From 17f430043ac229e091e18670be826c2d448f0408 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Eric=20Janouch?= <p@janouch.name>
Date: Fri, 28 May 2021 01:25:10 +0200
Subject: [PATCH] degesch: IRCv3.2 capability negotiation

We can receive and display capability values now.
---
 NEWS      |  2 ++
 degesch.c | 67 ++++++++++++++++++++++++++++++++++++-------------------
 2 files changed, 46 insertions(+), 23 deletions(-)

diff --git a/NEWS b/NEWS
index 4b79444..5ccd44c 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,8 @@
 
  * degesch: added a /squery command for IRCnet
 
+ * degesch: now supporting IRCv3.2 capability negotiation
+
 
 1.1.0 (2020-10-31) "What Do You Mean By 'This Isn't Germany'?"
 
diff --git a/degesch.c b/degesch.c
index cbc13da..8b0269b 100644
--- a/degesch.c
+++ b/degesch.c
@@ -1718,6 +1718,7 @@ struct server
 	char *irc_user_host;                ///< Our current user@host
 	bool autoaway_active;               ///< Autoaway is currently active
 
+	struct strv cap_ls_buf;             ///< Buffer for IRCv3.2 CAP LS
 	bool cap_echo_message;              ///< Whether the server echoes messages
 	bool cap_away_notify;               ///< Whether we get AWAY notifications
 
@@ -1841,6 +1842,7 @@ server_new (struct poller *poller)
 
 	self->irc_user_mode = str_make ();
 
+	self->cap_ls_buf = strv_make ();
 	server_init_specifics (self);
 	return self;
 }
@@ -1887,6 +1889,7 @@ server_destroy (struct server *self)
 	str_free (&self->irc_user_mode);
 	free (self->irc_user_host);
 
+	strv_free (&self->cap_ls_buf);
 	server_free_specifics (self);
 	free (self);
 }
@@ -4956,6 +4959,7 @@ irc_destroy_state (struct server *s)
 	str_reset (&s->irc_user_mode);
 	cstr_set (&s->irc_user_host, NULL);
 
+	strv_reset (&s->cap_ls_buf);
 	s->cap_away_notify = false;
 	s->cap_echo_message = false;
 
@@ -5692,9 +5696,9 @@ irc_register (struct server *s)
 	const char *realname = get_config_string (s->config, "realname");
 	hard_assert (username && realname);
 
-	// Start IRCv3.1 capability negotiation;
+	// Start IRCv3 capability negotiation, with up to 3.2 features;
 	// at worst the server will ignore this or send a harmless error message
-	irc_send (s, "CAP LS");
+	irc_send (s, "CAP LS 302");
 
 	const char *password = get_config_string (s->config, "password");
 	if (password)
@@ -6537,6 +6541,39 @@ irc_handle_away (struct server *s, const struct irc_message *msg)
 		user->away = !!msg->params.len;
 }
 
+static void
+irc_process_cap_ls (struct server *s)
+{
+	log_server_status (s, s->buffer,
+		"#s: #&S", "Capabilities supported", strv_join (&s->cap_ls_buf, " "));
+
+	struct strv chosen = strv_make ();
+	struct strv use    = strv_make ();
+
+	cstr_split (get_config_string (s->config, "capabilities"), ",", true, &use);
+
+	// Filter server capabilities for ones we can make use of
+	for (size_t i = 0; i < s->cap_ls_buf.len; i++)
+	{
+		const char *cap = s->cap_ls_buf.vector[i];
+		size_t cap_name_len = strcspn (cap, "=");
+		for (size_t k = 0; k < use.len; k++)
+			if (!strncasecmp_ascii (use.vector[k], cap, cap_name_len))
+				strv_append_owned (&chosen, xstrndup (cap, cap_name_len));
+	}
+	strv_reset (&s->cap_ls_buf);
+
+	char *chosen_str = strv_join (&chosen, " ");
+	strv_free (&chosen);
+	strv_free (&use);
+
+	// XXX: with IRCv3.2, this may end up being too long for one message,
+	// and we need to be careful with CAP END.  One probably has to count
+	// the number of sent CAP REQ vs the number of received CAP ACK/NAK.
+	irc_send (s, "CAP REQ :%s", chosen_str);
+	free (chosen_str);
+}
+
 static void
 irc_handle_cap (struct server *s, const struct irc_message *msg)
 {
@@ -6577,30 +6614,14 @@ irc_handle_cap (struct server *s, const struct irc_message *msg)
 	}
 	else if (!strcasecmp_ascii (subcommand, "LS"))
 	{
-		log_server_status (s, s->buffer,
-			"#s: #S", "Capabilities supported", args);
 
-		struct strv chosen = strv_make ();
-		struct strv use    = strv_make ();
-
-		cstr_split (get_config_string (s->config, "capabilities"),
-			",", true, &use);
-
-		// Filter server capabilities for ones we can make use of
-		for (size_t i = 0; i < v.len; i++)
+		if (msg->params.len > 3 && !strcmp (args, "*"))
+			cstr_split (msg->params.vector[3], " ", true, &s->cap_ls_buf);
+		else
 		{
-			const char *cap = v.vector[i];
-			for (size_t k = 0; k < use.len; k++)
-				if (!strcasecmp_ascii (use.vector[k], cap))
-					strv_append (&chosen, cap);
+			strv_append_vector (&s->cap_ls_buf, v.vector);
+			irc_process_cap_ls (s);
 		}
-
-		char *chosen_str = strv_join (&chosen, " ");
-		strv_free (&chosen);
-		strv_free (&use);
-
-		irc_send (s, "CAP REQ :%s", chosen_str);
-		free (chosen_str);
 	}
 
 	strv_free (&v);