[GOM] Warn when the roll is running behind

Tools/GardeningServer/scripts/ui.js

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 333 matching lines @@
             $(this).removeClass('processing');
     },
     newId: function() {
         var id = 'status-content-' + ++this._currentId;
         this._unfinishedIds[id] = 1;
         return id;
     }
 });
 
 ui.revisionDetails = base.extends('span', {
-    updateUI: function() {
+    // We only support 2 levels of visual escalation levels: warning and critical.
+    warnRollRevisionSpanThreshold: 45,
+    criticalRollRevisionSpanThreshold: 80,
+    classNameForUrgencyLevel: function(rollRevisionSpan) {
+        if (rollRevisionSpan < this.criticalRollRevisionSpanThreshold)
+            return "warning";
+        return "critical";
+    },
+    updateUI: function(totRevision) {
         this.appendChild(document.createElement("br"));
         this.appendChild(document.createTextNode('Last roll is to '));
         this.appendChild(ui.createLinkNode(trac.changesetURL(this.lastRolledRevision), this.lastRolledRevision));
+        var rollRevisionSpan = totRevision - this.lastRolledRevision;
+        // Don't clutter the UI if we haven't run behind.
+        if (rollRevisionSpan > this.warnRollRevisionSpanThreshold) {
+            var wrapper = document.createElement("span");
+            wrapper.className = this.classNameForUrgencyLevel(rollRevisionSpan);
+            wrapper.appendChild(document.createTextNode("(" + rollRevisionSpan + " revisions behind)"));
+            this.appendChild(wrapper);
+        }
         this.appendChild(document.createTextNode(', current autoroll '));
         if (this.roll) {
             var linkText = "" + this.roll.fromRevision + ":" + this.roll.toRevision;
             this.appendChild(ui.createLinkNode(this.roll.url, linkText));
             if (this.roll.isStopped)
                 this.appendChild(document.createTextNode(' (STOPPED) '));
         } else {
             this.appendChild(document.createTextNode(' None'));
         }
     },
@@ skipping 49 matching lines @@
             }
         });
 
         var totRevision = model.latestRevision();
         theSpan.appendChild(document.createTextNode(', trunk is at '));
         theSpan.appendChild(ui.createLinkNode(trac.changesetURL(totRevision), totRevision));
 
         Promise.all([checkout.lastBlinkRollRevision(), rollbot.fetchCurrentRoll()]).then(function(results) {
             theSpan.lastRolledRevision = results[0];
             theSpan.roll = results[1];
-            theSpan.updateUI();
+            theSpan.updateUI(totRevision);
         });
     }
 });
 
 })();