fix: give AudioTrackSource a dispose() to release its native reference

docs/guide/get-started.md

@@ -298,6 +298,7 @@ audioTrack.dispose();
 
 // Dispose of sources
 videoSource.dispose();
+audioSource.dispose();
 
 // Close peer connection and release resources
 peerConnection.close();

webrtc-examples/src/main/java/dev/onvoid/webrtc/examples/PeerConnectionExample.java

@@ -98,6 +98,7 @@ public static void main(String[] args) {
     private static class LocalPeer implements PeerConnectionObserver {
 
         private final RTCPeerConnection peerConnection;
+        private final AudioTrackSource audioSource;
         private final AudioTrack audioTrack;
         private final VideoTrack videoTrack;
         private final RTCRtpSender audioSender;
@@ -124,7 +125,7 @@ public LocalPeer(PeerConnectionFactory factory) {
             audioOptions.autoGainControl = true;
             audioOptions.noiseSuppression = true;
 
-            AudioTrackSource audioSource = factory.createAudioSource(audioOptions);
+            audioSource = factory.createAudioSource(audioOptions);
             audioTrack = factory.createAudioTrack("audio0", audioSource);
 
             VideoDeviceSource videoSource = new VideoDeviceSource();
@@ -160,6 +161,11 @@ public void dispose() {
             if (peerConnection != null) {
                 peerConnection.close();
             }
+            // AudioTrackSource is ref-counted and not owned by the audio
+            // track; the application must dispose it once no longer needed.
+            if (audioSource != null) {
+                audioSource.dispose();
+            }
         }
 
         // PeerConnectionObserver implementation.

webrtc-examples/src/main/java/dev/onvoid/webrtc/examples/web/connection/PeerConnectionManager.java

@@ -69,6 +69,7 @@ public class PeerConnectionManager implements PeerConnectionSignalingHandler {
     private final PeerConnectionFactory factory;
     private final RTCPeerConnection peerConnection;
     private final List<RTCRtpSender> senders = new ArrayList<>();
+    private final List<AudioTrackSource> audioSources = new ArrayList<>();
 
     private Consumer<RTCSessionDescription> onLocalDescriptionCreated;
     private Consumer<RTCIceCandidate> onIceCandidateGenerated;
@@ -120,6 +121,10 @@ public void addTrack(MediaStreamTrack track, List<String> streamIds) {
     public AudioTrack createAudioTrack(AudioOptions options, String label) {
         AudioTrackSource audioSource = factory.createAudioSource(options);
 
+        // Keep the source around so it can be disposed in close(); it is
+        // ref-counted and not owned by the audio track.
+        audioSources.add(audioSource);
+
         return factory.createAudioTrack(label, audioSource);
     }
 
@@ -156,6 +161,11 @@ public void close() {
         }
         senders.clear();
 
+        for (AudioTrackSource audioSource : audioSources) {
+            audioSource.dispose();
+        }
+        audioSources.clear();
+
         if (peerConnection != null) {
             peerConnection.close();
         }

webrtc-jni/src/main/cpp/src/JNI_AudioTrackSource.cpp

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2019 Alex Andres
+ *
+ * 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.
+ */
+
+#include "JNI_AudioTrackSource.h"
+#include "JavaUtils.h"
+
+#include "api/media_stream_interface.h"
+
+#include "rtc_base/logging.h"
+
+JNIEXPORT void JNICALL Java_dev_onvoid_webrtc_media_audio_AudioTrackSource_dispose
+(JNIEnv * env, jobject caller)
+{
+	webrtc::AudioSourceInterface * source = GetHandle<webrtc::AudioSourceInterface>(env, caller);
+	CHECK_HANDLE(source);
+
+	webrtc::RefCountReleaseStatus status = source->Release();
+
+	if (status != webrtc::RefCountReleaseStatus::kDroppedLastRef) {
+		RTC_LOG(LS_WARNING) << "Native object was not deleted. A reference is still around somewhere.";
+	}
+
+	SetHandle<std::nullptr_t>(env, caller, nullptr);
+
+	source = nullptr;
+}

webrtc/src/main/java/dev/onvoid/webrtc/media/audio/AudioTrackSource.java

@@ -29,4 +29,11 @@ protected AudioTrackSource() {
 
 	}
 
+	/**
+	 * Disposes of the native resources held by this audio source.
+	 * This method should be called when the audio source is no longer needed
+	 * to prevent memory leaks.
+	 */
+	public native void dispose();
+
 }

webrtc/src/test/java/dev/onvoid/webrtc/media/MediaSourceTests.java

@@ -20,6 +20,7 @@
 
 import dev.onvoid.webrtc.TestBase;
 import dev.onvoid.webrtc.media.audio.AudioOptions;
+import dev.onvoid.webrtc.media.audio.AudioTrack;
 import dev.onvoid.webrtc.media.audio.AudioTrackSource;
 
 import org.junit.jupiter.api.Test;
@@ -32,6 +33,21 @@ void audioSourceStateAfterCreation() {
 		AudioTrackSource audioSource = factory.createAudioSource(audioOptions);
 
 		assertEquals(MediaSource.State.LIVE, audioSource.getState());
+
+		audioSource.dispose();
+	}
+
+	@Test
+	void audioSourceDisposeAfterTrackDispose() {
+		// Regression test: AudioTrackSource used to have no dispose(), so the
+		// native AudioSourceInterface reference obtained from
+		// createAudioSource() could never be released by the application.
+		AudioOptions audioOptions = new AudioOptions();
+		AudioTrackSource audioSource = factory.createAudioSource(audioOptions);
+		AudioTrack audioTrack = factory.createAudioTrack("audio0", audioSource);
+
+		audioTrack.dispose();
+		audioSource.dispose();
 	}
 
 }