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/*
* Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import java.util.Set;
import java.util.Vector;
import jdk.internal.org.objectweb.asm.*;
public class BogoLoader extends ClassLoader {
static interface VisitorMaker {
ClassVisitor make(ClassVisitor visitor);
}
/**
* Use this property to verify that the desired classloading is happening.
*/
private final boolean verbose = Boolean.getBoolean("bogoloader.verbose");
/**
* Use this property to disable replacement for testing purposes.
*/
private final boolean noReplace = Boolean.getBoolean("bogoloader.noreplace");
/**
* Set of class names that should be loaded with this loader.
* Others are loaded with the system class loader, except for those
* that are transformed.
*/
private Set<String> nonSystem;
/**
* Map from class names to a bytecode transformer factory.
*/
private Map<String, VisitorMaker> replaced;
/**
* Keep track (not terribly efficiently) of which classes have already
* been loaded by this class loader.
*/
private final Vector<String> history = new Vector<String>();
private boolean useSystemLoader(String name) {
return ! nonSystem.contains(name) && ! replaced.containsKey(name);
}
public BogoLoader(Set<String> non_system, Map<String, VisitorMaker> replaced) {
super(Thread.currentThread().getContextClassLoader());
this.nonSystem = non_system;
this.replaced = replaced;
}
private byte[] readResource(String className) throws IOException {
return readResource(className, "class");
}
private byte[] readResource(String className, String suffix) throws IOException {
// Note to the unwary -- "/" works on Windows, leave it alone.
String fileName = className.replace('.', '/') + "." + suffix;
InputStream origStream = getResourceAsStream(fileName);
if (origStream == null) {
throw new IOException("Resource not found : " + fileName);
}
BufferedInputStream stream = new java.io.BufferedInputStream(origStream);
byte[] data = new byte[stream.available()];
int how_many = stream.read(data);
// Really ought to deal with the corner cases of stream.available()
return data;
}
protected byte[] getClass(String name) throws ClassNotFoundException,
IOException {
return readResource(name, "class");
}
/**
* Loads the named class from the system class loader unless
* the name appears in either replaced or nonSystem.
* nonSystem classes are loaded into this classloader,
* and replaced classes get their content from the specified array
* of bytes (and are also loaded into this classloader).
*/
protected Class<?> loadClass(String name, boolean resolve)
throws ClassNotFoundException {
Class<?> clazz;
if (history.contains(name)) {
Class<?> c = this.findLoadedClass(name);
return c;
}
if (useSystemLoader(name)) {
clazz = findSystemClass(name);
if (verbose) System.err.println("Loading system class " + name);
} else {
history.add(name);
try {
if (verbose) {
System.err.println("Loading classloader class " + name);
}
byte[] classData = getClass(name);;
boolean expanded = false;
if (!noReplace && replaced.containsKey(name)) {
if (verbose) {
System.err.println("Replacing class " + name);
}
ClassReader cr = new ClassReader(classData);
ClassWriter cw = new ClassWriter(0);
VisitorMaker vm = replaced.get(name);
cr.accept(vm.make(cw), 0);
classData = cw.toByteArray();
}
clazz = defineClass(name, classData, 0, classData.length);
} catch (java.io.EOFException ioe) {
throw new ClassNotFoundException(
"IO Exception in reading class : " + name + " ", ioe);
} catch (ClassFormatError ioe) {
throw new ClassNotFoundException(
"ClassFormatError in reading class file: ", ioe);
} catch (IOException ioe) {
throw new ClassNotFoundException(
"IO Exception in reading class file: ", ioe);
}
}
if (clazz == null) {
throw new ClassNotFoundException(name);
}
if (resolve) {
resolveClass(clazz);
}
return clazz;
}
}
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