/*
* 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.bytecode;
import java.io.
DataInputStream;
import java.io.
DataOutputStream;
import java.io.
IOException;
import java.util.
ArrayList;
import java.util.
List;
import java.util.
Map;
import javassist.
ClassPool;
import javassist.bytecode.stackmap.
MapMaker;
/**
* <code>method_info</code> structure.
*
* <p>The bytecode sequence of the method is represented
* by a <code>CodeAttribute</code> object.
*
* <p>The following code adds the default constructor to a class:
* of <code>int</code> type:
* <blockquote><pre>
* ClassFile cf = ...
* Bytecode code = new Bytecode(cf.getConstPool());
* code.addAload(0);
* code.addInvokespecial("java/lang/Object", MethodInfo.nameInit, "()V");
* code.addReturn(null);
* code.setMaxLocals(1);
*
* MethodInfo minfo = new MethodInfo(cf.getConstPool(), MethodInfo.nameInit, "()V");
* minfo.setCodeAttribute(code.toCodeAttribute());
* cf.addMethod(minfo);
* </pre></blockquote>
*
* @see #getCodeAttribute()
* @see CodeAttribute
* @see Bytecode
* @see javassist.CtMethod#getMethodInfo()
* @see javassist.CtConstructor#getMethodInfo()
*/
public class
MethodInfo {
ConstPool constPool;
int
accessFlags;
int
name;
String cachedName;
int
descriptor;
ArrayList attribute; // may be null
/**
* If this value is true, Javassist maintains a <code>StackMap</code> attribute
* generated by the <code>preverify</code> tool of J2ME (CLDC). The initial
* value of this field is <code>false</code>.
*/
public static boolean
doPreverify = false;
/**
* The name of constructors: <code><init></code>.
*/
public static final
String nameInit = "<init>";
/**
* The name of class initializer (static initializer):
* <code><clinit></code>.
*/
public static final
String nameClinit = "<clinit>";
private
MethodInfo(
ConstPool cp) {
constPool =
cp;
attribute = null;
}
/**
* Constructs a <code>method_info</code> structure. The initial value of
* <code>access_flags</code> is zero.
*
* @param cp
* a constant pool table
* @param methodname
* method name
* @param desc
* method descriptor
* @see Descriptor
*/
public
MethodInfo(
ConstPool cp,
String methodname,
String desc) {
this(
cp);
accessFlags = 0;
name =
cp.
addUtf8Info(
methodname);
cachedName =
methodname;
descriptor =
constPool.
addUtf8Info(
desc);
}
MethodInfo(
ConstPool cp,
DataInputStream in) throws
IOException {
this(
cp);
read(
in);
}
/**
* Constructs a copy of <code>method_info</code> structure. Class names
* appearing in the source <code>method_info</code> are renamed according
* to <code>classnameMap</code>.
*
* <p>
* Note: only <code>Code</code> and <code>Exceptions</code> attributes
* are copied from the source. The other attributes are ignored.
*
* @param cp
* a constant pool table
* @param methodname
* a method name
* @param src
* a source <code>method_info</code>
* @param classnameMap
* specifies pairs of replaced and substituted name.
* @see Descriptor
*/
public
MethodInfo(
ConstPool cp,
String methodname,
MethodInfo src,
Map classnameMap) throws
BadBytecode {
this(
cp);
read(
src,
methodname,
classnameMap);
}
/**
* Returns a string representation of the object.
*/
public
String toString() {
return
getName() + " " +
getDescriptor();
}
/**
* Copies all constant pool items to a given new constant pool
* and replaces the original items with the new ones.
* This is used for garbage collecting the items of removed fields
* and methods.
*
* @param cp the destination
*/
void
compact(
ConstPool cp) {
name =
cp.
addUtf8Info(
getName());
descriptor =
cp.
addUtf8Info(
getDescriptor());
attribute =
AttributeInfo.
copyAll(
attribute,
cp);
constPool =
cp;
}
void
prune(
ConstPool cp) {
ArrayList newAttributes = new
ArrayList();
AttributeInfo invisibleAnnotations
=
getAttribute(
AnnotationsAttribute.
invisibleTag);
if (
invisibleAnnotations != null) {
invisibleAnnotations =
invisibleAnnotations.
copy(
cp, null);
newAttributes.
add(
invisibleAnnotations);
}
AttributeInfo visibleAnnotations
=
getAttribute(
AnnotationsAttribute.
visibleTag);
if (
visibleAnnotations != null) {
visibleAnnotations =
visibleAnnotations.
copy(
cp, null);
newAttributes.
add(
visibleAnnotations);
}
AttributeInfo parameterInvisibleAnnotations
=
getAttribute(
ParameterAnnotationsAttribute.
invisibleTag);
if (
parameterInvisibleAnnotations != null) {
parameterInvisibleAnnotations =
parameterInvisibleAnnotations.
copy(
cp, null);
newAttributes.
add(
parameterInvisibleAnnotations);
}
AttributeInfo parameterVisibleAnnotations
=
getAttribute(
ParameterAnnotationsAttribute.
visibleTag);
if (
parameterVisibleAnnotations != null) {
parameterVisibleAnnotations =
parameterVisibleAnnotations.
copy(
cp, null);
newAttributes.
add(
parameterVisibleAnnotations);
}
AnnotationDefaultAttribute defaultAttribute
= (
AnnotationDefaultAttribute)
getAttribute(
AnnotationDefaultAttribute.
tag);
if (
defaultAttribute != null)
newAttributes.
add(
defaultAttribute);
ExceptionsAttribute ea =
getExceptionsAttribute();
if (
ea != null)
newAttributes.
add(
ea);
AttributeInfo signature
=
getAttribute(
SignatureAttribute.
tag);
if (
signature != null) {
signature =
signature.
copy(
cp, null);
newAttributes.
add(
signature);
}
attribute =
newAttributes;
name =
cp.
addUtf8Info(
getName());
descriptor =
cp.
addUtf8Info(
getDescriptor());
constPool =
cp;
}
/**
* Returns a method name.
*/
public
String getName() {
if (
cachedName == null)
cachedName =
constPool.
getUtf8Info(
name);
return
cachedName;
}
/**
* Sets a method name.
*/
public void
setName(
String newName) {
name =
constPool.
addUtf8Info(
newName);
cachedName =
newName;
}
/**
* Returns true if this is not a constructor or a class initializer (static
* initializer).
*/
public boolean
isMethod() {
String n =
getName();
return !
n.
equals(
nameInit) && !
n.
equals(
nameClinit);
}
/**
* Returns a constant pool table used by this method.
*/
public
ConstPool getConstPool() {
return
constPool;
}
/**
* Returns true if this is a constructor.
*/
public boolean
isConstructor() {
return
getName().
equals(
nameInit);
}
/**
* Returns true if this is a class initializer (static initializer).
*/
public boolean
isStaticInitializer() {
return
getName().
equals(
nameClinit);
}
/**
* Returns access flags.
*
* @see AccessFlag
*/
public int
getAccessFlags() {
return
accessFlags;
}
/**
* Sets access flags.
*
* @see AccessFlag
*/
public void
setAccessFlags(int
acc) {
accessFlags =
acc;
}
/**
* Returns a method descriptor.
*
* @see Descriptor
*/
public
String getDescriptor() {
return
constPool.
getUtf8Info(
descriptor);
}
/**
* Sets a method descriptor.
*
* @see Descriptor
*/
public void
setDescriptor(
String desc) {
if (!
desc.
equals(
getDescriptor()))
descriptor =
constPool.
addUtf8Info(
desc);
}
/**
* Returns all the attributes. The returned <code>List</code> object
* is shared with this object. If you add a new attribute to the list,
* the attribute is also added to the method represented by this
* object. If you remove an attribute from the list, it is also removed
* from the method.
*
* @return a list of <code>AttributeInfo</code> objects.
* @see AttributeInfo
*/
public
List getAttributes() {
if (
attribute == null)
attribute = new
ArrayList();
return
attribute;
}
/**
* Returns the attribute with the specified name. If it is not found, this
* method returns null.
*
* @param name attribute name
* @return an <code>AttributeInfo</code> object or null.
* @see #getAttributes()
*/
public
AttributeInfo getAttribute(
String name) {
return
AttributeInfo.
lookup(
attribute,
name);
}
/**
* Appends an attribute. If there is already an attribute with the same
* name, the new one substitutes for it.
*
* @see #getAttributes()
*/
public void
addAttribute(
AttributeInfo info) {
if (
attribute == null)
attribute = new
ArrayList();
AttributeInfo.
remove(
attribute,
info.
getName());
attribute.
add(
info);
}
/**
* Returns an Exceptions attribute.
*
* @return an Exceptions attribute or null if it is not specified.
*/
public
ExceptionsAttribute getExceptionsAttribute() {
AttributeInfo info =
AttributeInfo.
lookup(
attribute,
ExceptionsAttribute.
tag);
return (
ExceptionsAttribute)
info;
}
/**
* Returns a Code attribute.
*
* @return a Code attribute or null if it is not specified.
*/
public
CodeAttribute getCodeAttribute() {
AttributeInfo info =
AttributeInfo.
lookup(
attribute,
CodeAttribute.
tag);
return (
CodeAttribute)
info;
}
/**
* Removes an Exception attribute.
*/
public void
removeExceptionsAttribute() {
AttributeInfo.
remove(
attribute,
ExceptionsAttribute.
tag);
}
/**
* Adds an Exception attribute.
*
* <p>
* The added attribute must share the same constant pool table as this
* <code>method_info</code> structure.
*/
public void
setExceptionsAttribute(
ExceptionsAttribute cattr) {
removeExceptionsAttribute();
if (
attribute == null)
attribute = new
ArrayList();
attribute.
add(
cattr);
}
/**
* Removes a Code attribute.
*/
public void
removeCodeAttribute() {
AttributeInfo.
remove(
attribute,
CodeAttribute.
tag);
}
/**
* Adds a Code attribute.
*
* <p>
* The added attribute must share the same constant pool table as this
* <code>method_info</code> structure.
*/
public void
setCodeAttribute(
CodeAttribute cattr) {
removeCodeAttribute();
if (
attribute == null)
attribute = new
ArrayList();
attribute.
add(
cattr);
}
/**
* Rebuilds a stack map table if the class file is for Java 6
* or later. Java 5 or older Java VMs do not recognize a stack
* map table. If <code>doPreverify</code> is true, this method
* also rebuilds a stack map for J2ME (CLDC).
*
* @param pool used for making type hierarchy.
* @param cf rebuild if this class file is for Java 6 or later.
* @see #rebuildStackMap(ClassPool)
* @see #rebuildStackMapForME(ClassPool)
* @see #doPreverify
* @since 3.6
*/
public void
rebuildStackMapIf6(
ClassPool pool,
ClassFile cf)
throws
BadBytecode
{
if (
cf.
getMajorVersion() >=
ClassFile.
JAVA_6)
rebuildStackMap(
pool);
if (
doPreverify)
rebuildStackMapForME(
pool);
}
/**
* Rebuilds a stack map table. If no stack map table is included,
* a new one is created. If this <code>MethodInfo</code> does not
* include a code attribute, nothing happens.
*
* @param pool used for making type hierarchy.
* @see StackMapTable
* @since 3.6
*/
public void
rebuildStackMap(
ClassPool pool) throws
BadBytecode {
CodeAttribute ca =
getCodeAttribute();
if (
ca != null) {
StackMapTable smt =
MapMaker.
make(
pool, this);
ca.
setAttribute(
smt);
}
}
/**
* Rebuilds a stack map table for J2ME (CLDC). If no stack map table is included,
* a new one is created. If this <code>MethodInfo</code> does not
* include a code attribute, nothing happens.
*
* @param pool used for making type hierarchy.
* @see StackMap
* @since 3.12
*/
public void
rebuildStackMapForME(
ClassPool pool) throws
BadBytecode {
CodeAttribute ca =
getCodeAttribute();
if (
ca != null) {
StackMap sm =
MapMaker.
make2(
pool, this);
ca.
setAttribute(
sm);
}
}
/**
* Returns the line number of the source line corresponding to the specified
* bytecode contained in this method.
*
* @param pos
* the position of the bytecode (>= 0). an index into the code
* array.
* @return -1 if this information is not available.
*/
public int
getLineNumber(int
pos) {
CodeAttribute ca =
getCodeAttribute();
if (
ca == null)
return -1;
LineNumberAttribute ainfo = (
LineNumberAttribute)
ca
.
getAttribute(
LineNumberAttribute.
tag);
if (
ainfo == null)
return -1;
return
ainfo.
toLineNumber(
pos);
}
/**
* Changes a super constructor called by this constructor.
*
* <p>
* This method modifies a call to <code>super()</code>, which should be
* at the head of a constructor body, so that a constructor in a different
* super class is called. This method does not change actual parameters.
* Hence the new super class must have a constructor with the same signature
* as the original one.
*
* <p>
* This method should be called when the super class of the class declaring
* this method is changed.
*
* <p>
* This method does not perform anything unless this <code>MethodInfo</code>
* represents a constructor.
*
* @param superclass
* the new super class
*/
public void
setSuperclass(
String superclass) throws
BadBytecode {
if (!
isConstructor())
return;
CodeAttribute ca =
getCodeAttribute();
byte[]
code =
ca.
getCode();
CodeIterator iterator =
ca.
iterator();
int
pos =
iterator.
skipSuperConstructor();
if (
pos >= 0) { // not this()
ConstPool cp =
constPool;
int
mref =
ByteArray.
readU16bit(
code,
pos + 1);
int
nt =
cp.
getMethodrefNameAndType(
mref);
int
sc =
cp.
addClassInfo(
superclass);
int
mref2 =
cp.
addMethodrefInfo(
sc,
nt);
ByteArray.
write16bit(
mref2,
code,
pos + 1);
}
}
private void
read(
MethodInfo src,
String methodname,
Map classnames)
throws
BadBytecode {
ConstPool destCp =
constPool;
accessFlags =
src.
accessFlags;
name =
destCp.
addUtf8Info(
methodname);
cachedName =
methodname;
ConstPool srcCp =
src.
constPool;
String desc =
srcCp.
getUtf8Info(
src.
descriptor);
String desc2 =
Descriptor.
rename(
desc,
classnames);
descriptor =
destCp.
addUtf8Info(
desc2);
attribute = new
ArrayList();
ExceptionsAttribute eattr =
src.
getExceptionsAttribute();
if (
eattr != null)
attribute.
add(
eattr.
copy(
destCp,
classnames));
CodeAttribute cattr =
src.
getCodeAttribute();
if (
cattr != null)
attribute.
add(
cattr.
copy(
destCp,
classnames));
}
private void
read(
DataInputStream in) throws
IOException {
accessFlags =
in.
readUnsignedShort();
name =
in.
readUnsignedShort();
descriptor =
in.
readUnsignedShort();
int
n =
in.
readUnsignedShort();
attribute = new
ArrayList();
for (int
i = 0;
i <
n; ++
i)
attribute.
add(
AttributeInfo.
read(
constPool,
in));
}
void
write(
DataOutputStream out) throws
IOException {
out.
writeShort(
accessFlags);
out.
writeShort(
name);
out.
writeShort(
descriptor);
if (
attribute == null)
out.
writeShort(0);
else {
out.
writeShort(
attribute.
size());
AttributeInfo.
writeAll(
attribute,
out);
}
}
}