VoIP: check for support of PSTN protocol

vector/src/main/java/im/vector/app/features/call/webrtc/PSTNProtocol.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2021 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.features.call.webrtc
+
+import kotlinx.coroutines.delay
+import org.matrix.android.sdk.api.session.Session
+import org.matrix.android.sdk.api.session.room.model.thirdparty.ThirdPartyProtocol
+import org.matrix.android.sdk.internal.util.awaitCallback
+
+private const val PSTN_VECTOR_KEY = "im.vector.protocol.pstn"
+private const val PSTN_MATRIX_KEY = "m.protocol.pstn"
+
+suspend fun Session.supportPSTN(maxTries: Int): Boolean {
+    val thirdPartyProtocols: Map<String, ThirdPartyProtocol> = try {
+        awaitCallback {
+            getThirdPartyProtocol(it)
+        }
+    } catch (failure: Throwable) {
+        if (maxTries == 1) {
+            return false
+        } else {
+            // Wait for 10s before trying again
+            delay(10_000L)
+            return supportPSTN(maxTries - 1)
+        }
+    } ?: return false
+    return thirdPartyProtocols.containsKey(PSTN_VECTOR_KEY) || thirdPartyProtocols.containsKey(PSTN_MATRIX_KEY)
+}

vector/src/main/java/im/vector/app/features/call/webrtc/WebRtcCallManager.kt

@@ -28,7 +28,10 @@ import im.vector.app.features.call.CallAudioManager
 import im.vector.app.features.call.VectorCallActivity
 import im.vector.app.features.call.utils.EglUtils
 import im.vector.app.push.fcm.FcmHelper
+import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.asCoroutineDispatcher
+import kotlinx.coroutines.launch
+import org.matrix.android.sdk.api.extensions.orFalse
 import org.matrix.android.sdk.api.extensions.tryOrNull
 import org.matrix.android.sdk.api.session.Session
 import org.matrix.android.sdk.api.session.call.CallListener
@@ -67,6 +70,19 @@ class WebRtcCallManager @Inject constructor(
         fun onAudioDevicesChange() {}
     }
 
+    interface PSTNSupportListener {
+        fun onPSTNSupportUpdated()
+    }
+
+    private val pstnSupportListeners = emptyList<PSTNSupportListener>().toMutableList()
+    fun addPstnSupportListener(listener: PSTNSupportListener) {
+        pstnSupportListeners.add(listener)
+    }
+
+    fun removePstnSupportListener(listener: PSTNSupportListener) {
+        pstnSupportListeners.remove(listener)
+    }
+
     private val currentCallsListeners = emptyList<CurrentCallListener>().toMutableList()
     fun addCurrentCallListener(listener: CurrentCallListener) {
         currentCallsListeners.add(listener)
@@ -85,11 +101,22 @@ class WebRtcCallManager @Inject constructor(
     private var peerConnectionFactory: PeerConnectionFactory? = null
     private val executor = Executors.newSingleThreadExecutor()
     private val dispatcher = executor.asCoroutineDispatcher()
+    var supportsPSTNProtocol: Boolean = false
+        private set
 
     private val rootEglBase by lazy { EglUtils.rootEglBase }
 
     private var isInBackground: Boolean = true
 
+    init {
+        GlobalScope.launch {
+            supportsPSTNProtocol = currentSession?.supportPSTN(3).orFalse()
+            if (supportsPSTNProtocol) {
+                pstnSupportListeners.forEach { it.onPSTNSupportUpdated() }
+            }
+        }
+    }
+
     @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
     fun entersForeground() {
         isInBackground = false