Revert to old mark as unread on view behavior.

Effectively reverts 185e865 and b67e52d.

(imported from commit e9b95f1fd9e2ab7926f15910044e9e9879ea085f)

tools/jslint/check-all.js

@@ -41,7 +41,7 @@ var globals =
     + ' scroll_to_selected get_private_message_recipient'
     + ' load_old_messages'
     + ' at_top_of_viewport at_bottom_of_viewport within_viewport'
-    + ' viewport restart_get_updates force_get_updates'
+    + ' process_visible_unread_messages viewport restart_get_updates force_get_updates'
     + ' load_more_messages reset_load_more_status have_scrolled_away_from_top'
     + ' maybe_scroll_to_selected recenter_pointer_on_display suppress_scroll_pointer_update'
     + ' mark_current_list_as_read message_range message_in_table process_loaded_for_unread'

zephyr/static/js/narrow.js

@@ -430,8 +430,8 @@ exports.activate = function (operators, opts) {
             var then_scroll = !preserve_pre_narrowing_screen_position;
 
             narrowed_msg_list.select_id(then_select_id, {then_scroll: then_scroll,
-                                                         use_closest: true,
-                                                         mark_read: false});
+                                                         use_closest: true
+                                                        });
 
             if (preserve_pre_narrowing_screen_position) {
                 // Scroll so that the selected message is in the same
@@ -565,8 +565,7 @@ exports.deactivate = function () {
     // view since leaving it the old selected id might no longer be there
     home_msg_list.select_id(home_msg_list.selected_id(), {
         then_scroll: false,
-        use_closest: true,
-        mark_read: false
+        use_closest: true
     });
     // We scroll the user back to exactly the offset from the selected
     // message that he was at the time that he narrowed.

zephyr/static/js/notifications.js

@@ -30,6 +30,11 @@ exports.initialize = function () {
         $.each(notice_memory, function (index, notice_mem_entry) {
            notice_mem_entry.obj.cancel();
         });
+
+        // Update many places on the DOM to reflect unread
+        // counts.
+        process_visible_unread_messages();
+
     }).blur(function () {
         window_has_focus = false;
     });
@@ -270,11 +275,9 @@ function message_is_notifiable(message) {
 }
 
 exports.received_messages = function (messages) {
-    var vp = viewport.message_viewport_info();
-
     $.each(messages, function (index, message) {
         if (!message_is_notifiable(message)) return;
-        if (viewport.message_is_visible(vp, message)) return;
+        if (!unread.message_unread(message)) return;
 
         if (page_params.desktop_notifications_enabled &&
             browser_desktop_notifications_on()) {

zephyr/static/js/stream_list.js

@@ -289,6 +289,7 @@ $(function () {
                 stream_li.addClass('active-filter');
             }
             rebuild_recent_subjects(op_stream[0], subject);
+            process_visible_unread_messages();
         }
     });
 

zephyr/static/js/ui.js

@@ -675,6 +675,11 @@ $(function () {
             } else if (!have_scrolled_away_from_top) {
                 have_scrolled_away_from_top = true;
             }
+            // When the window scrolls, it may cause some messages to
+            // enter the screen and become read.  Calling
+            // process_visible_unread_messages will update necessary
+            // data structures and DOM elements.
+            setTimeout(process_visible_unread_messages, 0);
         }
     }
 
@@ -685,6 +690,7 @@ $(function () {
     }
 
     $(window).scroll($.throttle(50, function (e) {
+        process_visible_unread_messages();
         scroll_finish();
     }));
 

zephyr/static/js/viewport.js

@@ -106,6 +106,34 @@ exports.message_is_visible = function (vp, message) {
     return (row_height > height && row_offset.top > top) || within_viewport(row_offset, row_height);
 };
 
+exports.visible_messages = function () {
+    var selected = current_msg_list.selected_message();
+    var vp = viewport.message_viewport_info();
+    var top = vp.visible_top;
+    var height = vp.visible_height;
+
+    // Being simplistic about this, the smallest message is 30 px high.
+    var selected_row = rows.get(current_msg_list.selected_id(), current_msg_list.table_name);
+    var num_neighbors = Math.floor(height / 30);
+    var candidates = $.merge(selected_row.prevAll("tr.message_row[zid]:lt(" + num_neighbors + ")"),
+                             selected_row.nextAll("tr.message_row[zid]:lt(" + num_neighbors + ")"));
+
+    var visible_messages = [];
+    var i;
+
+    for (i = 0; i<candidates.length; i++) {
+        var row = $(candidates[i]);
+        var row_offset = row.offset();
+        var row_height = row.height();
+        // Mark very tall messages as read once we've gotten past them
+        if ((row_height > height && row_offset.top > top) || within_viewport(row_offset, row_height)) {
+            var message = current_msg_list.get(rows.id(row));
+            visible_messages.push(message);
+        }
+    }
+    return visible_messages;
+};
+
 exports.scrollTop = function viewport_scrollTop () {
     return jwindow.scrollTop.apply(jwindow, arguments);
 };

zephyr/static/js/zephyr.js

@@ -308,6 +308,23 @@ function process_read_messages(messages) {
     update_unread_counts();
 }
 
+// If we ever materially change the algorithm for this function, we
+// may need to update notifications.received_messages as well.
+function process_visible_unread_messages(update_cursor) {
+    // For any messages visible on the screen, make sure they have been marked
+    // as read.
+    if (! notifications.window_has_focus()) {
+        return;
+    }
+
+    var visible_messages = viewport.visible_messages();
+    var mark_as_read = $.grep(visible_messages, unread.message_unread);
+
+    if (mark_as_read.length > 0) {
+        process_read_messages(mark_as_read);
+    }
+}
+
 function mark_read_between(msg_list, start_id, end_id) {
     var msgs_in_range = message_range(msg_list, start_id, end_id);
     var unread_msgs = $.grep(msgs_in_range, unread.message_unread);
@@ -684,6 +701,7 @@ function maybe_add_narrowed_messages(messages, msg_list, messages_are_new) {
 
             new_messages = $.map(new_messages, add_message_metadata);
             add_messages(new_messages, msg_list, messages_are_new);
+            process_visible_unread_messages();
             compose.update_faded_messages();
         },
         error: function (xhr) {
@@ -864,6 +882,7 @@ function get_updates_success(data) {
             respond_to_cursor = saved_respond_to_cursor;
         }
 
+        process_visible_unread_messages();
         notifications.received_messages(messages);
         compose.update_faded_messages();
         stream_list.update_streams_sidebar();

zephyr/tests/frontend/tests/06-unread.js

@@ -6,6 +6,7 @@ var common = require('../common.js').common;
 // standalone
 // Silence jslint errors about the global
 /*global keep_pointer_in_view: true */
+/*global process_visible_unread_messages: true */
 
 function send_with_content(content) {
     common.send_message('stream', {
@@ -78,7 +79,8 @@ casper.then(function () {
         // Changing the scroll position in phantomjs doesn't seem to trigger on-scroll
         // handlers, so unread messages are not handled
         casper.page.scrollPosition = {top: ypos, left: 0};
-        casper.evaluate(function () { keep_pointer_in_view(); });
+        casper.evaluate(function () { keep_pointer_in_view();
+                                      process_visible_unread_messages(); });
     }
     var i = 0;
     scroll_to(0);