Processing timefences from the server.

chrome/browser/resources/google_now/cards.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';
+
+var MS_IN_SECOND = 1000;
+
+/**
+ * Builds an object to manage notification cards.
+ * @return {Object} Card manager interface.
+ */
+function buildCardManager() {
+  var cardShowPrefix = 'card-show-';
+  var cardShowPrefixLength = cardShowPrefix.length;

[rgustafson, 2013/07/19 23:37:12]

Does this actually save anything with the page being loaded and unloaded often?

[vadimt, 2013/07/22 19:22:52]

Done.

+  var cardHidePrefix = 'card-hide-';
+  var cardHidePrefixLength = cardHidePrefix.length;
+
+  /**
+   * Schedules hiding a notification.
+   * @param {string} cardId Card ID.
+   * @param {number=} opt_timeHide If specified, epoch time to hide the card. If
+   *      undefined, the card will be kept shown at least until next update.
+   */
+  function scheduleHiding(cardId, opt_timeHide) {
+    if (opt_timeHide === undefined)
+      return;
+
+    var alarmName = cardHidePrefix + cardId;
+    var alarmInfo = {when: opt_timeHide};
+    chrome.alarms.create(alarmName, alarmInfo);
+  }
+
+  /**
+   * Shows a notification.
+   * @param {string} cardId Card ID.
+   * @param {Object} cardCreateInfo Google Now card represented as a set of
+   *     parameters for showing a Chrome notification.
+   * @param {number=} opt_previousVersion The version of the shown card with
+   *     this id, if it exists, undefined otherwise.
+   */
+  function showNotification(cardId, cardCreateInfo, opt_previousVersion) {
+    console.log('cardManager.showNotification ' + cardId + ' ' +
+                JSON.stringify(cardCreateInfo) + ' ' + opt_previousVersion);
+
+    if (opt_previousVersion !== cardCreateInfo.version) {
+      try {
+        // Delete a notification with the specified id if it already exists, and
+        // then create a notification.
+        chrome.notifications.create(
+            cardId,
+            cardCreateInfo.notification,
+            function(newNotificationId) {
+              if (!newNotificationId || chrome.runtime.lastError) {
+                var errorMessage = chrome.runtime.lastError &&
+                                   chrome.runtime.lastError.message;
+                console.error('notifications.create: ID=' + newNotificationId +
+                              ', ERROR=' + errorMessage);
+                return;
+              }
+
+              scheduleHiding(cardId, cardCreateInfo.timeHide);
+            });
+      } catch (error) {
+        console.error('Error in notifications.create: ' + error);
+      }
+    } else {
+      try {
+        // Update existing notification.
+        chrome.notifications.update(
+            cardId,
+            cardCreateInfo.notification,
+            function(wasUpdated) {
+              if (!wasUpdated || chrome.runtime.lastError) {
+                var errorMessage = chrome.runtime.lastError &&
+                                   chrome.runtime.lastError.message;
+                console.error('notifications.update: UPDATED=' + wasUpdated +
+                              ', ERROR=' + errorMessage);
+                return;
+              }
+
+              scheduleHiding(cardId, cardCreateInfo.timeHide);
+            });
+      } catch (error) {
+        console.error('Error in notifications.update: ' + error);
+      }
+    }
+  }
+
+  /**
+   * Updates/creates a card notification with new data.
+   * @param {Object} card Google Now from the server.
+   * @param {number=} opt_previousVersion The version of the shown card with
+   *     this id, if it exists, undefined otherwise.
+   * @return {Object} Notification data entry for this card.
+   */
+  function update(card, opt_previousVersion) {
+    console.log('cardManager.update ' + JSON.stringify(card) + ' ' +
+        opt_previousVersion);
+
+    if (typeof card.version != 'number') {
+      console.log('cardCreateInfo.version is not a number');
+      // Fix card version.
+      card.version = opt_previousVersion || 0;
+    }
+
+    chrome.alarms.clear(cardHidePrefix + card.notificationId);

[rgustafson, 2013/07/19 23:37:12]

I don't like the fact that this (and a few other places where clear is called)
fills the console log with errors every time there is a refresh because of
failed alarm deletes. Check that the alarm exists before deleting?

[vadimt, 2013/07/22 19:22:52]

Added TODO item. With status quo this is hard to do because the task execution
will fork here. Current tasks are linear.
But as we switch to the model when you don't have to invoke task-provided
callback, this will become easy.
Or, a'll simply speak to extension folks, asking them to print these diags as
non-error output.

+
+    var timeHide = card.trigger && card.trigger.hideTimeSec !== undefined ?
+        Date.now() + card.trigger.hideTimeSec * MS_IN_SECOND : undefined;
+    var cardCreateInfo = {
+      notification: card.notification,
+      timeHide: timeHide,
+      version: card.version
+    };
+
+    var cardShowAlarmName = cardShowPrefix + card.notificationId;
+    if (card.trigger && card.trigger.showTimeSec) {
+      // Card needs to be shown later.
+      console.log('cardManager.register: postponed');
+      chrome.notifications.clear(card.notificationId, function() {});

[rgustafson, 2013/07/19 23:37:12]

This is a weird case. What if there is a low priority version of the card and we
want to show a high priority version at the given time? It doesn't seem like
clearing is the right thing here.

[vadimt, 2013/07/22 19:22:52]

Done.

+      var alarmInfo = {
+        when: Date.now() + card.trigger.showTimeSec * MS_IN_SECOND
+      };
+      chrome.alarms.create(cardShowAlarmName, alarmInfo);
+    } else {
+      // Card needs to be shown immediately.
+      console.log('cardManager.register: immediate');
+      chrome.alarms.clear(cardShowAlarmName);
+      showNotification(
+          card.notificationId, cardCreateInfo, opt_previousVersion);
+    }
+
+    return {actionUrls: card.actionUrls, cardCreateInfo: cardCreateInfo};
+  }
+
+  /**
+   * Removes a card notification.
+   * @param {string} cardId Card ID.
+   */
+  function clear(cardId) {
+    console.log('cardManager.unregister ' + cardId);
+
+    chrome.notifications.clear(cardId, function() {});
+    chrome.alarms.clear(cardShowPrefix + cardId);
+    chrome.alarms.clear(cardHidePrefix + cardId);
+  }
+
+  chrome.alarms.onAlarm.addListener(function(alarm) {
+    console.log('cardManager.onAlarm ' + JSON.stringify(alarm));
+
+    if (alarm.name.indexOf(cardShowPrefix) == 0) {
+      // Alarm to show the card.
+      var cardId = alarm.name.substring(cardShowPrefixLength);
+      storage.get('notificationsData', function(items) {
+        items.notificationsData = items.notificationsData || {};
+        console.log('cardManager.onAlarm.get ' + JSON.stringify(items));
+        var notificationData = items.notificationsData[cardId];
+        if (!notificationData)
+          return;
+
+        showNotification(cardId, notificationData.cardCreateInfo);
+      });
+    } else if (alarm.name.indexOf(cardHidePrefix) == 0) {
+      // Alarm to hide the card.
+      var cardId = alarm.name.substring(cardHidePrefixLength);
+      chrome.notifications.clear(cardId, function() {});
+    }
+  });
+
+  return {
+    update: update,
+    clear: clear
+  };
+}