/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.dev.js.ast;
import com.google.gwt.dev.jjs.SourceInfo;
/**
* Represents a JavaScript expression that references a name.
*/
public final class JsNameRef extends JsExpression implements CanBooleanEval,
HasName {
private boolean hasStaticRef;
private String ident;
private JsName name;
private JsExpression qualifier;
public JsNameRef(SourceInfo sourceInfo, JsName name) {
super(sourceInfo.makeChild(JsNameRef.class, "Reference"));
this.name = name;
maybeUpdateSourceInfo();
}
public JsNameRef(SourceInfo sourceInfo, String ident) {
super(sourceInfo);
this.ident = ident;
}
public String getIdent() {
return (name == null) ? ident : name.getIdent();
}
public JsName getName() {
return name;
}
public JsExpression getQualifier() {
return qualifier;
}
public String getShortIdent() {
return (name == null) ? ident : name.getShortIdent();
}
@Override
public SourceInfo getSourceInfo() {
return maybeUpdateSourceInfo();
}
@Override
public boolean hasSideEffects() {
if (qualifier == null) {
return false;
}
if (!qualifier.isDefinitelyNotNull()) {
// Could trigger NPE.
return true;
}
return qualifier.hasSideEffects();
}
public boolean isBooleanFalse() {
return isDefinitelyNull();
}
public boolean isBooleanTrue() {
return false;
}
@Override
public boolean isDefinitelyNotNull() {
// TODO: look for single-assignment of stuff from Java?
return false;
}
@Override
public boolean isDefinitelyNull() {
if (name != null) {
return (name.getEnclosing().getProgram().getUndefinedLiteral().getName() == name);
}
return false;
}
@Override
public boolean isLeaf() {
if (qualifier == null) {
return true;
} else {
return false;
}
}
public boolean isResolved() {
return name != null;
}
public void resolve(JsName name) {
this.name = name;
this.ident = null;
}
public void setQualifier(JsExpression qualifier) {
this.qualifier = qualifier;
}
public void traverse(JsVisitor v, JsContext<JsExpression> ctx) {
if (v.visit(this, ctx)) {
if (qualifier != null) {
qualifier = v.accept(qualifier);
}
}
v.endVisit(this, ctx);
}
/**
* This corrects the JsNameRef's SourceInfo derivation when the JsName is
* created with a JsName that has not yet had its static reference set. This
* is the case in GenerateJavaScriptAST after the names and scopes visitor has
* been run, but before the AST is fully realized.
*/
private SourceInfo maybeUpdateSourceInfo() {
SourceInfo toReturn = super.getSourceInfo();
if (!hasStaticRef && name != null) {
JsNode<?> staticRef = name.getStaticRef();
if (staticRef != null) {
toReturn.copyMissingCorrelationsFrom(name.getStaticRef().getSourceInfo());
hasStaticRef = true;
}
}
return toReturn;
}
}