memberresolver.java

Javassist是一个开源的分析、编辑和创建Java字节码的类库。是由东京技术学院的数学和计算机科学系的 Shigeru Chiba 所创建的。它已加入了开放源代码JBoss 应用服务器项目,通过使

/*
 * Javassist, a Java-bytecode translator toolkit.
 * Copyright (C) 1999-2006 Shigeru Chiba. All Rights Reserved.
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License.  Alternatively, the contents of this file may be used under
 * the terms of the GNU Lesser General Public License Version 2.1 or later.
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 */

package javassist.compiler;

import java.util.List;
import java.util.Iterator;
import javassist.*;
import javassist.bytecode.*;
import javassist.compiler.ast.*;

/* Code generator methods depending on javassist.* classes.
 */
public class MemberResolver implements TokenId {
    private ClassPool classPool;

    public MemberResolver(ClassPool cp) {
        classPool = cp;
    }

    public ClassPool getClassPool() { return classPool; }

    private static void fatal() throws CompileError {
        throw new CompileError("fatal");
    }

    /**
     * @param jvmClassName      a class name.  Not a package name.
     */
    public void recordPackage(String jvmClassName) {
        String classname = jvmToJavaName(jvmClassName);
        for (;;) {
            int i = classname.lastIndexOf('.');
            if (i > 0) {
                classname = classname.substring(0, i);
                classPool.recordInvalidClassName(classname);
            }
            else
                break;
        }
    }

    public static class Method {
        public CtClass declaring;
        public MethodInfo info;
        public int notmatch;

        public Method(CtClass c, MethodInfo i, int n) {
            declaring = c;
            info = i;
            notmatch = n;
        }

        /**
         * Returns true if the invoked method is static.
         */
        public boolean isStatic() {
            int acc = info.getAccessFlags();
            return (acc & AccessFlag.STATIC) != 0;
        }
    }

    public Method lookupMethod(CtClass clazz, CtClass currentClass, MethodInfo current,
                                String methodName,
                                int[] argTypes, int[] argDims,
                                String[] argClassNames)
        throws CompileError
    {
        Method maybe = null;
        // to enable the creation of a recursively called method
        if (current != null && clazz == currentClass)
            if (current.getName().equals(methodName)) {
                int res = compareSignature(current.getDescriptor(),
                                           argTypes, argDims, argClassNames);
                if (res != NO) {
                    Method r = new Method(clazz, current, res);
                    if (res == YES)
                        return r;
                    else
                        maybe = r;
                }
            }

        Method m = lookupMethod(clazz, methodName, argTypes, argDims,
                                argClassNames, maybe != null);
        if (m != null)
            return m;
        else
            return maybe;
    }

    private Method lookupMethod(CtClass clazz, String methodName,
                               int[] argTypes, int[] argDims,
                               String[] argClassNames, boolean onlyExact)
        throws CompileError
    {
        Method maybe = null;
        List list = clazz.getClassFile2().getMethods();
        int n = list.size();
        for (int i = 0; i < n; ++i) {
            MethodInfo minfo = (MethodInfo)list.get(i);
            if (minfo.getName().equals(methodName)) {
                int res = compareSignature(minfo.getDescriptor(),
                                           argTypes, argDims, argClassNames);
                if (res != NO) {
                    Method r = new Method(clazz, minfo, res);
                    if (res == YES)
                        return r;
                    else if (maybe == null || maybe.notmatch > res)
                        maybe = r;
                }
            }
        }

        if (onlyExact)
            maybe = null;
        else
            onlyExact = maybe != null;

        try {
            CtClass pclazz = clazz.getSuperclass();
            if (pclazz != null) {
                Method r = lookupMethod(pclazz, methodName, argTypes,
                                        argDims, argClassNames, onlyExact);
                if (r != null)
                    return r;
            }
        }
        catch (NotFoundException e) {}

        int mod = clazz.getModifiers();
        if (Modifier.isAbstract(mod) || Modifier.isInterface(mod))
            try {
                CtClass[] ifs = clazz.getInterfaces();
                int size = ifs.length;
                for (int i = 0; i < size; ++i) {
                    Method r = lookupMethod(ifs[i], methodName,
                                            argTypes, argDims, argClassNames,
                                            onlyExact);
                    if (r != null)
                        return r;
                }
            }
            catch (NotFoundException e) {}

        return maybe;
    }

    private static final int YES = 0;
    private static final int NO = -1;

    /*
     * Returns YES if actual parameter types matches the given signature.
     *
     * argTypes, argDims, and argClassNames represent actual parameters.
     *
     * This method does not correctly implement the Java method dispatch
     * algorithm.
     *
     * If some of the parameter types exactly match but others are subtypes of
     * the corresponding type in the signature, this method returns the number
     * of parameter types that do not exactly match.
     */
    private int compareSignature(String desc, int[] argTypes,
                                 int[] argDims, String[] argClassNames)
        throws CompileError
    {
        int result = YES;
        int i = 1;
        int nArgs = argTypes.length;
        if (nArgs != Descriptor.numOfParameters(desc))
            return NO;

        int len = desc.length();
        for (int n = 0; i < len; ++n) {
            char c = desc.charAt(i++);
            if (c == ')')
                return (n == nArgs ? result : NO);
            else if (n >= nArgs)
                return NO;

            int dim = 0;
            while (c == '[') {
                ++dim;
                c = desc.charAt(i++);
            }

            if (argTypes[n] == NULL) {
                if (dim == 0 && c != 'L')
                    return NO;

                if (c == 'L')
                    i = desc.indexOf(';', i) + 1;
            }
            else if (argDims[n] != dim) {
                if (!(dim == 0 && c == 'L'
                      && desc.startsWith("java/lang/Object;", i)))
                    return NO;

                // if the thread reaches here, c must be 'L'.
                i = desc.indexOf(';', i) + 1;
                result++;
                if (i <= 0)
                    return NO;  // invalid descriptor?
            }
            else if (c == 'L') {        // not compare
                int j = desc.indexOf(';', i);
                if (j < 0 || argTypes[n] != CLASS)
                    return NO;

                String cname = desc.substring(i, j);
                if (!cname.equals(argClassNames[n])) {
                    CtClass clazz = lookupClassByJvmName(argClassNames[n]);
                    try {
                        if (clazz.subtypeOf(lookupClassByJvmName(cname)))
                            result++;
                        else
                            return NO;
                    }
                    catch (NotFoundException e) {
                        result++; // should be NO?
                    }
                }

                i = j + 1;
            }
            else {
                int t = descToType(c);
                int at = argTypes[n];
                if (t != at)
                    if (t == INT
                        && (at == SHORT || at == BYTE || at == CHAR))
                        result++;
                    else
                        return NO;
            }
        }

        return NO;
    }

    /**
     * Only used by fieldAccess() in MemberCodeGen and TypeChecker.
     *
     * @param jvmClassName  a JVM class name.  e.g. java/lang/String
     */
    public CtField lookupFieldByJvmName2(String jvmClassName, Symbol fieldSym,
                                         ASTree expr) throws NoFieldException
    {
        String field = fieldSym.get();
        CtClass cc = null;
        try {
            cc = lookupClass(jvmToJavaName(jvmClassName), true);
        }
        catch (CompileError e) {
            // EXPR might be part of a qualified class name.
            throw new NoFieldException(jvmClassName + "/" + field, expr);
        }

        try {
            return cc.getField(field);
        }
        catch (NotFoundException e) {
            // maybe an inner class.
            jvmClassName = javaToJvmName(cc.getName());