DB/Index Redux

This change removes the timestamp field from messages and conversations
in favor of multiple semantically named timestamp fields: sent_at,
received_at on messages; active_at on conversations. This requires/lets
us rethink and improve our indexing scheme thusly:

The inbox index on conversations will order entries by the
conversation.active_at property, which should only appear on
conversations destined for the inbox.

The receipt index will use the message.sent_at property, for effecient
lookup of outgoing messages by timestamp, for use in processing delivery
receipts.

The group index on conversation.members is multi-entry, meaning that
looking up any phone number in this index will efficiently yield all
groups the number belongs to.

The conversation index lets us scan messages in a single conversation,
in the order they were received (or the reverse order). It is a compound
index on [conversationId, received_at].

js/database.js

@@ -24,12 +24,14 @@
         {
             version: "1.0",
             migrate: function(transaction, next) {
-                console.log('migratetion 1.0');
+                console.log('migration 1.0');
                 var messages = transaction.db.createObjectStore("messages");
-                messages.createIndex("conversation", "conversationId", { unique: false });
+                messages.createIndex("conversation", ["conversationId", "received_at"], { unique: false });
+                messages.createIndex("receipt", "sent_at", { unique: false });
 
                 var conversations = transaction.db.createObjectStore("conversations");
-                conversations.createIndex("timestamp", "timestamp", { unique: false });
+                conversations.createIndex("inbox", "active_at", { unique: false });
+                conversations.createIndex("group", "members", { unique: false, multiEntry: true });
                 next();
             }
         }

js/models/conversations.js

@@ -22,12 +22,13 @@
     database: Whisper.Database,
     storeName: 'conversations',
     defaults: function() {
+      var timestamp = new Date().getTime();
       return {
-        name: 'New Conversation',
-        image: '/images/default.png',
-        unreadCount: 0,
-        timestamp: new Date().getTime(),
-        active: true
+        name        : 'New Conversation',
+        image       : '/images/default.png',
+        unreadCount : 0,
+        timestamp   : timestamp,
+        active_at   : timestamp
       };
     },
 
@@ -42,18 +43,20 @@
     },
 
     sendMessage: function(message, attachments) {
-        var timestamp = Date.now();
+        var now = Date.now();
         this.messageCollection.add({
-            body             : message,
-            timestamp        : timestamp,
-            conversationId   : this.id,
-            type             : 'outgoing',
-            attachments      : attachments,
+            body           : message,
+            conversationId : this.id,
+            type           : 'outgoing',
+            attachments    : attachments,
+            sent_at        : now,
+            received_at    : now
         }).save();
 
-        this.save({ timestamp:   timestamp,
-                    unreadCount: 0,
-                    active:      true});
+        this.save({
+            unreadCount : 0,
+            active_at   : now
+        });
 
         if (this.get('type') == 'private') {
           return textsecure.messaging.sendMessageToNumber(this.get('id'), message, attachments);
@@ -85,15 +88,29 @@
 
     fetchMessages: function(options) {
         options = options || {};
-        options.conditions = {conversationId: this.id };
+        options.index = {
+            // 'conversation' index on conversationId
+            // WHERE conversationId = this.id ORDER received_at DESC
+            name  : 'conversation',
+            lower : [this.id],
+            upper : [this.id, Number.MAX_VALUE],
+            order : 'desc'
+        };
         return this.messageCollection.fetch(options);
+        // TODO pagination/infinite scroll
+        // limit: 10, offset: page*10,
+    },
+
+    archive: function() {
+        this.unset('active_at');
     },
 
     destroyMessages: function() {
         var models = this.messageCollection.models;
         this.messageCollection.reset([]);
         _.each(models, function(message) { message.destroy(); });
-        return this.save({active: false});
+        this.archive();
+        return this.save();
     }
   });
 
@@ -110,7 +127,7 @@
       var attributes = {};
       attributes = {
         name      : name,
-        numbers   : recipients,
+        members   : recipients,
         type      : 'group',
       };
       var conversation = this.add(attributes, {merge: true});

js/models/messages.js

@@ -19,16 +19,16 @@
     window.Whisper = window.Whisper || {};
 
     var Message  = Backbone.Model.extend({
-        database: Whisper.Database,
-        storeName: 'messages',
-        defaults: function() {
+        database  : Whisper.Database,
+        storeName : 'messages',
+        defaults  : function() {
             return {
                 timestamp: new Date().getTime(),
                 attachments: []
             };
         },
         validate: function(attributes, options) {
-            var required = ['timestamp', 'conversationId'];
+            var required = ['conversationId', 'received_at', 'sent_at'];
             var missing = _.filter(required, function(attr) { return !attributes[attr]; });
             if (missing.length) {
                 console.log("Message missing attributes: " + missing);
@@ -37,11 +37,11 @@
     });
 
     Whisper.MessageCollection = Backbone.Collection.extend({
-        model: Message,
-        database: Whisper.Database,
-        storeName: 'messages',
-        comparator: 'timestamp',
-        destroyAll: function () {
+        model      : Message,
+        database   : Whisper.Database,
+        storeName  : 'messages',
+        comparator : 'received_at',
+        destroyAll : function () {
             return Promise.all(this.models.map(function(m) {
                 return new Promise(function(resolve, reject) {
                     m.destroy().then(resolve).fail(reject);

js/views/inbox_view.js

@@ -32,11 +32,15 @@
                 collection : this.conversations
             });
 
-            this.conversations.fetch({ reset: true }).then(function() {
-                this.conversations.reset(
-                    //TODO: Add an index to support this operation at the db level
-                    this.conversations.filter(function(c) { return c.get('active'); })
-                );
+            this.conversations.fetch({
+                index: {
+                    name: 'inbox', // 'inbox' index on active_at
+                    order: 'desc'  // ORDER timestamp DESC
+                },
+                reset: true
+                // TODO pagination/infinite scroll
+                // limit: 10, offset: page*10,
+            }).then(function() {
                 if (this.conversations.length) {
                     this.conversations.at(0).trigger('render');
                 }

js/views/message_view.js

@@ -73,7 +73,7 @@
         this.$el.html(
           Mustache.render(this.template, {
             message: this.model.get('body'),
-            timestamp: moment(this.model.get('timestamp')).fromNow(),
+            timestamp: moment(this.model.get('received_at')).fromNow(),
             bubble_class: this.model.get('type') === 'outgoing' ? 'sent' : 'incoming',
             sender: this.model.get('sender')
           })