fix: quick patch for transport switch, need test

Author: BillCarsonFr

src/matrixrtc/RTCEncryptionManager.ts

@@ -23,6 +23,11 @@ import { logger as rootLogger, type Logger } from "../logger.ts";
 import { sleep } from "../utils.ts";
 import type { InboundEncryptionSession, ParticipantDeviceInfo, ParticipantId, Statistics } from "./types.ts";
 import { getParticipantId, KeyBuffer } from "./utils.ts";
+import {
+    type EnabledTransports,
+    RoomAndToDeviceEvents,
+    RoomAndToDeviceTransport,
+} from "./RoomAndToDeviceKeyTransport.ts";
 
 type OutboundEncryptionSession = {
     key: Uint8Array;
@@ -95,6 +100,11 @@ export class RTCEncryptionManager implements IEncryptionManager {
         this.logger.info(`Joining room`);
         this.delayRolloutTimeMillis = joinConfig?.useKeyDelay ?? 1000;
         this.transport.on(KeyTransportEvents.ReceivedKeys, this.onNewKeyReceived);
+        // Deprecate RoomKeyTransport: this can get removed.
+        if (this.transport instanceof RoomAndToDeviceTransport) {
+            this.transport.on(RoomAndToDeviceEvents.EnabledTransportsChanged, this.onTransportChanged);
+        }
+
         this.transport.start();
     }
 
@@ -104,6 +114,28 @@ export class RTCEncryptionManager implements IEncryptionManager {
         this.transport.stop();
     }
 
+    private onTransportChanged: (enabled: EnabledTransports) => void = () => {
+        this.logger.info("Transport change detected, restarting key distribution");
+        // Temporary for backwards compatibility
+        if (this.currentKeyDistributionPromise) {
+            this.currentKeyDistributionPromise
+                .then(() => {
+                    if (this.outboundSession) {
+                        this.outboundSession.sharedWith = [];
+                        this.ensureMediaKey();
+                    }
+                })
+                .catch((e) => {
+                    this.logger.error("Failed to restart key distribution", e);
+                });
+        } else {
+            if (this.outboundSession) {
+                this.outboundSession.sharedWith = [];
+                this.ensureMediaKey();
+            }
+        }
+    };
+
     /**
      * Will ensure that a new key is distributed and used to encrypt our media.
      * If this function is called repeatidly, the calls will be buffered to a single key rotation.