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package com.oracle.truffle.js.nodes.access;

import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.cast.JSToBooleanNode;
import com.oracle.truffle.js.runtime.JSContext;
import com.oracle.truffle.js.runtime.JSRuntime;
import com.oracle.truffle.js.runtime.Symbol;
import com.oracle.truffle.js.runtime.builtins.JSFunction;
import com.oracle.truffle.js.runtime.objects.JSDynamicObject;
import com.oracle.truffle.js.runtime.objects.JSObject;
import com.oracle.truffle.js.runtime.objects.Undefined;

import java.util.Set;

Reads the with binding object and performs Object Environment HasBinding(name). Returns undefined if the binding was not found or blocked by an unscopables property.
/** * Reads the {@code with} binding object and performs Object Environment HasBinding(name). Returns * {@code undefined} if the binding was not found or blocked by an {@code unscopables} property. */
public final class WithTargetNode extends JavaScriptNode { @Child private JavaScriptNode withVariable; @Child private HasPropertyCacheNode withObjectHasProperty; @Child private HasPropertyCacheNode globalObjectHasProperty; @Child private PropertyGetNode withObjectGetUnscopables; @Child private PropertyGetNode unscopablesGetProperty; @Child private JSToBooleanNode toBoolean; private final JSContext context; private WithTargetNode(JSContext context, String propertyName, JavaScriptNode withVariable) { this.withVariable = withVariable; this.context = context; this.withObjectHasProperty = HasPropertyCacheNode.create(propertyName, context); this.globalObjectHasProperty = HasPropertyCacheNode.create(propertyName, context); this.withObjectGetUnscopables = PropertyGetNode.create(Symbol.SYMBOL_UNSCOPABLES, false, context); this.unscopablesGetProperty = PropertyGetNode.create(propertyName, false, context); this.toBoolean = JSToBooleanNode.create(); } public static JavaScriptNode create(JSContext context, String propertyName, JavaScriptNode withVariable) { return new WithTargetNode(context, propertyName, withVariable); } @Override public Object execute(VirtualFrame frame) { Object target = withVariable.execute(frame); if (withObjectHasProperty.hasProperty(target) && isPropertyScopable(target)) { // with object has a scopable property return target; } else if (context.isOptionNashornCompatibilityMode() && hasNoSuchProperty(target, false) && !globalObjectHasProperty.hasProperty(GlobalObjectNode.getGlobalObject(context))) { // Nashorn extension: with object has a __noSuchProperty__ or __noSuchMethod__ // NB: this part is not 1:1 compatible with Nashorn w.r.t. chained scopes. return target; } // not found, fall back to default handler return Undefined.instance; }
Object Environment Records - HasBinding (ES6 8.1.1.2.1).
/** * Object Environment Records - HasBinding (ES6 8.1.1.2.1). */
private boolean isPropertyScopable(Object target) { if (context.getEcmaScriptVersion() >= 6) { if (JSDynamicObject.isJSDynamicObject(target)) { Object unscopables = withObjectGetUnscopables.getValue(target); if (JSRuntime.isObject(unscopables)) { boolean blocked = toBoolean.executeBoolean(unscopablesGetProperty.getValue(unscopables)); if (blocked) { return false; } } } else { // no unscopables in foreign objects return true; } } return true; } private boolean hasNoSuchProperty(Object thisTruffleObj, boolean isMethod) { if (JSRuntime.isObject(thisTruffleObj)) { DynamicObject thisObj = (DynamicObject) thisTruffleObj; if ((!isMethod && !context.getNoSuchPropertyUnusedAssumption().isValid() && JSObject.hasOwnProperty(thisObj, JSObject.NO_SUCH_PROPERTY_NAME)) || (isMethod && !context.getNoSuchMethodUnusedAssumption().isValid() && JSObject.hasOwnProperty(thisObj, JSObject.NO_SUCH_METHOD_NAME))) { return hasNoSuchPropertyImpl(thisObj, isMethod); } } return false; } private static boolean hasNoSuchPropertyImpl(DynamicObject thisObj, boolean isMethod) { assert JSRuntime.isObject(thisObj); Object function = JSObject.get(thisObj, isMethod ? JSObject.NO_SUCH_METHOD_NAME : JSObject.NO_SUCH_PROPERTY_NAME); return JSFunction.isJSFunction(function); } @Override protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) { return new WithTargetNode(context, (String) withObjectHasProperty.getKey(), cloneUninitialized(withVariable, materializedTags)); } }