/*
 * 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.
 
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.
/**
 * 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;
}