/*
* 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;
import com.google.gwt.dev.js.ast.JsArrayAccess;
import com.google.gwt.dev.js.ast.JsArrayLiteral;
import com.google.gwt.dev.js.ast.JsContext;
import com.google.gwt.dev.js.ast.JsExpression;
import com.google.gwt.dev.js.ast.JsFunction;
import com.google.gwt.dev.js.ast.JsInvocation;
import com.google.gwt.dev.js.ast.JsNameRef;
import com.google.gwt.dev.js.ast.JsNew;
import com.google.gwt.dev.js.ast.JsObjectLiteral;
import com.google.gwt.dev.js.ast.JsVisitable;
import com.google.gwt.dev.js.ast.JsVisitor;
/**
* Searches for method invocations in constructor expressions that would not
* normally be surrounded by parentheses.
*/
public class JsConstructExpressionVisitor extends JsVisitor {
public static boolean exec(JsExpression expression) {
if (JsPrecedenceVisitor.exec(expression) < JsPrecedenceVisitor.PRECEDENCE_NEW) {
return true;
}
JsConstructExpressionVisitor visitor = new JsConstructExpressionVisitor();
visitor.accept(expression);
return visitor.containsInvocation;
}
private boolean containsInvocation = false;
private JsConstructExpressionVisitor() {
}
/**
* We only look at the array expression since the index has its own scope.
*/
@Override
public boolean visit(JsArrayAccess x, JsContext<JsExpression> ctx) {
accept(x.getArrayExpr());
return false;
}
/**
* Array literals have their own scoping.
*/
@Override
public boolean visit(JsArrayLiteral x, JsContext<JsExpression> ctx) {
return false;
}
/**
* Functions have their own scoping.
*/
@Override
public boolean visit(JsFunction x, JsContext<JsExpression> ctx) {
return false;
}
@Override
public boolean visit(JsInvocation x, JsContext<JsExpression> ctx) {
containsInvocation = true;
return false;
}
@Override
public boolean visit(JsNameRef x, JsContext<JsExpression> ctx) {
if (!x.isLeaf()) {
accept(x.getQualifier());
}
return false;
}
/**
* New constructs bind to the nearest set of parentheses.
*/
@Override
public boolean visit(JsNew x, JsContext<JsExpression> ctx) {
return false;
}
/**
* Object literals have their own scope.
*/
@Override
public boolean visit(JsObjectLiteral x, JsContext<JsExpression> ctx) {
return false;
}
/**
* We only look at nodes that would not normally be surrounded by parentheses.
*/
@SuppressWarnings("cast")
protected <T extends JsVisitable<T>> T doAccept(T node) {
/*
* Extra casts to Object to prevent 'inconvertible types' compile errors due
* to http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6548436
* reproducible in jdk1.6.0_02.
*/
if ((Object) node instanceof JsExpression) {
JsExpression expression = (JsExpression) (Object) node;
int precedence = JsPrecedenceVisitor.exec(expression);
// Only visit expressions that won't automatically be surrounded by
// parentheses
if (precedence < JsPrecedenceVisitor.PRECEDENCE_NEW) {
return node;
}
}
return super.doAccept(node);
}
}