com.feilong.lib.javassist.bytecode.LocalVariableAttribute Maven / Gradle / Ivy
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/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999- Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later,
* or the Apache License Version 2.0.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package com.feilong.lib.javassist.bytecode;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Map;
/**
* LocalVariableTable_attribute.
*/
public class LocalVariableAttribute extends AttributeInfo{
/**
* The name of this attribute "LocalVariableTable".
*/
public static final String tag = "LocalVariableTable";
/**
* The name of the attribute "LocalVariableTypeTable".
*/
public static final String typeTag = "LocalVariableTypeTable";
/**
* Constructs an empty LocalVariableTable.
*/
public LocalVariableAttribute(ConstPool cp){
super(cp, tag, new byte[2]);
ByteArray.write16bit(0, info, 0);
}
LocalVariableAttribute(ConstPool cp, int n, DataInputStream in) throws IOException{
super(cp, n, in);
}
LocalVariableAttribute(ConstPool cp, String name, byte[] i){
super(cp, name, i);
}
/**
* Appends a new entry to local_variable_table.
*
* @param startPc
* start_pc
* @param length
* length
* @param nameIndex
* name_index
* @param descriptorIndex
* descriptor_index
* @param index
* index
*/
public void addEntry(int startPc,int length,int nameIndex,int descriptorIndex,int index){
int size = info.length;
byte[] newInfo = new byte[size + 10];
ByteArray.write16bit(tableLength() + 1, newInfo, 0);
for (int i = 2; i < size; ++i){
newInfo[i] = info[i];
}
ByteArray.write16bit(startPc, newInfo, size);
ByteArray.write16bit(length, newInfo, size + 2);
ByteArray.write16bit(nameIndex, newInfo, size + 4);
ByteArray.write16bit(descriptorIndex, newInfo, size + 6);
ByteArray.write16bit(index, newInfo, size + 8);
info = newInfo;
}
@Override
void renameClass(String oldname,String newname){
ConstPool cp = getConstPool();
int n = tableLength();
for (int i = 0; i < n; ++i){
int pos = i * 10 + 2;
int index = ByteArray.readU16bit(info, pos + 6);
if (index != 0){
String desc = cp.getUtf8Info(index);
desc = renameEntry(desc, oldname, newname);
ByteArray.write16bit(cp.addUtf8Info(desc), info, pos + 6);
}
}
}
String renameEntry(String desc,String oldname,String newname){
return Descriptor.rename(desc, oldname, newname);
}
@Override
void renameClass(Map classnames){
ConstPool cp = getConstPool();
int n = tableLength();
for (int i = 0; i < n; ++i){
int pos = i * 10 + 2;
int index = ByteArray.readU16bit(info, pos + 6);
if (index != 0){
String desc = cp.getUtf8Info(index);
desc = renameEntry(desc, classnames);
ByteArray.write16bit(cp.addUtf8Info(desc), info, pos + 6);
}
}
}
String renameEntry(String desc,Map classnames){
return Descriptor.rename(desc, classnames);
}
/**
* For each local_variable_table[i].index,
* this method increases index by delta.
*
* @param lessThan
* the index does not change if it
* is less than this value.
*/
public void shiftIndex(int lessThan,int delta){
int size = info.length;
for (int i = 2; i < size; i += 10){
int org = ByteArray.readU16bit(info, i + 8);
if (org >= lessThan){
ByteArray.write16bit(org + delta, info, i + 8);
}
}
}
/**
* Returns local_variable_table_length.
* This represents the number of entries in the table.
*/
public int tableLength(){
return ByteArray.readU16bit(info, 0);
}
/**
* Returns local_variable_table[i].start_pc.
* This represents the index into the code array from which the local
* variable is effective.
*
* @param i
* the i-th entry.
*/
public int startPc(int i){
return ByteArray.readU16bit(info, i * 10 + 2);
}
/**
* Returns local_variable_table[i].length.
* This represents the length of the code region in which the local
* variable is effective.
*
* @param i
* the i-th entry.
*/
public int codeLength(int i){
return ByteArray.readU16bit(info, i * 10 + 4);
}
/**
* Adjusts start_pc and length if bytecode is inserted in a method body.
*/
void shiftPc(int where,int gapLength,boolean exclusive){
int n = tableLength();
for (int i = 0; i < n; ++i){
int pos = i * 10 + 2;
int pc = ByteArray.readU16bit(info, pos);
int len = ByteArray.readU16bit(info, pos + 2);
/*
* if pc == 0, then the local variable is a method parameter.
*/
if (pc > where || (exclusive && pc == where && pc != 0)){
ByteArray.write16bit(pc + gapLength, info, pos);
}else if (pc + len > where || (exclusive && pc + len == where)){
ByteArray.write16bit(len + gapLength, info, pos + 2);
}
}
}
/**
* Returns the value of local_variable_table[i].name_index.
* This represents the name of the local variable.
*
* @param i
* the i-th entry.
*/
public int nameIndex(int i){
return ByteArray.readU16bit(info, i * 10 + 6);
}
/**
* Returns the name of the local variable
* specified by local_variable_table[i].name_index.
*
* @param i
* the i-th entry.
*/
public String variableName(int i){
return getConstPool().getUtf8Info(nameIndex(i));
}
/**
* Returns the value of
* local_variable_table[i].descriptor_index.
* This represents the type descriptor of the local variable.
*
* If this attribute represents a LocalVariableTypeTable attribute,
* this method returns the value of
* local_variable_type_table[i].signature_index.
* It represents the type of the local variable.
*
* @param i
* the i-th entry.
*/
public int descriptorIndex(int i){
return ByteArray.readU16bit(info, i * 10 + 8);
}
/**
* This method is equivalent to descriptorIndex().
* If this attribute represents a LocalVariableTypeTable attribute,
* this method should be used instead of descriptorIndex()
* since the method name is more appropriate.
*
* @param i
* the i-th entry.
* @see #descriptorIndex(int)
* @see SignatureAttribute#toFieldSignature(String)
*/
public int signatureIndex(int i){
return descriptorIndex(i);
}
/**
* Returns the type descriptor of the local variable
* specified by local_variable_table[i].descriptor_index.
*
* If this attribute represents a LocalVariableTypeTable attribute,
* this method returns the type signature of the local variable
* specified by local_variable_type_table[i].signature_index.
*
* @param i
* the i-th entry.
*/
public String descriptor(int i){
return getConstPool().getUtf8Info(descriptorIndex(i));
}
/**
* This method is equivalent to descriptor().
* If this attribute represents a LocalVariableTypeTable attribute,
* this method should be used instead of descriptor()
* since the method name is more appropriate.
*
*
* To parse the string, call toFieldSignature(String)
* in SignatureAttribute.
*
* @param i
* the i-th entry.
* @see #descriptor(int)
* @see SignatureAttribute#toFieldSignature(String)
*/
public String signature(int i){
return descriptor(i);
}
/**
* Returns local_variable_table[i].index.
* This represents the index of the local variable.
*
* @param i
* the i-th entry.
*/
public int index(int i){
return ByteArray.readU16bit(info, i * 10 + 10);
}
/**
* Makes a copy.
*
* @param newCp
* the constant pool table used by the new copy.
* @param classnames
* should be null.
*/
@Override
public AttributeInfo copy(ConstPool newCp,Map classnames){
byte[] src = get();
byte[] dest = new byte[src.length];
ConstPool cp = getConstPool();
LocalVariableAttribute attr = makeThisAttr(newCp, dest);
int n = ByteArray.readU16bit(src, 0);
ByteArray.write16bit(n, dest, 0);
int j = 2;
for (int i = 0; i < n; ++i){
int start = ByteArray.readU16bit(src, j);
int len = ByteArray.readU16bit(src, j + 2);
int name = ByteArray.readU16bit(src, j + 4);
int type = ByteArray.readU16bit(src, j + 6);
int index = ByteArray.readU16bit(src, j + 8);
ByteArray.write16bit(start, dest, j);
ByteArray.write16bit(len, dest, j + 2);
if (name != 0){
name = cp.copy(name, newCp, null);
}
ByteArray.write16bit(name, dest, j + 4);
if (type != 0){
String sig = cp.getUtf8Info(type);
sig = Descriptor.rename(sig, classnames);
type = newCp.addUtf8Info(sig);
}
ByteArray.write16bit(type, dest, j + 6);
ByteArray.write16bit(index, dest, j + 8);
j += 10;
}
return attr;
}
// LocalVariableTypeAttribute overrides this method.
LocalVariableAttribute makeThisAttr(ConstPool cp,byte[] dest){
return new LocalVariableAttribute(cp, tag, dest);
}
}