Drop responses in DefaultDrmSession if the session has been released

This prevents trying to post the response to possibly dead threads,
which causes an IllegalStateException to be logged.

Issue: #8328
PiperOrigin-RevId: 352388155

RELEASENOTES.md

@@ -80,8 +80,8 @@
             `MediaSourceEventListener` and `SingleSampleMediaSource.Factory`
         *   `SimpleExoPlayer.addVideoDebugListener`,
             `SimpleExoPlayer.removeVideoDebugListener`,
-            `SimpleExoPlayer.addAudioDebugListener`
-            and `SimpleExoPlayer.removeAudioDebugListener`. Use
+            `SimpleExoPlayer.addAudioDebugListener` and
+            `SimpleExoPlayer.removeAudioDebugListener`. Use
             `SimpleExoPlayer.addAnalyticsListener` and
             `SimpleExoPlayer.removeAnalyticsListener` instead.
         *   `AdaptiveMediaSourceEventListener`. Use `MediaSourceEventListener`
@@ -183,6 +183,10 @@
         Widevine or Clearkey protected content in a playlist.
     *   Add `ExoMediaDrm.KeyRequest.getRequestType`
         ([#7847](https://github.com/google/ExoPlayer/issues/7847)).
+    *   Drop key & provision responses if `DefaultDrmSession` is released while
+        waiting for the response. This fixes (harmless) `IllegalStateException:
+        sending message to a Handler on a dead thread` log messages
+        ([#8328](https://github.com/google/ExoPlayer/issues/8328)).
 *   Analytics:
     *   Pass a `DecoderReuseEvaluation` to `AnalyticsListener`'s
         `onVideoInputFormatChanged` and `onAudioInputFormatChanged` methods. The
@@ -219,9 +223,9 @@
         ad view group
         ([#7344](https://github.com/google/ExoPlayer/issues/7344)),
         ([#8339](https://github.com/google/ExoPlayer/issues/8339)).
-    *   Fix a bug that could cause the next content position played after a
-        seek to snap back to the cue point of the preceding ad, rather than
-        the requested content position.
+    *   Fix a bug that could cause the next content position played after a seek
+        to snap back to the cue point of the preceding ad, rather than the
+        requested content position.
 *   FFmpeg extension:
     *   Link the FFmpeg library statically, saving 350KB in binary size on
         average.

library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSession.java

@@ -26,6 +26,7 @@ import android.os.Looper;
 import android.os.Message;
 import android.os.SystemClock;
 import android.util.Pair;
+import androidx.annotation.GuardedBy;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import com.google.android.exoplayer2.C;
@@ -308,7 +309,7 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
       // Assigning null to various non-null variables for clean-up.
       state = STATE_RELEASED;
       Util.castNonNull(responseHandler).removeCallbacksAndMessages(null);
-      Util.castNonNull(requestHandler).removeCallbacksAndMessages(null);
+      Util.castNonNull(requestHandler).release();
       requestHandler = null;
       Util.castNonNull(requestHandlerThread).quit();
       requestHandlerThread = null;
@@ -570,6 +571,9 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
   @SuppressLint("HandlerLeak")
   private class RequestHandler extends Handler {
 
+    @GuardedBy("this")
+    private boolean isReleased;
+
     public RequestHandler(Looper backgroundLooper) {
       super(backgroundLooper);
     }
@@ -610,9 +614,13 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
         response = e;
       }
       loadErrorHandlingPolicy.onLoadTaskConcluded(requestTask.taskId);
-      responseHandler
-          .obtainMessage(msg.what, Pair.create(requestTask.request, response))
-          .sendToTarget();
+      synchronized (this) {
+        if (!isReleased) {
+          responseHandler
+              .obtainMessage(msg.what, Pair.create(requestTask.request, response))
+              .sendToTarget();
+        }
+      }
     }
 
     private boolean maybeRetryRequest(Message originalMsg, MediaDrmCallbackException exception) {
@@ -647,8 +655,18 @@ import org.checkerframework.checker.nullness.qual.RequiresNonNull;
         // The error is fatal.
         return false;
       }
-      sendMessageDelayed(Message.obtain(originalMsg), retryDelayMs);
-      return true;
+      synchronized (this) {
+        if (!isReleased) {
+          sendMessageDelayed(Message.obtain(originalMsg), retryDelayMs);
+          return true;
+        }
+      }
+      return false;
+    }
+
+    public synchronized void release() {
+      removeCallbacksAndMessages(/* token= */ null);
+      isReleased = true;
     }
   }