Use Closeable interface for DownloadStateCursor to simplify closing.

PiperOrigin-RevId: 240775823

demos/main/src/main/java/com/google/android/exoplayer2/demo/DownloadTracker.java

@@ -140,13 +140,11 @@ public class DownloadTracker implements DownloadManager.Listener {
   // Internal methods
 
   private void loadDownloads() {
-    try {
-      DownloadStateCursor loadedDownloadStates = downloadIndex.getDownloadStates();
+    try (DownloadStateCursor loadedDownloadStates = downloadIndex.getDownloadStates()) {
       while (loadedDownloadStates.moveToNext()) {
         DownloadState downloadState = loadedDownloadStates.getDownloadState();
         downloadStates.put(downloadState.uri, downloadState);
       }
-      loadedDownloadStates.close();
     } catch (IOException e) {
       Log.w(TAG, "Failed to query download states", e);
     }

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadManager.java

@@ -601,15 +601,13 @@ public final class DownloadManager {
     fileIOHandler.post(
         () -> {
           DownloadState[] loadedStates;
-          DownloadStateCursor cursor = null;
-          try {
-            cursor =
-                downloadIndex.getDownloadStates(
-                    STATE_QUEUED,
-                    STATE_STOPPED,
-                    STATE_DOWNLOADING,
-                    STATE_REMOVING,
-                    STATE_RESTARTING);
+          try (DownloadStateCursor cursor =
+              downloadIndex.getDownloadStates(
+                  STATE_QUEUED,
+                  STATE_STOPPED,
+                  STATE_DOWNLOADING,
+                  STATE_REMOVING,
+                  STATE_RESTARTING)) {
             loadedStates = new DownloadState[cursor.getCount()];
             for (int i = 0, length = loadedStates.length; i < length; i++) {
               cursor.moveToNext();
@@ -619,10 +617,6 @@ public final class DownloadManager {
           } catch (Throwable e) {
             Log.e(TAG, "Download state loading failed.", e);
             loadedStates = new DownloadState[0];
-          } finally {
-            if (cursor != null) {
-              cursor.close();
-            }
           }
           final DownloadState[] states = loadedStates;
           handler.post(

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadStateCursor.java

@@ -15,8 +15,10 @@
  */
 package com.google.android.exoplayer2.offline;
 
+import java.io.Closeable;
+
 /** Provides random read-write access to the result set returned by a database query. */
-public interface DownloadStateCursor {
+public interface DownloadStateCursor extends Closeable {
 
   /** Returns the DownloadState at the current position. */
   DownloadState getDownloadState();
@@ -119,9 +121,9 @@ public interface DownloadStateCursor {
     return getPosition() == getCount();
   }
 
-  /** Closes the Cursor, releasing all of its resources and making it completely invalid. */
-  void close();
-
   /** Returns whether the cursor is closed */
   boolean isClosed();
+
+  @Override
+  void close();
 }