8296832: Improve Swing platform support

Reviewed-by: skoivu, kizune, rhalade, prr

src/java.desktop/share/classes/javax/swing/plaf/basic/BasicHTML.java

@@ -33,6 +33,7 @@ import javax.swing.*;
 import javax.swing.text.*;
 import javax.swing.text.html.*;
 
+import sun.swing.SwingAccessor;
 import sun.swing.SwingUtilities2;
 
 /**
@@ -220,7 +221,7 @@ public class BasicHTML {
         View value = null;
         View oldValue = (View)c.getClientProperty(BasicHTML.propertyKey);
         Boolean htmlDisabled = (Boolean) c.getClientProperty(htmlDisable);
-        if (htmlDisabled != Boolean.TRUE && BasicHTML.isHTMLString(text)) {
+        if (!(Boolean.TRUE.equals(htmlDisabled)) && BasicHTML.isHTMLString(text)) {
             value = BasicHTML.createHTMLView(c, text);
         }
         if (value != oldValue && oldValue != null) {
@@ -376,15 +377,36 @@ public class BasicHTML {
      */
     static class BasicHTMLViewFactory extends HTMLEditorKit.HTMLFactory {
         public View create(Element elem) {
-            View view = super.create(elem);
 
+            View view = null;
+            try {
+                setAllowHTMLObject();
+                view = super.create(elem);
+            } finally {
+                clearAllowHTMLObject();
+            }
             if (view instanceof ImageView) {
                 ((ImageView)view).setLoadsSynchronously(true);
             }
             return view;
         }
-    }
 
+        private static Boolean useOV = null;
+
+        @SuppressWarnings("removal")
+        private static void setAllowHTMLObject() {
+            if (useOV == null) {
+                useOV = java.security.AccessController.doPrivileged(
+                    new sun.security.action.GetBooleanAction(
+                        "swing.html.object"));
+            };
+            SwingAccessor.setAllowHTMLObject(useOV);
+        }
+
+        private static void clearAllowHTMLObject() {
+            SwingAccessor.setAllowHTMLObject(null);
+        }
+    }
 
     /**
      * The subclass of HTMLDocument that is used as the model. getForeground

src/java.desktop/share/classes/javax/swing/text/html/HTMLEditorKit.java

@@ -93,6 +93,7 @@ import javax.swing.text.View;
 import javax.swing.text.ViewFactory;
 import javax.swing.text.html.parser.ParserDelegator;
 
+import sun.swing.SwingAccessor;
 import sun.awt.AppContext;
 
 import static java.nio.charset.StandardCharsets.ISO_8859_1;
@@ -1402,7 +1403,11 @@ public class HTMLEditorKit extends StyledEditorKit implements Accessible {
                            (kind == HTML.Tag.TEXTAREA)) {
                     return new FormView(elem);
                 } else if (kind == HTML.Tag.OBJECT) {
-                    return new ObjectView(elem);
+                   if (SwingAccessor.getAllowHTMLObject()) {
+                        return new ObjectView(elem);
+                    } else {
+                        return new ObjectView(elem, false);
+                    }
                 } else if (kind == HTML.Tag.FRAMESET) {
                      if (elem.getAttributes().isDefined(HTML.Attribute.ROWS)) {
                          return new FrameSetView(elem, View.Y_AXIS);

src/java.desktop/share/classes/javax/swing/text/html/ObjectView.java

@@ -71,6 +71,8 @@ import sun.reflect.misc.ReflectUtil;
  */
 public class ObjectView extends ComponentView  {
 
+    private boolean createComp = true; // default
+
     /**
      * Creates a new ObjectView object.
      *
@@ -80,6 +82,11 @@ public class ObjectView extends ComponentView  {
         super(elem);
     }
 
+    ObjectView(Element elem, boolean createComp) {
+        super(elem);
+        this.createComp = createComp;
+    }
+
     /**
      * Create the component.  The classid is used
      * as a specification of the classname, which
@@ -87,6 +94,9 @@ public class ObjectView extends ComponentView  {
      */
     @SuppressWarnings("deprecation")
     protected Component createComponent() {
+        if (!createComp) {
+            return getUnloadableRepresentation();
+        }
         AttributeSet attr = getElement().getAttributes();
         String classname = (String) attr.getAttribute(HTML.Attribute.CLASSID);
         try {

src/java.desktop/share/classes/sun/swing/SwingAccessor.java

@@ -321,4 +321,19 @@ public final class SwingAccessor {
             MethodHandles.lookup().ensureInitialized(c);
         } catch (IllegalAccessException e) {}
     }
+
+    private static ThreadLocal<Boolean> tlObj = new ThreadLocal<Boolean>();
+
+    public static Boolean getAllowHTMLObject() {
+        Boolean b = tlObj.get();
+        if (b == null) {
+            return Boolean.TRUE;
+        } else {
+            return b;
+        }
+    }
+
+    public static void setAllowHTMLObject(Boolean val) {
+        tlObj.set(val);
+    }
 }