SelectionVisitor.java

/*******************************************************************************
 * Copyright (c) 2010 xored software, Inc.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     xored software, Inc. - initial API and Implementation (Alex Panchenko)
 *******************************************************************************/
package org.eclipse.dltk.javascript.internal.core.codeassist;

import java.util.List;

import org.eclipse.dltk.ast.ASTNode;
import org.eclipse.dltk.internal.javascript.ti.ITypeInferenceContext;
import org.eclipse.dltk.internal.javascript.ti.PositionReachedException;
import org.eclipse.dltk.internal.javascript.ti.TypeInferencerVisitor;
import org.eclipse.dltk.javascript.ast.Argument;
import org.eclipse.dltk.javascript.ast.CallExpression;
import org.eclipse.dltk.javascript.ast.Expression;
import org.eclipse.dltk.javascript.ast.FunctionStatement;
import org.eclipse.dltk.javascript.ast.Identifier;
import org.eclipse.dltk.javascript.ast.VariableDeclaration;
import org.eclipse.dltk.javascript.typeinference.IValueCollection;
import org.eclipse.dltk.javascript.typeinference.IValueReference;
import org.eclipse.dltk.javascript.typeinference.ReferenceKind;

public class SelectionVisitor extends TypeInferencerVisitor {

	private final ASTNode target;
	private IValueReference value;
	private IValueReference[] arguments;

	public SelectionVisitor(ITypeInferenceContext context, ASTNode target) {
		super(context);
		this.target = target;
	}

	public IValueReference getValue() {
		return value;
	}

	public IValueReference[] getArguments() {
		return arguments;
	}

	@Override
	public IValueReference visit(ASTNode node) {
		final IValueReference result = super.visit(node);
		if (node == target) {
			value = result;
			earlyExit();
		}
		return result;
	}

	@Override
	public IValueReference visitCallExpression(CallExpression node) {
		final IValueReference reference;
		boolean nullValue = value == null;
		try {
			reference = visit(node.getExpression());
		} finally {
			boolean valueHit = value != null && nullValue;
			final List<ASTNode> callArgs = node.getArguments();
			final IValueReference[] arguments = new IValueReference[callArgs
					.size()];
			for (int i = 0, size = callArgs.size(); i < size; ++i) {
				arguments[i] = visit(callArgs.get(i));
			}
			if (valueHit) {
				this.arguments = arguments;
			}
		}
		if (reference != null) {
			return reference.getChild(IValueReference.FUNCTION_OP);
		} else {
			return null;
		}
	}

	@Override
	protected IValueReference extractNamedChild(IValueReference parent,
			Expression name) {
		final IValueReference result = super.extractNamedChild(parent, name);
		if (name == target) {
			value = result;
			earlyExit();
		}
		return result;
	}

	private IValueReference check(Identifier node, IValueReference reference) {
		if (node == target) {
			value = reference;
			earlyExit();
		}
		return reference;
	}

	@Override
	public void visitFunctionBody(FunctionStatement node) {
		for (Argument argument : node.getArguments()) {
			check(argument.getIdentifier(),
					peekContext().getChild(argument.getArgumentName()));
		}
		super.visitFunctionBody(node);
	}

	@Override
	protected IValueReference createVariable(
			IValueCollection context, VariableDeclaration declaration) {
		return check(declaration.getIdentifier(),
				super.createVariable(context, declaration));
	}

	@Override
	public IValueReference visitFunctionStatement(FunctionStatement node) {
		IValueReference fs = super.visitFunctionStatement(node);
		if (node.getName() != null)
			visit(node.getName());
		return fs;

	}

	private void earlyExit() {
		if (value == null || value.getKind() != ReferenceKind.UNKNOWN) {
			throw new PositionReachedException(target, value);
		}
	}

}