twitter: implemented filter based group chats

Filter group chats allow for the ability to read the tweets of select
users without actually following the users, and/or track keywords or
hashtags. A filter group chat can have multiple users, keywords, or
hashtags. These users, keywords, or hashtags can span multiple group
chats. This allows for rather robust filter organization.

The underlying structure for the filters is based on linked list, as
using the glib hash tables requires >= glib-2.16 for sanity. Since the
glib requirement of bitlbee is only 2.14, linked list are used in order
to prevent an overly complex implementation.

The idea for this patch was inspired by Artem Savkov's "Twitter search
channels" patch.

In order to use the filter group chats, a group chat must be added to
the twitter account. The channel room name is either follow:username,
track:keyword, and/or track:#hashtag. Multiple elements can be used by
separating each element by a semicolon.

protocols/twitter/twitter.c

@@ -30,6 +30,215 @@
 #include "url.h"
 
 GSList *twitter_connections = NULL;
+
+static int twitter_filter_cmp(struct twitter_filter *tf1,
+                              struct twitter_filter *tf2)
+{
+	int i1 = 0;
+	int i2 = 0;
+	int i;
+
+	static const twitter_filter_type_t types[] = {
+		/* Order of the types */
+		TWITTER_FILTER_TYPE_FOLLOW,
+		TWITTER_FILTER_TYPE_TRACK
+	};
+
+	for (i = 0; i < G_N_ELEMENTS(types); i++) {
+		if (types[i] == tf1->type) {
+			i1 = i + 1;
+			break;
+		}
+	}
+
+	for (i = 0; i < G_N_ELEMENTS(types); i++) {
+		if (types[i] == tf2->type) {
+			i2 = i + 1;
+			break;
+		}
+	}
+
+	if (i1 != i2) {
+		/* With different types, return their difference */
+		return i1 - i2;
+	}
+
+	/* With the same type, return the text comparison */
+	return g_strcasecmp(tf1->text, tf2->text);
+}
+
+static gboolean twitter_filter_update(gpointer data, gint fd,
+                                      b_input_condition cond)
+{
+	struct im_connection *ic = data;
+	struct twitter_data *td = ic->proto_data;
+
+	if (td->filters) {
+		twitter_open_filter_stream(ic);
+	} else if (td->filter_stream) {
+		http_close(td->filter_stream);
+		td->filter_stream = NULL;
+	}
+
+	td->filter_update_id = 0;
+	return FALSE;
+}
+
+static struct twitter_filter *twitter_filter_get(struct groupchat *c,
+                                                 twitter_filter_type_t type,
+                                                 const char *text)
+{
+	struct twitter_data *td = c->ic->proto_data;
+	struct twitter_filter *tf = NULL;
+	struct twitter_filter tfc = {type, (char*) text};
+	GSList *l;
+
+	for (l = td->filters; l; l = g_slist_next(l)) {
+		tf = l->data;
+
+		if (twitter_filter_cmp(tf, &tfc) == 0)
+			break;
+
+		tf = NULL;
+	}
+
+	if (!tf) {
+		tf = g_new0(struct twitter_filter, 1);
+		tf->type = type;
+		tf->text = g_strdup(text);
+		td->filters = g_slist_prepend(td->filters, tf);
+	}
+
+	if (!g_slist_find(tf->groupchats, c))
+		tf->groupchats = g_slist_prepend(tf->groupchats, c);
+
+	if (td->filter_update_id > 0)
+		b_event_remove(td->filter_update_id);
+
+	/* Wait for other possible filter changes to avoid request spam */
+	td->filter_update_id = b_timeout_add(TWITTER_FILTER_UPDATE_WAIT,
+					     twitter_filter_update, c->ic);
+	return tf;
+}
+
+static void twitter_filter_free(struct twitter_filter *tf)
+{
+	g_slist_free(tf->groupchats);
+	g_free(tf->text);
+	g_free(tf);
+}
+
+static void twitter_filter_remove(struct groupchat *c)
+{
+	struct twitter_data *td = c->ic->proto_data;
+	struct twitter_filter *tf;
+	GSList *l = td->filters;
+	GSList *p;
+
+	while (l != NULL) {
+		tf = l->data;
+		tf->groupchats = g_slist_remove(tf->groupchats, c);
+
+		p = l;
+		l = g_slist_next(l);
+
+		if (!tf->groupchats) {
+			twitter_filter_free(tf);
+			td->filters = g_slist_delete_link(td->filters, p);
+		}
+	}
+
+	if (td->filter_update_id > 0)
+		b_event_remove(td->filter_update_id);
+
+	/* Wait for other possible filter changes to avoid request spam */
+	td->filter_update_id = b_timeout_add(TWITTER_FILTER_UPDATE_WAIT,
+					     twitter_filter_update, c->ic);}
+
+static void twitter_filter_remove_all(struct im_connection *ic)
+{
+	struct twitter_data *td = ic->proto_data;
+	GSList *chats = NULL;
+	struct twitter_filter *tf;
+	GSList *l = td->filters;
+	GSList *p;
+
+	while (l != NULL) {
+		tf = l->data;
+
+		/* Build up a list of groupchats to be freed */
+		for (p = tf->groupchats; p; p = g_slist_next(p)) {
+			if (!g_slist_find(chats, p->data))
+				chats = g_slist_prepend(chats, p->data);
+		}
+
+		p = l;
+		l = g_slist_next(l);
+		twitter_filter_free(p->data);
+		td->filters = g_slist_delete_link(td->filters, p);
+	}
+
+	l = chats;
+
+	while (l != NULL) {
+		p = l;
+		l = g_slist_next(l);
+
+		/* Freed each remaining groupchat */
+		imcb_chat_free(p->data);
+		chats = g_slist_delete_link(chats, p);
+	}
+
+	if (td->filter_stream) {
+		http_close(td->filter_stream);
+		td->filter_stream = NULL;
+	}
+}
+
+static GSList *twitter_filter_parse(struct groupchat *c, const char *text)
+{
+	char **fs = g_strsplit(text, ";", 0);
+	GSList *ret = NULL;
+	struct twitter_filter *tf;
+	char **f;
+	char *v;
+	int i;
+	int t;
+
+	static const twitter_filter_type_t types[] = {
+		TWITTER_FILTER_TYPE_FOLLOW,
+		TWITTER_FILTER_TYPE_TRACK
+	};
+
+	static const char *typestrs[] = {
+		"follow",
+		"track"
+	};
+
+	for (f = fs; *f; f++) {
+		if ((v = strchr(*f, ':')) == NULL)
+			continue;
+
+		*(v++) = 0;
+
+		for (t = -1, i = 0; i < G_N_ELEMENTS(types); i++) {
+			if (g_strcasecmp(typestrs[i], *f) == 0) {
+				t = i;
+				break;
+			}
+		}
+
+		if (t < 0 || strlen(v) == 0)
+			continue;
+
+		tf = twitter_filter_get(c, types[t], v);
+		ret = g_slist_prepend(ret, tf);
+	}
+
+	g_strfreev(fs);
+	return ret;
+}
+
 /**
  * Main loop function
  */
@@ -435,7 +644,11 @@ static void twitter_logout(struct im_connection *ic)
 		imcb_chat_free(td->timeline_gc);
 
 	if (td) {
+		if (td->filter_update_id > 0)
+			b_event_remove(td->filter_update_id);
+
 		http_close(td->stream);
+		twitter_filter_remove_all(ic);
 		oauth_info_free(td->oauth_info);
 		g_free(td->user);
 		g_free(td->prefix);
@@ -508,12 +721,57 @@ static void twitter_chat_invite(struct groupchat *c, char *who, char *message)
 {
 }
 
+static struct groupchat *twitter_chat_join(struct im_connection *ic,
+                                           const char *room, const char *nick,
+                                           const char *password, set_t **sets)
+{
+	struct groupchat *c = imcb_chat_new(ic, room);
+	GSList *fs = twitter_filter_parse(c, room);
+	GString *topic = g_string_new("");
+	struct twitter_filter *tf;
+	GSList *l;
+
+	fs = g_slist_sort(fs, (GCompareFunc) twitter_filter_cmp);
+
+	for (l = fs; l; l = g_slist_next(l)) {
+		tf = l->data;
+
+		if (topic->len > 0)
+			g_string_append(topic, ", ");
+
+		if (tf->type == TWITTER_FILTER_TYPE_FOLLOW)
+			g_string_append_c(topic, '@');
+
+		g_string_append(topic, tf->text);
+	}
+
+	if (topic->len > 0)
+		g_string_prepend(topic, "Twitter Filter: ");
+
+	imcb_chat_topic(c, NULL, topic->str, 0);
+	imcb_chat_add_buddy(c, ic->acc->user);
+
+	if (topic->len == 0) {
+		imcb_error(ic, "Failed to handle any filters");
+		imcb_chat_free(c);
+		c = NULL;
+	}
+
+	g_string_free(topic, TRUE);
+	g_slist_free(fs);
+
+	return c;
+}
+
 static void twitter_chat_leave(struct groupchat *c)
 {
 	struct twitter_data *td = c->ic->proto_data;
 
-	if (c != td->timeline_gc)
-		return;		/* WTF? */
+	if (c != td->timeline_gc) {
+		twitter_filter_remove(c);
+		imcb_chat_free(c);
+		return;
+	}
 
 	/* If the user leaves the channel: Fine. Rejoin him/her once new
 	   tweets come in. */
@@ -747,6 +1005,7 @@ void twitter_initmodule()
 	ret->remove_buddy = twitter_remove_buddy;
 	ret->chat_msg = twitter_chat_msg;
 	ret->chat_invite = twitter_chat_invite;
+	ret->chat_join = twitter_chat_join;
 	ret->chat_leave = twitter_chat_leave;
 	ret->keepalive = twitter_keepalive;
 	ret->add_permit = twitter_add_permit;

protocols/twitter/twitter.h

@@ -44,6 +44,12 @@ typedef enum
 	TWITTER_GOT_MENTIONS   = 0x40000,
 } twitter_flags_t;
 
+typedef enum
+{
+	TWITTER_FILTER_TYPE_FOLLOW = 0,
+	TWITTER_FILTER_TYPE_TRACK
+} twitter_filter_type_t;
+
 struct twitter_log_data;
 
 struct twitter_data
@@ -57,10 +63,13 @@ struct twitter_data
 	guint64 timeline_id;
 
 	GSList *follow_ids;
+	GSList *filters;
 
 	guint64 last_status_id; /* For undo */
 	gint main_loop_id;
+	gint filter_update_id;
 	struct http_request *stream;
+	struct http_request *filter_stream;
 	struct groupchat *timeline_gc;
 	gint http_fails;
 	twitter_flags_t flags;
@@ -78,6 +87,15 @@ struct twitter_data
 	int log_id;
 };
 
+#define TWITTER_FILTER_UPDATE_WAIT 3000
+struct twitter_filter
+{
+	twitter_filter_type_t type;
+	char *text;
+	guint64 uid;
+	GSList *groupchats;
+};
+
 struct twitter_user_data
 {
 	guint64 last_id;