Bug 1210211 - Part 1: Delay updating push quota. r=kitcambridge

--HG--
extra : commitid : GXDHaPbe8pi
extra : rebase_source : 260a2a8e1434355671b25d58e36007c88b934464

dom/push/PushRecord.jsm

@@ -65,25 +65,15 @@ PushRecord.prototype = {
       this.quota = 0;
       return;
     }
-    let currentQuota;
     if (lastVisit > this.lastPush) {
       // If the user visited the site since the last time we received a
       // notification, reset the quota.
       let daysElapsed = (Date.now() - lastVisit) / 24 / 60 / 60 / 1000;
-      currentQuota = Math.min(
+      this.quota = Math.min(
         Math.round(8 * Math.pow(daysElapsed, -0.8)),
         prefs.get("maxQuotaPerSubscription")
       );
-      Services.telemetry.getHistogramById("PUSH_API_QUOTA_RESET_TO").add(currentQuota - 1);
-    } else {
-      // The user hasn't visited the site since the last notification.
-      currentQuota = this.quota;
-    }
-    this.quota = Math.max(currentQuota - 1, 0);
-    // We check for ctime > 0 to skip older records that did not have ctime.
-    if (this.isExpired() && this.ctime > 0) {
-      let duration = Date.now() - this.ctime;
-      Services.telemetry.getHistogramById("PUSH_API_QUOTA_EXPIRATION_TIME").add(duration / 1000);
+      Services.telemetry.getHistogramById("PUSH_API_QUOTA_RESET_TO").add(this.quota);
     }
   },
 
@@ -93,6 +83,15 @@ PushRecord.prototype = {
     this.lastPush = Date.now();
   },
 
+  reduceQuota() {
+    this.quota = Math.max(this.quota - 1, 0);
+    // We check for ctime > 0 to skip older records that did not have ctime.
+    if (this.isExpired() && this.ctime > 0) {
+      let duration = Date.now() - this.ctime;
+      Services.telemetry.getHistogramById("PUSH_API_QUOTA_EXPIRATION_TIME").add(duration / 1000);
+    }
+  },
+
   /**
    * Queries the Places database for the last time a user visited the site
    * associated with a push registration.

dom/push/PushService.jsm

@@ -45,6 +45,8 @@ const prefs = new Preferences("dom.push.");
 
 const kCHILD_PROCESS_MESSAGES = ["Push:Register", "Push:Unregister",
                                  "Push:Registration", "Push:RegisterEventNotificationListener",
+                                 "Push:NotificationForOriginShown",
+                                 "Push:NotificationForOriginClosed",
                                  "child-process-shutdown"];
 
 const PUSH_SERVICE_UNINIT = 0;
@@ -97,6 +99,11 @@ this.PushService = {
   _db: null,
   _options: null,
   _alarmID: null,
+  _visibleNotifications: new Map(),
+
+  // Callback that is called after attempting to
+  // reduce the quota for a record. Used for testing purposes.
+  _updateQuotaTestCallback: null,
 
   _childListeners: [],
 
@@ -883,20 +890,77 @@ this.PushService = {
         if (shouldNotify) {
           notified = this._notifyApp(record, message);
         }
-        if (record.isExpired()) {
-          this._recordDidNotNotify(kDROP_NOTIFICATION_REASON_EXPIRED);
-          // Drop the registration in the background. If the user returns to the
-          // site, the service worker will be notified on the next `idle-daily`
-          // event.
-          this._backgroundUnregister(record);
-        }
+        // Update quota after the delay, at which point
+        // we check for visible notifications.
+        setTimeout(() => this._updateQuota(keyID),
+          prefs.get("quotaUpdateDelay"));
         return notified;
       });
     }).catch(error => {
       console.error("receivedPushMessage: Error notifying app", error);
     });
   },
 
+  _updateQuota: function(keyID) {
+    console.debug("updateQuota()");
+
+    this._db.update(keyID, record => {
+      // Record may have expired from an earlier quota update.
+      if (record.isExpired()) {
+        console.debug(
+          "updateQuota: Trying to update quota for expired record", record);
+        return null;
+      }
+      // If there are visible notifications, don't apply the quota penalty
+      // for the message.
+      if (!this._visibleNotifications.has(record.uri.prePath)) {
+        record.reduceQuota();
+      }
+      return record;
+    }).then(record => {
+      if (record && record.isExpired()) {
+        this._recordDidNotNotify(kDROP_NOTIFICATION_REASON_EXPIRED);
+        // Drop the registration in the background. If the user returns to the
+        // site, the service worker will be notified on the next `idle-daily`
+        // event.
+        this._backgroundUnregister(record);
+      }
+      if (this._updateQuotaTestCallback) {
+        // Callback so that test may be notified when the quota update is complete.
+        this._updateQuotaTestCallback();
+      }
+    }).catch(error => {
+      console.debug("updateQuota: Error while trying to update quota", error);
+    });
+  },
+
+  _notificationForOriginShown(origin) {
+    console.debug("notificationForOriginShown()", origin);
+    let count;
+    if (this._visibleNotifications.has(origin)) {
+      count = this._visibleNotifications.get(origin);
+    } else {
+      count = 0;
+    }
+    this._visibleNotifications.set(origin, count + 1);
+  },
+
+  _notificationForOriginClosed(origin) {
+    console.debug("notificationForOriginClosed()", origin);
+    let count;
+    if (this._visibleNotifications.has(origin)) {
+      count = this._visibleNotifications.get(origin);
+    } else {
+      console.debug("notificationForOriginClosed: closing notification that has not been shown?");
+      return;
+    }
+    if (count > 1) {
+      this._visibleNotifications.set(origin, count - 1);
+    } else {
+      this._visibleNotifications.delete(origin);
+    }
+  },
+
   _notifyApp: function(aPushRecord, message) {
     if (!aPushRecord || !aPushRecord.scope ||
         aPushRecord.originAttributes === undefined) {
@@ -1055,6 +1119,20 @@ this.PushService = {
           this._childListeners.splice(i, 1);
         }
       }
+      console.debug("receiveMessage: Clearing notifications from child");
+      this._visibleNotifications.clear();
+      return;
+    }
+
+    if (aMessage.name === "Push:NotificationForOriginShown") {
+      console.debug("receiveMessage: Notification shown from child");
+      this._notificationForOriginShown(aMessage.data);
+      return;
+    }
+
+    if (aMessage.name === "Push:NotificationForOriginClosed") {
+      console.debug("receiveMessage: Notification closed from child");
+      this._notificationForOriginClosed(aMessage.data);
       return;
     }
 

dom/push/test/xpcshell/head.js

@@ -222,6 +222,7 @@ function setPrefs(prefs = {}) {
     'http2.retryInterval': 500,
     'http2.reset_retry_count_after_ms': 60000,
     maxQuotaPerSubscription: 16,
+    quotaUpdateDelay: 3000,
   }, prefs);
   for (let pref in defaultPrefs) {
     servicePrefs.set(pref, defaultPrefs[pref]);

modules/libpref/init/all.js

@@ -4501,10 +4501,14 @@ pref("dom.push.loglevel", "off");
 pref("dom.push.serverURL", "wss://push.services.mozilla.com/");
 pref("dom.push.userAgentID", "");
 
-// The maximum number of notifications that a service worker can receive
+// The maximum number of push messages that a service worker can receive
 // without user interaction.
 pref("dom.push.maxQuotaPerSubscription", 16);
 
+// The delay between receiving a push message and updating the quota for a
+// subscription.
+pref("dom.push.quotaUpdateDelay", 3000); // 3 seconds
+
 // Is the network connection allowed to be up?
 // This preference should be used in UX to enable/disable push.
 pref("dom.push.connection.enabled", true);