protocol: support client-to-client communication

1 files changed, 123 insertions, 0 deletions

diff --git a/src/client_subscribe.c b/src/client_subscribe.c
new file mode 100644
index 000000000..c65a7ed31
--- /dev/null
+++ b/src/client_subscribe.c
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2003-2011 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * 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 along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "client_subscribe.h"
+#include "client_internal.h"
+#include "client_idle.h"
+#include "idle.h"
+
+#include <string.h>
+
+G_GNUC_PURE
+static GSList *
+client_find_subscription(const struct client *client, const char *channel)
+{
+	for (GSList *i = client->subscriptions; i != NULL; i = g_slist_next(i))
+		if (strcmp((const char *)i->data, channel) == 0)
+			return i;
+
+	return NULL;
+}
+
+enum client_subscribe_result
+client_subscribe(struct client *client, const char *channel)
+{
+	assert(client != NULL);
+	assert(channel != NULL);
+
+	if (!client_message_valid_channel_name(channel))
+		return CLIENT_SUBSCRIBE_INVALID;
+
+	if (client_find_subscription(client, channel) != NULL)
+		return CLIENT_SUBSCRIBE_ALREADY;
+
+	if (client->num_subscriptions >= CLIENT_MAX_SUBSCRIPTIONS)
+		return CLIENT_SUBSCRIBE_FULL;
+
+	client->subscriptions = g_slist_prepend(client->subscriptions,
+						g_strdup(channel));
+	++client->num_subscriptions;
+
+	idle_add(IDLE_SUBSCRIPTION);
+
+	return CLIENT_SUBSCRIBE_OK;
+}
+
+bool
+client_unsubscribe(struct client *client, const char *channel)
+{
+	GSList *i = client_find_subscription(client, channel);
+	if (i == NULL)
+		return false;
+
+	assert(client->num_subscriptions > 0);
+
+	client->subscriptions = g_slist_remove(client->subscriptions, i->data);
+	--client->num_subscriptions;
+
+	idle_add(IDLE_SUBSCRIPTION);
+
+	assert((client->num_subscriptions == 0) ==
+	       (client->subscriptions == NULL));
+
+	return true;
+}
+
+void
+client_unsubscribe_all(struct client *client)
+{
+	for (GSList *i = client->subscriptions; i != NULL; i = g_slist_next(i))
+		g_free(i->data);
+
+	g_slist_free(client->subscriptions);
+	client->subscriptions = NULL;
+	client->num_subscriptions = 0;
+}
+
+bool
+client_push_message(struct client *client, const struct client_message *msg)
+{
+	assert(client != NULL);
+	assert(msg != NULL);
+	assert(client_message_defined(msg));
+
+	if (client->num_messages >= CLIENT_MAX_MESSAGES ||
+	    client_find_subscription(client, msg->channel) == NULL)
+		return false;
+
+	if (client->messages == NULL)
+		client_idle_add(client, IDLE_MESSAGE);
+
+	client->messages = g_slist_prepend(client->messages,
+					   client_message_dup(msg));
+	++client->num_messages;
+
+	return true;
+}
+
+GSList *
+client_read_messages(struct client *client)
+{
+	GSList *messages = g_slist_reverse(client->messages);
+
+	client->messages = NULL;
+	client->num_messages = 0;
+
+	return messages;
+}