Merge cherrypicks of [19028669] into tm-release.android-vts-13.0_r8android-vts-13.0_r7android-vts-13.0_r6android-vts-13.0_r5android-vts-13.0_r4android-vts-13.0_r3android-vts-13.0_r2android-vts-13.0_r1android-security-13.0.0_r9android-security-13.0.0_r8android-security-13.0.0_r7android-security-13.0.0_r6android-security-13.0.0_r5android-security-13.0.0_r4android-security-13.0.0_r3android-security-13.0.0_r2android-security-13.0.0_r18android-security-13.0.0_r17android-security-13.0.0_r16android-security-13.0.0_r15android-security-13.0.0_r14android-security-13.0.0_r13android-security-13.0.0_r12android-security-13.0.0_r11android-security-13.0.0_r10android-security-13.0.0_r1android-platform-13.0.0_r2android-platform-13.0.0_r1android-cts-13.0_r8android-cts-13.0_r7android-cts-13.0_r6android-cts-13.0_r5android-cts-13.0_r4android-cts-13.0_r3android-cts-13.0_r2android-cts-13.0_r1android-13.0.0_r8android-13.0.0_r7android-13.0.0_r6android-13.0.0_r5android-13.0.0_r4android-13.0.0_r31android-13.0.0_r3android-13.0.0_r2android-13.0.0_r12android-13.0.0_r1android13-tests-releaseandroid13-security-releaseandroid13-s3-releaseandroid13-s2-releaseandroid13-s1-releaseandroid13-release

Change-Id: I51c768e6a810381c84d2046a37ea3d7ff9bf936c

2 files changed, 77 insertions, 19 deletions

diff --git a/java/com/android/modules/utils/SynchronousResultReceiver.java b/java/com/android/modules/utils/SynchronousResultReceiver.java
index ad270d2..c12d739 100644
--- a/java/com/android/modules/utils/SynchronousResultReceiver.java
+++ b/java/com/android/modules/utils/SynchronousResultReceiver.java
@@ -25,11 +25,14 @@ import android.os.RemoteException;
 import android.os.SystemClock;
 import android.util.Log;
 
+import com.android.internal.annotations.GuardedBy;
+
 import java.io.Serializable;
 import java.time.Duration;
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
@@ -39,19 +42,59 @@ import java.util.concurrent.TimeoutException;
  * Allow the server end to synchronously wait on the response from the client.
  * This enables an RPC like system but with the ability to timeout and discard late results.
  *
- * <p>NOTE: Can only be used for one response.
- * Subsequent responses on the same instance will throw a {@link IllegalStateException}
+ * <p>NOTE: Use the static {@link #get} method to retrieve an available instance of this class.
+ * If no instances are available, a new one is created.
  */
 public final class SynchronousResultReceiver<T> implements Parcelable {
     private static final String TAG = "SynchronousResultReceiver";
     private final boolean mLocal;
     private boolean mIsCompleted;
+    private final static Object sLock = new Object();
+    private final static int QUEUE_THRESHOLD = 4;
+
+    @GuardedBy("sLock")
+    private CompletableFuture<Result<T>> mFuture = new CompletableFuture<>();
+
+    @GuardedBy("sLock")
+    private static final ConcurrentLinkedQueue<SynchronousResultReceiver> sAvailableReceivers
+            = new ConcurrentLinkedQueue<>();
 
-    public SynchronousResultReceiver() {
+    public static <T> SynchronousResultReceiver<T> get() {
+        synchronized(sLock) {
+            if (sAvailableReceivers.isEmpty()) {
+                return new SynchronousResultReceiver();
+            }
+            SynchronousResultReceiver receiver = sAvailableReceivers.poll();
+            receiver.resetLocked();
+            return receiver;
+        }
+    }
+
+    private SynchronousResultReceiver() {
         mLocal = true;
         mIsCompleted = false;
     }
 
+    @GuardedBy("sLock")
+    private void releaseLocked() {
+        mFuture = null;
+        if (sAvailableReceivers.size() < QUEUE_THRESHOLD) {
+            sAvailableReceivers.add(this);
+        }
+    }
+
+    @GuardedBy("sLock")
+    private void resetLocked() {
+        mFuture = new CompletableFuture<>();
+        mIsCompleted = false;
+    }
+
+    private CompletableFuture<Result<T>> getFuture() {
+       synchronized (sLock) {
+           return mFuture;
+       }
+    }
+
     public static class Result<T> implements Parcelable {
         private final @Nullable T mObject;
         private final RuntimeException mException;
@@ -105,20 +148,24 @@ public final class SynchronousResultReceiver<T> implements Parcelable {
             };
     }
 
-    private final CompletableFuture<Result<T>> mFuture = new CompletableFuture<>();
-
     private void complete(Result<T> result) {
         if (mIsCompleted) {
             throw new IllegalStateException("Receiver has already been completed");
         }
         mIsCompleted = true;
         if (mLocal) {
-            mFuture.complete(result);
-        } else if (mReceiver != null) {
-            try {
-                mReceiver.send(result);
-            } catch (RemoteException e) {
-                Log.w(TAG, "Failed to complete future");
+            getFuture().complete(result);
+        } else {
+            final ISynchronousResultReceiver rr;
+            synchronized (this) {
+                rr = mReceiver;
+            }
+            if (rr != null) {
+                try {
+                    rr.send(result);
+                } catch (RemoteException e) {
+                    Log.w(TAG, "Failed to complete future");
+                }
             }
         }
     }
@@ -160,7 +207,11 @@ public final class SynchronousResultReceiver<T> implements Parcelable {
         Duration remainingTime = timeout;
         while (!remainingTime.isNegative()) {
             try {
-                return mFuture.get(remainingTime.toMillis(), TimeUnit.MILLISECONDS);
+                Result<T> result = getFuture().get(remainingTime.toMillis(), TimeUnit.MILLISECONDS);
+                synchronized (sLock) {
+                    releaseLocked();
+                    return result;
+                }
             } catch (ExecutionException e) {
                 // This will NEVER happen.
                 throw new AssertionError("Error receiving response", e);
@@ -171,6 +222,9 @@ public final class SynchronousResultReceiver<T> implements Parcelable {
                         Duration.ofNanos(SystemClock.elapsedRealtimeNanos() - startWaitNanoTime));
             }
         }
+        synchronized (sLock) {
+            releaseLocked();
+        }
         throw new TimeoutException();
     }
 
@@ -179,7 +233,11 @@ public final class SynchronousResultReceiver<T> implements Parcelable {
     private final class MyResultReceiver extends ISynchronousResultReceiver.Stub {
         public void send(@SuppressWarnings("rawtypes") @NonNull Result result) {
             @SuppressWarnings("unchecked") Result<T> res = (Result<T>) result;
-            mFuture.complete(res);
+            CompletableFuture<Result<T>> future;
+            future = getFuture();
+            if (future != null) {
+                future.complete(res);
+            }
         }
     }
 
diff --git a/javatests/com/android/modules/utils/SynchronousResultReceiverTest.java b/javatests/com/android/modules/utils/SynchronousResultReceiverTest.java
index 43345a9..82aa97d 100644
--- a/javatests/com/android/modules/utils/SynchronousResultReceiverTest.java
+++ b/javatests/com/android/modules/utils/SynchronousResultReceiverTest.java
@@ -35,7 +35,7 @@ public class SynchronousResultReceiverTest extends TestCase {
 
     @Test
     public void testSimpleData() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         recv.send(true);
         final boolean result = recv.awaitResultNoInterrupt(OK_TIME).getValue(false);
         assertTrue(result);
@@ -43,7 +43,7 @@ public class SynchronousResultReceiverTest extends TestCase {
 
     @Test
     public void testDoubleComplete() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         recv.send(true);
         Assert.assertThrows(IllegalStateException.class,
                 () -> recv.send(true));
@@ -51,14 +51,14 @@ public class SynchronousResultReceiverTest extends TestCase {
 
     @Test
     public void testDefaultValue() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         recv.send(null);
         assertTrue(recv.awaitResultNoInterrupt(OK_TIME).getValue(true));
     }
 
     @Test
     public void testPropagateException() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         recv.propagateException(new RuntimeException("Placeholder exception"));
         Assert.assertThrows(RuntimeException.class,
                 () -> recv.awaitResultNoInterrupt(OK_TIME).getValue(false));
@@ -66,14 +66,14 @@ public class SynchronousResultReceiverTest extends TestCase {
 
     @Test
     public void testTimeout() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         Assert.assertThrows(TimeoutException.class,
                 () -> recv.awaitResultNoInterrupt(OK_TIME));
     }
 
     @Test
     public void testNegativeTime() throws Exception {
-        final SynchronousResultReceiver<Boolean> recv = new SynchronousResultReceiver();
+        final SynchronousResultReceiver<Boolean> recv = SynchronousResultReceiver.get();
         recv.send(false);
         Assert.assertThrows(TimeoutException.class,
                 () -> recv.awaitResultNoInterrupt(NEG_TIME));