/*

 * Copyright (c) 2008, 2016, 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.io.ByteArrayOutputStream;

import java.io.DataOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import static com.sun.tools.classfile.Annotation.*;

import static com.sun.tools.classfile.ConstantPool.*;

import static com.sun.tools.classfile.StackMapTable_attribute.*;

import static com.sun.tools.classfile.StackMapTable_attribute.verification_type_info.*;

/**

 * Write a ClassFile data structure to a file or stream.

 *

 *  <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 ClassWriter {

    public ClassWriter() {

        attributeWriter = new AttributeWriter();

        constantPoolWriter = new ConstantPoolWriter();

        out = new ClassOutputStream();

    }

    /**

     * Write a ClassFile data structure to a file.

     * @param classFile the classfile object to be written

     * @param f the file

     * @throws IOException if an error occurs while writing the file

     */

    public void write(ClassFile classFile, File f) throws IOException {

        try (FileOutputStream f_out = new FileOutputStream(f)) {

            write(classFile, f_out);

        }

    }

    /**

     * Write a ClassFile data structure to a stream.

     * @param classFile the classfile object to be written

     * @param s the stream

     * @throws IOException if an error occurs while writing the file

     */

    public void write(ClassFile classFile, OutputStream s) throws IOException {

        this.classFile = classFile;

        out.reset();

        write();

        out.writeTo(s);

    }

    protected void write() throws IOException {

        writeHeader();

        writeConstantPool();

        writeAccessFlags(classFile.access_flags);

        writeClassInfo();

        writeFields();

        writeMethods();

        writeAttributes(classFile.attributes);

    }

    protected void writeHeader() {

        out.writeInt(classFile.magic);

        out.writeShort(classFile.minor_version);

        out.writeShort(classFile.major_version);

    }

    protected void writeAccessFlags(AccessFlags flags) {

        out.writeShort(flags.flags);

    }

    protected void writeAttributes(Attributes attributes) {

        int size = attributes.size();

        out.writeShort(size);

        for (Attribute attr: attributes)

            attributeWriter.write(attr, out);

    }

    protected void writeClassInfo() {

        out.writeShort(classFile.this_class);

        out.writeShort(classFile.super_class);

        int[] interfaces = classFile.interfaces;

        out.writeShort(interfaces.length);

        for (int i: interfaces)

            out.writeShort(i);

    }

    protected void writeDescriptor(Descriptor d) {

        out.writeShort(d.index);

    }

    protected void writeConstantPool() {

        ConstantPool pool = classFile.constant_pool;

        int size = pool.size();

        out.writeShort(size);

        for (CPInfo cpInfo: pool.entries())

            constantPoolWriter.write(cpInfo, out);

    }

    protected void writeFields() throws IOException {

        Field[] fields = classFile.fields;

        out.writeShort(fields.length);

        for (Field f: fields)

            writeField(f);

    }

    protected void writeField(Field f) throws IOException {

        writeAccessFlags(f.access_flags);

        out.writeShort(f.name_index);

        writeDescriptor(f.descriptor);

        writeAttributes(f.attributes);

    }

    protected void writeMethods() throws IOException {

        Method[] methods = classFile.methods;

        out.writeShort(methods.length);

        for (Method m: methods) {

            writeMethod(m);

        }

    }

    protected void writeMethod(Method m) throws IOException {

        writeAccessFlags(m.access_flags);

        out.writeShort(m.name_index);

        writeDescriptor(m.descriptor);

        writeAttributes(m.attributes);

    }

    protected ClassFile classFile;

    protected ClassOutputStream out;

    protected AttributeWriter attributeWriter;

    protected ConstantPoolWriter constantPoolWriter;

    /**

     * Subtype of ByteArrayOutputStream with the convenience methods of

     * a DataOutputStream. Since ByteArrayOutputStream does not throw

     * IOException, there are no exceptions from the additional

     * convenience methods either,

     */

    protected static class ClassOutputStream extends ByteArrayOutputStream {

        public ClassOutputStream() {

            d = new DataOutputStream(this);

        }

        public void writeByte(int value) {

            try {

                d.writeByte(value);

            } catch (IOException ignore) {

            }

        }

        public void writeShort(int value) {

            try {

                d.writeShort(value);

            } catch (IOException ignore) {

            }

        }

        public void writeInt(int value) {

            try {

                d.writeInt(value);

            } catch (IOException ignore) {

            }

        }

        public void writeLong(long value) {

            try {

                d.writeLong(value);

            } catch (IOException ignore) {

            }

        }

        public void writeFloat(float value) {

            try {

                d.writeFloat(value);

            } catch (IOException ignore) {

            }

        }

        public void writeDouble(double value) {

            try {

                d.writeDouble(value);

            } catch (IOException ignore) {

            }

        }

        public void writeUTF(String value) {

            try {

                d.writeUTF(value);

            } catch (IOException ignore) {

            }

        }

        public void writeTo(ClassOutputStream s) {

            try {

                super.writeTo(s);

            } catch (IOException ignore) {

            }

        }

        private final DataOutputStream d;

    }

    /**

     * Writer for the entries in the constant pool.

     */

    protected static class ConstantPoolWriter

           implements ConstantPool.Visitor<Integer,ClassOutputStream> {

        protected int write(CPInfo info, ClassOutputStream out) {

            out.writeByte(info.getTag());

            return info.accept(this, out);

        }

        @Override

        public Integer visitClass(CONSTANT_Class_info info, ClassOutputStream out) {

            out.writeShort(info.name_index);

            return 1;

        }

        @Override

        public Integer visitDouble(CONSTANT_Double_info info, ClassOutputStream out) {

            out.writeDouble(info.value);

            return 2;

        }

        @Override

        public Integer visitFieldref(CONSTANT_Fieldref_info info, ClassOutputStream out) {

            writeRef(info, out);

            return 1;

        }

        @Override

        public Integer visitFloat(CONSTANT_Float_info info, ClassOutputStream out) {

            out.writeFloat(info.value);

            return 1;

        }

        @Override

        public Integer visitInteger(CONSTANT_Integer_info info, ClassOutputStream out) {

            out.writeInt(info.value);

            return 1;

        }

        @Override

        public Integer visitInterfaceMethodref(CONSTANT_InterfaceMethodref_info info, ClassOutputStream out) {

            writeRef(info, out);

            return 1;

        }

        @Override

        public Integer visitInvokeDynamic(CONSTANT_InvokeDynamic_info info, ClassOutputStream out) {

            out.writeShort(info.bootstrap_method_attr_index);

            out.writeShort(info.name_and_type_index);

            return 1;

        }

        @Override

        public Integer visitLong(CONSTANT_Long_info info, ClassOutputStream out) {

            out.writeLong(info.value);

            return 2;

        }

        @Override

        public Integer visitMethodHandle(CONSTANT_MethodHandle_info info, ClassOutputStream out) {

            out.writeByte(info.reference_kind.tag);

            out.writeShort(info.reference_index);

            return 1;

        }

        @Override

        public Integer visitMethodType(CONSTANT_MethodType_info info, ClassOutputStream out) {

            out.writeShort(info.descriptor_index);

            return 1;

        }

        @Override

        public Integer visitMethodref(CONSTANT_Methodref_info info, ClassOutputStream out) {

            return writeRef(info, out);

        }

        @Override

        public Integer visitModule(CONSTANT_Module_info info, ClassOutputStream out) {

            out.writeShort(info.name_index);

            return 1;

        }

        @Override

        public Integer visitNameAndType(CONSTANT_NameAndType_info info, ClassOutputStream out) {

            out.writeShort(info.name_index);

            out.writeShort(info.type_index);

            return 1;

        }

        @Override

        public Integer visitPackage(CONSTANT_Package_info info, ClassOutputStream out) {

            out.writeShort(info.name_index);

            return 1;

        }

        @Override

        public Integer visitString(CONSTANT_String_info info, ClassOutputStream out) {

            out.writeShort(info.string_index);

            return 1;

        }

        @Override

        public Integer visitUtf8(CONSTANT_Utf8_info info, ClassOutputStream out) {

            out.writeUTF(info.value);

            return 1;

        }

        protected Integer writeRef(CPRefInfo info, ClassOutputStream out) {

            out.writeShort(info.class_index);

            out.writeShort(info.name_and_type_index);

            return 1;

        }

    }

    /**

     * Writer for the different types of attribute.

     */

    protected static class AttributeWriter implements Attribute.Visitor<Void,ClassOutputStream> {

        public void write(Attributes attributes, ClassOutputStream out) {

            int size = attributes.size();

            out.writeShort(size);

            for (Attribute a: attributes)

                write(a, out);

        }

        // Note: due to the use of shared resources, this method is not reentrant.

        public void write(Attribute attr, ClassOutputStream out) {

            out.writeShort(attr.attribute_name_index);

            sharedOut.reset();

            attr.accept(this, sharedOut);

            out.writeInt(sharedOut.size());

            sharedOut.writeTo(out);

        }

        protected ClassOutputStream sharedOut = new ClassOutputStream();

        protected AnnotationWriter annotationWriter = new AnnotationWriter();

        @Override

        public Void visitDefault(DefaultAttribute attr, ClassOutputStream out) {

            out.write(attr.info, 0, attr.info.length);

            return null;

        }

        @Override

        public Void visitAnnotationDefault(AnnotationDefault_attribute attr, ClassOutputStream out) {

            annotationWriter.write(attr.default_value, out);

            return null;

        }

        @Override

        public Void visitBootstrapMethods(BootstrapMethods_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.bootstrap_method_specifiers.length);

            for (BootstrapMethods_attribute.BootstrapMethodSpecifier bsm : attr.bootstrap_method_specifiers) {

                out.writeShort(bsm.bootstrap_method_ref);

                int bsm_args_count = bsm.bootstrap_arguments.length;

                out.writeShort(bsm_args_count);

                for (int i : bsm.bootstrap_arguments) {

                    out.writeShort(i);

                }

            }

            return null;

        }

        @Override

        public Void visitCharacterRangeTable(CharacterRangeTable_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.character_range_table.length);

            for (CharacterRangeTable_attribute.Entry e: attr.character_range_table)

                writeCharacterRangeTableEntry(e, out);

            return null;

        }

        protected void writeCharacterRangeTableEntry(CharacterRangeTable_attribute.Entry entry, ClassOutputStream out) {

            out.writeShort(entry.start_pc);

            out.writeShort(entry.end_pc);

            out.writeInt(entry.character_range_start);

            out.writeInt(entry.character_range_end);

            out.writeShort(entry.flags);

        }

        @Override

        public Void visitCode(Code_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.max_stack);

            out.writeShort(attr.max_locals);

            out.writeInt(attr.code.length);

            out.write(attr.code, 0, attr.code.length);

            out.writeShort(attr.exception_table.length);

            for (Code_attribute.Exception_data e: attr.exception_table)

                writeExceptionTableEntry(e, out);

            new AttributeWriter().write(attr.attributes, out);

            return null;

        }

        protected void writeExceptionTableEntry(Code_attribute.Exception_data exception_data, ClassOutputStream out) {

            out.writeShort(exception_data.start_pc);

            out.writeShort(exception_data.end_pc);

            out.writeShort(exception_data.handler_pc);

            out.writeShort(exception_data.catch_type);

        }

        @Override

        public Void visitCompilationID(CompilationID_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.compilationID_index);

            return null;

        }

        @Override

        public Void visitConstantValue(ConstantValue_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.constantvalue_index);

            return null;

        }

        @Override

        public Void visitDeprecated(Deprecated_attribute attr, ClassOutputStream out) {

            return null;

        }

        @Override

        public Void visitEnclosingMethod(EnclosingMethod_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.class_index);

            out.writeShort(attr.method_index);

            return null;

        }

        @Override

        public Void visitExceptions(Exceptions_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.exception_index_table.length);

            for (int i: attr.exception_index_table)

                out.writeShort(i);

            return null;

        }

        @Override

        public Void visitInnerClasses(InnerClasses_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.classes.length);

            for (InnerClasses_attribute.Info info: attr.classes)

                writeInnerClassesInfo(info, out);

            return null;

        }

        protected void writeInnerClassesInfo(InnerClasses_attribute.Info info, ClassOutputStream out) {

            out.writeShort(info.inner_class_info_index);

            out.writeShort(info.outer_class_info_index);

            out.writeShort(info.inner_name_index);

            writeAccessFlags(info.inner_class_access_flags, out);

        }

        @Override

        public Void visitLineNumberTable(LineNumberTable_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.line_number_table.length);

            for (LineNumberTable_attribute.Entry e: attr.line_number_table)

                writeLineNumberTableEntry(e, out);

            return null;

        }

        protected void writeLineNumberTableEntry(LineNumberTable_attribute.Entry entry, ClassOutputStream out) {

            out.writeShort(entry.start_pc);

            out.writeShort(entry.line_number);

        }

        @Override

        public Void visitLocalVariableTable(LocalVariableTable_attribute attr, ClassOutputStream out) {

            out.writeShort(attr.local_variable_table.length);

            for (LocalVariableTable_attribute.Entry e: attr.local_variable_table)

                writeLocalVariableTableEntry(e, out);

            return null;

        }

        protected void writeLocalVariableTableEntry(LocalVariableTable_attribute.Entry entry, ClassOutputStream out) {

            out.writeShort(entry.start_pc);

            out.writeShort(entry.length);

            out.writeShort(entry.name_index);

            out.writeShort(entry.descriptor_index);

            out.writeShort(entry.index);

        }

        @Override

        public Void visitLocalVariableTypeTable(LocalVariableTypeTable_attribute attr, ClassOutputStream out) {