TestApi for easy HandwritingGesture serial/deserialization

Introduce TestApi for easier serialization and deserialization of
HandwritingGesture.

Bug: 217957587
Test: atest CtsInputMethodTestCases

Change-Id: I37b3c24bb427ca22b33e14aa2c40b21821cab4e4

core/api/test-current.txt

@@ -3321,7 +3321,9 @@ package android.view.displayhash {
 package android.view.inputmethod {
 
   public abstract class HandwritingGesture {
+    method @NonNull public static android.view.inputmethod.HandwritingGesture fromByteArray(@NonNull byte[]);
     method public final int getGestureType();
+    method @NonNull public final byte[] toByteArray();
     field public static final int GESTURE_TYPE_DELETE = 4; // 0x4
     field public static final int GESTURE_TYPE_DELETE_RANGE = 64; // 0x40
     field public static final int GESTURE_TYPE_INSERT = 2; // 0x2

core/java/android/view/inputmethod/HandwritingGesture.java

@@ -17,10 +17,13 @@
 package android.view.inputmethod;
 
 import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.TestApi;
 import android.graphics.RectF;
 import android.inputmethodservice.InputMethodService;
+import android.os.Parcel;
+import android.os.Parcelable;
 import android.view.MotionEvent;
 
 import java.lang.annotation.Retention;
@@ -198,4 +201,56 @@ public abstract class HandwritingGesture {
     public final String getFallbackText() {
         return mFallbackText;
     }
+
+    /**
+     * Dump data into a byte array so that you can pass the data across process boundary.
+     *
+     * @return byte array data.
+     * @see #fromByteArray(byte[])
+     * @hide
+     */
+    @TestApi
+    @NonNull
+    public final byte[] toByteArray() {
+        if (!(this instanceof Parcelable)) {
+            throw new UnsupportedOperationException(getClass() + " is not Parcelable");
+        }
+        final Parcelable self = (Parcelable) this;
+        if ((self.describeContents() & Parcelable.CONTENTS_FILE_DESCRIPTOR) != 0) {
+            throw new UnsupportedOperationException("Gesture that contains FD is not supported");
+        }
+        Parcel parcel = null;
+        try {
+            parcel = Parcel.obtain();
+            ParcelableHandwritingGesture.of(this).writeToParcel(parcel, 0);
+            return parcel.marshall();
+        } finally {
+            if (parcel != null) {
+                parcel.recycle();
+            }
+        }
+    }
+
+    /**
+     * Create a new instance from byte array obtained from {@link #toByteArray()}.
+     *
+     * @param buffer byte array obtained from {@link #toByteArray()}
+     * @return A new instance of {@link HandwritingGesture} subclass.
+     * @hide
+     */
+    @TestApi
+    @NonNull
+    public static HandwritingGesture fromByteArray(@NonNull byte[] buffer) {
+        Parcel parcel = null;
+        try {
+            parcel = Parcel.obtain();
+            parcel.unmarshall(buffer, 0, buffer.length);
+            parcel.setDataPosition(0);
+            return ParcelableHandwritingGesture.CREATOR.createFromParcel(parcel).get();
+        } finally {
+            if (parcel != null) {
+                parcel.recycle();
+            }
+        }
+    }
 }