CodeAttr.java

package task8.jvm.attr;


import task8.jvm.clz.ClassFile;
import task8.jvm.cmd.ByteCodeCommand;
import task8.jvm.cmd.CommandParser;
import task8.jvm.constant.ConstantPool;
import task8.jvm.loader.ByteCodeIterator;

public class CodeAttr extends AttributeInfo {
    private int maxStack;
    private int maxLocals;
    private int codeLen;
    private String code;

    public String getCode() {
        return code;
    }

    private ByteCodeCommand[] cmds;

    public ByteCodeCommand[] getCmds() {
        return cmds;
    }

    private LineNumberTable lineNumTable;
    private LocalVariableTable localVarTable;
    private StackMapTable stackMapTable;

    public CodeAttr(int attrNameIndex, int attrLen, int maxStack, int maxLocals, int codeLen, String code /*ByteCodeCommand[] cmds*/) {
        super(attrNameIndex, attrLen);
        this.maxStack = maxStack;
        this.maxLocals = maxLocals;
        this.codeLen = codeLen;
        this.code = code;
        //this.cmds = cmds;
    }

    public void setLineNumberTable(LineNumberTable t) {
        this.lineNumTable = t;
    }

    public void setLocalVariableTable(LocalVariableTable t) {
        this.localVarTable = t;
    }

    public static CodeAttr parse(ClassFile clzFile, ByteCodeIterator iter) {

        int attrNameIndex = iter.next2Bytes();
        int attrLen = iter.next4Bytes();
        int maxStack = iter.next2Bytes();
        int maxLocals = iter.next2Bytes();
        int codeLen = iter.next4Bytes();

        String code = iter.nextUxToHexString(codeLen);

        System.out.println(code);

        ByteCodeCommand[] cmds = CommandParser.parse(clzFile, code);

        CodeAttr codeAttr = new CodeAttr(attrNameIndex, attrLen, maxStack, maxLocals, codeLen, code);

        int exceptionTableLen = iter.next2Bytes();
        //TODO 处理exception
        if (exceptionTableLen > 0) {
            String exTable = iter.nextUxToHexString(exceptionTableLen);
            System.out.println("Encountered exception table , just ignore it :" + exTable);

        }


        int subAttrCount = iter.next2Bytes();

        for (int x = 1; x <= subAttrCount; x++) {
            int subAttrIndex = iter.next2Bytes();
            String subAttrName = clzFile.getConstantPool().getUTF8String(subAttrIndex);

            //已经向前移动了U2, 现在退回去。
            iter.back(2);
            //line item table
            if (AttributeInfo.LINE_NUM_TABLE.equalsIgnoreCase(subAttrName)) {

                LineNumberTable t = LineNumberTable.parse(iter);
                codeAttr.setLineNumberTable(t);
            } else if (AttributeInfo.LOCAL_VAR_TABLE.equalsIgnoreCase(subAttrName)) {
                LocalVariableTable t = LocalVariableTable.parse(iter);
                codeAttr.setLocalVariableTable(t);
            } else if (AttributeInfo.STACK_MAP_TABLE.equalsIgnoreCase(subAttrName)) {
                StackMapTable t = StackMapTable.parse(iter);
                codeAttr.setStackMapTable(t);
            } else {
                throw new RuntimeException("Need code to process " + subAttrName);
            }


        }

        return codeAttr;
    }


    public String toString(ConstantPool pool) {
        StringBuilder buffer = new StringBuilder();
        buffer.append("Code:").append(code).append("\n");
        for (int i = 0; i < cmds.length; i++) {
            buffer.append(cmds[i].toString(pool)).append("\n");
        }
        buffer.append("\n");
        buffer.append(this.lineNumTable.toString());
        buffer.append(this.localVarTable.toString(pool));
        return buffer.toString();
    }

    private void setStackMapTable(StackMapTable t) {
        this.stackMapTable = t;

    }


}