Processing groups with nextPollSeconds === undefined

chrome/browser/resources/google_now/background.js

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 'use strict';
 
 /**
  * @fileoverview The event page for Google Now for Chrome implementation.
  * The Google Now event page gets Google Now cards from the server and shows
  * them as Chrome notifications.
@@ skipping 90 matching lines @@
  *   version: number,
  *   chromeNotificationOptions: Object,
  *   actionUrls: Object=,
  *   dismissal: Object
  * }}
  */
 var UnmergedNotification;
 
 /**
  * Notification group as the client stores it. |cardsTimestamp| and |rank| are
- * defined if |cards| is non-empty.
+ * defined if |cards| is non-empty. |nextPollTime| is undefined if the server
+ * (1) never sent 'nextPollSeconds' for the group or
+ * (2) didn't send 'nextPollSeconds' with the last group update containing a
+ *     cards update and all the times after that.
  *
  * @typedef {{
  *   cards: Array.<UnmergedNotification>,
  *   cardsTimestamp: number=,
- *   nextPollTime: number,
+ *   nextPollTime: number=,
  *   rank: number=
  * }}
  */
 var StorageGroup;
 
 /**
  * Checks if a new task can't be scheduled when another task is already
  * scheduled.
  * @param {string} newTaskName Name of the new task.
  * @param {string} scheduledTaskName Name of the scheduled task.
@@ skipping 298 matching lines @@
 /**
  * Schedules next cards poll.
  * @param {Object.<string, StorageGroup>} groups Map from group name to group
  *     information.
  */
 function scheduleNextPoll(groups) {
   var nextPollTime = null;
 
   for (var groupName in groups) {
     var group = groups[groupName];
-    nextPollTime = nextPollTime == null ?
-        group.nextPollTime : Math.min(group.nextPollTime, nextPollTime);
+    if (group.nextPollTime !== undefined) {
+      nextPollTime = nextPollTime == null ?
+          group.nextPollTime : Math.min(group.nextPollTime, nextPollTime);
+    }
   }
 
+  // At least one of the groups must have nextPollTime.
   verify(nextPollTime != null, 'scheduleNextPoll: nextPollTime is null');
 
   var nextPollDelaySeconds = Math.max(
       (nextPollTime - Date.now()) / MS_IN_SECOND,
       MINIMUM_POLLING_PERIOD_SECONDS);
   updateCardsAttempts.start(nextPollDelaySeconds);
 }
 
 /**
  * Merges notification groups into a set of Chrome notifications and shows them.
@@ skipping 38 matching lines @@
     var now = Date.now();
 
     // Build updated set of groups.
     var updatedGroups = {};
 
     for (var groupName in receivedGroups) {
       var receivedGroup = receivedGroups[groupName];
       var storageGroup = items.notificationGroups[groupName] || {
         cards: [],
         cardsTimestamp: undefined,
-        nextPollTime: now,
+        nextPollTime: undefined,
         rank: undefined
       };
 
       if (receivedGroup.requested)
         receivedGroup.cards = receivedGroup.cards || [];
 
       if (receivedGroup.cards) {
+        // If the group contains a cards update, all its fields will get new
+        // values.
         storageGroup.cards = receivedGroup.cards;
         storageGroup.cardsTimestamp = now;
         storageGroup.rank = receivedGroup.rank;
+        storageGroup.nextPollTime = undefined;
+        // The code below assigns nextPollTime a defined value if
+        // nextPollSeconds is specified in the received group.
+        // If the group's cards are not updated, and nextPollSeconds is
+        // unspecified, this method doesn't change group's nextPollTime.
       }
 
+      // 'nextPollSeconds' may be sent even for groups that don't contain cards
+      // updates.
       if (receivedGroup.nextPollSeconds !== undefined) {
         storageGroup.nextPollTime =
             now + receivedGroup.nextPollSeconds * MS_IN_SECOND;
       }
 
       updatedGroups[groupName] = storageGroup;
     }
 
     scheduleNextPoll(updatedGroups);
     chrome.storage.local.set({notificationGroups: updatedGroups});
@@ skipping 52 matching lines @@
                 JSON.stringify(items));
     items = items || {};
 
     var groupsToRequest = [];
 
     if (items.notificationGroups) {
       var now = Date.now();
 
       for (var groupName in items.notificationGroups) {
         var group = items.notificationGroups[groupName];
-        if (group.nextPollTime <= now)
+        if (group.nextPollTime !== undefined && group.nextPollTime <= now)
           groupsToRequest.push(groupName);
       }
     }
 
     requestNotificationGroups(groupsToRequest);
   });
 }
 
 /**
  * Starts getting location for a cards update.
@@ skipping 479 matching lines @@
 
           updateCardsAttempts.isRunning(function(running) {
             if (running)
               requestNotificationGroups([]);
           });
         }
       });
     });
   }
 });