Make classes PFileIO.FD/OwnFD final

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/io/PFileIO.java

@@ -42,10 +42,11 @@
 
 import com.oracle.graal.python.builtins.objects.object.PythonBuiltinObject;
 import com.oracle.graal.python.runtime.AsyncHandler;
+import com.oracle.graal.python.runtime.AsyncHandler.SharedFinalizer.FinalizableReference;
 import com.oracle.graal.python.runtime.GilNode;
 import com.oracle.graal.python.runtime.PosixSupportLibrary;
 import com.oracle.graal.python.runtime.PythonContext;
-import com.oracle.truffle.api.CompilerDirectives;
+import com.oracle.truffle.api.CompilerDirectives.ValueType;
 import com.oracle.truffle.api.object.Shape;
 
 public final class PFileIO extends PythonBuiltinObject {
@@ -174,8 +175,8 @@ public void setUTF8Write(boolean utf8Write) {
     }
 }
 
-@CompilerDirectives.ValueType
-class FD {
+@ValueType
+final class FD {
     private final int fd;
     private final OwnFD ownFD;
 
@@ -205,7 +206,7 @@ public int getFD() {
     }
 }
 
-class OwnFD extends AsyncHandler.SharedFinalizer.FinalizableReference {
+final class OwnFD extends FinalizableReference {
 
     private final PythonContext context;
 
@@ -215,7 +216,7 @@ public OwnFD(Object referent, int fd, PythonContext context) {
     }
 
     @SuppressWarnings("try")
-    protected void doRelease() {
+    void doRelease() {
         markReleased();
         try (GilNode.UncachedRelease gil = GilNode.uncachedRelease()) {
             PosixSupportLibrary.getUncached().close(context.getPosixSupport(), (int) getReference());