SLING-12516 - Migrate SlingContext to Rhino Context(ContextFactory) API

* Replaced the deprecated Rhino Context() API with the updated Context(ContextFactory) API.
* Eliminated dependency on the Rhino global static singleton context factory.

Author: scottyuancoc

src/main/java/org/apache/sling/scripting/javascript/helper/SlingContext.java

@@ -19,6 +19,7 @@
 package org.apache.sling.scripting.javascript.helper;
 
 import org.mozilla.javascript.Context;
+import org.mozilla.javascript.ContextFactory;
 import org.mozilla.javascript.ImporterTopLevel;
 import org.mozilla.javascript.ScriptableObject;
 
@@ -29,6 +30,10 @@
  */
 public class SlingContext extends Context {
 
+    protected SlingContext( ContextFactory factory ) {
+        super( factory );
+    }
+
     @Override
     public ScriptableObject initStandardObjects(ScriptableObject scope,
             boolean sealed) {

src/main/java/org/apache/sling/scripting/javascript/helper/SlingContextFactory.java

@@ -18,8 +18,6 @@
  */
 package org.apache.sling.scripting.javascript.helper;
 
-import java.lang.reflect.Field;
-
 import org.mozilla.javascript.Context;
 import org.mozilla.javascript.ContextFactory;
 import org.mozilla.javascript.tools.debugger.ScopeProvider;
@@ -45,47 +43,14 @@ public class SlingContextFactory extends ContextFactory {
 
     private int languageVersion;
 
-    // conditionally setup the global ContextFactory to be ours. If
-    // a global context factory has already been set, we have lost
-    // and cannot set this one.
-    public static void setup(ScopeProvider sp, int languageVersion) {
-        // TODO what do we do in the other case? debugger won't work
-        if (!hasExplicitGlobal()) {
-            initGlobal(new SlingContextFactory(sp,
-                    Context.isValidLanguageVersion(languageVersion) ? languageVersion : Context.VERSION_DEFAULT));
-        }
-    }
-
-    public static void teardown() {
-        ContextFactory factory = getGlobal();
-        if (factory instanceof SlingContextFactory) {
-            ((SlingContextFactory) factory).dispose();
-        }
-    }
-
-    // private as instances of this class are only used by setup()
-    private SlingContextFactory(ScopeProvider sp, int languageVersion) {
+    public SlingContextFactory(ScopeProvider sp, int languageVersion) {
         scopeProvider = sp;
         this.languageVersion = languageVersion;
     }
 
-    private void dispose() {
-        // ensure the debugger is closed
-        exitDebugger();
-        
-        // reset the context factory class for future use
-        ContextFactory newGlobal = new ContextFactory();
-        setField(newGlobal, "hasCustomGlobal", Boolean.FALSE);
-        setField(newGlobal, "global", newGlobal);
-        setField(newGlobal, "sealed", Boolean.FALSE);
-        setField(newGlobal, "listeners", null);
-        setField(newGlobal, "disabledListening", Boolean.FALSE);
-        setField(newGlobal, "applicationClassLoader", null);
-    }
-
     @Override
     protected Context makeContext() {
-        Context context = new SlingContext();
+        Context context = new SlingContext(this);
         context.setLanguageVersion(languageVersion);
         return context;
     }
@@ -142,19 +107,4 @@ public boolean isDebugging() {
         return debuggerActive;
     }
 
-    private void setField(Object instance, String fieldName, Object value) {
-        try {
-            Field field = instance.getClass().getDeclaredField(fieldName);
-            if (!field.isAccessible()) {
-                field.setAccessible(true);
-            }
-            field.set(instance, value);
-        } catch (IllegalArgumentException iae) {
-            // don't care, but it is strange anyhow
-        } catch (IllegalAccessException iae) {
-            // don't care, but it is strange anyhow
-        } catch (NoSuchFieldException nsfe) {
-            // don't care, but it is strange anyhow
-        }
-    }
 }

src/main/java/org/apache/sling/scripting/javascript/internal/RhinoJavaScriptEngineFactory.java

@@ -134,6 +134,8 @@ public class RhinoJavaScriptEngineFactory extends AbstractScriptEngineFactory im
 
     private final Set<RhinoHostObjectProvider> hostObjectProvider = new HashSet<RhinoHostObjectProvider>();
 
+    private SlingContextFactory contextFactory;
+
     @Reference
     private DynamicClassLoaderManager dynamicClassLoaderManager = null;
 
@@ -251,10 +253,7 @@ private void dropRootScope() {
         // ensure the debugger is closed if the root scope will
         // be replaced to ensure no references to the old scope
         // and context remain
-        ContextFactory contextFactory = ContextFactory.getGlobal();
-        if (contextFactory instanceof SlingContextFactory) {
-            ((SlingContextFactory) contextFactory).exitDebugger();
-        }
+        contextFactory.exitDebugger();
 
         // drop the scope
         rootScope = null;
@@ -304,18 +303,15 @@ protected void activate(final ComponentContext context, final RhinoJavaScriptEng
             wrapFactory = new SlingWrapFactory();
 
             // initialize the Rhino Context Factory
-            SlingContextFactory.setup(this, RHINO_LANGUAGE_VERSION);
+            contextFactory = new SlingContextFactory(this, RHINO_LANGUAGE_VERSION);
+            contextFactory.setDebugging(debugging);
 
             setEngineName(getEngineName() + " (Rhino " + (rhinoVersion != null ? rhinoVersion : "unknown") + ")");
 
             setExtensions(PropertiesUtil.toStringArray(props.get("extensions")));
             setMimeTypes(PropertiesUtil.toStringArray(props.get("mimeTypes")));
             setNames(PropertiesUtil.toStringArray(props.get("names")));
 
-            final ContextFactory contextFactory = ContextFactory.getGlobal();
-            if (contextFactory instanceof SlingContextFactory) {
-                ((SlingContextFactory) contextFactory).setDebugging(debugging);
-            }
             // set the dynamic class loader as the application class loader
             final DynamicClassLoaderManager dclm = this.dynamicClassLoaderManager;
             if (dclm != null) {
@@ -337,10 +333,8 @@ protected void deactivate(ComponentContext context) {
             // remove the root scope
             dropRootScope();
 
-            // remove our context factory
-            SlingContextFactory.teardown();
-
             // remove references
+            contextFactory = null;
             wrapFactory = null;
             hostObjectProvider.clear();