com.github.drinkjava2.cglib.transform.impl.InterceptFieldTransformer Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of jsqlbox Show documentation
Show all versions of jsqlbox Show documentation
jSqlBox is a full function DAO tool
/*
* Copyright 2003 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.drinkjava2.cglib.transform.impl;
import com.github.drinkjava2.asm.Label;
import com.github.drinkjava2.asm.Type;
import com.github.drinkjava2.cglib.core.CodeEmitter;
import com.github.drinkjava2.cglib.core.Constants;
import com.github.drinkjava2.cglib.core.Local;
import com.github.drinkjava2.cglib.core.Signature;
import com.github.drinkjava2.cglib.core.TypeUtils;
import com.github.drinkjava2.cglib.transform.ClassEmitterTransformer;
/**
* @author Juozas Baliuka, Chris Nokleberg
*/
public class InterceptFieldTransformer extends ClassEmitterTransformer {
private static final String CALLBACK_FIELD = "$CGLIB_READ_WRITE_CALLBACK";
private static final Type CALLBACK =
TypeUtils.parseType("com.github.drinkjava2.cglib.transform.impl.InterceptFieldCallback");
private static final Type ENABLED =
TypeUtils.parseType("com.github.drinkjava2.cglib.transform.impl.InterceptFieldEnabled");
private static final Signature ENABLED_SET =
new Signature("setInterceptFieldCallback", Type.VOID_TYPE, new Type[]{ CALLBACK });
private static final Signature ENABLED_GET =
new Signature("getInterceptFieldCallback", CALLBACK, new Type[0]);
private InterceptFieldFilter filter;
public InterceptFieldTransformer(InterceptFieldFilter filter) {
this.filter = filter;
}
public void begin_class(int version, int access, String className, Type superType, Type[] interfaces, String sourceFile) {
if (!TypeUtils.isInterface(access)) {
super.begin_class(version, access, className, superType, TypeUtils.add(interfaces, ENABLED), sourceFile);
super.declare_field(Constants.ACC_PRIVATE | Constants.ACC_TRANSIENT,
CALLBACK_FIELD,
CALLBACK,
null);
CodeEmitter e;
e = super.begin_method(Constants.ACC_PUBLIC, ENABLED_GET, null);
e.load_this();
e.getfield(CALLBACK_FIELD);
e.return_value();
e.end_method();
e = super.begin_method(Constants.ACC_PUBLIC, ENABLED_SET, null);
e.load_this();
e.load_arg(0);
e.putfield(CALLBACK_FIELD);
e.return_value();
e.end_method();
} else {
super.begin_class(version, access, className, superType, interfaces, sourceFile);
}
}
public void declare_field(int access, String name, Type type, Object value) {
super.declare_field(access, name, type, value);
if (!TypeUtils.isStatic(access)) {
if (filter.acceptRead(getClassType(), name)) {
addReadMethod(name, type);
}
if (filter.acceptWrite(getClassType(), name)) {
addWriteMethod(name, type);
}
}
}
private void addReadMethod(String name, Type type) {
CodeEmitter e = super.begin_method(Constants.ACC_PUBLIC,
readMethodSig(name, type.getDescriptor()),
null);
e.load_this();
e.getfield(name);
e.load_this();
e.invoke_interface(ENABLED,ENABLED_GET);
Label intercept = e.make_label();
e.ifnonnull(intercept);
e.return_value();
e.mark(intercept);
Local result = e.make_local(type);
e.store_local(result);
e.load_this();
e.invoke_interface(ENABLED,ENABLED_GET);
e.load_this();
e.push(name);
e.load_local(result);
e.invoke_interface(CALLBACK, readCallbackSig(type));
if (!TypeUtils.isPrimitive(type)) {
e.checkcast(type);
}
e.return_value();
e.end_method();
}
private void addWriteMethod(String name, Type type) {
CodeEmitter e = super.begin_method(Constants.ACC_PUBLIC,
writeMethodSig(name, type.getDescriptor()),
null);
e.load_this();
e.dup();
e.invoke_interface(ENABLED,ENABLED_GET);
Label skip = e.make_label();
e.ifnull(skip);
e.load_this();
e.invoke_interface(ENABLED,ENABLED_GET);
e.load_this();
e.push(name);
e.load_this();
e.getfield(name);
e.load_arg(0);
e.invoke_interface(CALLBACK, writeCallbackSig(type));
if (!TypeUtils.isPrimitive(type)) {
e.checkcast(type);
}
Label go = e.make_label();
e.goTo(go);
e.mark(skip);
e.load_arg(0);
e.mark(go);
e.putfield(name);
e.return_value();
e.end_method();
}
public CodeEmitter begin_method(int access, Signature sig, Type[] exceptions) {
return new CodeEmitter(super.begin_method(access, sig, exceptions)) {
public void visitFieldInsn(int opcode, String owner, String name, String desc) {
Type towner = TypeUtils.fromInternalName(owner);
switch (opcode) {
case Constants.GETFIELD:
if (filter.acceptRead(towner, name)) {
helper(towner, readMethodSig(name, desc));
return;
}
break;
case Constants.PUTFIELD:
if (filter.acceptWrite(towner, name)) {
helper(towner, writeMethodSig(name, desc));
return;
}
break;
}
super.visitFieldInsn(opcode, owner, name, desc);
}
private void helper(Type owner, Signature sig) {
invoke_virtual(owner, sig);
}
};
}
private static Signature readMethodSig(String name, String desc) {
return new Signature("$cglib_read_" + name, "()" + desc);
}
private static Signature writeMethodSig(String name, String desc) {
return new Signature("$cglib_write_" + name, "(" + desc + ")V");
}
private static Signature readCallbackSig(Type type) {
Type remap = remap(type);
return new Signature("read" + callbackName(remap),
remap,
new Type[]{ Constants.TYPE_OBJECT,
Constants.TYPE_STRING,
remap });
}
private static Signature writeCallbackSig(Type type) {
Type remap = remap(type);
return new Signature("write" + callbackName(remap),
remap,
new Type[]{ Constants.TYPE_OBJECT,
Constants.TYPE_STRING,
remap,
remap });
}
private static Type remap(Type type) {
switch (type.getSort()) {
case Type.OBJECT:
case Type.ARRAY:
return Constants.TYPE_OBJECT;
default:
return type;
}
}
private static String callbackName(Type type) {
return (type == Constants.TYPE_OBJECT) ?
"Object" :
TypeUtils.upperFirst(TypeUtils.getClassName(type));
}
}