verifier.java

大名鼎鼎的java动态脚本语言。已经通过了sun的认证

/*
 $Id: Verifier.java,v 1.55 2006/06/25 19:58:43 blackdrag Exp $

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

 Redistribution and use of this software and associated documentation
 ("Software"), with or without modification, are permitted provided
 that the following conditions are met:

 1. Redistributions of source code must retain copyright
    statements and notices.  Redistributions must also contain a
    copy of this document.

 2. Redistributions in binary form must reproduce the
    above copyright notice, this list of conditions and the
    following disclaimer in the documentation and/or other
    materials provided with the distribution.

 3. The name "groovy" must not be used to endorse or promote
    products derived from this Software without prior written
    permission of The Codehaus.  For written permission,
    please contact [e-mail].

 4. Products derived from this Software may not be called "groovy"
    nor may "groovy" appear in their names without prior written
    permission of The Codehaus. "groovy" is a registered
    trademark of The Codehaus.

 5. Due credit should be given to The Codehaus -
    http://groovy.codehaus.org/

 THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
 ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 OF THE POSSIBILITY OF SUCH DAMAGE.

 */
package org.codehaus.groovy.classgen;

import groovy.lang.Closure;
import groovy.lang.GroovyObject;
import groovy.lang.MetaClass;

import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.CodeVisitorSupport;
import org.codehaus.groovy.ast.ConstructorNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.GroovyClassVisitor;
import org.codehaus.groovy.ast.InnerClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.PropertyNode;
import org.codehaus.groovy.ast.VariableScope;
import org.codehaus.groovy.ast.expr.ArgumentListExpression;
import org.codehaus.groovy.ast.expr.BinaryExpression;
import org.codehaus.groovy.ast.expr.BooleanExpression;
import org.codehaus.groovy.ast.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.ConstructorCallExpression;
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.StaticMethodCallExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.EmptyStatement;
import org.codehaus.groovy.ast.stmt.ExpressionStatement;
import org.codehaus.groovy.ast.stmt.IfStatement;
import org.codehaus.groovy.ast.stmt.ReturnStatement;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.runtime.ScriptBytecodeAdapter;
import org.codehaus.groovy.syntax.Types;
import org.codehaus.groovy.syntax.Token;
import org.codehaus.groovy.syntax.RuntimeParserException;
import org.objectweb.asm.Opcodes;

/**
 * Verifies the AST node and adds any defaulted AST code before
 * bytecode generation occurs.
 * 
 * @author <a href="mailto:[e-mail]">James Strachan</a>
 * @version $Revision: 1.55 $
 */
public class Verifier implements GroovyClassVisitor, Opcodes {

    public static final String __TIMESTAMP = "__timeStamp";
	private ClassNode classNode;
    private MethodNode methodNode;

    public ClassNode getClassNode() {
        return classNode;
    }

    public MethodNode getMethodNode() {
        return methodNode;
    }

    /**
     * add code to implement GroovyObject
     * @param node
     */
    public void visitClass(ClassNode node) {
        this.classNode = node;
                
        if ((classNode.getModifiers() & Opcodes.ACC_INTERFACE) >0) {
            //interfaces have no construcotrs, but this code expects one, 
            //so creta a dummy and don't add it to the class node
            ConstructorNode dummy = new ConstructorNode(0,null);
            addInitialization(node, dummy);
            node.visitContents(this);
            return;
        }
        
        addDefaultParameterMethods(node);

        if (!node.isDerivedFromGroovyObject()) {
            node.addInterface(ClassHelper.make(GroovyObject.class));

            // lets add a new field for the metaclass
            StaticMethodCallExpression initMetaClassCall =
                new StaticMethodCallExpression(
                    ClassHelper.make(ScriptBytecodeAdapter.class),
                    "getMetaClass",
                    VariableExpression.THIS_EXPRESSION);

            PropertyNode metaClassProperty =
                node.addProperty("metaClass", ACC_PUBLIC, ClassHelper.make(MetaClass.class), initMetaClassCall, null, null);
            metaClassProperty.setSynthetic(true);
            FieldNode metaClassField = metaClassProperty.getField();
            metaClassField.setModifiers(metaClassField.getModifiers() | ACC_TRANSIENT);

            FieldExpression metaClassVar = new FieldExpression(metaClassField);
            IfStatement initMetaClassField =
                new IfStatement(
                    new BooleanExpression(
                        new BinaryExpression(metaClassVar, Token.newSymbol( Types.COMPARE_EQUAL, -1, -1), ConstantExpression.NULL)),
                    new ExpressionStatement(new BinaryExpression(metaClassVar, Token.newSymbol( Types.EQUAL, -1, -1), initMetaClassCall)),
                    EmptyStatement.INSTANCE);

            node.addSyntheticMethod(
                "getMetaClass",
                ACC_PUBLIC,
                ClassHelper.make(MetaClass.class),
                Parameter.EMPTY_ARRAY,
                ClassNode.EMPTY_ARRAY,
                new BlockStatement(new Statement[] { initMetaClassField, new ReturnStatement(metaClassVar)}, new VariableScope())
            );

            // @todo we should check if the base class implements the invokeMethod method

            // lets add the invokeMethod implementation
            ClassNode superClass = node.getSuperClass();
            boolean addDelegateObject =
                (node instanceof InnerClassNode && superClass.equals(Closure.class.getName()))
                    || superClass.equals(ClassHelper.GSTRING_TYPE);

            // don't do anything as the base class implements the invokeMethod
            if (!addDelegateObject) {
                
                VariableExpression vMethods = new VariableExpression("method");
                VariableExpression vArguments = new VariableExpression("arguments");
                VariableScope blockScope = new VariableScope();
                blockScope.getReferencedLocalVariables().put("method",vMethods);
                blockScope.getReferencedLocalVariables().put("arguments",vArguments);
                
                node.addSyntheticMethod(
                    "invokeMethod",
                    ACC_PUBLIC,
                    ClassHelper.OBJECT_TYPE,
                    new Parameter[] {
                        new Parameter(ClassHelper.STRING_TYPE, "method"),
                        new Parameter(ClassHelper.OBJECT_TYPE, "arguments")
                    },
                    ClassNode.EMPTY_ARRAY,    
                    new BlockStatement(
                        new Statement[] {
                            initMetaClassField,
                            new ReturnStatement(
                                new MethodCallExpression(
                                    metaClassVar,
                                    "invokeMethod",
                                    new ArgumentListExpression(
                                        new Expression[] {
                                            VariableExpression.THIS_EXPRESSION,
                                            vMethods,
                                            vArguments}
                                        )
                                    )
                                )
                        },
                        blockScope
                    )
                );
                

                if (!node.isScript()) {
                    node.addSyntheticMethod(
                        "getProperty",
                        ACC_PUBLIC,
                        ClassHelper.OBJECT_TYPE,
                        new Parameter[] { new Parameter(ClassHelper.STRING_TYPE, "property")},
                        ClassNode.EMPTY_ARRAY,
                        new BlockStatement(
                            new Statement[] {
                                initMetaClassField,
                                new ReturnStatement(
                                    new MethodCallExpression(
                                        metaClassVar,
                                        "getProperty",
                                        new ArgumentListExpression(
                                            new Expression[] {
                                                VariableExpression.THIS_EXPRESSION,
                                                new VariableExpression("property")})))
                            },
                            new VariableScope()
                        ));
                    VariableExpression vProp = new VariableExpression("property");
                    VariableExpression vValue = new VariableExpression("value");
                    blockScope = new VariableScope();
                    blockScope.getReferencedLocalVariables().put("property",vProp);
                    blockScope.getReferencedLocalVariables().put("value",vValue);
                    
                    node.addSyntheticMethod(
                        "setProperty",
                        ACC_PUBLIC,
                        ClassHelper.VOID_TYPE,
                        new Parameter[] {
                            new Parameter(ClassHelper.STRING_TYPE, "property"),
                            new Parameter(ClassHelper.OBJECT_TYPE, "value")
                        },
                        ClassNode.EMPTY_ARRAY,
                        new BlockStatement(
                            new Statement[] {
                                initMetaClassField,
                                new ExpressionStatement(
                                    new MethodCallExpression(
                                        metaClassVar,
                                        "setProperty",
                                        new ArgumentListExpression(
                                            new Expression[] {
                                                VariableExpression.THIS_EXPRESSION,
                                                vProp,
                                                vValue})))
                            },
                            blockScope
                    ));
                }
            }
        }

        if (node.getDeclaredConstructors().isEmpty()) {
            ConstructorNode constructor = new ConstructorNode(ACC_PUBLIC, null);
            constructor.setSynthetic(true);
            node.addConstructor(constructor);
        }
        
        if (!(node instanceof InnerClassNode)) {// add a static timestamp field to the class
            FieldNode timeTagField = new FieldNode(
                    Verifier.__TIMESTAMP,
                    Modifier.PUBLIC | Modifier.STATIC,
                    ClassHelper.Long_TYPE,
                    //"",
                    node,
                    new ConstantExpression(new Long(System.currentTimeMillis())));
            // alternatively , FieldNode timeTagField = SourceUnit.createFieldNode("public static final long __timeStamp = " + System.currentTimeMillis() + "L");
            timeTagField.setSynthetic(true);
            node.addField(timeTagField);
        }
        
        addInitialization(node);
        node.getObjectInitializerStatements().clear();
        node.visitContents(this);
    }
    public void visitConstructor(ConstructorNode node) {
        CodeVisitorSupport checkSuper = new CodeVisitorSupport() {
            boolean firstMethodCall = true;
            String type=null;
            public void visitMethodCallExpression(MethodCallExpression call) {
                if (!firstMethodCall) return;
                firstMethodCall = false;
                String name = call.getMethod();
                if (!name.equals("super") && !name.equals("this")) return;
                type=name;
                call.getArguments().visit(this);
                type=null;
            }
            public void visitVariableExpression(VariableExpression expression) {
                if (type==null) return;
                String name = expression.getName();
                if (!name.equals("this") && !name.equals("super")) return;
                throw new RuntimeParserException("cannot reference "+name+" inside of "+type+"(....) before supertype constructor has been called",expression);
            }            
        };
        Statement s = node.getCode();
        //todo why can a statement can be null?
        if (s == null) return;
        s.visit(checkSuper);
    }

    public void visitMethod(MethodNode node) {
        this.methodNode = node;
        Statement statement = node.getCode();
        if (!node.isVoidMethod()) {
            if (statement instanceof ExpressionStatement) {
                ExpressionStatement expStmt = (ExpressionStatement) statement;
                node.setCode(new ReturnStatement(expStmt.getExpression()));
            }
            else if (statement instanceof BlockStatement) {
                BlockStatement block = (BlockStatement) statement;

                // lets copy the list so we create a new block
                List list = new ArrayList(block.getStatements());
                if (!list.isEmpty()) {
                    int idx = list.size() - 1;
                    Statement last = (Statement) list.get(idx);
                    if (last instanceof ExpressionStatement) {
                        ExpressionStatement expStmt = (ExpressionStatement) last;
                        list.set(idx, new ReturnStatement(expStmt));
                    }
                    else if (!(last instanceof ReturnStatement)) {
                        list.add(new ReturnStatement(ConstantExpression.NULL));
                    }
                }
                else {
                    list.add(new ReturnStatement(ConstantExpression.NULL));
                }

                node.setCode(new BlockStatement(filterStatements(list),block.getVariableScope()));
            }