com.feilong.lib.javassist.expr.NewExpr 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.expr;
import com.feilong.lib.javassist.CannotCompileException;
import com.feilong.lib.javassist.ClassPool;
import com.feilong.lib.javassist.CtBehavior;
import com.feilong.lib.javassist.CtClass;
import com.feilong.lib.javassist.CtConstructor;
import com.feilong.lib.javassist.NotFoundException;
import com.feilong.lib.javassist.bytecode.BadBytecode;
import com.feilong.lib.javassist.bytecode.Bytecode;
import com.feilong.lib.javassist.bytecode.CodeAttribute;
import com.feilong.lib.javassist.bytecode.CodeIterator;
import com.feilong.lib.javassist.bytecode.ConstPool;
import com.feilong.lib.javassist.bytecode.Descriptor;
import com.feilong.lib.javassist.bytecode.MethodInfo;
import com.feilong.lib.javassist.bytecode.Opcode;
import com.feilong.lib.javassist.compiler.CompileError;
import com.feilong.lib.javassist.compiler.Javac;
import com.feilong.lib.javassist.compiler.JvstCodeGen;
import com.feilong.lib.javassist.compiler.JvstTypeChecker;
import com.feilong.lib.javassist.compiler.ProceedHandler;
import com.feilong.lib.javassist.compiler.ast.ASTList;
/**
* Object creation (new expression).
*/
public class NewExpr extends Expr{
String newTypeName;
int newPos;
/**
* Undocumented constructor. Do not use; internal-use only.
*/
protected NewExpr(int pos, CodeIterator i, CtClass declaring, MethodInfo m, String type, int np){
super(pos, i, declaring, m);
newTypeName = type;
newPos = np;
}
/*
* Not used
*
* private int getNameAndType(ConstPool cp) {
* int pos = currentPos;
* int c = iterator.byteAt(pos);
* int index = iterator.u16bitAt(pos + 1);
*
* if (c == INVOKEINTERFACE)
* return cp.getInterfaceMethodrefNameAndType(index);
* else
* return cp.getMethodrefNameAndType(index);
* }
*/
/**
* Returns the method or constructor containing the new
* expression represented by this object.
*/
@Override
public CtBehavior where(){
return super.where();
}
/**
* Returns the line number of the source line containing the
* new expression.
*
* @return -1 if this information is not available.
*/
@Override
public int getLineNumber(){
return super.getLineNumber();
}
/**
* Returns the source file containing the new expression.
*
* @return null if this information is not available.
*/
@Override
public String getFileName(){
return super.getFileName();
}
/**
* Returns the class of the created object.
*/
private CtClass getCtClass() throws NotFoundException{
return thisClass.getClassPool().get(newTypeName);
}
/**
* Returns the class name of the created object.
*/
public String getClassName(){
return newTypeName;
}
/**
* Get the signature of the constructor
*
* The signature is represented by a character string
* called method descriptor, which is defined in the JVM specification.
*
* @see com.feilong.lib.javassist.CtBehavior#getSignature()
* @see com.feilong.lib.javassist.bytecode.Descriptor
* @return the signature
*/
public String getSignature(){
ConstPool constPool = getConstPool();
int methodIndex = iterator.u16bitAt(currentPos + 1); // constructor
return constPool.getMethodrefType(methodIndex);
}
/**
* Returns the constructor called for creating the object.
*/
public CtConstructor getConstructor() throws NotFoundException{
ConstPool cp = getConstPool();
int index = iterator.u16bitAt(currentPos + 1);
String desc = cp.getMethodrefType(index);
return getCtClass().getConstructor(desc);
}
/**
* Returns the list of exceptions that the expression may throw.
* This list includes both the exceptions that the try-catch statements
* including the expression can catch and the exceptions that
* the throws declaration allows the method to throw.
*/
@Override
public CtClass[] mayThrow(){
return super.mayThrow();
}
/*
* Returns the parameter types of the constructor.
*
* public CtClass[] getParameterTypes() throws NotFoundException {
* ConstPool cp = getConstPool();
* int index = iterator.u16bitAt(currentPos + 1);
* String desc = cp.getMethodrefType(index);
* return Descriptor.getParameterTypes(desc, thisClass.getClassPool());
* }
*/
private int canReplace() throws CannotCompileException{
int op = iterator.byteAt(newPos + 3);
if (op == Opcode.DUP){
return ((iterator.byteAt(newPos + 4) == Opcode.DUP2_X2 && iterator.byteAt(newPos + 5) == Opcode.POP2)) ? 6 : 4;
}else if (op == Opcode.DUP_X1 && iterator.byteAt(newPos + 4) == Opcode.SWAP){
return 5;
}else{
return 3; // for Eclipse. The generated code may include no DUP.
// throw new CannotCompileException(
// "sorry, cannot edit NEW followed by no DUP");
}
}
/**
* Replaces the new expression with the bytecode derived from
* the given source text.
*
*
* $0 is available but the value is null.
*
* @param statement
* a Java statement except try-catch.
*/
@Override
public void replace(String statement) throws CannotCompileException{
thisClass.getClassFile(); // to call checkModify().
final int bytecodeSize = 3;
int pos = newPos;
int newIndex = iterator.u16bitAt(pos + 1);
/*
* delete the preceding NEW and DUP (or DUP_X1, SWAP) instructions.
*/
int codeSize = canReplace();
int end = pos + codeSize;
for (int i = pos; i < end; ++i){
iterator.writeByte(NOP, i);
}
ConstPool constPool = getConstPool();
pos = currentPos;
int methodIndex = iterator.u16bitAt(pos + 1); // constructor
String signature = constPool.getMethodrefType(methodIndex);
Javac jc = new Javac(thisClass);
ClassPool cp = thisClass.getClassPool();
CodeAttribute ca = iterator.get();
try{
CtClass[] params = Descriptor.getParameterTypes(signature, cp);
CtClass newType = cp.get(newTypeName);
int paramVar = ca.getMaxLocals();
jc.recordParams(newTypeName, params, true, paramVar, withinStatic());
int retVar = jc.recordReturnType(newType, true);
jc.recordProceed(new ProceedForNew(newType, newIndex, methodIndex));
/*
* Is $_ included in the source code?
*/
checkResultValue(newType, statement);
Bytecode bytecode = jc.getBytecode();
storeStack(params, true, paramVar, bytecode);
jc.recordLocalVariables(ca, pos);
bytecode.addConstZero(newType);
bytecode.addStore(retVar, newType); // initialize $_
jc.compileStmnt(statement);
if (codeSize > 3){
bytecode.addAload(retVar);
}
replace0(pos, bytecode, bytecodeSize);
}catch (CompileError e){
throw new CannotCompileException(e);
}catch (NotFoundException e){
throw new CannotCompileException(e);
}catch (BadBytecode e){
throw new CannotCompileException("broken method");
}
}
static class ProceedForNew implements ProceedHandler{
CtClass newType;
int newIndex, methodIndex;
ProceedForNew(CtClass nt, int ni, int mi){
newType = nt;
newIndex = ni;
methodIndex = mi;
}
@Override
public void doit(JvstCodeGen gen,Bytecode bytecode,ASTList args) throws CompileError{
bytecode.addOpcode(NEW);
bytecode.addIndex(newIndex);
bytecode.addOpcode(DUP);
gen.atMethodCallCore(newType, MethodInfo.nameInit, args, false, true, -1, null);
gen.setType(newType);
}
@Override
public void setReturnType(JvstTypeChecker c,ASTList args) throws CompileError{
c.atMethodCallCore(newType, MethodInfo.nameInit, args);
c.setType(newType);
}
}
}