org.testifyprojects.objenesis.instantiator.util.ClassDefinitionUtils Maven / Gradle / Ivy
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/**
* Copyright 2006-2017 the original author or authors.
*
* 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 org.testifyprojects.objenesis.instantiator.util;
import org.testifyprojects.objenesis.ObjenesisException;
import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import sun.misc.Unsafe;
/**
* Helper class for ProxyObjectInstantiator. We can see the details of a class specification
* here
*
* @author Henri Tremblay
*/
public final class ClassDefinitionUtils {
public static final byte OPS_aload_0 = 42;
public static final byte OPS_invokespecial = -73; // has two bytes parameters
public static final byte OPS_return = -79;
public static final byte OPS_new = -69;
public static final byte OPS_dup = 89;
public static final byte OPS_areturn = -80;
public static final int CONSTANT_Utf8 = 1;
public static final int CONSTANT_Integer = 3;
public static final int CONSTANT_Float = 4;
public static final int CONSTANT_Long = 5;
public static final int CONSTANT_Double = 6;
public static final int CONSTANT_Class = 7;
public static final int CONSTANT_String = 8;
public static final int CONSTANT_Fieldref = 9;
public static final int CONSTANT_Methodref = 10;
public static final int CONSTANT_InterfaceMethodref = 11;
public static final int CONSTANT_NameAndType = 12;
public static final int CONSTANT_MethodHandle = 15;
public static final int CONSTANT_MethodType = 16;
public static final int CONSTANT_InvokeDynamic = 18;
public static final int ACC_PUBLIC = 0x0001; // Declared public; may be accessed from outside its package.
public static final int ACC_FINAL = 0x0010; // Declared final; no subclasses allowed.
public static final int ACC_SUPER = 0x0020; // Treat superclass methods specially when invoked by the invokespecial instruction.
public static final int ACC_INTERFACE = 0x0200; // Is an interface, not a class.
public static final int ACC_ABSTRACT = 0x0400; // Declared abstract; must not be instantiated.
public static final int ACC_SYNTHETIC = 0x1000; // Declared synthetic; not present in the source code.
public static final int ACC_ANNOTATION = 0x2000; // Declared as an annotation type.
public static final int ACC_ENUM = 0x4000; // Declared as an enum type.
public static final byte[] MAGIC = { (byte) 0xca, (byte) 0xfe, (byte) 0xba, (byte) 0xbe };
public static final byte[] VERSION = { (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x31 }; // minor_version, major_version (Java 5)
private ClassDefinitionUtils() { }
// private static Method DEFINE_CLASS;
private static final ProtectionDomain PROTECTION_DOMAIN;
static {
PROTECTION_DOMAIN = AccessController.doPrivileged(new PrivilegedAction() {
public ProtectionDomain run() {
return ClassDefinitionUtils.class.getProtectionDomain();
}
});
}
/**
* Define a class in the provided class loader from the array of bytes. Inspired by cglib
* ReflectUtils.defineClass
*
* @param type of the class returned
* @param className class name in the format org.testifyprojects.objenesis.MyClass
* @param b bytes representing the class
* @param loader the class loader where the class will be loaded
* @return the newly loaded class
* @throws Exception whenever something goes wrong
*/
@SuppressWarnings("unchecked")
public static Class defineClass(String className, byte[] b, ClassLoader loader)
throws Exception {
Class c = (Class) UnsafeUtils.getUnsafe().defineClass(className, b, 0, b.length, loader, PROTECTION_DOMAIN);
// Force static initializers to run.
Class.forName(className, true, loader);
return c;
}
/**
* Read the bytes of a class from the classpath
*
* @param className full class name including the package
* @return the bytes representing the class
* @throws IllegalArgumentException if the class is longer than 2500 bytes
* @throws IOException if we fail to read the class
*/
public static byte[] readClass(String className) throws IOException {
// convert to a resource
className = classNameToResource(className);
byte[] b = new byte[2500]; // I'm assuming that I'm reading class that are not too big
int length;
InputStream in = ClassDefinitionUtils.class.getClassLoader().getResourceAsStream(className);
try {
length = in.read(b);
}
finally {
in.close();
}
if(length >= 2500) {
throw new IllegalArgumentException("The class is longer that 2500 bytes which is currently unsupported");
}
byte[] copy = new byte[length];
System.arraycopy(b, 0, copy, 0, length);
return copy;
}
/**
* Write all class bytes to a file.
*
* @param fileName file where the bytes will be written
* @param bytes bytes representing the class
* @throws IOException if we fail to write the class
*/
public static void writeClass(String fileName, byte[] bytes) throws IOException {
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(fileName));
try {
out.write(bytes);
}
finally {
out.close();
}
}
/**
* Will convert a class name to its name in the class definition format (e.g {@code org.testifyprojects.objenesis.EmptyClass}
* becomes {@code org.testifyprojects.objenesis/EmptyClass})
*
* @param className full class name including the package
* @return the internal name
*/
public static String classNameToInternalClassName(String className) {
return className.replace('.', '/');
}
/**
* Will convert a class name to its class loader resource name (e.g {@code org.testifyprojects.objenesis.EmptyClass}
* becomes {@code org.testifyprojects.objenesis/EmptyClass.class})
*
* @param className full class name including the package
* @return the resource name
*/
public static String classNameToResource(String className) {
return classNameToInternalClassName(className) + ".class";
}
/**
* Check if this class already exists in the class loader and return it if it does
*
* @param type of the class returned
* @param classLoader Class loader where to search the class
* @param className Class name with full path
* @return the class if it already exists or null
*/
@SuppressWarnings("unchecked")
public static Class getExistingClass(ClassLoader classLoader, String className) {
try {
return (Class) Class.forName(className, true, classLoader);
}
catch (ClassNotFoundException e) {
return null;
}
}
}