[nearby] Returns error code for startBroadcast if there is an existing broadcast

Fix: 294461081
Test: -m
Ignore-AOSP-First: nearby_not_in_aosp_yet
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7b40aa36e8419e134c8171e22a7fa2a2d3bf85a7)
Merged-In: Icc3227ec5aa7d0ea7d33b7100ef131928577b5a7
Change-Id: Icc3227ec5aa7d0ea7d33b7100ef131928577b5a7
diff --git a/nearby/service/java/com/android/server/nearby/managers/BroadcastProviderManager.java b/nearby/service/java/com/android/server/nearby/managers/BroadcastProviderManager.java
index d95032c..28a33fa 100644
--- a/nearby/service/java/com/android/server/nearby/managers/BroadcastProviderManager.java
+++ b/nearby/service/java/com/android/server/nearby/managers/BroadcastProviderManager.java
@@ -79,6 +79,12 @@
                 if (listener == null) {
                     return;
                 }
+                if (mBroadcastListener != null) {
+                    Log.i(TAG, "We do not support multi clients yet,"
+                            + " please stop previous broadcast first.");
+                    reportBroadcastStatus(listener, BroadcastCallback.STATUS_FAILURE);
+                    return;
+                }
                 if (!mNearbyConfiguration.isTestAppSupported()) {
                     NearbyConfiguration configuration = new NearbyConfiguration();
                     if (!configuration.isPresenceBroadcastLegacyEnabled()) {
diff --git a/nearby/tests/unit/src/com/android/server/nearby/managers/BroadcastProviderManagerTest.java b/nearby/tests/unit/src/com/android/server/nearby/managers/BroadcastProviderManagerTest.java
index 47133f4..7ff7b13 100644
--- a/nearby/tests/unit/src/com/android/server/nearby/managers/BroadcastProviderManagerTest.java
+++ b/nearby/tests/unit/src/com/android/server/nearby/managers/BroadcastProviderManagerTest.java
@@ -24,6 +24,7 @@
 
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.eq;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -126,6 +127,16 @@
     }
 
     @Test
+    public void testRegisterAdvertising_twoTimes_fail() throws Exception {
+        IBroadcastListener newListener = mock(IBroadcastListener.class);
+        IBinder newBinder = mock(IBinder.class);
+        when(newListener.asBinder()).thenReturn(newBinder);
+        mBroadcastProviderManager.startBroadcast(mBroadcastRequest, mBroadcastListener);
+        mBroadcastProviderManager.startBroadcast(mBroadcastRequest, newListener);
+        verify(newListener).onStatusChanged(eq(BroadcastCallback.STATUS_FAILURE));
+    }
+
+    @Test
     public void testStartAdvertising_featureDisabled() throws Exception {
         DeviceConfig.setProperty(
                 NAMESPACE, NEARBY_ENABLE_PRESENCE_BROADCAST_LEGACY, "false", false);