/*

 * Copyright (c) 2009, 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.javap;

import com.sun.tools.classfile.Attribute;

import com.sun.tools.classfile.Code_attribute;

import com.sun.tools.classfile.ConstantPool;

import com.sun.tools.classfile.ConstantPoolException;

import com.sun.tools.classfile.Descriptor;

import com.sun.tools.classfile.Descriptor.InvalidDescriptor;

import com.sun.tools.classfile.Instruction;

import com.sun.tools.classfile.LocalVariableTable_attribute;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.ListIterator;

import java.util.Map;

/**

 * Annotate instructions with details about local variables.

 *

 *  <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 LocalVariableTableWriter extends  InstructionDetailWriter {

    public enum NoteKind {

        START("start") {

            public boolean match(LocalVariableTable_attribute.Entry entry, int pc) {

                return (pc == entry.start_pc);

            }

        },

        END("end") {

            public boolean match(LocalVariableTable_attribute.Entry entry, int pc) {

                return (pc == entry.start_pc + entry.length);

            }

        };

        NoteKind(String text) {

            this.text = text;

        }

        public abstract boolean match(LocalVariableTable_attribute.Entry entry, int pc);

        public final String text;

    }

    static LocalVariableTableWriter instance(Context context) {

        LocalVariableTableWriter instance = context.get(LocalVariableTableWriter.class);

        if (instance == null)

            instance = new LocalVariableTableWriter(context);

        return instance;

    }

    protected LocalVariableTableWriter(Context context) {

        super(context);

        context.put(LocalVariableTableWriter.class, this);

        classWriter = ClassWriter.instance(context);

    }

    public void reset(Code_attribute attr) {

        codeAttr = attr;

        pcMap = new HashMap<>();

        LocalVariableTable_attribute lvt =

                (LocalVariableTable_attribute) (attr.attributes.get(Attribute.LocalVariableTable));

        if (lvt == null)

            return;

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

            LocalVariableTable_attribute.Entry entry = lvt.local_variable_table[i];

            put(entry.start_pc, entry);

            put(entry.start_pc + entry.length, entry);

        }

    }

    public void writeDetails(Instruction instr) {

        int pc = instr.getPC();

        writeLocalVariables(pc, NoteKind.END);

        writeLocalVariables(pc, NoteKind.START);

    }

    @Override

    public void flush() {

        int pc = codeAttr.code_length;

        writeLocalVariables(pc, NoteKind.END);

    }

    public void writeLocalVariables(int pc, NoteKind kind) {

        ConstantPool constant_pool = classWriter.getClassFile().constant_pool;

        String indent = space(2); // get from Options?

        List<LocalVariableTable_attribute.Entry> entries = pcMap.get(pc);

        if (entries != null) {

            for (ListIterator<LocalVariableTable_attribute.Entry> iter =

                    entries.listIterator(kind == NoteKind.END ? entries.size() : 0);

                    kind == NoteKind.END ? iter.hasPrevious() : iter.hasNext() ; ) {

                LocalVariableTable_attribute.Entry entry =

                        kind == NoteKind.END ? iter.previous() : iter.next();

                if (kind.match(entry, pc)) {

                    print(indent);

                    print(kind.text);

                    print(" local ");

                    print(entry.index);

                    print(" // ");

                    Descriptor d = new Descriptor(entry.descriptor_index);

                    try {

                        print(d.getFieldType(constant_pool));

                    } catch (InvalidDescriptor e) {

                        print(report(e));

                    } catch (ConstantPoolException e) {

                        print(report(e));

                    }

                    print(" ");

                    try {

                        print(constant_pool.getUTF8Value(entry.name_index));

                    } catch (ConstantPoolException e) {

                        print(report(e));

                    }

                    println();

                }

            }

        }

    }

    private void put(int pc, LocalVariableTable_attribute.Entry entry) {

        List<LocalVariableTable_attribute.Entry> list = pcMap.get(pc);

        if (list == null) {

            list = new ArrayList<>();

            pcMap.put(pc, list);

        }

        if (!list.contains(entry))

            list.add(entry);

    }

    private ClassWriter classWriter;

    private Code_attribute codeAttr;

    private Map<Integer, List<LocalVariableTable_attribute.Entry>> pcMap;

}