resource: move the event formatting to object_v1_update

Move the text/event-stream formatting to object_v1_update() from
object_v1_send() to avoid the formatting and memory allocation
overhead per client.

Signed-off-by: Russell King <rmk@armlinux.org.uk>

1 files changed, 21 insertions, 21 deletions

diff --git a/resource.c b/resource.c
index c1473e7..085a66a 100644
--- a/resource.c
+++ b/resource.c
@@ -6,7 +6,7 @@
 
 struct resource_object {
 	GList *client_list;
-	char *str;
+	GString *string;
 };
 
 static struct resource_object position_object;
@@ -14,21 +14,12 @@ static struct resource_object signal_object;
 
 static void object_v1_send(struct client *c, struct resource_object *obj)
 {
-	const char *str = obj->str;
-	GString *s;
+	GString *string = obj->string;
 
-	if (!str)
+	if (!string)
 		return;
 
-	// Format the text/event-stream response
-	// The double newline terminates this event
-	// See https://www.html5rocks.com/en/tutorials/eventsource/basics/
-	s = g_string_sized_new(1024);
-	g_string_printf(s, "data:%s\n", str);
-	g_string_append_c(s, '\n');
-
-	respond_chunk(c, s);
-	g_string_free(s, TRUE);
+	respond_chunk(c, string);
 }
 
 static int object_v1_get(struct client *c, struct resource *r)
@@ -62,14 +53,23 @@ static void object_v1_client_update(gpointer data, gpointer user_data)
 static int object_v1_update(struct client *c, struct resource *r, const char *m)
 {
 	struct resource_object *obj = r->data;
-	char *n, *o;
-
-	n = g_strdup(m);
-	g_strchomp(n);
-	o = obj->str;
-	obj->str = n;
-	if (o)
-		g_free(o);
+	GString *string, *old;
+	char *n;
+
+	// Remove any trailing whitespace.
+	n = g_strchomp(g_strdup(m));
+
+	// Format the text/event-stream response
+	// We prefix the string with the "data:" tag in preparation for
+	// sending to via the text/event-stream connection.
+	// The double newline terminates this event
+	// See https://www.html5rocks.com/en/tutorials/eventsource/basics/
+	string = g_string_new(NULL);
+	g_string_printf(string, "data:%s\n\n", n);
+	old = obj->string;
+	obj->string = string;
+	g_string_free(old, TRUE);
+	g_free(n);
 
 	g_list_foreach(obj->client_list, object_v1_client_update, obj);