diff --git a/media/java/android/media/MediaRouter2.java b/media/java/android/media/MediaRouter2.java index d8995b419f505..891ab45c7a6e4 100644 --- a/media/java/android/media/MediaRouter2.java +++ b/media/java/android/media/MediaRouter2.java @@ -48,6 +48,7 @@ import java.util.Objects; import java.util.Set; import java.util.concurrent.CopyOnWriteArrayList; import java.util.concurrent.Executor; +import java.util.concurrent.atomic.AtomicBoolean; import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; @@ -118,6 +119,7 @@ public final class MediaRouter2 { private final Map mNonSystemRoutingControllers = new ArrayMap<>(); private final AtomicInteger mNextRequestId = new AtomicInteger(1); + private final AtomicBoolean mIsScanning = new AtomicBoolean(/* initialValue= */ false); final Handler mHandler; @@ -234,7 +236,9 @@ public final class MediaRouter2 { @RequiresPermission(Manifest.permission.MEDIA_CONTENT_CONTROL) public void startScan() { if (isSystemRouter()) { - sManager.startScan(); + if (!mIsScanning.getAndSet(true)) { + sManager.registerScanRequest(); + } } } @@ -260,7 +264,9 @@ public final class MediaRouter2 { @RequiresPermission(Manifest.permission.MEDIA_CONTENT_CONTROL) public void stopScan() { if (isSystemRouter()) { - sManager.stopScan(); + if (mIsScanning.getAndSet(false)) { + sManager.unregisterScanRequest(); + } } } diff --git a/media/java/android/media/MediaRouter2Manager.java b/media/java/android/media/MediaRouter2Manager.java index c84f5b09f166a..24c117911f7c6 100644 --- a/media/java/android/media/MediaRouter2Manager.java +++ b/media/java/android/media/MediaRouter2Manager.java @@ -82,6 +82,7 @@ public final class MediaRouter2Manager { @GuardedBy("sLock") private Client mClient; private final IMediaRouterService mMediaRouterService; + private final AtomicInteger mScanRequestCount = new AtomicInteger(/* initialValue= */ 0); final Handler mHandler; final CopyOnWriteArrayList mCallbackRecords = new CopyOnWriteArrayList<>(); @@ -155,20 +156,17 @@ public final class MediaRouter2Manager { } /** - * Starts scanning remote routes. - *

- * Route discovery can happen even when the {@link #startScan()} is not called. - * This is because the scanning could be started before by other apps. - * Therefore, calling this method after calling {@link #stopScan()} does not necessarily mean - * that the routes found before are removed and added again. - *

- * Use {@link Callback} to get the route related events. - *

- * @see #stopScan() + * Registers a request to scan for remote routes. + * + *

Increases the count of active scanning requests. When the count transitions from zero to + * one, sends a request to the system server to start scanning. + * + *

Clients must {@link #unregisterScanRequest() unregister their scan requests} when scanning + * is no longer needed, to avoid unnecessary resource usage. */ - public void startScan() { - Client client = getOrCreateClient(); - if (client != null) { + public void registerScanRequest() { + if (mScanRequestCount.getAndIncrement() == 0) { + Client client = getOrCreateClient(); try { mMediaRouterService.startScan(client); } catch (RemoteException ex) { @@ -178,21 +176,25 @@ public final class MediaRouter2Manager { } /** - * Stops scanning remote routes to reduce resource consumption. - *

- * Route discovery can be continued even after this method is called. - * This is because the scanning is only turned off when all the apps stop scanning. - * Therefore, calling this method does not necessarily mean the routes are removed. - * Also, for the same reason it does not mean that {@link Callback#onRoutesAdded(List)} - * is not called afterwards. - *

- * Use {@link Callback} to get the route related events. + * Unregisters a scan request made by {@link #registerScanRequest()}. * - * @see #startScan() + *

Decreases the count of active scanning requests. When the count transitions from one to + * zero, sends a request to the system server to stop scanning. + * + * @throws IllegalStateException If called while there are no active scan requests. */ - public void stopScan() { - Client client = getOrCreateClient(); - if (client != null) { + public void unregisterScanRequest() { + if (mScanRequestCount.updateAndGet( + count -> { + if (count == 0) { + throw new IllegalStateException( + "No active scan requests to unregister."); + } else { + return --count; + } + }) + == 0) { + Client client = getOrCreateClient(); try { mMediaRouterService.stopScan(client); } catch (RemoteException ex) { diff --git a/media/tests/MediaRouter/src/com/android/mediaroutertest/MediaRouter2ManagerTest.java b/media/tests/MediaRouter/src/com/android/mediaroutertest/MediaRouter2ManagerTest.java index b4aad9df64a7d..4086dec99218d 100644 --- a/media/tests/MediaRouter/src/com/android/mediaroutertest/MediaRouter2ManagerTest.java +++ b/media/tests/MediaRouter/src/com/android/mediaroutertest/MediaRouter2ManagerTest.java @@ -39,6 +39,7 @@ import static org.junit.Assert.assertEquals; import static org.junit.Assert.assertFalse; import static org.junit.Assert.assertNotNull; import static org.junit.Assert.assertNull; +import static org.junit.Assert.assertThrows; import static org.junit.Assert.assertTrue; import android.Manifest; @@ -121,7 +122,7 @@ public class MediaRouter2ManagerTest { MediaRouter2ManagerTestActivity.startActivity(mContext); mManager = MediaRouter2Manager.getInstance(mContext); - mManager.startScan(); + mManager.registerScanRequest(); mRouter2 = MediaRouter2.getInstance(mContext); // If we need to support thread pool executors, change this to thread pool executor. @@ -152,7 +153,7 @@ public class MediaRouter2ManagerTest { @After public void tearDown() { - mManager.stopScan(); + mManager.unregisterScanRequest(); // order matters (callbacks should be cleared at the last) releaseAllSessions(); @@ -818,6 +819,13 @@ public class MediaRouter2ManagerTest { assertFalse(failureLatch.await(WAIT_TIME_MS, TimeUnit.MILLISECONDS)); } + @Test + public void unregisterScanRequest_enforcesANonNegativeCount() { + mManager.unregisterScanRequest(); // One request was made in the test setup. + assertThrows(IllegalStateException.class, () -> mManager.unregisterScanRequest()); + mManager.registerScanRequest(); // So that the cleanup doesn't fail. + } + /** * Tests if getSelectableRoutes and getDeselectableRoutes filter routes based on * selected routes diff --git a/packages/SettingsLib/src/com/android/settingslib/media/InfoMediaManager.java b/packages/SettingsLib/src/com/android/settingslib/media/InfoMediaManager.java index 192872f5f926c..d9262cce3cb99 100644 --- a/packages/SettingsLib/src/com/android/settingslib/media/InfoMediaManager.java +++ b/packages/SettingsLib/src/com/android/settingslib/media/InfoMediaManager.java @@ -92,14 +92,14 @@ public class InfoMediaManager extends MediaManager { public void startScan() { mMediaDevices.clear(); mRouterManager.registerCallback(mExecutor, mMediaRouterCallback); - mRouterManager.startScan(); + mRouterManager.registerScanRequest(); refreshDevices(); } @Override public void stopScan() { mRouterManager.unregisterCallback(mMediaRouterCallback); - mRouterManager.stopScan(); + mRouterManager.unregisterScanRequest(); } /**