From ee5b8748b58e8b94aef81c61c14a89c9d4227bc4 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 24 Aug 2017 13:32:19 +0100
Subject: [PATCH 1/2] Add MatrixEvent.isDecryptionFailure()

---
 src/models/event.js | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/models/event.js b/src/models/event.js
index 89f574851..3a4e87f59 100644
--- a/src/models/event.js
+++ b/src/models/event.js
@@ -318,6 +318,19 @@ utils.extend(module.exports.MatrixEvent.prototype, {
         return this._decryptionPromise != null;
     },
 
+    /**
+     * Check if this event is an encrypted event which we failed to decrypt
+     *
+     * (This implies that we might retry decryption at some point in the future)
+     *
+     * @return {boolean} True if this event is an encrypted event which we
+     *     couldn't decrypt.
+     */
+    isDecryptionFailure: function() {
+        return this._clearEvent && this._clearEvent.content &&
+            this._clearEvent.content.msgtype === "m.bad.encrypted";
+    },
+
     /**
      * Start the process of trying to decrypt this event.
      *

From ec5f9a28920a859ec42c990fb1769e5f0860ab56 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 24 Aug 2017 13:24:02 +0100
Subject: [PATCH 2/2] Handle m.call.* events which are decrypted asynchronously

Handle the case where received m.call.* events are not decrypted at the point
of the 'event' notification by adding an 'Event.decrypted' listener for them.
---
 src/client.js | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/client.js b/src/client.js
index 59718f6f1..f8126e8e7 100644
--- a/src/client.js
+++ b/src/client.js
@@ -3053,6 +3053,10 @@ function setupCallEventHandler(client) {
             // now loop through the buffer chronologically and inject them
             callEventBuffer.forEach(function(e) {
                 if (ignoreCallIds[e.getContent().call_id]) {
+                    console.log(
+                        'Ignoring previously answered/hungup call ' +
+                            e.getContent().call_id,
+                    );
                     return;
                 }
                 callEventHandler(e);
@@ -3061,20 +3065,25 @@ function setupCallEventHandler(client) {
         }
     });
 
-    client.on("event", function(event) {
-        if (!isClientPrepared) {
-            if (event.getType().indexOf("m.call.") === 0) {
-                callEventBuffer.push(event);
+    client.on("event", onEvent);
+
+    function onEvent(event) {
+        if (event.getType().indexOf("m.call.") !== 0) {
+            // not a call event
+            if (event.isBeingDecrypted() || event.isDecryptionFailure()) {
+                // not *yet* a call event, but might become one...
+                event.once("Event.decrypted", onEvent);
             }
             return;
         }
+        if (!isClientPrepared) {
+            callEventBuffer.push(event);
+            return;
+        }
         callEventHandler(event);
-    });
+    }
 
     function callEventHandler(event) {
-        if (event.getType().indexOf("m.call.") !== 0) {
-            return; // not a call event
-        }
         const content = event.getContent();
         let call = content.call_id ? client.callList[content.call_id] : undefined;
         let i;