Fix notifications for encrypted events (#1336)

Remember events that we may need to notify for once decrypted and
evaluate them in an Event.decrypted listener.

Author: dbkr

src/Notifier.js

@@ -33,9 +33,16 @@ import Modal from './Modal';
  * }
  */
 
+const MAX_PENDING_ENCRYPTED = 20;
+
 const Notifier = {
     notifsByRoom: {},
 
+    // A list of event IDs that we've received but need to wait until
+    // they're decrypted until we decide whether to notify for them
+    // or not
+    pendingEncryptedEventIds: [],
+
     notificationMessageForEvent: function(ev) {
         return TextForEvent.textForEvent(ev);
     },
@@ -98,8 +105,10 @@ const Notifier = {
         this.boundOnRoomTimeline = this.onRoomTimeline.bind(this);
         this.boundOnSyncStateChange = this.onSyncStateChange.bind(this);
         this.boundOnRoomReceipt = this.onRoomReceipt.bind(this);
+        this.boundOnEventDecrypted = this.onEventDecrypted.bind(this);
         MatrixClientPeg.get().on('Room.timeline', this.boundOnRoomTimeline);
         MatrixClientPeg.get().on('Room.receipt', this.boundOnRoomReceipt);
+        MatrixClientPeg.get().on('Event.decrypted', this.boundOnEventDecrypted);
         MatrixClientPeg.get().on("sync", this.boundOnSyncStateChange);
         this.toolbarHidden = false;
         this.isSyncing = false;
@@ -109,6 +118,7 @@ const Notifier = {
         if (MatrixClientPeg.get() && this.boundOnRoomTimeline) {
             MatrixClientPeg.get().removeListener('Room.timeline', this.boundOnRoomTimeline);
             MatrixClientPeg.get().removeListener('Room.receipt', this.boundOnRoomReceipt);
+            MatrixClientPeg.get().removeListener('Event.decrypted', this.boundOnEventDecrypted);
             MatrixClientPeg.get().removeListener('sync', this.boundOnSyncStateChange);
         }
         this.isSyncing = false;
@@ -244,16 +254,26 @@ const Notifier = {
         if (ev.sender && ev.sender.userId === MatrixClientPeg.get().credentials.userId) return;
         if (data.timeline.getTimelineSet() !== room.getUnfilteredTimelineSet()) return;
 
-        const actions = MatrixClientPeg.get().getPushActionsForEvent(ev);
-        if (actions && actions.notify) {
-            if (this.isEnabled()) {
-                this._displayPopupNotification(ev, room);
-            }
-            if (actions.tweaks.sound && this.isAudioEnabled()) {
-                PlatformPeg.get().loudNotification(ev, room);
-                this._playAudioNotification(ev, room);
+        // If it's an encrypted event and the type is still 'm.room.encrypted',
+        // it hasn't yet been decrypted, so wait until it is.
+        if (event.isBeingDecrypted() || event.isDecryptionFailure()) {
+            this.pendingEncryptedEventIds.push(ev.getId());
+            // don't let the list fill up indefinitely
+            while (this.pendingEncryptedEventIds.length > MAX_PENDING_ENCRYPTED) {
+                this.pendingEncryptedEventIds.shift();
             }
+            return;
         }
+
+        this._evaluateEvent(ev);
+    },
+
+    onEventDecrypted: function(ev) {
+        const idx = this.pendingEncryptedEventIds.indexOf(ev.getId());
+        if (idx === -1) return;
+
+        this.pendingEncryptedEventIds.splice(idx, 1);
+        this._evaluateEvent(ev);
     },
 
     onRoomReceipt: function(ev, room) {
@@ -273,6 +293,20 @@ const Notifier = {
             delete this.notifsByRoom[room.roomId];
         }
     },
+
+    _evaluateEvent: function(ev) {
+        const room = MatrixClientPeg.get().getRoom(ev.getRoomId());
+        const actions = MatrixClientPeg.get().getPushActionsForEvent(ev);
+        if (actions && actions.notify) {
+            if (this.isEnabled()) {
+                this._displayPopupNotification(ev, room);
+            }
+            if (actions.tweaks.sound && this.isAudioEnabled()) {
+                PlatformPeg.get().loudNotification(ev, room);
+                this._playAudioNotification(ev, room);
+            }
+        }
+    }
 };
 
 if (!global.mxNotifier) {