0 )
                icc->type |= IRC_CC_TYPE_DEFAULT;
        else if( strcmp( s, "rest" ) == 0 )
                icc->type |= IRC_CC_TYPE_REST;
        else if( strcmp( s, "group" ) == 0 )
                icc->type |= IRC_CC_TYPE_GROUP;
        else if( strcmp( s, "account" ) == 0 )
                icc->type |= IRC_CC_TYPE_ACCOUNT;
        else if( strcmp( s, "protocol" ) == 0 )
                icc->type |= IRC_CC_TYPE_PROTOCOL;
        else
                return SET_INVALID;
        
        bee_irc_channel_update( ic->irc, ic, NULL );
        return value;
}

static char *set_eval_by_group( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        struct irc_control_channel *icc = ic->data;
        
        icc->group = bee_group_by_name( ic->irc->b, value, TRUE );
        if( ( icc->type & IRC_CC_TYPE_MASK ) == IRC_CC_TYPE_GROUP )
                bee_irc_channel_update( ic->irc, ic, NULL );
        
        return g_strdup( icc->group->name );
}

static char *set_eval_by_protocol( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        struct irc_control_channel *icc = ic->data;
        struct prpl *prpl;
        
        if( !( prpl = find_protocol( value ) ) )
                return SET_INVALID;
        
        icc->protocol = prpl;
        if( ( icc->type & IRC_CC_TYPE_MASK ) == IRC_CC_TYPE_PROTOCOL )
                bee_irc_channel_update( ic->irc, ic, NULL );
        
        return value;
}

static char *set_eval_show_users( set_t *set, char *value )
{
        struct irc_channel *ic = set->data;
        struct irc_control_channel *icc = ic->data;
        char **parts = g_strsplit( value, ",", 0 ), **part;
        char modes[5];
        
        memset( modes, 0, 5 );
        for( part = parts; *part; part ++ )
        {
                char last, modechar = IRC_CHANNEL_USER_NONE;
                
                if( **part == '\0' )
                        goto fail;
                
                last = (*part)[strlen(*part+1)];
                if( last == '+' )
                        modechar = IRC_CHANNEL_USER_VOICE;
                else if( last == '%' )
                        modechar = IRC_CHANNEL_USER_HALFOP;
                else if( last == '@' )
                        modechar = IRC_CHANNEL_USER_OP;
                
                if( strncmp( *part, "offline", 7 ) == 0 )
                        modes[0] = modechar;
                else if( strncmp( *part, "away", 4 ) == 0 )
                        modes[1] = modechar;
                else if( strncmp( *part, "special", 7 ) == 0 )
                        modes[2] = modechar;
                else if( strncmp( *part, "online", 6 ) == 0 )
                        modes[3] = modechar;
                else
                        goto fail;
        }
        memcpy( icc->modes, modes, 5 );
        bee_irc_channel_update( ic->irc, ic, NULL );
        
        g_strfreev( parts );
        return value;
        
fail:
        g_strfreev( parts );
        return SET_INVALID;     
}

/* Figure out if a channel is supposed to have the user, assuming s/he is
   online or otherwise also selected by the show_users setting. Only works
   for control channels, but does *not* check if this channel is of that
   type. Beware! */
gboolean irc_channel_wants_user( irc_channel_t *ic, irc_user_t *iu )
{
        struct irc_control_channel *icc = ic->data;
        gboolean ret = FALSE;
        
        if( iu->bu == NULL )
                return FALSE;
        
        switch( icc->type & IRC_CC_TYPE_MASK )
        {
        case IRC_CC_TYPE_GROUP:
                ret = iu->bu->group == icc->group;
                break;
        case IRC_CC_TYPE_ACCOUNT:
                ret = iu->bu->ic->acc == icc->account;
                break;
        case IRC_CC_TYPE_PROTOCOL:
                ret = iu->bu->ic->acc->prpl == icc->protocol;
                break;
        case IRC_CC_TYPE_DEFAULT:
        default:
                ret = TRUE;
                break;
        }
        
        if( icc->type & IRC_CC_TYPE_INVERT )
                ret = !ret;
        
        return ret;
}

static gboolean control_channel_free( irc_channel_t *ic )
{
        struct irc_control_channel *icc = ic->data;
        
        set_del( &ic->set, "account" );
        set_del( &ic->set, "fill_by" );
        set_del( &ic->set, "group" );
        set_del( &ic->set, "protocol" );
        set_del( &ic->set, "show_users" );
        
        g_free( icc );
        ic->data = NULL;
        
        /* For scripts that care. */
        irc_channel_set_mode( ic, "-C" );
        
        return TRUE;
}

static const struct irc_channel_funcs control_channel_funcs = {
        control_channel_privmsg,
        control_channel_join,
        NULL,
        NULL,
        control_channel_invite,
        control_channel_kick,
        
        control_channel_init,
        control_channel_free,
};