fix some issues in infinite scrolling

backend.php

@@ -221,11 +221,16 @@
 
 		print "<headlines id=\"$feed\"><![CDATA[";
 
-		$topmost_article_ids = outputHeadlinesList($link, $feed, $subop, 
+		$ret = outputHeadlinesList($link, $feed, $subop, 
 			$view_mode, $limit, $cat_view, $next_unread_feed, $offset);
 
+		$topmost_article_ids = $ret[0];
+		$headlines_count = $ret[1];
+
 		print "]]></headlines>";
 
+		print "<headlines-count value=\"$headlines_count\"/>";
+
 		if ($_GET["debug"]) $timing_info = print_checkpoint("10", $timing_info);
 
 		if (is_array($topmost_article_ids) && !get_pref($link, 'COMBINED_DISPLAY_MODE')) {

feedlist.js

@@ -1,6 +1,7 @@
 //var xmlhttp = Ajax.getTransport();
 
 var _feed_cur_page = 0;
+var _infscroll_disable = 0;
 
 function viewCategory(cat) {
 	active_feed_is_cat = true;
@@ -25,35 +26,14 @@ function feedlist_callback2(transport) {
 	}
 }
 
-var page_offset = 0;
-
-function viewFeedGoPage(i) {
-	try {
-		if (!getActiveFeedId()) return;
-
-		if (i != 0) {
-			page_offset = page_offset + i;
-		} else {
-			page_offset = 0;
-		}
-
-		if (page_offset < 0) page_offset = 0;
-		viewfeed(getActiveFeedId(), undefined, undefined, undefined,
-			undefined, page_offset);
-	} catch (e) {
-		exception_error(e, "viewFeedGoPage");
-	}
-}
-
-
 function viewNextFeedPage() {
 	try {
 		if (!getActiveFeedId()) return;
 
-		_feed_cur_page++;
+		notify_progress("Loading, please wait...");
 
 		viewfeed(getActiveFeedId(), undefined, undefined, undefined,
-			undefined, _feed_cur_page);
+			undefined, _feed_cur_page+1);
 
 	} catch (e) {
 		exception_error(e, "viewFeedGoPage");
@@ -72,11 +52,13 @@ function viewfeed(feed, subop, is_cat, subop_param, skip_history, offset) {
 		} else {
 			page_offset = 0;
 			_feed_cur_page = 0;
+			_infscroll_disable = 0;
 		}
 
 		if (getActiveFeedId() != feed) {
 			_feed_cur_page = 0;
 			active_post_id = 0;
+			_infscroll_disable = 0;
 		}
 
 		enableHotkeys();
@@ -187,8 +169,9 @@ function viewfeed(feed, subop, is_cat, subop_param, skip_history, offset) {
 		}  */
 
 		new Ajax.Request(query, {
+			asynchronous: page_offset == 0,
 			onComplete: function(transport) { 
-				headlines_callback2(transport, feed, is_cat, _feed_cur_page); 
+				headlines_callback2(transport, feed, is_cat, page_offset); 
 			} });
 
 	} catch (e) {

functions.php

@@ -4216,6 +4216,8 @@
 			print "<div id=\"headlinesInnerContainer\" onscroll=\"headlines_scroll_handler()\">";
 		}
 
+		$headlines_count = db_num_rows($result);
+
 		if (db_num_rows($result) > 0) {
 
 #			print "\{$offset}";
@@ -4464,7 +4466,7 @@
 			print "</div>";
 		}
 
-		return $topmost_article_ids;
+		return array($topmost_article_ids, $headlines_count);
 	}
 
 // from here: http://www.roscripts.com/Create_tag_cloud-71.html

viewfeed.js

@@ -46,7 +46,8 @@ function catchup_callback2(transport, callback) {
 }
 
 function headlines_callback2(transport, active_feed_id, active_feed_is_cat, feed_cur_page) {
-	debug("headlines_callback2");
+	debug("headlines_callback2 [page=" + feed_cur_page + "]");
+
 	var f = document.getElementById("headlines-frame");
 	try {
 		if (feed_cur_page == 0) { 
@@ -57,6 +58,12 @@ function headlines_callback2(transport, active_feed_id, active_feed_is_cat, feed
 
 	if (transport.responseXML) {
 		var headlines = transport.responseXML.getElementsByTagName("headlines")[0];
+		var headlines_count_obj = transport.responseXML.getElementsByTagName("headlines-count")[0];
+
+		var headlines_count = headlines_count_obj.getAttribute("value");
+
+		if (headlines_count == 0) _infscroll_disable = 1;
+
 		var counters = transport.responseXML.getElementsByTagName("counters")[0];
 		var articles = transport.responseXML.getElementsByTagName("article");
 		var runtime_info = transport.responseXML.getElementsByTagName("runtime-info");
@@ -71,15 +78,19 @@ function headlines_callback2(transport, active_feed_id, active_feed_is_cat, feed
 			}
 		} else {
 			if (headlines) {
-				debug("adding some more headlines...");
+				if (headlines_count > 0) {
+					debug("adding some more headlines...");
 
-				var c = document.getElementById("headlinesList");
+					var c = document.getElementById("headlinesList");
+	
+					if (!c) {
+						c = document.getElementById("headlinesInnerContainer");
+					}
 
-				if (!c) {
+					c.innerHTML = c.innerHTML + headlines.firstChild.nodeValue;
-					c = document.getElementById("headlinesInnerContainer");
+				} else {
+					debug("no new headlines received");
 				}
-
-				c.innerHTML = c.innerHTML + headlines.firstChild.nodeValue;
 			} else {
 				debug("headlines_callback: returned no data");
 				notify_error("Error while trying to load more headlines");	
@@ -140,6 +151,8 @@ function headlines_callback2(transport, active_feed_id, active_feed_is_cat, feed
 		} catch (e) { }
 	}
 
+	_feed_cur_page = feed_cur_page;
+
 	notify("");
 }
 
@@ -1244,9 +1257,10 @@ function headlines_scroll_handler() {
 		var e = document.getElementById("headlinesInnerContainer");
 
 		if (e.scrollTop + e.offsetHeight > e.scrollHeight - 300) {
-			debug("more cowbell!");
+			if (!_infscroll_disable) {
-
+				debug("more cowbell!");
-			viewNextFeedPage();
+				viewNextFeedPage();
+			}
 		}
 
 	} catch (e) {