Cancellable gesture should always have cancellation token

With the current CancellableHandwritingGesture,
cancellationToken is only attached at the time of writeToParcel. However
if editor is in same process as IME (i.e. IME contains the editor),
writeToParcel will never be called and token will never be set.

This change refactors code to not unbeam if we didn't beam cancellation Token.

Bug: 280268494
Test: atest InputConnectionEndToEndTest InsertModeGestureTest
Change-Id: Idb9292fa087d98395d778dd3cd4a528554909ffc

core/java/android/os/CancellationSignalBeamer.java

@@ -18,6 +18,7 @@ package android.os;
 
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SuppressLint;
 import android.system.SystemCleaner;
 import android.util.Pair;
 import android.view.inputmethod.CancellableHandwritingGesture;
@@ -137,7 +138,7 @@ public class CancellationSignalBeamer {
          * MUST be forwarded to {@link Receiver#cancel} with proper ordering. See
          * {@link CancellationSignalBeamer} for details.
          */
-        public abstract void onCancel(IBinder token);
+        public abstract void onCancel(@NonNull IBinder token);
 
         /**
          * A {@link #beam}ed {@link CancellationSignal} was GC'd.
@@ -145,7 +146,7 @@ public class CancellationSignalBeamer {
          * MUST be forwarded to {@link Receiver#forget} with proper ordering. See
          * {@link CancellationSignalBeamer} for details.
          */
-        public abstract void onForget(IBinder token);
+        public abstract void onForget(@NonNull IBinder token);
 
         private static final ThreadLocal<Pair<Sender, ArrayList<CloseableToken>>> sScope =
                 new ThreadLocal<>();
@@ -159,7 +160,8 @@ public class CancellationSignalBeamer {
          *  try-with-resources. {@code null} if {@code cs} was {@code null} or if
          *  {@link HandwritingGesture} isn't {@link CancellableHandwritingGesture cancellable}.
          */
-        public MustClose beamScopeIfNeeded(HandwritingGesture gesture) {
+        @NonNull
+        public MustClose beamScopeIfNeeded(@NonNull HandwritingGesture gesture) {
             if (!(gesture instanceof CancellableHandwritingGesture)) {
                 return null;
             }
@@ -189,7 +191,8 @@ public class CancellationSignalBeamer {
          * @param cs {@link CancellationSignal} for which token should be returned.
          * @return {@link IBinder} token.
          */
-        public static IBinder beamFromScope(CancellationSignal cs) {
+        @NonNull
+        public static IBinder beamFromScope(@NonNull CancellationSignal cs) {
             var state = sScope.get();
             if (state != null) {
                 var token = state.first.beam(cs);
@@ -291,6 +294,7 @@ public class CancellationSignalBeamer {
          * @return a {@link CancellationSignal} linked to the given token.
          */
         @Nullable
+        @SuppressLint("VisiblySynchronized")
         public CancellationSignal unbeam(@Nullable IBinder token) {
             if (token == null) {
                 return null;
@@ -327,6 +331,7 @@ public class CancellationSignalBeamer {
          *
          * @param token the token to forget. No-op if {@code null}.
          */
+        @SuppressLint("VisiblySynchronized")
         public void forget(@Nullable IBinder token) {
             synchronized (this) {
                 if (mTokenMap.remove(token) != null) {
@@ -347,6 +352,7 @@ public class CancellationSignalBeamer {
          *
          * @param token the token to forget. No-op if {@code null}.
          */
+        @SuppressLint("VisiblySynchronized")
         public void cancel(@Nullable IBinder token) {
             CancellationSignal cs;
             synchronized (this) {

core/java/android/view/inputmethod/CancellableHandwritingGesture.java

@@ -17,6 +17,7 @@
 package android.view.inputmethod;
 
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.TestApi;
 import android.os.CancellationSignal;
 import android.os.CancellationSignalBeamer;
@@ -28,10 +29,13 @@ import android.os.IBinder;
  */
 @TestApi
 public abstract class CancellableHandwritingGesture extends HandwritingGesture {
+    @NonNull
     CancellationSignal mCancellationSignal;
 
+    @Nullable
     IBinder mCancellationSignalToken;
 
+
     /**
      * Set {@link CancellationSignal} for testing only.
      * @hide
@@ -41,13 +45,20 @@ public abstract class CancellableHandwritingGesture extends HandwritingGesture {
         mCancellationSignal = cancellationSignal;
     }
 
+    @NonNull
     CancellationSignal getCancellationSignal() {
         return mCancellationSignal;
     }
 
-    void unbeamCancellationSignal(CancellationSignalBeamer.Receiver receiver) {
-        mCancellationSignal = receiver.unbeam(mCancellationSignalToken);
-        mCancellationSignalToken = null;
+    /**
+     * Unbeam cancellation token.
+     * @hide
+     */
+    public void unbeamCancellationSignal(@NonNull CancellationSignalBeamer.Receiver receiver) {
+        if (mCancellationSignalToken != null) {
+            mCancellationSignal = receiver.unbeam(mCancellationSignalToken);
+            mCancellationSignalToken = null;
+        }
     }
 
 }

core/tests/coretests/src/android/view/inputmethod/InsertModeGestureTest.java

@@ -21,6 +21,7 @@ import static org.junit.Assert.assertNotNull;
 
 import android.graphics.PointF;
 import android.os.CancellationSignal;
+import android.os.CancellationSignalBeamer;
 import android.platform.test.annotations.Presubmit;
 
 import androidx.test.filters.SmallTest;
@@ -54,4 +55,15 @@ public class InsertModeGestureTest {
         assertEquals(FALLBACK_TEXT, gesture.getFallbackText());
         assertEquals(CANCELLATION_SIGNAL, gesture.getCancellationSignal());
     }
+
+    @Test
+    public void testCancellationSignal() {
+        var cs = CANCELLATION_SIGNAL;
+        var gesture = new InsertModeGesture.Builder().setInsertionPoint(INSERTION_POINT)
+                .setCancellationSignal(CANCELLATION_SIGNAL)
+                .setFallbackText(FALLBACK_TEXT).build();
+        gesture.unbeamCancellationSignal(
+                new CancellationSignalBeamer.Receiver(true /* cancelOnSenderDeath */));
+        assertEquals(gesture.getCancellationSignal(), cs);
+    }
 }