digest: do not show catchup/loadmore prompt when there's nothing to load

digest.js

@@ -47,9 +47,8 @@ function catchup_feed(feed_id, callback) {
 	}
 }
 
-function catchup_visible_articles(callback) {
+function get_visible_article_ids() {
 	try {
-
 		var elems = $("headlines-content").getElementsByTagName("LI");
 		var ids = [];
 			
@@ -59,6 +58,18 @@ function catchup_visible_articles(callback) {
 			}
 		}
 
+		return ids;
+
+	} catch (e) {
+		exception_error("get_visible_article_ids", e);
+	}
+}
+
+function catchup_visible_articles(callback) {
+	try {
+
+		var ids = get_visible_article_ids();
+
 		if (confirm(__("Mark %d displayed articles as read?").replace("%d", ids.length))) {
 
 			var query = "?op=rpc&subop=catchupSelected" +
@@ -565,6 +576,9 @@ function parse_headlines(transport, replace, no_effects) {
 				}
 			}
 
+			var ids = get_visible_article_ids();
+
+			if (ids.length > 0) {
 				if (pr) {
 					$('headlines-content').appendChild(pr);
 					if (!no_effects) new Effect.ScrollTo(inserted);
@@ -579,6 +593,9 @@ function parse_headlines(transport, replace, no_effects) {
 						"id=\"H-LOADING-IMG\" src='images/indicator_tiny.gif'>" +
 						"</div></li>";
 				}
+			} else {
+				// FIXME : display some kind of "nothing to see here" prompt here
+			}
 
 			if (replace && !no_effects) 
 				new Effect.Appear('headlines-content', {duration : 0.3});