/*
* JBoss, Home of Professional Open Source
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
* @authors Andrew Dinn
*/
package org.jboss.byteman.rule;
import org.jboss.byteman.rule.binding.Bindings;
import org.jboss.byteman.rule.binding.Binding;
import org.jboss.byteman.rule.compiler.CompileContext;
import org.jboss.byteman.rule.grammar.ParseNode;
import static org.jboss.byteman.rule.grammar.ParseNode.*;
import org.jboss.byteman.rule.grammar.ECATokenLexer;
import org.jboss.byteman.rule.grammar.ECAGrammarParser;
import org.jboss.byteman.rule.expression.Expression;
import org.jboss.byteman.rule.expression.ExpressionHelper;
import org.jboss.byteman.rule.type.Type;
import org.jboss.byteman.rule.exception.ParseException;
import org.jboss.byteman.rule.exception.TypeException;
import org.jboss.byteman.rule.exception.ExecuteException;
import org.jboss.byteman.rule.exception.CompileException;
import org.jboss.byteman.rule.helper.HelperAdapter;
import org.objectweb.asm.MethodVisitor;
import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.io.StringWriter;
import java.io.StringReader;
import java_cup.runtime.Symbol;
/**
* class which represents a rule event comprising of a set of abstract bindings of event variables to
* evaluable expressions.
*/
public class Event extends RuleElement {
public static Event create(Rule rule, ParseNode eventTree)
throws TypeException
{
Event event = new Event(rule, eventTree);
return event;
}
public static Event create(Rule rule, String text)
throws ParseException, TypeException
{
if ("".equals(text)) {
return new Event(rule);
}
String fullText = "BIND\n" + text + "\nIF TRUE DO NOTHING";
try {
ECATokenLexer lexer = new ECATokenLexer(new StringReader(fullText));
ECAGrammarParser parser = new ECAGrammarParser(lexer);
Symbol event_parse = parser.parse();
ParseNode eventTree = (ParseNode)event_parse.value;
Event event = new Event(rule, eventTree);
return event;
} catch (Exception e) {
throw new ParseException("org.jboss.byteman.rule.Event : error parsing event\n" + text, e);
}
}
protected Event(Rule rule, ParseNode eventTree) throws TypeException
{
super(rule);
createBindings(eventTree);
}
protected Event(Rule rule)
{
super(rule);
}
public Bindings getBindings()
{
return rule.getBindings();
}
public Type typeCheck(Type expected) throws TypeException {
// expected must be Type.VOID
Iterator<Binding> iterator = getBindings().iterator();
while (iterator.hasNext()) {
Binding binding = iterator.next();
typeCheck(binding);
}
return Type.VOID;
}
private void typeCheck(Binding binding)
throws TypeException
{
binding.typeCheck(Type.UNDEFINED);
}
private void createBindings(ParseNode eventTree) throws TypeException
{
// we expect BINDINGS = NOTHING | BINDING | (COMMA BINDING BINDINGS)
// where BINDING = (BIND BINDSYM EXPR)
if (eventTree == null || eventTree.getTag() == NOTHING) {
return;
}
Bindings bindings = getBindings();
// we bundle exceptions from each binding to report more than just the first error
List<TypeException> exceptions = new ArrayList<TypeException>();
while (eventTree != null) {
try {
int tag = eventTree.getTag();
switch (tag) {
case COMMA:
{
// update before we risk an exception
ParseNode child0 = (ParseNode)eventTree.getChild(0);
eventTree = (ParseNode)eventTree.getChild(1);
addBinding(bindings, child0);
}
break;
case ASSIGN:
{
// update before we risk an exception
ParseNode saveTree = eventTree;
eventTree = null;
addBinding(bindings, saveTree);
}
break;
default:
{
String message = "Event.createBindings : unexpected token Type in binding list " + tag + " for token " + eventTree.getText() + eventTree.getPos();
eventTree = null;
throw new TypeException(message);
}
}
} catch (TypeException te) {
exceptions.add(te);
}
}
if (!exceptions.isEmpty()) {
if (exceptions.size() == 1) {
throw exceptions.get(0);
} else {
StringBuffer buffer = new StringBuffer();
buffer.append("Event.createBindings : invalid event bindings");
for (TypeException exception : exceptions) {
buffer.append("\n\t");
buffer.append(exception.getMessage());
}
throw new TypeException(buffer.toString());
}
}
}
private void addBinding(Bindings bindings, ParseNode bindingTree) throws TypeException
{
int tag = bindingTree.getTag();
if (tag != ASSIGN) {
String message = "Event.createBindings : unexpected token Type in binding " + tag + " for token " + bindingTree.getText() + bindingTree.getPos();
throw new TypeException(message);
}
ParseNode varTree = (ParseNode)bindingTree.getChild(0);
ParseNode exprTree = (ParseNode)bindingTree.getChild(1);
Binding binding;
binding = createBinding(varTree);
// don't allow current binding to be used when parsing the expression
// but do use any type supplied for the binding
Expression expr;
expr = ExpressionHelper.createExpression(rule, bindings, exprTree, binding.getType());
// check bindings
expr.bind();
String name = binding.getName();
if (bindings.lookup(name) != null) {
// oops rebinding not allowed
String message = "Event.createBindings : rebinding disallowed for variable " + name + varTree.getPos();
throw new TypeException(message);
}
// if the binding type is undefined and the expression type is defined propagate the
// expression type to the binding
if (binding.getType() == Type.UNDEFINED && expr.getType() != Type.UNDEFINED) {
binding.setType(expr.getType());
}
binding.setValue(expr);
bindings.append(binding);
}
public Binding createBinding(ParseNode varTree) throws TypeException
{
int tag = varTree.getTag();
// we expect either (COLON IDENTIFIER TYPE) or IDENTIFIER
switch (tag) {
case IDENTIFIER:
{
return new Binding(rule, varTree.getText());
}
case COLON:
{
ParseNode child0 = (ParseNode)varTree.getChild(0);
ParseNode child1 = (ParseNode)varTree.getChild(1);
if (child0.getTag() != IDENTIFIER) {
throw new TypeException("Event.createBindings : unexpected token type in variable declaration" + child0.getTag() + " for token " + child0.getText() + child0.getPos());
} else if (child1.getTag() != IDENTIFIER && child1.getTag() != ARRAY) {
throw new TypeException("Event.createBindings : unexpected token Type in variable type declaration" + child1.getTag() + " for token " + child1.getText() + child1.getPos());
}
Type type = getBindingType(child1);
if (type == null) {
throw new TypeException("Event.createBindings : incompatible type in declaration of variable " + child1.getText() + child1.getPos());
}
return new Binding(rule, child0.getText(), type);
}
default:
{
throw new TypeException("Event.createBindings : unexpected token type in binding variable declaration" + tag + " for token " + varTree.getText() + varTree.getPos());
}
}
}
/**
* create and return a type for a binding or return null if the type cannot be created
* @param typeTree
* @return the binding type or null
*/
private Type getBindingType(ParseNode typeTree)
{
int tag = typeTree.getTag();
// we expect either TYPE = (IDENTIFIER) or (ARRAY TYPE)
switch (tag) {
case IDENTIFIER:
{
String typeName = typeTree.getText();
return getTypeGroup().create(typeName);
}
case ARRAY:
{
ParseNode child0 = (ParseNode)typeTree.getChild(0);
Type baseType = getBindingType(child0);
if (baseType != null) {
return getTypeGroup().createArray(baseType);
} else {
return null;
}
}
default:
{
return null;
}
}
}
public Object interpret(HelperAdapter helper)
throws ExecuteException
{
Iterator<Binding> iterator = getBindings().iterator();
while (iterator.hasNext()) {
Binding binding = iterator.next();
binding.interpret(helper);
}
return null;
}
public void compile(MethodVisitor mv, CompileContext compileContext) throws CompileException
{
int currentStack = compileContext.getStackCount();
Iterator<Binding> iterator = getBindings().iterator();
while (iterator.hasNext()) {
Binding binding = iterator.next();
binding.compile(mv, compileContext);
}
// check stack heights
if (compileContext.getStackCount() != currentStack) {
throw new CompileException("Event.compile : invalid stack height " + compileContext.getStackCount() + " expecting " + currentStack);
}
}
public void writeTo(StringWriter stringWriter)
{
Iterator<Binding> iter = getBindings().iterator();
if (!iter.hasNext()) {
stringWriter.write("BIND NOTHING");
} else {
String prefix = "BIND ";
while (iter.hasNext()) {
Binding binding = iter.next();
stringWriter.write(prefix);
binding.writeTo(stringWriter);
prefix = ",\n ";
}
}
stringWriter.write("\n");
}
}