/*
 * 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.
 
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 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 = { };
}