SurfaceComposerClient: Expose default apply token

The default apply token specifies which transaction queue transactions
from a process is sent to in surfaceflinger. This queue is used to
ensure transactions from a process are applied in order.

If a transaction from multiple processes need to be applied in order,
we can use a commit callback to act as a barrier or pass transactions
across processes to be applied on a single process. In some cases
where operations are intertwined it may be advantageous to set a
single transaction queue for multiple processes. In this case
this api can be used to set a single queue to apply transactions by
setting the same apply token on both processes.

Note this api if misused can result in surprising out of order
transactions.

Test: manually set the same applytoken on multiple processes and
verify they go into the same queue.
Bug: 242193885

Change-Id: I507b44686b393c1bb854bd593535a3a3874497af

core/java/android/view/SurfaceControl.java

@@ -274,6 +274,9 @@ public final class SurfaceControl implements Parcelable {
     private static native void nativeSanitize(long transactionObject);
     private static native void nativeSetDestinationFrame(long transactionObj, long nativeObject,
             int l, int t, int r, int b);
+    private static native void nativeSetDefaultApplyToken(IBinder token);
+    private static native IBinder nativeGetDefaultApplyToken();
+
 
     /**
      * Transforms that can be applied to buffers as they are displayed to a window.
@@ -2773,6 +2776,22 @@ public final class SurfaceControl implements Parcelable {
             readFromParcel(in);
         }
 
+        /**
+         *
+         * @hide
+         */
+        public static void setDefaultApplyToken(IBinder token) {
+            nativeSetDefaultApplyToken(token);
+        }
+
+        /**
+         *
+         * @hide
+         */
+        public static IBinder getDefaultApplyToken() {
+            return nativeGetDefaultApplyToken();
+        }
+
         /**
          * Apply the transaction, clearing it's state, and making it usable
          * as a new transaction.

core/jni/android_view_SurfaceControl.cpp

@@ -2121,6 +2121,20 @@ static jint nativeGetLayerId(JNIEnv* env, jclass clazz, jlong nativeSurfaceContr
     return surface->getLayerId();
 }
 
+static void nativeSetDefaultApplyToken(JNIEnv* env, jclass clazz, jobject applyToken) {
+    sp<IBinder> token(ibinderForJavaObject(env, applyToken));
+    if (token == nullptr) {
+        ALOGE("Null apply token provided.");
+        return;
+    }
+    SurfaceComposerClient::Transaction::setDefaultApplyToken(token);
+}
+
+static jobject nativeGetDefaultApplyToken(JNIEnv* env, jclass clazz) {
+    sp<IBinder> token = SurfaceComposerClient::Transaction::getDefaultApplyToken();
+    return javaObjectForIBinder(env, token);
+}
+
 // ----------------------------------------------------------------------------
 
 static const JNINativeMethod sSurfaceControlMethods[] = {
@@ -2343,6 +2357,10 @@ static const JNINativeMethod sSurfaceControlMethods[] = {
             (void*) nativeSanitize },
     {"nativeSetDestinationFrame", "(JJIIII)V",
                 (void*)nativeSetDestinationFrame },
+    {"nativeSetDefaultApplyToken", "(Landroid/os/IBinder;)V",
+                (void*)nativeSetDefaultApplyToken },
+    {"nativeGetDefaultApplyToken", "()Landroid/os/IBinder;",
+                (void*)nativeGetDefaultApplyToken },
         // clang-format on
 };