javassist.expr.MethodCall Maven / Gradle / Ivy
/*
* 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 javassist.expr;
import javassist.CannotCompileException;
import javassist.ClassPool;
import javassist.CtBehavior;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.NotFoundException;
import javassist.bytecode.BadBytecode;
import javassist.bytecode.Bytecode;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.CodeIterator;
import javassist.bytecode.ConstPool;
import javassist.bytecode.Descriptor;
import javassist.bytecode.MethodInfo;
import javassist.compiler.CompileError;
import javassist.compiler.Javac;
/**
* Method invocation (caller-side expression).
*/
public class MethodCall extends Expr {
/**
* Undocumented constructor. Do not use; internal-use only.
*/
protected MethodCall(int pos, CodeIterator i, CtClass declaring,
MethodInfo m) {
super(pos, i, declaring, m);
}
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);
return cp.getMethodrefNameAndType(index);
}
/**
* Returns the method or constructor containing the method-call
* expression represented by this object.
*/
@Override
public CtBehavior where() { return super.where(); }
/**
* Returns the line number of the source line containing the
* method call.
*
* @return -1 if this information is not available.
*/
@Override
public int getLineNumber() {
return super.getLineNumber();
}
/**
* Returns the source file containing the method call.
*
* @return null if this information is not available.
*/
@Override
public String getFileName() {
return super.getFileName();
}
/**
* Returns the class of the target object,
* which the method is called on.
*/
protected CtClass getCtClass() throws NotFoundException {
return thisClass.getClassPool().get(getClassName());
}
/**
* Returns the class name of the target object,
* which the method is called on.
*/
public String getClassName() {
String cname;
ConstPool cp = getConstPool();
int pos = currentPos;
int c = iterator.byteAt(pos);
int index = iterator.u16bitAt(pos + 1);
if (c == INVOKEINTERFACE)
cname = cp.getInterfaceMethodrefClassName(index);
else
cname = cp.getMethodrefClassName(index);
if (cname.charAt(0) == '[')
cname = Descriptor.toClassName(cname);
return cname;
}
/**
* Returns the name of the called method.
*/
public String getMethodName() {
ConstPool cp = getConstPool();
int nt = getNameAndType(cp);
return cp.getUtf8Info(cp.getNameAndTypeName(nt));
}
/**
* Returns the called method.
*/
public CtMethod getMethod() throws NotFoundException {
return getCtClass().getMethod(getMethodName(), getSignature());
}
/**
* Returns the method signature (the parameter types
* and the return type).
* The method signature is represented by a character string
* called method descriptor, which is defined in the JVM specification.
*
* @see javassist.CtBehavior#getSignature()
* @see javassist.bytecode.Descriptor
* @since 3.1
*/
public String getSignature() {
ConstPool cp = getConstPool();
int nt = getNameAndType(cp);
return cp.getUtf8Info(cp.getNameAndTypeDescriptor(nt));
}
/**
* 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 true if the called method is of a superclass of the current
* class.
*/
public boolean isSuper() {
return iterator.byteAt(currentPos) == INVOKESPECIAL
&& !where().getDeclaringClass().getName().equals(getClassName());
}
/*
* Returns the parameter types of the called method.
public CtClass[] getParameterTypes() throws NotFoundException {
return Descriptor.getParameterTypes(getMethodDesc(),
thisClass.getClassPool());
}
*/
/*
* Returns the return type of the called method.
public CtClass getReturnType() throws NotFoundException {
return Descriptor.getReturnType(getMethodDesc(),
thisClass.getClassPool());
}
*/
/**
* Replaces the method call with the bytecode derived from
* the given source text.
*
* $0 is available even if the called method is static.
*
* @param statement a Java statement except try-catch.
*/
@Override
public void replace(String statement) throws CannotCompileException {
thisClass.getClassFile(); // to call checkModify().
ConstPool constPool = getConstPool();
int pos = currentPos;
int index = iterator.u16bitAt(pos + 1);
String classname, methodname, signature;
int opcodeSize;
int c = iterator.byteAt(pos);
if (c == INVOKEINTERFACE) {
opcodeSize = 5;
classname = constPool.getInterfaceMethodrefClassName(index);
methodname = constPool.getInterfaceMethodrefName(index);
signature = constPool.getInterfaceMethodrefType(index);
}
else if (c == INVOKESTATIC
|| c == INVOKESPECIAL || c == INVOKEVIRTUAL) {
opcodeSize = 3;
classname = constPool.getMethodrefClassName(index);
methodname = constPool.getMethodrefName(index);
signature = constPool.getMethodrefType(index);
}
else
throw new CannotCompileException("not method invocation");
Javac jc = new Javac(thisClass);
ClassPool cp = thisClass.getClassPool();
CodeAttribute ca = iterator.get();
try {
CtClass[] params = Descriptor.getParameterTypes(signature, cp);
CtClass retType = Descriptor.getReturnType(signature, cp);
int paramVar = ca.getMaxLocals();
jc.recordParams(classname, params,
true, paramVar, withinStatic());
int retVar = jc.recordReturnType(retType, true);
if (c == INVOKESTATIC)
jc.recordStaticProceed(classname, methodname);
else if (c == INVOKESPECIAL)
jc.recordSpecialProceed(Javac.param0Name, classname,
methodname, signature, index);
else
jc.recordProceed(Javac.param0Name, methodname);
/* Is $_ included in the source code?
*/
checkResultValue(retType, statement);
Bytecode bytecode = jc.getBytecode();
storeStack(params, c == INVOKESTATIC, paramVar, bytecode);
jc.recordLocalVariables(ca, pos);
if (retType != CtClass.voidType) {
bytecode.addConstZero(retType);
bytecode.addStore(retVar, retType); // initialize $_
}
jc.compileStmnt(statement);
if (retType != CtClass.voidType)
bytecode.addLoad(retVar, retType);
replace0(pos, bytecode, opcodeSize);
}
catch (CompileError e) { throw new CannotCompileException(e); }
catch (NotFoundException e) { throw new CannotCompileException(e); }
catch (BadBytecode e) {
throw new CannotCompileException("broken method");
}
}
}