[PATCH 8/9] Battery: Add support for notifications

[Chen Ganir <chen.ganir@ti.com>]

Add support for emitting PropertyChanged when a battery level
characteristic notification is sent from the peer device.
---
 doc/battery-api.txt                  |    5 ++
 profiles/batterystate/batterystate.c |  107 +++++++++++++++++++++++++++++++++-
 2 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/doc/battery-api.txt b/doc/battery-api.txt
index 5d7510d..f31e7e5 100644
--- a/doc/battery-api.txt
+++ b/doc/battery-api.txt
@@ -16,6 +16,11 @@ Methods	dict GetProperties()
 			Returns all properties for the interface. See the
 			Properties section for the available properties.
 
+Signals		PropertyChanged(string name, variant value)
+
+		This signal indicates a changed value of the given
+		property.
+
 Properties	byte Namespace [readonly]
 
 			Namespace value from the battery format characteristic
diff --git a/profiles/batterystate/batterystate.c b/profiles/batterystate/batterystate.c
index 152dc67..cbb5d5e 100644
--- a/profiles/batterystate/batterystate.c
+++ b/profiles/batterystate/batterystate.c
@@ -50,6 +50,7 @@ struct battery {
 	GAttrib			*attrib;	/* GATT connection */
 	guint			attioid;	/* Att watcher id */
 	struct att_range	*svc_range;	/* Battery range */
+	guint                   attnotid;       /* Att notifications id */
 	GSList			*chars;		/* Characteristics */
 };
 
@@ -104,6 +105,14 @@ static gint cmp_device(gconstpointer a, gconstpointer b)
 	return -1;
 }
 
+static gint cmp_char_val_handle(gconstpointer a, gconstpointer b)
+{
+	const struct characteristic *ch = a;
+	const uint16_t *handle = b;
+
+	return ch->attr.value_handle - *handle;
+}
+
 static void batterystate_free(gpointer user_data)
 {
 	struct battery *batt = user_data;
@@ -117,6 +126,10 @@ static void batterystate_free(gpointer user_data)
 	if (batt->attrib != NULL)
 		g_attrib_unref(batt->attrib);
 
+	if (batt->attrib != NULL) {
+		g_attrib_unregister(batt->attrib, batt->attnotid);
+		g_attrib_unref(batt->attrib);
+	}
 
 	dbus_connection_unref(batt->conn);
 	btd_device_unref(batt->dev);
@@ -158,6 +171,17 @@ static void process_batteryservice_char(struct characteristic *ch)
 	}
 }
 
+static void batterylevel_enable_notify_cb(guint8 status, const guint8 *pdu,
+						guint16 len, gpointer user_data)
+{
+	char *msg = user_data;
+
+	if (status != 0)
+		error("Could not enable battery level notification: %s", msg);
+
+	g_free(msg);
+}
+
 static void batterylevel_presentation_format_desc_cb(guint8 status,
 						const guint8 *pdu, guint16 len,
 						gpointer user_data)
@@ -194,6 +218,23 @@ static void process_batterylevel_desc(struct descriptor *desc)
 	char uuidstr[MAX_LEN_UUID_STR];
 	bt_uuid_t btuuid;
 
+	bt_uuid16_create(&btuuid, GATT_CLIENT_CHARAC_CFG_UUID);
+
+	if (bt_uuid_cmp(&desc->uuid, &btuuid) == 0 && g_strcmp0(ch->attr.uuid,
+						BATTERY_LEVEL_UUID) == 0) {
+		uint8_t atval[2];
+		uint16_t val;
+		char *msg;
+
+		val = GATT_CLIENT_CHARAC_CFG_NOTIF_BIT;
+		msg = g_strdup("Enable BatteryLevel notification");
+
+		att_put_u16(val, atval);
+		gatt_write_char(ch->batt->attrib, desc->handle, atval, 2,
+					batterylevel_enable_notify_cb, msg);
+		return;
+	}
+
 	bt_uuid16_create(&btuuid, GATT_CHARAC_FMT_UUID);
 
 	if (bt_uuid_cmp(&desc->uuid, &btuuid) == 0) {
@@ -277,6 +318,12 @@ static DBusMessage *get_properties(DBusConnection *conn, DBusMessage *msg,
 	return reply;
 }
 
+static void emit_battery_level_changed(struct characteristic *c)
+{
+	emit_property_changed(c->batt->conn, c->path, BATTERY_INTERFACE,
+					"Level", DBUS_TYPE_BYTE, &c->level);
+}
+
 static GDBusMethodTable battery_methods[] = {
 	{ GDBUS_METHOD("GetProperties",
 				NULL, GDBUS_ARGS({ "properties", "a{sv}" }),
@@ -284,6 +331,11 @@ static GDBusMethodTable battery_methods[] = {
 	{ }
 };
 
+static GDBusSignalTable battery_signals[] = {
+	{ GDBUS_SIGNAL("PropertyChanged",
+		GDBUS_ARGS({ "name", "s" }, { "value", "v" })) },
+	{ }
+};
 
 static void configure_batterystate_cb(GSList *characteristics, guint8 status,
 							gpointer user_data)
@@ -318,7 +370,7 @@ static void configure_batterystate_cb(GSList *characteristics, guint8 status,
 
 			if (!g_dbus_register_interface(batt->conn, ch->path,
 						BATTERY_INTERFACE,
-						battery_methods, NULL, NULL,
+						battery_methods, battery_signals, NULL,
 						ch, NULL)) {
 				error("D-Bus register interface %s failed",
 							BATTERY_INTERFACE);
@@ -346,12 +398,63 @@ static void configure_batterystate_cb(GSList *characteristics, guint8 status,
 	}
 }
 
+static void proc_batterylevel(struct characteristic *c, const uint8_t *pdu,
+						uint16_t len, gboolean final)
+{
+	uint8_t new_batt_level = 0;
+	gboolean changed = FALSE;
+
+	if (!pdu) {
+		error("Battery level notification: Invalid pdu length");
+		goto done;
+	}
+
+	new_batt_level = pdu[1];
+
+	if (new_batt_level != c->level)
+		changed = TRUE;
+
+	c->level = new_batt_level;
+
+done:
+	if (changed)
+		emit_battery_level_changed(c);
+}
+
+static void notif_handler(const uint8_t *pdu, uint16_t len, gpointer user_data)
+{
+	struct battery *batt = user_data;
+	struct characteristic *ch;
+	uint16_t handle;
+	GSList *l;
+
+	if (len < 3) {
+		error("notif_handler: Bad pdu received");
+		return;
+	}
+
+	handle = att_get_u16(&pdu[1]);
+	l = g_slist_find_custom(batt->chars, &handle, cmp_char_val_handle);
+	if (l == NULL) {
+		error("notif_handler: Unexpected handle 0x%04x", handle);
+		return;
+	}
+
+	ch = l->data;
+	if (g_strcmp0(ch->attr.uuid, BATTERY_LEVEL_UUID) == 0) {
+		proc_batterylevel(ch, pdu, len, FALSE);
+	}
+}
+
 static void attio_connected_cb(GAttrib *attrib, gpointer user_data)
 {
 	struct battery *batt = user_data;
 
 	batt->attrib = g_attrib_ref(attrib);
 
+	batt->attnotid = g_attrib_register(batt->attrib, ATT_OP_HANDLE_NOTIFY,
+						notif_handler, batt, NULL);
+
 	if (batt->chars == NULL) {
 		gatt_discover_char(batt->attrib, batt->svc_range->start,
 					batt->svc_range->end, NULL,
@@ -369,6 +472,8 @@ static void attio_disconnected_cb(gpointer user_data)
 {
 	struct battery *batt = user_data;
 
+	g_attrib_unregister(batt->attrib, batt->attnotid);
+	batt->attnotid = 0;
 	g_attrib_unref(batt->attrib);
 	batt->attrib = NULL;
 }
-- 
1.7.9.5