variablescopevisitor.java

大名鼎鼎的java动态脚本语言。已经通过了sun的认证

/*
 $Id: VariableScopeVisitor.java,v 1.4 2006/06/15 17:21:33 blackdrag Exp $

 Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.

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 ("Software"), with or without modification, are permitted provided
 that the following conditions are met:

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    statements and notices.  Redistributions must also contain a
    copy of this document.

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    following disclaimer in the documentation and/or other
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    products derived from this Software without prior written
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    please contact [e-mail].

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    trademark of The Codehaus.

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    http://groovy.codehaus.org/

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 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
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package org.codehaus.groovy.classgen;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.ClassCodeVisitorSupport;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.PropertyNode;
import org.codehaus.groovy.ast.DynamicVariable;
import org.codehaus.groovy.ast.Variable;
import org.codehaus.groovy.ast.VariableScope;
import org.codehaus.groovy.ast.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.DeclarationExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.FieldExpression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.CatchStatement;
import org.codehaus.groovy.ast.stmt.ForStatement;
import org.codehaus.groovy.control.SourceUnit;

/**
 * goes through an AST and initializes the scopes 
 * @author Jochen Theodorou
 */
public class VariableScopeVisitor extends ClassCodeVisitorSupport {
    private VariableScope currentScope = null;
    private VariableScope headScope = new VariableScope();
    private ClassNode currentClass=null;
    private SourceUnit source;
    private boolean inClosure=false;
    
    private LinkedList stateStack=new LinkedList();
    
    private class StateStackElement {
        VariableScope scope;
        ClassNode clazz;
        boolean dynamic;
        boolean closure;
        
        StateStackElement() {
            scope = VariableScopeVisitor.this.currentScope;
            clazz = VariableScopeVisitor.this.currentClass;
            closure = VariableScopeVisitor.this.inClosure;
        }
    }
    
    public VariableScopeVisitor(SourceUnit source) {
        this.source = source;
        currentScope  = headScope;
    }
    
    
    // ------------------------------
    // helper methods   
    //------------------------------
    
    private void pushState(boolean isStatic) {
        stateStack.add(new StateStackElement());
        currentScope = new VariableScope(currentScope);
        currentScope.setInStaticContext(isStatic);
    }
    
    private void pushState() {
        pushState(currentScope.isInStaticContext());
    }
    
    private void popState() {
        // a scope in a closure is never really static
        // the checking needs this to be as the surrounding
        // method to correctly check the access to variables.
        // But a closure and all nested scopes are a result
        // of calling a non static method, so the context
        // is not static.
        if (inClosure) currentScope.setInStaticContext(false);
        
        StateStackElement element = (StateStackElement) stateStack.removeLast();
        currentScope = element.scope;
        currentClass = element.clazz;
        inClosure = element.closure;
    }
    
    private void declare(Parameter[] parameters, ASTNode node) {
        for (int i = 0; i < parameters.length; i++) {
            if (parameters[i].hasInitialExpression()) {
                parameters[i].getInitialExpression().visit(this);
            }
            declare(parameters[i],node);
        }
    }        
    
    private void declare(VariableExpression expr) {
        declare(expr,expr);
    }
    
    private void declare(Variable var, ASTNode expr) {
        String scopeType = "scope";
        String variableType = "variable";
        
        if (expr.getClass()==FieldNode.class){
            scopeType = "class"; 
            variableType = "field";
        } else if (expr.getClass()==PropertyNode.class){
            scopeType = "class"; 
            variableType = "property";
        }
        
        StringBuffer msg = new StringBuffer();
        msg.append("The current ").append(scopeType);
        msg.append(" does already contain a ").append(variableType);
        msg.append(" of the name ").append(var.getName());
        
        if (currentScope.getDeclaredVariable(var.getName())!=null) {
            addError(msg.toString(),expr);
            return;
        }
        
        for (VariableScope scope = currentScope.getParent(); scope!=null; scope = scope.getParent()) {
            // if we are in a class and no variable is declared until
            // now, then we can break the loop, because we are allowed
            // to declare a variable of the same name as a class member
            if (scope.getClassScope()!=null) break;
            
            Map declares = scope.getDeclaredVariables();
            if (declares.get(var.getName())!=null) {
                // variable already declared
                addError(msg.toString(), expr);
                break;
            }
        }
        // declare the variable even if there was an error to allow more checks
        currentScope.getDeclaredVariables().put(var.getName(),var);
    }
    
    protected SourceUnit getSourceUnit() {
        return source;
    }
    
    private Variable findClassMember(ClassNode cn, String name) {
        if (cn == null) return null;
        if (cn.isScript()) {
            return new DynamicVariable(name,false);
        }
        List l = cn.getFields();
        for (Iterator iter = l.iterator(); iter.hasNext();) {
            FieldNode f = (FieldNode) iter.next();
            if (f.getName().equals(name)) return f;
        }

        l = cn.getMethods();
        for (Iterator iter = l.iterator(); iter.hasNext();) {
            MethodNode f =(MethodNode) iter.next();
            String methodName = f.getName();
            String pName = getPropertyName(f);
            if (pName == null) continue; 
            if (!pName.equals(name)) continue;
            PropertyNode var = new PropertyNode(pName,f.getModifiers(),getPropertyType(f),cn,null,null,null);
            return var;
        }

        l = cn.getProperties();
        for (Iterator iter = l.iterator(); iter.hasNext();) {
            PropertyNode f = (PropertyNode) iter.next();
            if (f.getName().equals(name)) return f;
        }
        
        Variable ret = findClassMember(cn.getSuperClass(),name);
        if (ret!=null) return ret;
        return findClassMember(cn.getOuterClass(),name); 
    }
    
    private ClassNode getPropertyType(MethodNode m) {
        String name = m.getName();
        if (m.getReturnType()!=ClassHelper.VOID_TYPE) {
            return m.getReturnType();
        }