Add away-notify client capability.

doc/away-notify.txt

@@ -0,0 +1,43 @@
+away-notify client capability specification
+----------------------------------------------
+
+Copyright (c) 2012 Keith Buck <mr_flea@esper.net>.
+
+Unlimited redistribution and modification of this document is allowed
+provided that the above copyright notice and this permission notice
+remains in tact.
+
+The away-notify client capability allows a client to specify that it
+would like to be notified when users are marked/unmarked as away. This
+capability is referred to as 'away-notify' at capability negotiation
+time.
+
+This capability is designed to replace polling of WHO as a more
+efficient method of tracking the away state of users in a channel. The
+away-notify capability both conserves bandwidth as WHO requests are
+not continually sent and allows the client to be notified immediately
+upon a user setting or removing their away state (as opposed to when
+WHO is next polled).
+
+When this capability is enabled, clients will be sent an AWAY message
+when a user sharing a channel with them sets or removes their away
+state, as well as when a user joins and has an away message set.
+(Note that AWAY will not be sent for joining users with no away
+message set.)
+
+The format of the AWAY message is as follows:
+
+   :nick!user@host AWAY [:message]
+
+If the message is present, the user (specified by the nick!user@host
+mask) is going away.  If the message is not present, the user is
+removing their away message/state.
+
+To fully track the away state of users, clients should:
+
+1) Enable the away-notify capability at negotiation time.
+
+2) Execute WHO when joining a channel to capture the current away
+   state of all users in that channel.
+
+3) Update state appropriately upon receiving an AWAY message.

include/client.h

@@ -444,6 +444,7 @@ struct ListClient
 #define CLICAP_SASL		0x0002
 #define CLICAP_ACCOUNT_NOTIFY	0x0004
 #define CLICAP_EXTENDED_JOIN	0x0008
+#define CLICAP_AWAY_NOTIFY	0x0010
 
 /*
  * flags macros.

modules/m_away.c

@@ -84,6 +84,9 @@ m_away(struct Client *client_p, struct Client *source_p, int parc, const char *p
 			sendto_server(client_p, NULL, CAP_TS6, NOCAPS,
 				      ":%s AWAY", use_id(source_p));
 			free_away(source_p);
+
+			sendto_common_channels_local_butone(source_p, CLICAP_AWAY_NOTIFY, ":%s!%s@%s AWAY",
+							    source_p->name, source_p->username, source_p->host);
 		}
 		if(MyConnect(source_p))
 			sendto_one_numeric(source_p, RPL_UNAWAY, form_str(RPL_UNAWAY));
@@ -102,5 +105,9 @@ m_away(struct Client *client_p, struct Client *source_p, int parc, const char *p
 	if(MyConnect(source_p))
 		sendto_one_numeric(source_p, RPL_NOWAWAY, form_str(RPL_NOWAWAY));
 
+	sendto_common_channels_local_butone(source_p, CLICAP_AWAY_NOTIFY, ":%s!%s@%s AWAY :%s",
+					    source_p->name, source_p->username, source_p->host,
+					    source_p->user->away);
+
 	return 0;
 }

modules/m_cap.c

@@ -72,6 +72,7 @@ static struct clicap
 	_CLICAP("sasl", CLICAP_SASL, 0, 0),
 	_CLICAP("account-notify", CLICAP_ACCOUNT_NOTIFY, 0, 0),
 	_CLICAP("extended-join", CLICAP_EXTENDED_JOIN, 0, 0),
+	_CLICAP("away-notify", CLICAP_AWAY_NOTIFY, 0, 0),
 };
 
 #define CLICAP_LIST_LEN (sizeof(clicap_list) / sizeof(struct clicap))

src/channel.c

@@ -136,6 +136,12 @@ send_channel_join(struct Channel *chptr, struct Client *client_p)
 					     client_p->name, client_p->username, client_p->host, chptr->chname,
 					     EmptyString(client_p->user->suser) ? "*" : client_p->user->suser,
 					     client_p->info);
+
+	/* Send away message to away-notify enabled clients. */
+	if (client_p->user->away)
+		sendto_channel_local_with_capability_butone(client_p, ALL_MEMBERS, CLICAP_AWAY_NOTIFY, NOCAPS, chptr,
+							    ":%s!%s@%s AWAY :%s", client_p->name, client_p->username,
+							    client_p->host, client_p->user->away);
 }
 
 /* find_channel_membership()

src/s_user.c

@@ -1468,6 +1468,12 @@ change_nick_user_host(struct Client *target_p,	const char *nick, const char *use
 			*modeval = '\0';
 		}
 
+		/* Resend away message to away-notify enabled clients. */
+		if (target_p->user->away)
+			sendto_common_channels_local_butone(target_p, CLICAP_AWAY_NOTIFY, ":%s!%s@%s AWAY :%s",
+							    target_p->name, target_p->username, target_p->host,
+							    target_p->user->away);
+
 		if(MyClient(target_p) && changed_case)
 			sendto_one(target_p, ":%s!%s@%s NICK %s",
 					target_p->name, target_p->username, target_p->host, nick);