From 4dde0c3698231546fc2827d1ba38731bdec8cce6 Mon Sep 17 00:00:00 2001
From: Olivier Martin <olivier@labapart.com>
Date: Wed, 15 Mar 2017 01:43:04 +0100
Subject: [PATCH] gattlib.h: Introduced gattlib_notification_(start|stop)

---
 bluez/gattlib_read_write.c | 26 ++++++++++++++
 dbus/gattlib.c             | 73 ++++++++++++++++++++++++++++++++++++--
 gattlib_common.c           | 10 ++++++
 include/gattlib.h          |  6 ++++
 4 files changed, 113 insertions(+), 2 deletions(-)

diff --git a/bluez/gattlib_read_write.c b/bluez/gattlib_read_write.c
index 3854908..62318f4 100644
--- a/bluez/gattlib_read_write.c
+++ b/bluez/gattlib_read_write.c
@@ -197,3 +197,29 @@ int gattlib_write_char_by_uuid(gatt_connection_t* connection, uuid_t* uuid, void
 
 	return gattlib_write_char_by_handle(connection, handle, buffer, sizeof(buffer));
 }
+
+int gattlib_notification_start(gatt_connection_t* connection, const uuid_t* uuid) {
+	uint16_t handle;
+	uint16_t enable_notification = 0x0001;
+
+	int ret = get_handle_from_uuid(connection, uuid, &handle);
+	if (ret) {
+		return -1;
+	}
+
+	// Enable Status Notification
+	return gattlib_write_char_by_handle(connection, handle + 1, &enable_notification, sizeof(enable_notification));
+}
+
+int gattlib_notification_stop(gatt_connection_t* connection, const uuid_t* uuid) {
+	uint16_t handle;
+	uint16_t enable_notification = 0x0000;
+
+	int ret = get_handle_from_uuid(connection, uuid, &handle);
+	if (ret) {
+		return -1;
+	}
+
+	// Enable Status Notification
+	return gattlib_write_char_by_handle(connection, handle + 1, &enable_notification, sizeof(enable_notification));
+}
diff --git a/dbus/gattlib.c b/dbus/gattlib.c
index ad580a8..76c6b39 100644
--- a/dbus/gattlib.c
+++ b/dbus/gattlib.c
@@ -848,8 +848,77 @@ int gattlib_write_char_by_handle(gatt_connection_t* connection, uint16_t handle,
 	return -1;
 }
 
-void gattlib_register_notification(gatt_connection_t* connection, gattlib_event_handler_t notification_handler, void* user_data) {
+gboolean on_handle_characteristic_property_change(
+	    OrgBluezGattCharacteristic1 *object,
+	    GVariant *arg_changed_properties,
+	    const gchar *const *arg_invalidated_properties,
+	    gpointer user_data)
+{
+	gatt_connection_t* connection = user_data;
+
+	if (connection->notification_handler) {
+		// Retrieve 'Value' from 'arg_changed_properties'
+		if (g_variant_n_children (arg_changed_properties) > 0) {
+			GVariantIter *iter;
+			const gchar *key;
+			GVariant *value;
+
+			g_variant_get (arg_changed_properties, "a{sv}", &iter);
+			while (g_variant_iter_loop (iter, "{&sv}", &key, &value)) {
+				if (strcmp(key, "Value") == 0) {
+					uuid_t uuid;
+					size_t data_length;
+					const uint8_t* data = g_variant_get_fixed_array(value, &data_length, sizeof(guchar));
+
+					gattlib_string_to_uuid(
+							org_bluez_gatt_characteristic1_get_uuid(object),
+							MAX_LEN_UUID_STR + 1,
+							&uuid);
+
+					connection->notification_handler(&uuid, data, data_length, user_data);
+					break;
+				}
+			}
+		}
+	}
+	return TRUE;
 }
 
-void gattlib_register_indication(gatt_connection_t* connection, gattlib_event_handler_t indication_handler, void* user_data) {
+int gattlib_notification_start(gatt_connection_t* connection, const uuid_t* uuid) {
+	OrgBluezGattCharacteristic1 *characteristic = get_characteristic_from_uuid(uuid);
+	if (characteristic == NULL) {
+		return -1;
+	}
+
+	// Register a handle for notification
+	g_signal_connect(characteristic,
+		"g-properties-changed",
+		G_CALLBACK (on_handle_characteristic_property_change),
+		connection);
+
+	GError *error = NULL;
+	org_bluez_gatt_characteristic1_call_start_notify_sync(characteristic, NULL, &error);
+
+	if (error) {
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+int gattlib_notification_stop(gatt_connection_t* connection, const uuid_t* uuid) {
+	OrgBluezGattCharacteristic1 *characteristic = get_characteristic_from_uuid(uuid);
+	if (characteristic == NULL) {
+		return -1;
+	}
+
+	GError *error = NULL;
+	org_bluez_gatt_characteristic1_call_stop_notify_sync(
+		characteristic, NULL, &error);
+
+	if (error) {
+		return 1;
+	} else {
+		return 0;
+	}
 }
diff --git a/gattlib_common.c b/gattlib_common.c
index 0b38bb8..363191a 100644
--- a/gattlib_common.c
+++ b/gattlib_common.c
@@ -1,5 +1,15 @@
 #include "gattlib_internal.h"
 
+void gattlib_register_notification(gatt_connection_t* connection, gattlib_event_handler_t notification_handler, void* user_data) {
+	connection->notification_handler = notification_handler;
+	connection->notification_user_data = user_data;
+}
+
+void gattlib_register_indication(gatt_connection_t* connection, gattlib_event_handler_t indication_handler, void* user_data) {
+	connection->indication_handler = indication_handler;
+	connection->indication_user_data = user_data;
+}
+
 void bt_uuid_to_uuid(bt_uuid_t* bt_uuid, uuid_t* uuid) {
 	memcpy(&uuid->value, &bt_uuid->value, sizeof(uuid->value));
 	if (bt_uuid->type == BT_UUID16) {
diff --git a/include/gattlib.h b/include/gattlib.h
index 76cb698..bcb09a9 100644
--- a/include/gattlib.h
+++ b/include/gattlib.h
@@ -140,6 +140,12 @@ int gattlib_read_char_by_uuid_async(gatt_connection_t* connection, uuid_t* uuid,
 int gattlib_write_char_by_uuid(gatt_connection_t* connection, uuid_t* uuid, void* buffer, size_t buffer_len);
 int gattlib_write_char_by_handle(gatt_connection_t* connection, uint16_t handle, void* buffer, size_t buffer_len);
 
+/*
+ * @param uuid     UUID of the characteristic that will trigger the notification
+ */
+int gattlib_notification_start(gatt_connection_t* connection, const uuid_t* uuid);
+int gattlib_notification_stop(gatt_connection_t* connection, const uuid_t* uuid);
+
 void gattlib_register_notification(gatt_connection_t* connection, gattlib_event_handler_t notification_handler, void* user_data);
 void gattlib_register_indication(gatt_connection_t* connection, gattlib_event_handler_t indication_handler, void* user_data);