Expose transaction id

We will need to dump the transaction id in transition traces to be able to reliably associated the start and end of a transition to the states in the SF trace.

Bug: 230462538
Test: N/A
Change-Id: I2a040503d9e1f4f4636549bae6b7fe12d5632049

core/java/android/view/SurfaceControl.java

@@ -121,6 +121,7 @@ public final class SurfaceControl implements Parcelable {
     private static native void nativeSetAnimationTransaction(long transactionObj);
     private static native void nativeSetEarlyWakeupStart(long transactionObj);
     private static native void nativeSetEarlyWakeupEnd(long transactionObj);
+    private static native long nativeGetTransactionId(long transactionObj);
 
     private static native void nativeSetLayer(long transactionObj, long nativeObject, int zorder);
     private static native void nativeSetRelativeLayer(long transactionObj, long nativeObject,
@@ -3536,6 +3537,15 @@ public final class SurfaceControl implements Parcelable {
             return this;
         }
 
+        /**
+         * @hide
+         * @return The transaction's current id.
+         *         The id changed every time the transaction is applied.
+         */
+        public long getId() {
+            return nativeGetTransactionId(mNativeObject);
+        }
+
         /**
          * Sets an arbitrary piece of metadata on the surface. This is a helper for int data.
          * @hide

core/jni/android_view_SurfaceControl.cpp

@@ -580,6 +580,11 @@ static void nativeSetEarlyWakeupEnd(JNIEnv* env, jclass clazz, jlong transaction
     transaction->setEarlyWakeupEnd();
 }
 
+static jlong nativeGetTransactionId(JNIEnv* env, jclass clazz, jlong transactionObj) {
+    auto transaction = reinterpret_cast<SurfaceComposerClient::Transaction*>(transactionObj);
+    return transaction->getId();
+}
+
 static void nativeSetLayer(JNIEnv* env, jclass clazz, jlong transactionObj,
         jlong nativeObject, jint zorder) {
     auto transaction = reinterpret_cast<SurfaceComposerClient::Transaction*>(transactionObj);
@@ -2103,6 +2108,8 @@ static const JNINativeMethod sSurfaceControlMethods[] = {
             (void*)nativeSetEarlyWakeupStart },
     {"nativeSetEarlyWakeupEnd", "(J)V",
             (void*)nativeSetEarlyWakeupEnd },
+    {"nativeGetTransactionId", "(J)J",
+                (void*)nativeGetTransactionId },
     {"nativeSetLayer", "(JJI)V",
             (void*)nativeSetLayer },
     {"nativeSetRelativeLayer", "(JJJI)V",