Rework expiring messages management

// FREEBIE

js/background.js

@@ -86,6 +86,7 @@
         }
 
         RotateSignedPreKeyListener.init();
+        ExpiringMessagesListener.update();
     });
 
     window.getSyncRequest = function() {

js/database.js

@@ -189,6 +189,16 @@
                 messages.createIndex('expire', 'expireTimer', { unique: false });
                 next();
             }
+        },
+        {
+            version: "11.0",
+            migrate: function(transaction, next) {
+                console.log('migration 11.0');
+                console.log('creating expires_at message index');
+                var messages = transaction.objectStore('messages');
+                messages.createIndex('expires_at', 'expires_at', { unique: false });
+                next();
+            }
         }
     ];
 }());

js/expiring_messages.js

@@ -5,12 +5,40 @@
 ;(function() {
     'use strict';
     window.Whisper = window.Whisper || {};
-    Whisper.ExpiringMessages = new (Whisper.MessageCollection.extend({
-        initialize: function() {
-            this.on('expired', this.remove);
-            this.fetchExpiring();
-        }
-    }))();
+
+    function destroyExpiredMessages() {
+        // Load messages that have expired and destroy them
+        var expired = new Whisper.MessageCollection();
+        expired.on('add', function(message) {
+            console.log('message', message.get('sent_at'), 'expired');
+            message.destroy();
+            message.getConversation().trigger('expired', message);
+        });
+        expired.on('reset', checkExpiringMessages);
+
+        expired.fetchExpired();
+    }
+
+    var timeout;
+    function checkExpiringMessages() {
+        // Look up the next expiring message and set a timer to destroy it
+        var expiring = new Whisper.MessageCollection();
+        expiring.once('add', function(next) {
+            var expires_at = next.get('expires_at');
+            console.log('next message expires', new Date(expires_at));
+
+            var wait = expires_at - Date.now();
+            if (wait < 0) { wait = 0; }
+
+            clearTimeout(timeout);
+            timeout = setTimeout(destroyExpiredMessages, wait);
+        });
+        expiring.fetchNextExpiring();
+    }
+
+    window.ExpiringMessagesListener = {
+        update: checkExpiringMessages
+    };
 
     var TimerOption = Backbone.Model.extend({
       getName: function() {

js/models/messages.js

@@ -459,15 +459,6 @@
             }));
             return this.save();
         },
-        markExpired: function() {
-            console.log('message', this.get('sent_at'), 'expired');
-            clearInterval(this.expirationTimeout);
-            this.expirationTimeout = null;
-            this.trigger('expired', this);
-            this.destroy();
-
-            this.getConversation().trigger('expired', this);
-        },
         isExpiring: function() {
             return this.get('expireTimer') && this.get('expirationStartTimestamp');
         },
@@ -485,10 +476,13 @@
               return ms_from_now;
         },
         setToExpire: function() {
-            if (this.isExpiring() && !this.expirationTimeout) {
-                var ms_from_now = this.msTilExpire();
-                console.log('message', this.get('sent_at'), 'expires in', ms_from_now, 'ms');
-                this.expirationTimeout = setTimeout(this.markExpired.bind(this), ms_from_now);
+            if (this.isExpiring() && !this.get('expires_at')) {
+                var start = this.get('expirationStartTimestamp');
+                var delta = this.get('expireTimer') * 1000;
+                var expires_at = start + delta;
+                this.save('expires_at', expires_at);
+                ExpiringMessagesListener.update();
+                console.log('message', this.get('sent_at'), 'expires at', expires_at);
             }
         }
 
@@ -551,8 +545,16 @@
             }.bind(this));
         },
 
-        fetchExpiring: function() {
-            this.fetch({conditions: {expireTimer: {$gt: 0}}});
+        fetchNextExpiring: function() {
+            this.fetch({ index: { name: 'expires_at' }, limit: 1 });
+        },
+
+        fetchExpired: function() {
+            console.log('loading expired messages');
+            this.fetch({
+                conditions: { expires_at: { $lte: Date.now() } },
+                addIndividually: true
+            });
         },
 
         hasKeyConflicts: function() {

js/views/conversation_view.js

@@ -227,6 +227,7 @@
             }
         },
         onExpiredCollection: function(message) {
+            console.log('removing message', message.get('sent_at'), 'from collection');
             this.model.messageCollection.remove(message.id);
         },
 

js/views/message_view.js

@@ -144,6 +144,9 @@
                   this.remove();
                 }
             }.bind(this));
+
+            // Failsafe: if in the background, animation events don't fire
+            setTimeout(this.remove.bind(this), 1000);
         },
         onDestroy: function() {
             if (this.$el.hasClass('expired')) {