diff -r d382dacfd73f -r 9ee9b36adb53 rt/emul/compact/src/main/java/org/apidesign/bck2brwsr/emul/reflect/ProxyImpl.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/rt/emul/compact/src/main/java/org/apidesign/bck2brwsr/emul/reflect/ProxyImpl.java Mon Oct 21 14:34:12 2013 +0200 @@ -0,0 +1,1620 @@ +/* + * Copyright (c) 1999, 2010, 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. Oracle designates this + * particular file as subject to the "Classpath" exception as provided + * by Oracle in the LICENSE file that accompanied this code. + * + * 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. + */ + +package org.apidesign.bck2brwsr.emul.reflect; + +import java.io.ByteArrayOutputStream; +import java.io.DataOutputStream; +import java.io.IOException; +import java.io.OutputStream; +import java.lang.ref.Reference; +import java.lang.ref.WeakReference; +import java.lang.reflect.Array; +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.lang.reflect.Modifier; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.LinkedList; +import java.util.Map; +import java.util.Set; +import java.util.List; +import java.util.ListIterator; +import java.util.WeakHashMap; +import org.apidesign.bck2brwsr.core.JavaScriptBody; +import org.apidesign.bck2brwsr.emul.reflect.MethodImpl; + +/** + * {@code Proxy} provides static methods for creating dynamic proxy + * classes and instances, and it is also the superclass of all + * dynamic proxy classes created by those methods. + * + *

To create a proxy for some interface {@code Foo}: + * 

+ *     InvocationHandler handler = new MyInvocationHandler(...);
+ *     Class proxyClass = Proxy.getProxyClass(
+ *         Foo.class.getClassLoader(), new Class[] { Foo.class });
+ *     Foo f = (Foo) proxyClass.
+ *         getConstructor(new Class[] { InvocationHandler.class }).
+ *         newInstance(new Object[] { handler });
+ *
+ * or more simply: + * 
+ *     Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
+ *                                          new Class[] { Foo.class },
+ *                                          handler);
+ *
+ * + *

A dynamic proxy class (simply referred to as a proxy + * class below) is a class that implements a list of interfaces + * specified at runtime when the class is created, with behavior as + * described below. + * + * A proxy interface is such an interface that is implemented + * by a proxy class. + * + * A proxy instance is an instance of a proxy class. + * + * Each proxy instance has an associated invocation handler + * object, which implements the interface {@link InvocationHandler}. + * A method invocation on a proxy instance through one of its proxy + * interfaces will be dispatched to the {@link InvocationHandler#invoke + * invoke} method of the instance's invocation handler, passing the proxy + * instance, a {@code java.lang.reflect.Method} object identifying + * the method that was invoked, and an array of type {@code Object} + * containing the arguments. The invocation handler processes the + * encoded method invocation as appropriate and the result that it + * returns will be returned as the result of the method invocation on + * the proxy instance. + * + *

A proxy class has the following properties: + * + *

+ * + *

A proxy instance has the following properties: + * + *

+ * + *

Methods Duplicated in Multiple Proxy Interfaces

+ * + *

When two or more interfaces of a proxy class contain a method with + * the same name and parameter signature, the order of the proxy class's + * interfaces becomes significant. When such a duplicate method + * is invoked on a proxy instance, the {@code Method} object passed + * to the invocation handler will not necessarily be the one whose + * declaring class is assignable from the reference type of the interface + * that the proxy's method was invoked through. This limitation exists + * because the corresponding method implementation in the generated proxy + * class cannot determine which interface it was invoked through. + * Therefore, when a duplicate method is invoked on a proxy instance, + * the {@code Method} object for the method in the foremost interface + * that contains the method (either directly or inherited through a + * superinterface) in the proxy class's list of interfaces is passed to + * the invocation handler's {@code invoke} method, regardless of the + * reference type through which the method invocation occurred. + * + *

If a proxy interface contains a method with the same name and + * parameter signature as the {@code hashCode}, {@code equals}, + * or {@code toString} methods of {@code java.lang.Object}, + * when such a method is invoked on a proxy instance, the + * {@code Method} object passed to the invocation handler will have + * {@code java.lang.Object} as its declaring class. In other words, + * the public, non-final methods of {@code java.lang.Object} + * logically precede all of the proxy interfaces for the determination of + * which {@code Method} object to pass to the invocation handler. + * + *

Note also that when a duplicate method is dispatched to an + * invocation handler, the {@code invoke} method may only throw + * checked exception types that are assignable to one of the exception + * types in the {@code throws} clause of the method in all of + * the proxy interfaces that it can be invoked through. If the + * {@code invoke} method throws a checked exception that is not + * assignable to any of the exception types declared by the method in one + * of the proxy interfaces that it can be invoked through, then an + * unchecked {@code UndeclaredThrowableException} will be thrown by + * the invocation on the proxy instance. This restriction means that not + * all of the exception types returned by invoking + * {@code getExceptionTypes} on the {@code Method} object + * passed to the {@code invoke} method can necessarily be thrown + * successfully by the {@code invoke} method. + * + * @author Peter Jones + * @see InvocationHandler + * @since 1.3 + */ +public final class ProxyImpl implements java.io.Serializable { + + private static final long serialVersionUID = -2222568056686623797L; + + /** prefix for all proxy class names */ + private final static String proxyClassNamePrefix = "$Proxy"; + + /** parameter types of a proxy class constructor */ + private final static Class[] constructorParams = + { InvocationHandler.class }; + + /** maps a class loader to the proxy class cache for that loader */ + private static Map, Object>> loaderToCache + = new WeakHashMap<>(); + + /** marks that a particular proxy class is currently being generated */ + private static Object pendingGenerationMarker = new Object(); + + /** next number to use for generation of unique proxy class names */ + private static long nextUniqueNumber = 0; + private static Object nextUniqueNumberLock = new Object(); + + /** set of all generated proxy classes, for isProxyClass implementation */ + private static Map, Void> proxyClasses = + Collections.synchronizedMap(new WeakHashMap, Void>()); + + /** + * the invocation handler for this proxy instance. + * @serial + */ + protected InvocationHandler h; + + /** + * Prohibits instantiation. + */ + private ProxyImpl() { + } + + /** + * Constructs a new {@code Proxy} instance from a subclass + * (typically, a dynamic proxy class) with the specified value + * for its invocation handler. + * + * @param h the invocation handler for this proxy instance + */ + protected ProxyImpl(InvocationHandler h) { + this.h = h; + } + + /** + * Returns the {@code java.lang.Class} object for a proxy class + * given a class loader and an array of interfaces. The proxy class + * will be defined by the specified class loader and will implement + * all of the supplied interfaces. If a proxy class for the same + * permutation of interfaces has already been defined by the class + * loader, then the existing proxy class will be returned; otherwise, + * a proxy class for those interfaces will be generated dynamically + * and defined by the class loader. + * + *

There are several restrictions on the parameters that may be + * passed to {@code Proxy.getProxyClass}: + * + *

+ * + *

If any of these restrictions are violated, + * {@code Proxy.getProxyClass} will throw an + * {@code IllegalArgumentException}. If the {@code interfaces} + * array argument or any of its elements are {@code null}, a + * {@code NullPointerException} will be thrown. + * + *

Note that the order of the specified proxy interfaces is + * significant: two requests for a proxy class with the same combination + * of interfaces but in a different order will result in two distinct + * proxy classes. + * + * @param loader the class loader to define the proxy class + * @param interfaces the list of interfaces for the proxy class + * to implement + * @return a proxy class that is defined in the specified class loader + * and that implements the specified interfaces + * @throws IllegalArgumentException if any of the restrictions on the + * parameters that may be passed to {@code getProxyClass} + * are violated + * @throws NullPointerException if the {@code interfaces} array + * argument or any of its elements are {@code null} + */ + public static Class getProxyClass(ClassLoader loader, + Class... interfaces) + throws IllegalArgumentException + { + if (interfaces.length > 65535) { + throw new IllegalArgumentException("interface limit exceeded"); + } + + Class proxyClass = null; + + /* collect interface names to use as key for proxy class cache */ + String[] interfaceNames = new String[interfaces.length]; + + // for detecting duplicates + Set> interfaceSet = new HashSet<>(); + + for (int i = 0; i < interfaces.length; i++) { + /* + * Verify that the class loader resolves the name of this + * interface to the same Class object. + */ + String interfaceName = interfaces[i].getName(); + Class interfaceClass = null; + try { + interfaceClass = Class.forName(interfaceName, false, loader); + } catch (ClassNotFoundException e) { + } + if (interfaceClass != interfaces[i]) { + throw new IllegalArgumentException( + interfaces[i] + " is not visible from class loader"); + } + + /* + * Verify that the Class object actually represents an + * interface. + */ + if (!interfaceClass.isInterface()) { + throw new IllegalArgumentException( + interfaceClass.getName() + " is not an interface"); + } + + /* + * Verify that this interface is not a duplicate. + */ + if (interfaceSet.contains(interfaceClass)) { + throw new IllegalArgumentException( + "repeated interface: " + interfaceClass.getName()); + } + interfaceSet.add(interfaceClass); + + interfaceNames[i] = interfaceName; + } + + /* + * Using string representations of the proxy interfaces as + * keys in the proxy class cache (instead of their Class + * objects) is sufficient because we require the proxy + * interfaces to be resolvable by name through the supplied + * class loader, and it has the advantage that using a string + * representation of a class makes for an implicit weak + * reference to the class. + */ + List key = Arrays.asList(interfaceNames); + + /* + * Find or create the proxy class cache for the class loader. + */ + Map, Object> cache; + synchronized (loaderToCache) { + cache = loaderToCache.get(loader); + if (cache == null) { + cache = new HashMap<>(); + loaderToCache.put(loader, cache); + } + /* + * This mapping will remain valid for the duration of this + * method, without further synchronization, because the mapping + * will only be removed if the class loader becomes unreachable. + */ + } + + /* + * Look up the list of interfaces in the proxy class cache using + * the key. This lookup will result in one of three possible + * kinds of values: + * null, if there is currently no proxy class for the list of + * interfaces in the class loader, + * the pendingGenerationMarker object, if a proxy class for the + * list of interfaces is currently being generated, + * or a weak reference to a Class object, if a proxy class for + * the list of interfaces has already been generated. + */ + synchronized (cache) { + /* + * Note that we need not worry about reaping the cache for + * entries with cleared weak references because if a proxy class + * has been garbage collected, its class loader will have been + * garbage collected as well, so the entire cache will be reaped + * from the loaderToCache map. + */ + do { + Object value = cache.get(key); + if (value instanceof Reference) { + proxyClass = (Class) ((Reference) value).get(); + } + if (proxyClass != null) { + // proxy class already generated: return it + return proxyClass; + } else if (value == pendingGenerationMarker) { + // proxy class being generated: wait for it + try { + cache.wait(); + } catch (InterruptedException e) { + /* + * The class generation that we are waiting for should + * take a small, bounded time, so we can safely ignore + * thread interrupts here. + */ + } + continue; + } else { + /* + * No proxy class for this list of interfaces has been + * generated or is being generated, so we will go and + * generate it now. Mark it as pending generation. + */ + cache.put(key, pendingGenerationMarker); + break; + } + } while (true); + } + + try { + String proxyPkg = null; // package to define proxy class in + + /* + * Record the package of a non-public proxy interface so that the + * proxy class will be defined in the same package. Verify that + * all non-public proxy interfaces are in the same package. + */ + for (int i = 0; i < interfaces.length; i++) { + int flags = interfaces[i].getModifiers(); + if (!Modifier.isPublic(flags)) { + String name = interfaces[i].getName(); + int n = name.lastIndexOf('.'); + String pkg = ((n == -1) ? "" : name.substring(0, n + 1)); + if (proxyPkg == null) { + proxyPkg = pkg; + } else if (!pkg.equals(proxyPkg)) { + throw new IllegalArgumentException( + "non-public interfaces from different packages"); + } + } + } + + if (proxyPkg == null) { // if no non-public proxy interfaces, + proxyPkg = ""; // use the unnamed package + } + + { + /* + * Choose a name for the proxy class to generate. + */ + long num; + synchronized (nextUniqueNumberLock) { + num = nextUniqueNumber++; + } + String proxyName = proxyPkg + proxyClassNamePrefix + num; + /* + * Verify that the class loader hasn't already + * defined a class with the chosen name. + */ + + /* + * Generate the specified proxy class. + */ + Generator gen = new Generator(proxyName, interfaces); + final byte[] proxyClassFile = gen.generateClassFile(); + try { + proxyClass = defineClass0(loader, proxyName, + proxyClassFile); + } catch (ClassFormatError e) { + /* + * A ClassFormatError here means that (barring bugs in the + * proxy class generation code) there was some other + * invalid aspect of the arguments supplied to the proxy + * class creation (such as virtual machine limitations + * exceeded). + */ + throw new IllegalArgumentException(e.toString()); + } + gen.fillInMethods(proxyClass); + } + // add to set of all generated proxy classes, for isProxyClass + proxyClasses.put(proxyClass, null); + + } finally { + /* + * We must clean up the "pending generation" state of the proxy + * class cache entry somehow. If a proxy class was successfully + * generated, store it in the cache (with a weak reference); + * otherwise, remove the reserved entry. In all cases, notify + * all waiters on reserved entries in this cache. + */ + synchronized (cache) { + if (proxyClass != null) { + cache.put(key, new WeakReference>(proxyClass)); + } else { + cache.remove(key); + } + cache.notifyAll(); + } + } + return proxyClass; + } + + /** + * Returns an instance of a proxy class for the specified interfaces + * that dispatches method invocations to the specified invocation + * handler. This method is equivalent to: + * 

+     *     Proxy.getProxyClass(loader, interfaces).
+     *         getConstructor(new Class[] { InvocationHandler.class }).
+     *         newInstance(new Object[] { handler });
+     *
+ * + *

{@code Proxy.newProxyInstance} throws + * {@code IllegalArgumentException} for the same reasons that + * {@code Proxy.getProxyClass} does. + * + * @param loader the class loader to define the proxy class + * @param interfaces the list of interfaces for the proxy class + * to implement + * @param h the invocation handler to dispatch method invocations to + * @return a proxy instance with the specified invocation handler of a + * proxy class that is defined by the specified class loader + * and that implements the specified interfaces + * @throws IllegalArgumentException if any of the restrictions on the + * parameters that may be passed to {@code getProxyClass} + * are violated + * @throws NullPointerException if the {@code interfaces} array + * argument or any of its elements are {@code null}, or + * if the invocation handler, {@code h}, is + * {@code null} + */ + public static Object newProxyInstance(ClassLoader loader, + Class[] interfaces, + InvocationHandler h) + throws IllegalArgumentException + { + if (h == null) { + throw new NullPointerException(); + } + + /* + * Look up or generate the designated proxy class. + */ + Class cl = getProxyClass(loader, interfaces); + + /* + * Invoke its constructor with the designated invocation handler. + */ + try { + Constructor cons = cl.getConstructor(constructorParams); + return cons.newInstance(new Object[] { h }); + } catch (NoSuchMethodException e) { + throw new InternalError(e.toString()); + } catch (IllegalAccessException e) { + throw new InternalError(e.toString()); + } catch (InstantiationException e) { + throw new InternalError(e.toString()); + } catch (InvocationTargetException e) { + throw new InternalError(e.toString()); + } + } + + /** + * Returns true if and only if the specified class was dynamically + * generated to be a proxy class using the {@code getProxyClass} + * method or the {@code newProxyInstance} method. + * + *

The reliability of this method is important for the ability + * to use it to make security decisions, so its implementation should + * not just test if the class in question extends {@code Proxy}. + * + * @param cl the class to test + * @return {@code true} if the class is a proxy class and + * {@code false} otherwise + * @throws NullPointerException if {@code cl} is {@code null} + */ + public static boolean isProxyClass(Class cl) { + if (cl == null) { + throw new NullPointerException(); + } + + return proxyClasses.containsKey(cl); + } + + /** + * Returns the invocation handler for the specified proxy instance. + * + * @param proxy the proxy instance to return the invocation handler for + * @return the invocation handler for the proxy instance + * @throws IllegalArgumentException if the argument is not a + * proxy instance + */ + public static InvocationHandler getInvocationHandler(Object proxy) + throws IllegalArgumentException + { + /* + * Verify that the object is actually a proxy instance. + */ + if (!isProxyClass(proxy.getClass())) { + throw new IllegalArgumentException("not a proxy instance"); + } + + ProxyImpl p = (ProxyImpl) proxy; + return p.h; + } + + @JavaScriptBody(args = { "ignore", "name", "byteCode" }, + body = "return vm._reload(name, byteCode).constructor.$class;" + ) + private static native Class defineClass0( + ClassLoader loader, String name, byte[] b + ); + + private static class Generator { + /* + * In the comments below, "JVMS" refers to The Java Virtual Machine + * Specification Second Edition and "JLS" refers to the original + * version of The Java Language Specification, unless otherwise + * specified. + */ + + /* need 1.6 bytecode */ + private static final int CLASSFILE_MAJOR_VERSION = 50; + private static final int CLASSFILE_MINOR_VERSION = 0; + + /* + * beginning of constants copied from + * sun.tools.java.RuntimeConstants (which no longer exists): + */ + + /* constant pool tags */ + private static final int CONSTANT_UTF8 = 1; + private static final int CONSTANT_UNICODE = 2; + private static final int CONSTANT_INTEGER = 3; + private static final int CONSTANT_FLOAT = 4; + private static final int CONSTANT_LONG = 5; + private static final int CONSTANT_DOUBLE = 6; + private static final int CONSTANT_CLASS = 7; + private static final int CONSTANT_STRING = 8; + private static final int CONSTANT_FIELD = 9; + private static final int CONSTANT_METHOD = 10; + private static final int CONSTANT_INTERFACEMETHOD = 11; + private static final int CONSTANT_NAMEANDTYPE = 12; + + /* access and modifier flags */ + private static final int ACC_PUBLIC = 0x00000001; + private static final int ACC_FINAL = 0x00000010; + private static final int ACC_SUPER = 0x00000020; + + // end of constants copied from sun.tools.java.RuntimeConstants + /** + * name of the superclass of proxy classes + */ + private final static String superclassName = "java/lang/reflect/Proxy"; + + /** + * name of field for storing a proxy instance's invocation handler + */ + private final static String handlerFieldName = "h"; + + /* preloaded Method objects for methods in java.lang.Object */ + private static Method hashCodeMethod; + private static Method equalsMethod; + private static Method toStringMethod; + + static { + try { + hashCodeMethod = Object.class.getMethod("hashCode"); + equalsMethod + = Object.class.getMethod("equals", new Class[]{Object.class}); + toStringMethod = Object.class.getMethod("toString"); + } catch (NoSuchMethodException e) { + throw new IllegalStateException(e.getMessage()); + } + } + + /** + * name of proxy class + */ + private String className; + + /** + * proxy interfaces + */ + private Class[] interfaces; + + /** + * constant pool of class being generated + */ + private ConstantPool cp = new ConstantPool(); + + /** + * maps method signature string to list of ProxyMethod objects for proxy + * methods with that signature + */ + private Map> proxyMethods + = new HashMap>(); + + /** + * count of ProxyMethod objects added to proxyMethods + */ + private int proxyMethodCount = 0; + + /** + * Construct a ProxyGenerator to generate a proxy class with the + * specified name and for the given interfaces. + * + * A ProxyGenerator object contains the state for the ongoing generation + * of a particular proxy class. + */ + private Generator(String className, Class[] interfaces) { + this.className = className; + this.interfaces = interfaces; + } + + /** + * Generate a class file for the proxy class. This method drives the + * class file generation process. + */ + private byte[] generateClassFile() { + + /* ============================================================ + * Step 1: Assemble ProxyMethod objects for all methods to + * generate proxy dispatching code for. + */ + + /* + * Record that proxy methods are needed for the hashCode, equals, + * and toString methods of java.lang.Object. This is done before + * the methods from the proxy interfaces so that the methods from + * java.lang.Object take precedence over duplicate methods in the + * proxy interfaces. + */ + addProxyMethod(hashCodeMethod, Object.class); + addProxyMethod(equalsMethod, Object.class); + addProxyMethod(toStringMethod, Object.class); + + /* + * Now record all of the methods from the proxy interfaces, giving + * earlier interfaces precedence over later ones with duplicate + * methods. + */ + for (int i = 0; i < interfaces.length; i++) { + Method[] methods = interfaces[i].getMethods(); + for (int j = 0; j < methods.length; j++) { + addProxyMethod(methods[j], interfaces[i]); + } + } + + /* + * For each set of proxy methods with the same signature, + * verify that the methods' return types are compatible. + */ + for (List sigmethods : proxyMethods.values()) { + checkReturnTypes(sigmethods); + } + + /* ============================================================ + * Step 2: Assemble FieldInfo and MethodInfo structs for all of + * fields and methods in the class we are generating. + */ + + // will be done in fillInMethods + + /* ============================================================ + * Step 3: Write the final class file. + */ + + /* + * Make sure that constant pool indexes are reserved for the + * following items before starting to write the final class file. + */ + cp.getClass(dotToSlash(className)); + cp.getClass(superclassName); + for (int i = 0; i < interfaces.length; i++) { + cp.getClass(dotToSlash(interfaces[i].getName())); + } + + /* + * Disallow new constant pool additions beyond this point, since + * we are about to write the final constant pool table. + */ + cp.setReadOnly(); + + ByteArrayOutputStream bout = new ByteArrayOutputStream(); + DataOutputStream dout = new DataOutputStream(bout); + + try { + /* + * Write all the items of the "ClassFile" structure. + * See JVMS section 4.1. + */ + // u4 magic; + dout.writeInt(0xCAFEBABE); + // u2 minor_version; + dout.writeShort(CLASSFILE_MINOR_VERSION); + // u2 major_version; + dout.writeShort(CLASSFILE_MAJOR_VERSION); + + cp.write(dout); // (write constant pool) + + // u2 access_flags; + dout.writeShort(ACC_PUBLIC | ACC_FINAL | ACC_SUPER); + // u2 this_class; + dout.writeShort(cp.getClass(dotToSlash(className))); + // u2 super_class; + dout.writeShort(cp.getClass(superclassName)); + + // u2 interfaces_count; + dout.writeShort(interfaces.length); + // u2 interfaces[interfaces_count]; + for (int i = 0; i < interfaces.length; i++) { + dout.writeShort(cp.getClass( + dotToSlash(interfaces[i].getName()))); + } + + // u2 fields_count; + dout.writeShort(0); + + // u2 methods_count; + dout.writeShort(0); + + // u2 attributes_count; + dout.writeShort(0); // (no ClassFile attributes for proxy classes) + + } catch (IOException e) { + throw new InternalError("unexpected I/O Exception"); + } + + return bout.toByteArray(); + } + + @JavaScriptBody(args = { "c", "sig", "method", "primitive" }, body = + "var p = c.cnstr.prototype;\n" + + "p[sig] = function() {\n" + + " var h = this._h();\n" + + " var res = h.invoke__Ljava_lang_Object_2Ljava_lang_Object_2Ljava_lang_reflect_Method_2_3Ljava_lang_Object_2(this, method, arguments);\n" + + " \n" + + " \n" + + " return res;\n" + + "};" + ) + private static native void defineMethod(Class proxyClass, String sig, Method method, boolean primitive); + + @JavaScriptBody(args = "c", body = + "var h = c.cnstr.cons__VLjava_lang_reflect_InvocationHandler_2 = function(h) {\n" + + " c.superclass.cnstr.cons__VLjava_lang_reflect_InvocationHandler_2.call(this, h);\n" + + "}\n" + + "h.cls = c.cnstr;\n" + ) + private static native void defineConstructor(Class proxyClass); + + final void fillInMethods(Class proxyClass) { + for (List sigmethods : proxyMethods.values()) { + for (ProxyMethod pm : sigmethods) { + String sig = MethodImpl.toSignature(pm.method); + defineMethod(proxyClass, sig, pm.method, pm.method.getReturnType().isPrimitive()); + } + } + defineConstructor(proxyClass); + } + + /** + * Add another method to be proxied, either by creating a new + * ProxyMethod object or augmenting an old one for a duplicate method. + * + * "fromClass" indicates the proxy interface that the method was found + * through, which may be different from (a subinterface of) the method's + * "declaring class". Note that the first Method object passed for a + * given name and descriptor identifies the Method object (and thus the + * declaring class) that will be passed to the invocation handler's + * "invoke" method for a given set of duplicate methods. + */ + private void addProxyMethod(Method m, Class fromClass) { + String name = m.getName(); + Class[] parameterTypes = m.getParameterTypes(); + Class returnType = m.getReturnType(); + Class[] exceptionTypes = m.getExceptionTypes(); + + String sig = MethodImpl.toSignature(m); + List sigmethods = proxyMethods.get(sig); + if (sigmethods != null) { + for (ProxyMethod pm : sigmethods) { + if (returnType == pm.returnType) { + /* + * Found a match: reduce exception types to the + * greatest set of exceptions that can thrown + * compatibly with the throws clauses of both + * overridden methods. + */ + List> legalExceptions = new ArrayList>(); + collectCompatibleTypes( + exceptionTypes, pm.exceptionTypes, legalExceptions); + collectCompatibleTypes( + pm.exceptionTypes, exceptionTypes, legalExceptions); + pm.exceptionTypes = new Class[legalExceptions.size()]; + pm.exceptionTypes + = legalExceptions.toArray(pm.exceptionTypes); + return; + } + } + } else { + sigmethods = new ArrayList(3); + proxyMethods.put(sig, sigmethods); + } + sigmethods.add(new ProxyMethod(m, name, parameterTypes, returnType, + exceptionTypes, fromClass)); + } + + /** + * For a given set of proxy methods with the same signature, check that + * their return types are compatible according to the Proxy + * specification. + * + * Specifically, if there is more than one such method, then all of the + * return types must be reference types, and there must be one return + * type that is assignable to each of the rest of them. + */ + private static void checkReturnTypes(List methods) { + /* + * If there is only one method with a given signature, there + * cannot be a conflict. This is the only case in which a + * primitive (or void) return type is allowed. + */ + if (methods.size() < 2) { + return; + } + + /* + * List of return types that are not yet known to be + * assignable from ("covered" by) any of the others. + */ + LinkedList> uncoveredReturnTypes = new LinkedList>(); + + nextNewReturnType: + for (ProxyMethod pm : methods) { + Class newReturnType = pm.returnType; + if (newReturnType.isPrimitive()) { + throw new IllegalArgumentException( + "methods with same signature " + + getFriendlyMethodSignature(pm.methodName, + pm.parameterTypes) + + " but incompatible return types: " + + newReturnType.getName() + " and others"); + } + boolean added = false; + + /* + * Compare the new return type to the existing uncovered + * return types. + */ + ListIterator> liter = uncoveredReturnTypes.listIterator(); + while (liter.hasNext()) { + Class uncoveredReturnType = liter.next(); + + /* + * If an existing uncovered return type is assignable + * to this new one, then we can forget the new one. + */ + if (newReturnType.isAssignableFrom(uncoveredReturnType)) { + assert !added; + continue nextNewReturnType; + } + + /* + * If the new return type is assignable to an existing + * uncovered one, then should replace the existing one + * with the new one (or just forget the existing one, + * if the new one has already be put in the list). + */ + if (uncoveredReturnType.isAssignableFrom(newReturnType)) { + // (we can assume that each return type is unique) + if (!added) { + liter.set(newReturnType); + added = true; + } else { + liter.remove(); + } + } + } + + /* + * If we got through the list of existing uncovered return + * types without an assignability relationship, then add + * the new return type to the list of uncovered ones. + */ + if (!added) { + uncoveredReturnTypes.add(newReturnType); + } + } + + /* + * We shouldn't end up with more than one return type that is + * not assignable from any of the others. + */ + if (uncoveredReturnTypes.size() > 1) { + ProxyMethod pm = methods.get(0); + throw new IllegalArgumentException( + "methods with same signature " + + getFriendlyMethodSignature(pm.methodName, pm.parameterTypes) + + " but incompatible return types: " + uncoveredReturnTypes); + } + } + + + /** + * A ProxyMethod object represents a proxy method in the proxy class + * being generated: a method whose implementation will encode and + * dispatch invocations to the proxy instance's invocation handler. + */ + private class ProxyMethod { + + private final Method method; + public String methodName; + public Class[] parameterTypes; + public Class returnType; + public Class[] exceptionTypes; + public Class fromClass; + public String methodFieldName; + + private ProxyMethod(Method m, + String methodName, Class[] parameterTypes, + Class returnType, Class[] exceptionTypes, + Class fromClass + ) { + this.method = m; + this.methodName = methodName; + this.parameterTypes = parameterTypes; + this.returnType = returnType; + this.exceptionTypes = exceptionTypes; + this.fromClass = fromClass; + this.methodFieldName = "m" + proxyMethodCount++; + } + + } + + /* + * ==================== General Utility Methods ==================== + */ + /** + * Convert a fully qualified class name that uses '.' as the package + * separator, the external representation used by the Java language and + * APIs, to a fully qualified class name that uses '/' as the package + * separator, the representation used in the class file format (see JVMS + * section 4.2). + */ + private static String dotToSlash(String name) { + return name.replace('.', '/'); + } + + /** + * Return the list of "parameter descriptor" strings enclosed in + * parentheses corresponding to the given parameter types (in other + * words, a method descriptor without a return descriptor). This string + * is useful for constructing string keys for methods without regard to + * their return type. + */ + private static String getParameterDescriptors(Class[] parameterTypes) { + StringBuilder desc = new StringBuilder("("); + for (int i = 0; i < parameterTypes.length; i++) { + desc.append(getFieldType(parameterTypes[i])); + } + desc.append(')'); + return desc.toString(); + } + + /** + * Return the "field type" string for the given type, appropriate for a + * field descriptor, a parameter descriptor, or a return descriptor + * other than "void". See JVMS section 4.3.2. + */ + private static String getFieldType(Class type) { + if (type.isPrimitive()) { + return PrimitiveTypeInfo.get(type).baseTypeString; + } else if (type.isArray()) { + /* + * According to JLS 20.3.2, the getName() method on Class does + * return the VM type descriptor format for array classes (only); + * using that should be quicker than the otherwise obvious code: + * + * return "[" + getTypeDescriptor(type.getComponentType()); + */ + return type.getName().replace('.', '/'); + } else { + return "L" + dotToSlash(type.getName()) + ";"; + } + } + + /** + * Returns a human-readable string representing the signature of a + * method with the given name and parameter types. + */ + private static String getFriendlyMethodSignature(String name, + Class[] parameterTypes) { + StringBuilder sig = new StringBuilder(name); + sig.append('('); + for (int i = 0; i < parameterTypes.length; i++) { + if (i > 0) { + sig.append(','); + } + Class parameterType = parameterTypes[i]; + int dimensions = 0; + while (parameterType.isArray()) { + parameterType = parameterType.getComponentType(); + dimensions++; + } + sig.append(parameterType.getName()); + while (dimensions-- > 0) { + sig.append("[]"); + } + } + sig.append(')'); + return sig.toString(); + } + + /** + * Add to the given list all of the types in the "from" array that are + * not already contained in the list and are assignable to at least one + * of the types in the "with" array. + * + * This method is useful for computing the greatest common set of + * declared exceptions from duplicate methods inherited from different + * interfaces. + */ + private static void collectCompatibleTypes(Class[] from, + Class[] with, + List> list) { + for (int i = 0; i < from.length; i++) { + if (!list.contains(from[i])) { + for (int j = 0; j < with.length; j++) { + if (with[j].isAssignableFrom(from[i])) { + list.add(from[i]); + break; + } + } + } + } + } + + + /** + * A PrimitiveTypeInfo object contains assorted information about a + * primitive type in its public fields. The struct for a particular + * primitive type can be obtained using the static "get" method. + */ + private static class PrimitiveTypeInfo { + + /** + * "base type" used in various descriptors (see JVMS section 4.3.2) + */ + public String baseTypeString; + + /** + * name of corresponding wrapper class + */ + public String wrapperClassName; + + /** + * method descriptor for wrapper class "valueOf" factory method + */ + public String wrapperValueOfDesc; + + /** + * name of wrapper class method for retrieving primitive value + */ + public String unwrapMethodName; + + /** + * descriptor of same method + */ + public String unwrapMethodDesc; + + private static Map table + = new HashMap(); + + static { + add(byte.class, Byte.class); + add(char.class, Character.class); + add(double.class, Double.class); + add(float.class, Float.class); + add(int.class, Integer.class); + add(long.class, Long.class); + add(short.class, Short.class); + add(boolean.class, Boolean.class); + } + + private static void add(Class primitiveClass, Class wrapperClass) { + table.put(primitiveClass, + new PrimitiveTypeInfo(primitiveClass, wrapperClass)); + } + + private PrimitiveTypeInfo(Class primitiveClass, Class wrapperClass) { + assert primitiveClass.isPrimitive(); + + baseTypeString + = Array.newInstance(primitiveClass, 0) + .getClass().getName().substring(1); + wrapperClassName = dotToSlash(wrapperClass.getName()); + wrapperValueOfDesc + = "(" + baseTypeString + ")L" + wrapperClassName + ";"; + unwrapMethodName = primitiveClass.getName() + "Value"; + unwrapMethodDesc = "()" + baseTypeString; + } + + public static PrimitiveTypeInfo get(Class cl) { + return table.get(cl); + } + } + + /** + * A ConstantPool object represents the constant pool of a class file + * being generated. This representation of a constant pool is designed + * specifically for use by ProxyGenerator; in particular, it assumes + * that constant pool entries will not need to be resorted (for example, + * by their type, as the Java compiler does), so that the final index + * value can be assigned and used when an entry is first created. + * + * Note that new entries cannot be created after the constant pool has + * been written to a class file. To prevent such logic errors, a + * ConstantPool instance can be marked "read only", so that further + * attempts to add new entries will fail with a runtime exception. + * + * See JVMS section 4.4 for more information about the constant pool of + * a class file. + */ + private static class ConstantPool { + + /** + * list of constant pool entries, in constant pool index order. + * + * This list is used when writing the constant pool to a stream and + * for assigning the next index value. Note that element 0 of this + * list corresponds to constant pool index 1. + */ + private List pool = new ArrayList(32); + + /** + * maps constant pool data of all types to constant pool indexes. + * + * This map is used to look up the index of an existing entry for + * values of all types. + */ + private Map map = new HashMap(16); + + /** + * true if no new constant pool entries may be added + */ + private boolean readOnly = false; + + /** + * Get or assign the index for a CONSTANT_Utf8 entry. + */ + public short getUtf8(String s) { + if (s == null) { + throw new NullPointerException(); + } + return getValue(s); + } + + /** + * Get or assign the index for a CONSTANT_Integer entry. + */ + public short getInteger(int i) { + return getValue(new Integer(i)); + } + + /** + * Get or assign the index for a CONSTANT_Float entry. + */ + public short getFloat(float f) { + return getValue(new Float(f)); + } + + /** + * Get or assign the index for a CONSTANT_Class entry. + */ + public short getClass(String name) { + short utf8Index = getUtf8(name); + return getIndirect(new IndirectEntry( + CONSTANT_CLASS, utf8Index)); + } + + /** + * Get or assign the index for a CONSTANT_String entry. + */ + public short getString(String s) { + short utf8Index = getUtf8(s); + return getIndirect(new IndirectEntry( + CONSTANT_STRING, utf8Index)); + } + + /** + * Get or assign the index for a CONSTANT_FieldRef entry. + */ + public short getFieldRef(String className, + String name, String descriptor) { + short classIndex = getClass(className); + short nameAndTypeIndex = getNameAndType(name, descriptor); + return getIndirect(new IndirectEntry( + CONSTANT_FIELD, classIndex, nameAndTypeIndex)); + } + + /** + * Get or assign the index for a CONSTANT_MethodRef entry. + */ + public short getMethodRef(String className, + String name, String descriptor) { + short classIndex = getClass(className); + short nameAndTypeIndex = getNameAndType(name, descriptor); + return getIndirect(new IndirectEntry( + CONSTANT_METHOD, classIndex, nameAndTypeIndex)); + } + + /** + * Get or assign the index for a CONSTANT_InterfaceMethodRef entry. + */ + public short getInterfaceMethodRef(String className, String name, + String descriptor) { + short classIndex = getClass(className); + short nameAndTypeIndex = getNameAndType(name, descriptor); + return getIndirect(new IndirectEntry( + CONSTANT_INTERFACEMETHOD, classIndex, nameAndTypeIndex)); + } + + /** + * Get or assign the index for a CONSTANT_NameAndType entry. + */ + public short getNameAndType(String name, String descriptor) { + short nameIndex = getUtf8(name); + short descriptorIndex = getUtf8(descriptor); + return getIndirect(new IndirectEntry( + CONSTANT_NAMEANDTYPE, nameIndex, descriptorIndex)); + } + + /** + * Set this ConstantPool instance to be "read only". + * + * After this method has been called, further requests to get an + * index for a non-existent entry will cause an InternalError to be + * thrown instead of creating of the entry. + */ + public void setReadOnly() { + readOnly = true; + } + + /** + * Write this constant pool to a stream as part of the class file + * format. + * + * This consists of writing the "constant_pool_count" and + * "constant_pool[]" items of the "ClassFile" structure, as + * described in JVMS section 4.1. + */ + public void write(OutputStream out) throws IOException { + DataOutputStream dataOut = new DataOutputStream(out); + + // constant_pool_count: number of entries plus one + dataOut.writeShort(pool.size() + 1); + + for (Entry e : pool) { + e.write(dataOut); + } + } + + /** + * Add a new constant pool entry and return its index. + */ + private short addEntry(Entry entry) { + pool.add(entry); + /* + * Note that this way of determining the index of the + * added entry is wrong if this pool supports + * CONSTANT_Long or CONSTANT_Double entries. + */ + if (pool.size() >= 65535) { + throw new IllegalArgumentException( + "constant pool size limit exceeded"); + } + return (short) pool.size(); + } + + /** + * Get or assign the index for an entry of a type that contains a + * direct value. The type of the given object determines the type of + * the desired entry as follows: + * + * java.lang.String CONSTANT_Utf8 java.lang.Integer CONSTANT_Integer + * java.lang.Float CONSTANT_Float java.lang.Long CONSTANT_Long + * java.lang.Double CONSTANT_DOUBLE + */ + private short getValue(Object key) { + Short index = map.get(key); + if (index != null) { + return index.shortValue(); + } else { + if (readOnly) { + throw new InternalError( + "late constant pool addition: " + key); + } + short i = addEntry(new ValueEntry(key)); + map.put(key, new Short(i)); + return i; + } + } + + /** + * Get or assign the index for an entry of a type that contains + * references to other constant pool entries. + */ + private short getIndirect(IndirectEntry e) { + Short index = map.get(e); + if (index != null) { + return index.shortValue(); + } else { + if (readOnly) { + throw new InternalError("late constant pool addition"); + } + short i = addEntry(e); + map.put(e, new Short(i)); + return i; + } + } + + /** + * Entry is the abstact superclass of all constant pool entry types + * that can be stored in the "pool" list; its purpose is to define a + * common method for writing constant pool entries to a class file. + */ + private static abstract class Entry { + + public abstract void write(DataOutputStream out) + throws IOException; + } + + /** + * ValueEntry represents a constant pool entry of a type that + * contains a direct value (see the comments for the "getValue" + * method for a list of such types). + * + * ValueEntry objects are not used as keys for their entries in the + * Map "map", so no useful hashCode or equals methods are defined. + */ + private static class ValueEntry extends Entry { + + private Object value; + + public ValueEntry(Object value) { + this.value = value; + } + + public void write(DataOutputStream out) throws IOException { + if (value instanceof String) { + out.writeByte(CONSTANT_UTF8); + out.writeUTF((String) value); + } else if (value instanceof Integer) { + out.writeByte(CONSTANT_INTEGER); + out.writeInt(((Integer) value).intValue()); + } else if (value instanceof Float) { + out.writeByte(CONSTANT_FLOAT); + out.writeFloat(((Float) value).floatValue()); + } else if (value instanceof Long) { + out.writeByte(CONSTANT_LONG); + out.writeLong(((Long) value).longValue()); + } else if (value instanceof Double) { + out.writeDouble(CONSTANT_DOUBLE); + out.writeDouble(((Double) value).doubleValue()); + } else { + throw new InternalError("bogus value entry: " + value); + } + } + } + + /** + * IndirectEntry represents a constant pool entry of a type that + * references other constant pool entries, i.e., the following + * types: + * + * CONSTANT_Class, CONSTANT_String, CONSTANT_Fieldref, + * CONSTANT_Methodref, CONSTANT_InterfaceMethodref, and + * CONSTANT_NameAndType. + * + * Each of these entry types contains either one or two indexes of + * other constant pool entries. + * + * IndirectEntry objects are used as the keys for their entries in + * the Map "map", so the hashCode and equals methods are overridden + * to allow matching. + */ + private static class IndirectEntry extends Entry { + + private int tag; + private short index0; + private short index1; + + /** + * Construct an IndirectEntry for a constant pool entry type + * that contains one index of another entry. + */ + public IndirectEntry(int tag, short index) { + this.tag = tag; + this.index0 = index; + this.index1 = 0; + } + + /** + * Construct an IndirectEntry for a constant pool entry type + * that contains two indexes for other entries. + */ + public IndirectEntry(int tag, short index0, short index1) { + this.tag = tag; + this.index0 = index0; + this.index1 = index1; + } + + public void write(DataOutputStream out) throws IOException { + out.writeByte(tag); + out.writeShort(index0); + /* + * If this entry type contains two indexes, write + * out the second, too. + */ + if (tag == CONSTANT_FIELD + || tag == CONSTANT_METHOD + || tag == CONSTANT_INTERFACEMETHOD + || tag == CONSTANT_NAMEANDTYPE) { + out.writeShort(index1); + } + } + + public int hashCode() { + return tag + index0 + index1; + } + + public boolean equals(Object obj) { + if (obj instanceof IndirectEntry) { + IndirectEntry other = (IndirectEntry) obj; + if (tag == other.tag + && index0 == other.index0 && index1 == other.index1) { + return true; + } + } + return false; + } + } + } + } + +}