/*

 * Copyright (c) 2008, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.classfile;

import java.util.Map;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Class_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Double_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Fieldref_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Float_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Integer_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_InterfaceMethodref_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_InvokeDynamic_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Long_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_MethodHandle_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_MethodType_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Methodref_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_NameAndType_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_String_info;

import com.sun.tools.classfile.ConstantPool.CONSTANT_Utf8_info;

import com.sun.tools.classfile.ConstantPool.CPInfo;

/**

 * Rewrites a class file using a map of translations.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class ClassTranslator

        implements ConstantPool.Visitor<ConstantPool.CPInfo,Map<Object,Object>> {

    /**

     * Create a new ClassFile from {@code cf}, such that for all entries

     * {@code k -\> v} in {@code translations},

     * each occurrence of {@code k} in {@code cf} will be replaced by {@code v}.

     * in

     * @param cf the class file to be processed

     * @param translations the set of translations to be applied

     * @return a copy of {@code} with the values in {@code translations} substituted

     */

    public ClassFile translate(ClassFile cf, Map<Object,Object> translations) {

        ClassFile cf2 = (ClassFile) translations.get(cf);

        if (cf2 == null) {

            ConstantPool constant_pool2 = translate(cf.constant_pool, translations);

            Field[] fields2 = translate(cf.fields, cf.constant_pool, translations);

            Method[] methods2 = translateMethods(cf.methods, cf.constant_pool, translations);

            Attributes attributes2 = translateAttributes(cf.attributes, cf.constant_pool,

                    translations);

            if (constant_pool2 == cf.constant_pool &&

                    fields2 == cf.fields &&

                    methods2 == cf.methods &&

                    attributes2 == cf.attributes)

                cf2 = cf;

            else

                cf2 = new ClassFile(

                        cf.magic,

                        cf.minor_version,

                        cf.major_version,

                        constant_pool2,

                        cf.access_flags,

                        cf.this_class,

                        cf.super_class,

                        cf.interfaces,

                        fields2,

                        methods2,

                        attributes2);

            translations.put(cf, cf2);

        }

        return cf2;

    }

    ConstantPool translate(ConstantPool cp, Map<Object,Object> translations) {

        ConstantPool cp2 = (ConstantPool) translations.get(cp);

        if (cp2 == null) {

            ConstantPool.CPInfo[] pool2 = new ConstantPool.CPInfo[cp.size()];

            boolean eq = true;

            for (int i = 0; i < cp.size(); ) {

                ConstantPool.CPInfo cpInfo;

                try {

                    cpInfo = cp.get(i);

                } catch (ConstantPool.InvalidIndex e) {

                    throw new IllegalStateException(e);

                }

                ConstantPool.CPInfo cpInfo2 = translate(cpInfo, translations);

                eq &= (cpInfo == cpInfo2);

                pool2[i] = cpInfo2;

                if (cpInfo.getTag() != cpInfo2.getTag())

                    throw new IllegalStateException();

                i += cpInfo.size();

            }

            if (eq)

                cp2 = cp;

            else

                cp2 = new ConstantPool(pool2);

            translations.put(cp, cp2);

        }

        return cp2;

    }

    ConstantPool.CPInfo translate(ConstantPool.CPInfo cpInfo, Map<Object,Object> translations) {

        ConstantPool.CPInfo cpInfo2 = (ConstantPool.CPInfo) translations.get(cpInfo);

        if (cpInfo2 == null) {

            cpInfo2 = cpInfo.accept(this, translations);

            translations.put(cpInfo, cpInfo2);

        }

        return cpInfo2;

    }

    Field[] translate(Field[] fields, ConstantPool constant_pool, Map<Object,Object> translations) {

        Field[] fields2 = (Field[]) translations.get(fields);

        if (fields2 == null) {

            fields2 = new Field[fields.length];

            for (int i = 0; i < fields.length; i++)

                fields2[i] = translate(fields[i], constant_pool, translations);

            if (equal(fields, fields2))

                fields2 = fields;

            translations.put(fields, fields2);

        }

        return fields2;

    }

    Field translate(Field field, ConstantPool constant_pool, Map<Object,Object> translations) {

        Field field2 = (Field) translations.get(field);

        if (field2 == null) {

            Attributes attributes2 = translateAttributes(field.attributes, constant_pool,

                    translations);

            if (attributes2 == field.attributes)

                field2 = field;

            else

                field2 = new Field(

                        field.access_flags,

                        field.name_index,

                        field.descriptor,

                        attributes2);

            translations.put(field, field2);

        }

        return field2;

    }

    Method[] translateMethods(Method[] methods, ConstantPool constant_pool, Map<Object,Object> translations) {

        Method[] methods2 = (Method[]) translations.get(methods);

        if (methods2 == null) {

            methods2 = new Method[methods.length];

            for (int i = 0; i < methods.length; i++)

                methods2[i] = translate(methods[i], constant_pool, translations);

            if (equal(methods, methods2))

                methods2 = methods;

            translations.put(methods, methods2);

        }

        return methods2;

    }

    Method translate(Method method, ConstantPool constant_pool, Map<Object,Object> translations) {

        Method method2 = (Method) translations.get(method);

        if (method2 == null) {

            Attributes attributes2 = translateAttributes(method.attributes, constant_pool,

                    translations);

            if (attributes2 == method.attributes)

                method2 = method;

            else

                method2 = new Method(

                        method.access_flags,

                        method.name_index,

                        method.descriptor,

                        attributes2);

            translations.put(method, method2);

        }

        return method2;

    }

    Attributes translateAttributes(Attributes attributes,

            ConstantPool constant_pool, Map<Object,Object> translations) {

        Attributes attributes2 = (Attributes) translations.get(attributes);

        if (attributes2 == null) {

            Attribute[] attrArray2 = new Attribute[attributes.size()];

            ConstantPool constant_pool2 = translate(constant_pool, translations);

            boolean attrsEqual = true;

            for (int i = 0; i < attributes.size(); i++) {

                Attribute attr = attributes.get(i);

                Attribute attr2 = translate(attr, translations);

                if (attr2 != attr)

                    attrsEqual = false;

                attrArray2[i] = attr2;

            }

            if ((constant_pool2 == constant_pool) && attrsEqual)

                attributes2 = attributes;

            else

                attributes2 = new Attributes(constant_pool2, attrArray2);

            translations.put(attributes, attributes2);

        }

        return attributes2;

    }

    Attribute translate(Attribute attribute, Map<Object,Object> translations) {

        Attribute attribute2 = (Attribute) translations.get(attribute);

        if (attribute2 == null) {

            attribute2 = attribute; // don't support translation within attributes yet

                                    // (what about Code attribute)

            translations.put(attribute, attribute2);

        }

        return attribute2;

    }

    private static <T> boolean equal(T[] a1, T[] a2) {

        if (a1 == null || a2 == null)

            return (a1 == a2);

        if (a1.length != a2.length)

            return false;

        for (int i = 0; i < a1.length; i++) {

            if (a1[i] != a2[i])

                return false;

        }

        return true;

    }

    public CPInfo visitClass(CONSTANT_Class_info info, Map<Object, Object> translations) {

        CONSTANT_Class_info info2 = (CONSTANT_Class_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp)

                info2 = info;

            else

                info2 = new CONSTANT_Class_info(cp2, info.name_index);

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitDouble(CONSTANT_Double_info info, Map<Object, Object> translations) {

        CONSTANT_Double_info info2 = (CONSTANT_Double_info) translations.get(info);

        if (info2 == null) {

            info2 = info;

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitFieldref(CONSTANT_Fieldref_info info, Map<Object, Object> translations) {

        CONSTANT_Fieldref_info info2 = (CONSTANT_Fieldref_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp)

                info2 = info;

            else

                info2 = new CONSTANT_Fieldref_info(cp2, info.class_index, info.name_and_type_index);

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitFloat(CONSTANT_Float_info info, Map<Object, Object> translations) {

        CONSTANT_Float_info info2 = (CONSTANT_Float_info) translations.get(info);

        if (info2 == null) {

            info2 = info;

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitInteger(CONSTANT_Integer_info info, Map<Object, Object> translations) {

        CONSTANT_Integer_info info2 = (CONSTANT_Integer_info) translations.get(info);

        if (info2 == null) {

            info2 = info;

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, Map<Object, Object> translations) {

        CONSTANT_InterfaceMethodref_info info2 = (CONSTANT_InterfaceMethodref_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp)

                info2 = info;

            else

                info2 = new CONSTANT_InterfaceMethodref_info(cp2, info.class_index, info.name_and_type_index);

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, Map<Object, Object> translations) {

        CONSTANT_InvokeDynamic_info info2 = (CONSTANT_InvokeDynamic_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp) {

                info2 = info;

            } else {

                info2 = new CONSTANT_InvokeDynamic_info(cp2, info.bootstrap_method_attr_index, info.name_and_type_index);

            }

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitLong(CONSTANT_Long_info info, Map<Object, Object> translations) {

        CONSTANT_Long_info info2 = (CONSTANT_Long_info) translations.get(info);

        if (info2 == null) {

            info2 = info;

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitMethodref(CONSTANT_Methodref_info info, Map<Object, Object> translations) {

        CONSTANT_Methodref_info info2 = (CONSTANT_Methodref_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp)

                info2 = info;

            else

                info2 = new CONSTANT_Methodref_info(cp2, info.class_index, info.name_and_type_index);

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitMethodHandle(CONSTANT_MethodHandle_info info, Map<Object, Object> translations) {

        CONSTANT_MethodHandle_info info2 = (CONSTANT_MethodHandle_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp) {

                info2 = info;

            } else {

                info2 = new CONSTANT_MethodHandle_info(cp2, info.reference_kind, info.reference_index);

            }

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitMethodType(CONSTANT_MethodType_info info, Map<Object, Object> translations) {

        CONSTANT_MethodType_info info2 = (CONSTANT_MethodType_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp) {

                info2 = info;

            } else {

                info2 = new CONSTANT_MethodType_info(cp2, info.descriptor_index);

            }

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitString(CONSTANT_String_info info, Map<Object, Object> translations) {

        CONSTANT_String_info info2 = (CONSTANT_String_info) translations.get(info);

        if (info2 == null) {

            ConstantPool cp2 = translate(info.cp, translations);

            if (cp2 == info.cp)

                info2 = info;

            else

                info2 = new CONSTANT_String_info(cp2, info.string_index);

            translations.put(info, info2);

        }

        return info;

    }

    public CPInfo visitUtf8(CONSTANT_Utf8_info info, Map<Object, Object> translations) {

        CONSTANT_Utf8_info info2 = (CONSTANT_Utf8_info) translations.get(info);

        if (info2 == null) {

            info2 = info;

            translations.put(info, info2);

        }

        return info;

    }

}