aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.xml.internal.bind.v2.runtime.reflect.opt;
aoqi@0: 
aoqi@0: import java.lang.reflect.InvocationTargetException;
aoqi@0: import java.lang.reflect.Method;
aoqi@0: import java.lang.ref.WeakReference;
aoqi@0: import java.security.AccessController;
aoqi@0: import java.security.PrivilegedAction;
aoqi@0: import java.util.concurrent.locks.Lock;
aoqi@0: import java.util.concurrent.locks.ReentrantReadWriteLock;
aoqi@0: import java.util.HashMap;
aoqi@0: import java.util.Map;
aoqi@0: import java.util.WeakHashMap;
aoqi@0: import java.util.logging.Level;
aoqi@0: import java.util.logging.Logger;
aoqi@0: 
aoqi@0: import com.sun.xml.internal.bind.Util;
aoqi@0: import com.sun.xml.internal.bind.v2.runtime.reflect.Accessor;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * A {@link ClassLoader} used to "inject" optimized accessor classes
aoqi@0:  * into the VM.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * Its parent class loader needs to be set to the one that can see the user
aoqi@0:  * class.
aoqi@0:  *
aoqi@0:  * @author Kohsuke Kawaguchi
aoqi@0:  */
aoqi@0: final class Injector {
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * {@link Injector}s keyed by their parent {@link ClassLoader}.
aoqi@0:      *
aoqi@0:      * We only need one injector per one user class loader.
aoqi@0:      */
aoqi@0:     private static final ReentrantReadWriteLock irwl = new ReentrantReadWriteLock();
aoqi@0:     private static final Lock ir = irwl.readLock();
aoqi@0:     private static final Lock iw = irwl.writeLock();
aoqi@0:     private static final Map<ClassLoader, WeakReference<Injector>> injectors =
aoqi@0:             new WeakHashMap<ClassLoader, WeakReference<Injector>>();
aoqi@0:     private static final Logger logger = Util.getClassLogger();
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Injects a new class into the given class loader.
aoqi@0:      *
aoqi@0:      * @return null
aoqi@0:      *      if it fails to inject.
aoqi@0:      */
aoqi@0:     static Class inject(ClassLoader cl, String className, byte[] image) {
aoqi@0:         Injector injector = get(cl);
aoqi@0:         if (injector != null) {
aoqi@0:             return injector.inject(className, image);
aoqi@0:         } else {
aoqi@0:             return null;
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Returns the already injected class, or null.
aoqi@0:      */
aoqi@0:     static Class find(ClassLoader cl, String className) {
aoqi@0:         Injector injector = get(cl);
aoqi@0:         if (injector != null) {
aoqi@0:             return injector.find(className);
aoqi@0:         } else {
aoqi@0:             return null;
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     /**
aoqi@0:      * Gets or creates an {@link Injector} for the given class loader.
aoqi@0:      *
aoqi@0:      * @return null
aoqi@0:      *      if it fails.
aoqi@0:      */
aoqi@0:     private static Injector get(ClassLoader cl) {
aoqi@0:         Injector injector = null;
aoqi@0:         WeakReference<Injector> wr;
aoqi@0:         ir.lock();
aoqi@0:         try {
aoqi@0:             wr = injectors.get(cl);
aoqi@0:         } finally {
aoqi@0:             ir.unlock();
aoqi@0:         }
aoqi@0:         if (wr != null) {
aoqi@0:             injector = wr.get();
aoqi@0:         }
aoqi@0:         if (injector == null) {
aoqi@0:             try {
aoqi@0:                 wr = new WeakReference<Injector>(injector = new Injector(cl));
aoqi@0:                 iw.lock();
aoqi@0:                 try {
aoqi@0:                     if (!injectors.containsKey(cl)) {
aoqi@0:                         injectors.put(cl, wr);
aoqi@0:                     }
aoqi@0:                 } finally {
aoqi@0:                     iw.unlock();
aoqi@0:                 }
aoqi@0:             } catch (SecurityException e) {
aoqi@0:                 logger.log(Level.FINE, "Unable to set up a back-door for the injector", e);
aoqi@0:                 return null;
aoqi@0:             }
aoqi@0:         }
aoqi@0:         return injector;
aoqi@0:     }
aoqi@0:     /**
aoqi@0:      * Injected classes keyed by their names.
aoqi@0:      */
aoqi@0:     private final Map<String, Class> classes = new HashMap<String, Class>();
aoqi@0:     private final ReentrantReadWriteLock rwl = new ReentrantReadWriteLock();
aoqi@0:     private final Lock r = rwl.readLock();
aoqi@0:     private final Lock w = rwl.writeLock();
aoqi@0:     private final ClassLoader parent;
aoqi@0:     /**
aoqi@0:      * True if this injector is capable of injecting accessors.
aoqi@0:      * False otherwise, which happens if this classloader can't see {@link Accessor}.
aoqi@0:      */
aoqi@0:     private final boolean loadable;
aoqi@0:     private static final Method defineClass;
aoqi@0:     private static final Method resolveClass;
aoqi@0:     private static final Method findLoadedClass;
aoqi@0: 
aoqi@0:     static {
aoqi@0:         try {
aoqi@0:             defineClass = ClassLoader.class.getDeclaredMethod("defineClass", String.class, byte[].class, Integer.TYPE, Integer.TYPE);
aoqi@0:             resolveClass = ClassLoader.class.getDeclaredMethod("resolveClass", Class.class);
aoqi@0:             findLoadedClass = ClassLoader.class.getDeclaredMethod("findLoadedClass", String.class);
aoqi@0:         } catch (NoSuchMethodException e) {
aoqi@0:             // impossible
aoqi@0:             throw new NoSuchMethodError(e.getMessage());
aoqi@0:         }
aoqi@0:         AccessController.doPrivileged(new PrivilegedAction<Void>() {
aoqi@0: 
aoqi@0:             @Override
aoqi@0:             public Void run() {
aoqi@0:                 // TODO: check security implication
aoqi@0:                 // do these setAccessible allow anyone to call these methods freely?s
aoqi@0:                 defineClass.setAccessible(true);
aoqi@0:                 resolveClass.setAccessible(true);
aoqi@0:                 findLoadedClass.setAccessible(true);
aoqi@0:                 return null;
aoqi@0:             }
aoqi@0:         });
aoqi@0:     }
aoqi@0: 
aoqi@0:     private Injector(ClassLoader parent) {
aoqi@0:         this.parent = parent;
aoqi@0:         assert parent != null;
aoqi@0: 
aoqi@0:         boolean loadableCheck = false;
aoqi@0: 
aoqi@0:         try {
aoqi@0:             loadableCheck = parent.loadClass(Accessor.class.getName()) == Accessor.class;
aoqi@0:         } catch (ClassNotFoundException e) {
aoqi@0:             // not loadable
aoqi@0:         }
aoqi@0: 
aoqi@0:         this.loadable = loadableCheck;
aoqi@0:     }
aoqi@0: 
aoqi@0:     @SuppressWarnings("LockAcquiredButNotSafelyReleased")
aoqi@0:     private Class inject(String className, byte[] image) {
aoqi@0:         if (!loadable) // this injector cannot inject anything
aoqi@0:         {
aoqi@0:             return null;
aoqi@0:         }
aoqi@0: 
aoqi@0:         boolean wlocked = false;
aoqi@0:         boolean rlocked = false;
aoqi@0:         try {
aoqi@0: 
aoqi@0:             r.lock();
aoqi@0:             rlocked = true;
aoqi@0: 
aoqi@0:             Class c = classes.get(className);
aoqi@0: 
aoqi@0:             // Unlock now during the findLoadedClass process to avoid
aoqi@0:             // deadlocks
aoqi@0:             r.unlock();
aoqi@0:             rlocked = false;
aoqi@0: 
aoqi@0:             //find loaded class from classloader
aoqi@0:             if (c == null) {
aoqi@0: 
aoqi@0:                 try {
aoqi@0:                     c = (Class) findLoadedClass.invoke(parent, className.replace('/', '.'));
aoqi@0:                 } catch (IllegalArgumentException e) {
aoqi@0:                     logger.log(Level.FINE, "Unable to find " + className, e);
aoqi@0:                 } catch (IllegalAccessException e) {
aoqi@0:                     logger.log(Level.FINE, "Unable to find " + className, e);
aoqi@0:                 } catch (InvocationTargetException e) {
aoqi@0:                     Throwable t = e.getTargetException();
aoqi@0:                     logger.log(Level.FINE, "Unable to find " + className, t);
aoqi@0:                 }
aoqi@0: 
aoqi@0:                 if (c != null) {
aoqi@0: 
aoqi@0:                     w.lock();
aoqi@0:                     wlocked = true;
aoqi@0: 
aoqi@0:                     classes.put(className, c);
aoqi@0: 
aoqi@0:                     w.unlock();
aoqi@0:                     wlocked = false;
aoqi@0: 
aoqi@0:                     return c;
aoqi@0:                 }
aoqi@0:             }
aoqi@0: 
aoqi@0:             if (c == null) {
aoqi@0: 
aoqi@0:                 r.lock();
aoqi@0:                 rlocked = true;
aoqi@0: 
aoqi@0:                 c = classes.get(className);
aoqi@0: 
aoqi@0:                 // Unlock now during the define/resolve process to avoid
aoqi@0:                 // deadlocks
aoqi@0:                 r.unlock();
aoqi@0:                 rlocked = false;
aoqi@0: 
aoqi@0:                 if (c == null) {
aoqi@0: 
aoqi@0:                     // we need to inject a class into the
aoqi@0:                     try {
aoqi@0:                         c = (Class) defineClass.invoke(parent, className.replace('/', '.'), image, 0, image.length);
aoqi@0:                         resolveClass.invoke(parent, c);
aoqi@0:                     } catch (IllegalAccessException e) {
aoqi@0:                         logger.log(Level.FINE, "Unable to inject " + className, e);
aoqi@0:                         return null;
aoqi@0:                     } catch (InvocationTargetException e) {
aoqi@0:                         Throwable t = e.getTargetException();
aoqi@0:                         if (t instanceof LinkageError) {
aoqi@0:                             logger.log(Level.FINE, "duplicate class definition bug occured? Please report this : " + className, t);
aoqi@0:                         } else {
aoqi@0:                             logger.log(Level.FINE, "Unable to inject " + className, t);
aoqi@0:                         }
aoqi@0:                         return null;
aoqi@0:                     } catch (SecurityException e) {
aoqi@0:                         logger.log(Level.FINE, "Unable to inject " + className, e);
aoqi@0:                         return null;
aoqi@0:                     } catch (LinkageError e) {
aoqi@0:                         logger.log(Level.FINE, "Unable to inject " + className, e);
aoqi@0:                         return null;
aoqi@0:                     }
aoqi@0: 
aoqi@0:                     w.lock();
aoqi@0:                     wlocked = true;
aoqi@0: 
aoqi@0:                     // During the time we were unlocked, we could have tried to
aoqi@0:                     // load the class from more than one thread. Check now to see
aoqi@0:                     // if someone else beat us to registering this class
aoqi@0:                     if (!classes.containsKey(className)) {
aoqi@0:                         classes.put(className, c);
aoqi@0:                     }
aoqi@0: 
aoqi@0:                     w.unlock();
aoqi@0:                     wlocked = false;
aoqi@0:                 }
aoqi@0:             }
aoqi@0:             return c;
aoqi@0:         } finally {
aoqi@0:             if (rlocked) {
aoqi@0:                 r.unlock();
aoqi@0:             }
aoqi@0:             if (wlocked) {
aoqi@0:                 w.unlock();
aoqi@0:             }
aoqi@0:         }
aoqi@0:     }
aoqi@0: 
aoqi@0:     private Class find(String className) {
aoqi@0:         r.lock();
aoqi@0:         try {
aoqi@0:             return classes.get(className);
aoqi@0:         } finally {
aoqi@0:             r.unlock();
aoqi@0:         }
aoqi@0:     }
aoqi@0: }