From a7ee7d5badb352e3ebdc4f3df79cbf831fdedc51 Mon Sep 17 00:00:00 2001
From: Thomas Zeitlhofer <tz+github@ze-it.at>
Date: Thu, 20 Aug 2020 14:11:44 +0200
Subject: [PATCH] Renew turnserver credentials when ttl runs out

The previous implementation caches the turnserver response indefinitely.
This breaks VoIP calls as soon as the ttl of the received turnserver
credentials runs out. So, take care to renew the turnserver credentials
by allowing the cache to expire.

Fixes: d8cf44fdc901 ("Simple cache of turn server response")
Signed-off-by: Thomas Zeitlhofer <tz+github@ze-it.at>
---
 .../call/DefaultCallSignalingService.kt       | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/call/DefaultCallSignalingService.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/call/DefaultCallSignalingService.kt
index 0c1a129733..8e8bbfa691 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/call/DefaultCallSignalingService.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/call/DefaultCallSignalingService.kt
@@ -58,18 +58,32 @@ internal class DefaultCallSignalingService @Inject constructor(
 
     private val activeCalls = mutableListOf<MxCall>()
 
-    private var cachedTurnServerResponse: TurnServerResponse? = null
+    private var cachedTurnServerResponse = object {
+
+        private val MIN_TTL = 60
+
+        private val now = { System.currentTimeMillis() / 1000 }
+
+        private var expiresAt: Long = 0
+
+        var data: TurnServerResponse? = null
+            get() = if (expiresAt > now()) field else null
+            set(value) {
+                expiresAt = now() + (value?.ttl ?: 0) - MIN_TTL
+                field = value
+            }
+    }
 
     override fun getTurnServer(callback: MatrixCallback<TurnServerResponse>): Cancelable {
-        if (cachedTurnServerResponse != null) {
-            cachedTurnServerResponse?.let { callback.onSuccess(it) }
+        if (cachedTurnServerResponse.data != null) {
+            cachedTurnServerResponse.data?.let { callback.onSuccess(it) }
             return NoOpCancellable
         }
         return turnServerTask
                 .configureWith(GetTurnServerTask.Params) {
                     this.callback = object : MatrixCallback<TurnServerResponse> {
                         override fun onSuccess(data: TurnServerResponse) {
-                            cachedTurnServerResponse = data
+                            cachedTurnServerResponse.data = data
                             callback.onSuccess(data)
                         }