/*

 * Copyright (c) 2009, 2013, 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 java.util.Arrays;

import java.util.HashMap;

import java.util.Map;

import com.sun.tools.classfile.AccessFlags;

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.Method;

import com.sun.tools.classfile.StackMapTable_attribute;

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

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

/**

 * Annotate instructions with stack map.

 *

 *  <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 StackMapWriter extends InstructionDetailWriter {

    static StackMapWriter instance(Context context) {

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

        if (instance == null)

            instance = new StackMapWriter(context);

        return instance;

    }

    protected StackMapWriter(Context context) {

        super(context);

        context.put(StackMapWriter.class, this);

        classWriter = ClassWriter.instance(context);

    }

    public void reset(Code_attribute attr) {

        setStackMap((StackMapTable_attribute) attr.attributes.get(Attribute.StackMapTable));

    }

    void setStackMap(StackMapTable_attribute attr) {

        if (attr == null) {

            map = null;

            return;

        }

        Method m = classWriter.getMethod();

        Descriptor d = m.descriptor;

        String[] args;

        try {

            ConstantPool cp = classWriter.getClassFile().constant_pool;

            String argString = d.getParameterTypes(cp);

            args = argString.substring(1, argString.length() - 1).split("[, ]+");

        } catch (ConstantPoolException | InvalidDescriptor e) {

            return;

        }

        boolean isStatic = m.access_flags.is(AccessFlags.ACC_STATIC);

        verification_type_info[] initialLocals = new verification_type_info[(isStatic ? 0 : 1) + args.length];

        if (!isStatic)

            initialLocals[0] = new CustomVerificationTypeInfo("this");

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

            initialLocals[(isStatic ? 0 : 1) + i] =

                    new CustomVerificationTypeInfo(args[i].replace(".", "/"));

        }

        map = new HashMap<>();

        StackMapBuilder builder = new StackMapBuilder();

        // using -1 as the pc for the initial frame effectively compensates for

        // the difference in behavior for the first stack map frame (where the

        // pc offset is just offset_delta) compared to subsequent frames (where

        // the pc offset is always offset_delta+1).

        int pc = -1;

        map.put(pc, new StackMap(initialLocals, empty));

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

            pc = attr.entries[i].accept(builder, pc);

    }

    public void writeInitialDetails() {

        writeDetails(-1);

    }

    public void writeDetails(Instruction instr) {

        writeDetails(instr.getPC());

    }

    private void writeDetails(int pc) {

        if (map == null)

            return;

        StackMap m = map.get(pc);

        if (m != null) {

            print("StackMap locals: ", m.locals);

            print("StackMap stack: ", m.stack);

        }

    }

    void print(String label, verification_type_info[] entries) {

        print(label);

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

            print(" ");

            print(entries[i]);

        }

        println();

    }

    void print(verification_type_info entry) {

        if (entry == null) {

            print("ERROR");

            return;

        }

        switch (entry.tag) {

            case -1:

                print(((CustomVerificationTypeInfo) entry).text);

                break;

            case ITEM_Top:

                print("top");

                break;

            case ITEM_Integer:

                print("int");

                break;

            case ITEM_Float:

                print("float");

                break;

            case ITEM_Long:

                print("long");

                break;

            case ITEM_Double:

                print("double");

                break;

            case ITEM_Null:

                print("null");

                break;

            case ITEM_UninitializedThis:

                print("uninit_this");

                break;

            case ITEM_Object:

                try {

                    ConstantPool cp = classWriter.getClassFile().constant_pool;

                    ConstantPool.CONSTANT_Class_info class_info = cp.getClassInfo(((Object_variable_info) entry).cpool_index);

                    print(cp.getUTF8Value(class_info.name_index));

                } catch (ConstantPoolException e) {

                    print("??");

                }

                break;

            case ITEM_Uninitialized:

                print(((Uninitialized_variable_info) entry).offset);

                break;

        }

    }

    private Map<Integer, StackMap> map;

    private ClassWriter classWriter;

    class StackMapBuilder

            implements StackMapTable_attribute.stack_map_frame.Visitor<Integer, Integer> {

        public Integer visit_same_frame(same_frame frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap m = map.get(pc);

            assert (m != null);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_same_locals_1_stack_item_frame(same_locals_1_stack_item_frame frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap prev = map.get(pc);

            assert (prev != null);

            StackMap m = new StackMap(prev.locals, frame.stack);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_same_locals_1_stack_item_frame_extended(same_locals_1_stack_item_frame_extended frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap prev = map.get(pc);

            assert (prev != null);

            StackMap m = new StackMap(prev.locals, frame.stack);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_chop_frame(chop_frame frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap prev = map.get(pc);

            assert (prev != null);

            int k = 251 - frame.frame_type;

            verification_type_info[] new_locals = Arrays.copyOf(prev.locals, prev.locals.length - k);

            StackMap m = new StackMap(new_locals, empty);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_same_frame_extended(same_frame_extended frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta();

            StackMap m = map.get(pc);

            assert (m != null);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_append_frame(append_frame frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap prev = map.get(pc);

            assert (prev != null);

            verification_type_info[] new_locals = new verification_type_info[prev.locals.length + frame.locals.length];

            System.arraycopy(prev.locals, 0, new_locals, 0, prev.locals.length);

            System.arraycopy(frame.locals, 0, new_locals, prev.locals.length, frame.locals.length);

            StackMap m = new StackMap(new_locals, empty);

            map.put(new_pc, m);

            return new_pc;

        }

        public Integer visit_full_frame(full_frame frame, Integer pc) {

            int new_pc = pc + frame.getOffsetDelta() + 1;

            StackMap m = new StackMap(frame.locals, frame.stack);

            map.put(new_pc, m);

            return new_pc;

        }

    }

    static class StackMap {

        StackMap(verification_type_info[] locals, verification_type_info[] stack) {

            this.locals = locals;

            this.stack = stack;

        }

        private final verification_type_info[] locals;

        private final verification_type_info[] stack;

    }

    static class CustomVerificationTypeInfo extends verification_type_info {

        public CustomVerificationTypeInfo(String text) {

            super(-1);

            this.text = text;

        }

        private String text;

    }

    private final verification_type_info[] empty = { };

}