--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/lang/reflect/ProxyGenerator.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,2031 @@
+/*
+ * Copyright (c) 1999, 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. 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 java.lang.reflect;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.reflect.Array;
+import java.lang.reflect.Method;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Map;
+import sun.security.action.GetBooleanAction;
+
+/**
+ * ProxyGenerator contains the code to generate a dynamic proxy class
+ * for the java.lang.reflect.Proxy API.
+ *
+ * The external interfaces to ProxyGenerator is the static
+ * "generateProxyClass" method.
+ *
+ * @author Peter Jones
+ * @since 1.3
+ */
+class ProxyGenerator {
+ /*
+ * 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.
+ */
+
+ /* generate 1.5-era class file version */
+ private static final int CLASSFILE_MAJOR_VERSION = 49;
+ 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_PRIVATE = 0x00000002;
+// private static final int ACC_PROTECTED = 0x00000004;
+ private static final int ACC_STATIC = 0x00000008;
+ private static final int ACC_FINAL = 0x00000010;
+// private static final int ACC_SYNCHRONIZED = 0x00000020;
+// private static final int ACC_VOLATILE = 0x00000040;
+// private static final int ACC_TRANSIENT = 0x00000080;
+// private static final int ACC_NATIVE = 0x00000100;
+// private static final int ACC_INTERFACE = 0x00000200;
+// private static final int ACC_ABSTRACT = 0x00000400;
+ private static final int ACC_SUPER = 0x00000020;
+// private static final int ACC_STRICT = 0x00000800;
+
+ /* opcodes */
+// private static final int opc_nop = 0;
+ private static final int opc_aconst_null = 1;
+// private static final int opc_iconst_m1 = 2;
+ private static final int opc_iconst_0 = 3;
+// private static final int opc_iconst_1 = 4;
+// private static final int opc_iconst_2 = 5;
+// private static final int opc_iconst_3 = 6;
+// private static final int opc_iconst_4 = 7;
+// private static final int opc_iconst_5 = 8;
+// private static final int opc_lconst_0 = 9;
+// private static final int opc_lconst_1 = 10;
+// private static final int opc_fconst_0 = 11;
+// private static final int opc_fconst_1 = 12;
+// private static final int opc_fconst_2 = 13;
+// private static final int opc_dconst_0 = 14;
+// private static final int opc_dconst_1 = 15;
+ private static final int opc_bipush = 16;
+ private static final int opc_sipush = 17;
+ private static final int opc_ldc = 18;
+ private static final int opc_ldc_w = 19;
+// private static final int opc_ldc2_w = 20;
+ private static final int opc_iload = 21;
+ private static final int opc_lload = 22;
+ private static final int opc_fload = 23;
+ private static final int opc_dload = 24;
+ private static final int opc_aload = 25;
+ private static final int opc_iload_0 = 26;
+// private static final int opc_iload_1 = 27;
+// private static final int opc_iload_2 = 28;
+// private static final int opc_iload_3 = 29;
+ private static final int opc_lload_0 = 30;
+// private static final int opc_lload_1 = 31;
+// private static final int opc_lload_2 = 32;
+// private static final int opc_lload_3 = 33;
+ private static final int opc_fload_0 = 34;
+// private static final int opc_fload_1 = 35;
+// private static final int opc_fload_2 = 36;
+// private static final int opc_fload_3 = 37;
+ private static final int opc_dload_0 = 38;
+// private static final int opc_dload_1 = 39;
+// private static final int opc_dload_2 = 40;
+// private static final int opc_dload_3 = 41;
+ private static final int opc_aload_0 = 42;
+// private static final int opc_aload_1 = 43;
+// private static final int opc_aload_2 = 44;
+// private static final int opc_aload_3 = 45;
+// private static final int opc_iaload = 46;
+// private static final int opc_laload = 47;
+// private static final int opc_faload = 48;
+// private static final int opc_daload = 49;
+// private static final int opc_aaload = 50;
+// private static final int opc_baload = 51;
+// private static final int opc_caload = 52;
+// private static final int opc_saload = 53;
+// private static final int opc_istore = 54;
+// private static final int opc_lstore = 55;
+// private static final int opc_fstore = 56;
+// private static final int opc_dstore = 57;
+ private static final int opc_astore = 58;
+// private static final int opc_istore_0 = 59;
+// private static final int opc_istore_1 = 60;
+// private static final int opc_istore_2 = 61;
+// private static final int opc_istore_3 = 62;
+// private static final int opc_lstore_0 = 63;
+// private static final int opc_lstore_1 = 64;
+// private static final int opc_lstore_2 = 65;
+// private static final int opc_lstore_3 = 66;
+// private static final int opc_fstore_0 = 67;
+// private static final int opc_fstore_1 = 68;
+// private static final int opc_fstore_2 = 69;
+// private static final int opc_fstore_3 = 70;
+// private static final int opc_dstore_0 = 71;
+// private static final int opc_dstore_1 = 72;
+// private static final int opc_dstore_2 = 73;
+// private static final int opc_dstore_3 = 74;
+ private static final int opc_astore_0 = 75;
+// private static final int opc_astore_1 = 76;
+// private static final int opc_astore_2 = 77;
+// private static final int opc_astore_3 = 78;
+// private static final int opc_iastore = 79;
+// private static final int opc_lastore = 80;
+// private static final int opc_fastore = 81;
+// private static final int opc_dastore = 82;
+ private static final int opc_aastore = 83;
+// private static final int opc_bastore = 84;
+// private static final int opc_castore = 85;
+// private static final int opc_sastore = 86;
+ private static final int opc_pop = 87;
+// private static final int opc_pop2 = 88;
+ private static final int opc_dup = 89;
+// private static final int opc_dup_x1 = 90;
+// private static final int opc_dup_x2 = 91;
+// private static final int opc_dup2 = 92;
+// private static final int opc_dup2_x1 = 93;
+// private static final int opc_dup2_x2 = 94;
+// private static final int opc_swap = 95;
+// private static final int opc_iadd = 96;
+// private static final int opc_ladd = 97;
+// private static final int opc_fadd = 98;
+// private static final int opc_dadd = 99;
+// private static final int opc_isub = 100;
+// private static final int opc_lsub = 101;
+// private static final int opc_fsub = 102;
+// private static final int opc_dsub = 103;
+// private static final int opc_imul = 104;
+// private static final int opc_lmul = 105;
+// private static final int opc_fmul = 106;
+// private static final int opc_dmul = 107;
+// private static final int opc_idiv = 108;
+// private static final int opc_ldiv = 109;
+// private static final int opc_fdiv = 110;
+// private static final int opc_ddiv = 111;
+// private static final int opc_irem = 112;
+// private static final int opc_lrem = 113;
+// private static final int opc_frem = 114;
+// private static final int opc_drem = 115;
+// private static final int opc_ineg = 116;
+// private static final int opc_lneg = 117;
+// private static final int opc_fneg = 118;
+// private static final int opc_dneg = 119;
+// private static final int opc_ishl = 120;
+// private static final int opc_lshl = 121;
+// private static final int opc_ishr = 122;
+// private static final int opc_lshr = 123;
+// private static final int opc_iushr = 124;
+// private static final int opc_lushr = 125;
+// private static final int opc_iand = 126;
+// private static final int opc_land = 127;
+// private static final int opc_ior = 128;
+// private static final int opc_lor = 129;
+// private static final int opc_ixor = 130;
+// private static final int opc_lxor = 131;
+// private static final int opc_iinc = 132;
+// private static final int opc_i2l = 133;
+// private static final int opc_i2f = 134;
+// private static final int opc_i2d = 135;
+// private static final int opc_l2i = 136;
+// private static final int opc_l2f = 137;
+// private static final int opc_l2d = 138;
+// private static final int opc_f2i = 139;
+// private static final int opc_f2l = 140;
+// private static final int opc_f2d = 141;
+// private static final int opc_d2i = 142;
+// private static final int opc_d2l = 143;
+// private static final int opc_d2f = 144;
+// private static final int opc_i2b = 145;
+// private static final int opc_i2c = 146;
+// private static final int opc_i2s = 147;
+// private static final int opc_lcmp = 148;
+// private static final int opc_fcmpl = 149;
+// private static final int opc_fcmpg = 150;
+// private static final int opc_dcmpl = 151;
+// private static final int opc_dcmpg = 152;
+// private static final int opc_ifeq = 153;
+// private static final int opc_ifne = 154;
+// private static final int opc_iflt = 155;
+// private static final int opc_ifge = 156;
+// private static final int opc_ifgt = 157;
+// private static final int opc_ifle = 158;
+// private static final int opc_if_icmpeq = 159;
+// private static final int opc_if_icmpne = 160;
+// private static final int opc_if_icmplt = 161;
+// private static final int opc_if_icmpge = 162;
+// private static final int opc_if_icmpgt = 163;
+// private static final int opc_if_icmple = 164;
+// private static final int opc_if_acmpeq = 165;
+// private static final int opc_if_acmpne = 166;
+// private static final int opc_goto = 167;
+// private static final int opc_jsr = 168;
+// private static final int opc_ret = 169;
+// private static final int opc_tableswitch = 170;
+// private static final int opc_lookupswitch = 171;
+ private static final int opc_ireturn = 172;
+ private static final int opc_lreturn = 173;
+ private static final int opc_freturn = 174;
+ private static final int opc_dreturn = 175;
+ private static final int opc_areturn = 176;
+ private static final int opc_return = 177;
+ private static final int opc_getstatic = 178;
+ private static final int opc_putstatic = 179;
+ private static final int opc_getfield = 180;
+// private static final int opc_putfield = 181;
+ private static final int opc_invokevirtual = 182;
+ private static final int opc_invokespecial = 183;
+ private static final int opc_invokestatic = 184;
+ private static final int opc_invokeinterface = 185;
+ private static final int opc_new = 187;
+// private static final int opc_newarray = 188;
+ private static final int opc_anewarray = 189;
+// private static final int opc_arraylength = 190;
+ private static final int opc_athrow = 191;
+ private static final int opc_checkcast = 192;
+// private static final int opc_instanceof = 193;
+// private static final int opc_monitorenter = 194;
+// private static final int opc_monitorexit = 195;
+ private static final int opc_wide = 196;
+// private static final int opc_multianewarray = 197;
+// private static final int opc_ifnull = 198;
+// private static final int opc_ifnonnull = 199;
+// private static final int opc_goto_w = 200;
+// private static final int opc_jsr_w = 201;
+
+ // end of constants copied from sun.tools.java.RuntimeConstants
+
+ /** name of the superclass of proxy classes */
+ private static final String superclassName = "java/lang/reflect/Proxy";
+
+ /** name of field for storing a proxy instance's invocation handler */
+ private static final String handlerFieldName = "h";
+
+ /** debugging flag for saving generated class files */
+ private static final boolean saveGeneratedFiles =
+ java.security.AccessController.doPrivileged(
+ new GetBooleanAction(
+ "jdk.proxy.ProxyGenerator.saveGeneratedFiles")).booleanValue();
+
+ /**
+ * Generate a public proxy class given a name and a list of proxy interfaces.
+ */
+ static byte[] generateProxyClass(final String name,
+ Class<?>[] interfaces) {
+ return generateProxyClass(name, interfaces, (ACC_PUBLIC | ACC_FINAL | ACC_SUPER));
+ }
+
+ /**
+ * Generate a proxy class given a name and a list of proxy interfaces.
+ *
+ * @param name the class name of the proxy class
+ * @param interfaces proxy interfaces
+ * @param accessFlags access flags of the proxy class
+ */
+ static byte[] generateProxyClass(final String name,
+ Class<?>[] interfaces,
+ int accessFlags)
+ {
+ ProxyGenerator gen = new ProxyGenerator(name, interfaces, accessFlags);
+ final byte[] classFile = gen.generateClassFile();
+
+ if (saveGeneratedFiles) {
+ java.security.AccessController.doPrivileged(
+ new java.security.PrivilegedAction<Void>() {
+ public Void run() {
+ try {
+ int i = name.lastIndexOf('.');
+ Path path;
+ if (i > 0) {
+ Path dir = Paths.get(name.substring(0, i).replace('.', File.separatorChar));
+ Files.createDirectories(dir);
+ path = dir.resolve(name.substring(i+1, name.length()) + ".class");
+ } else {
+ path = Paths.get(name + ".class");
+ }
+ Files.write(path, classFile);
+ return null;
+ } catch (IOException e) {
+ throw new InternalError(
+ "I/O exception saving generated file: " + e);
+ }
+ }
+ });
+ }
+
+ return classFile;
+ }
+
+ /* 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 NoSuchMethodError(e.getMessage());
+ }
+ }
+
+ /** name of proxy class */
+ private String className;
+
+ /** proxy interfaces */
+ private Class<?>[] interfaces;
+
+ /** proxy class access flags */
+ private int accessFlags;
+
+ /** constant pool of class being generated */
+ private ConstantPool cp = new ConstantPool();
+
+ /** FieldInfo struct for each field of generated class */
+ private List<FieldInfo> fields = new ArrayList<>();
+
+ /** MethodInfo struct for each method of generated class */
+ private List<MethodInfo> methods = new ArrayList<>();
+
+ /**
+ * maps method signature string to list of ProxyMethod objects for
+ * proxy methods with that signature
+ */
+ private Map<String, List<ProxyMethod>> 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 ProxyGenerator(String className, Class<?>[] interfaces, int accessFlags) {
+ this.className = className;
+ this.interfaces = interfaces;
+ this.accessFlags = accessFlags;
+ }
+
+ /**
+ * 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 (Class<?> intf : interfaces) {
+ for (Method m : intf.getMethods()) {
+ addProxyMethod(m, intf);
+ }
+ }
+
+ /*
+ * For each set of proxy methods with the same signature,
+ * verify that the methods' return types are compatible.
+ */
+ for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
+ checkReturnTypes(sigmethods);
+ }
+
+ /* ============================================================
+ * Step 2: Assemble FieldInfo and MethodInfo structs for all of
+ * fields and methods in the class we are generating.
+ */
+ try {
+ methods.add(generateConstructor());
+
+ for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
+ for (ProxyMethod pm : sigmethods) {
+
+ // add static field for method's Method object
+ fields.add(new FieldInfo(pm.methodFieldName,
+ "Ljava/lang/reflect/Method;",
+ ACC_PRIVATE | ACC_STATIC));
+
+ // generate code for proxy method and add it
+ methods.add(pm.generateMethod());
+ }
+ }
+
+ methods.add(generateStaticInitializer());
+
+ } catch (IOException e) {
+ throw new InternalError("unexpected I/O Exception", e);
+ }
+
+ if (methods.size() > 65535) {
+ throw new IllegalArgumentException("method limit exceeded");
+ }
+ if (fields.size() > 65535) {
+ throw new IllegalArgumentException("field limit exceeded");
+ }
+
+ /* ============================================================
+ * 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 (Class<?> intf: interfaces) {
+ cp.getClass(dotToSlash(intf.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(accessFlags);
+ // 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 (Class<?> intf : interfaces) {
+ dout.writeShort(cp.getClass(
+ dotToSlash(intf.getName())));
+ }
+
+ // u2 fields_count;
+ dout.writeShort(fields.size());
+ // field_info fields[fields_count];
+ for (FieldInfo f : fields) {
+ f.write(dout);
+ }
+
+ // u2 methods_count;
+ dout.writeShort(methods.size());
+ // method_info methods[methods_count];
+ for (MethodInfo m : methods) {
+ m.write(dout);
+ }
+
+ // u2 attributes_count;
+ dout.writeShort(0); // (no ClassFile attributes for proxy classes)
+
+ } catch (IOException e) {
+ throw new InternalError("unexpected I/O Exception", e);
+ }
+
+ return bout.toByteArray();
+ }
+
+ /**
+ * 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 = name + getParameterDescriptors(parameterTypes);
+ List<ProxyMethod> 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<Class<?>> 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(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<ProxyMethod> 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<Class<?>> 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<Class<?>> 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 FieldInfo object contains information about a particular field
+ * in the class being generated. The class mirrors the data items of
+ * the "field_info" structure of the class file format (see JVMS 4.5).
+ */
+ private class FieldInfo {
+ public int accessFlags;
+ public String name;
+ public String descriptor;
+
+ public FieldInfo(String name, String descriptor, int accessFlags) {
+ this.name = name;
+ this.descriptor = descriptor;
+ this.accessFlags = accessFlags;
+
+ /*
+ * Make sure that constant pool indexes are reserved for the
+ * following items before starting to write the final class file.
+ */
+ cp.getUtf8(name);
+ cp.getUtf8(descriptor);
+ }
+
+ public void write(DataOutputStream out) throws IOException {
+ /*
+ * Write all the items of the "field_info" structure.
+ * See JVMS section 4.5.
+ */
+ // u2 access_flags;
+ out.writeShort(accessFlags);
+ // u2 name_index;
+ out.writeShort(cp.getUtf8(name));
+ // u2 descriptor_index;
+ out.writeShort(cp.getUtf8(descriptor));
+ // u2 attributes_count;
+ out.writeShort(0); // (no field_info attributes for proxy classes)
+ }
+ }
+
+ /**
+ * An ExceptionTableEntry object holds values for the data items of
+ * an entry in the "exception_table" item of the "Code" attribute of
+ * "method_info" structures (see JVMS 4.7.3).
+ */
+ private static class ExceptionTableEntry {
+ public short startPc;
+ public short endPc;
+ public short handlerPc;
+ public short catchType;
+
+ public ExceptionTableEntry(short startPc, short endPc,
+ short handlerPc, short catchType)
+ {
+ this.startPc = startPc;
+ this.endPc = endPc;
+ this.handlerPc = handlerPc;
+ this.catchType = catchType;
+ }
+ };
+
+ /**
+ * A MethodInfo object contains information about a particular method
+ * in the class being generated. This class mirrors the data items of
+ * the "method_info" structure of the class file format (see JVMS 4.6).
+ */
+ private class MethodInfo {
+ public int accessFlags;
+ public String name;
+ public String descriptor;
+ public short maxStack;
+ public short maxLocals;
+ public ByteArrayOutputStream code = new ByteArrayOutputStream();
+ public List<ExceptionTableEntry> exceptionTable =
+ new ArrayList<ExceptionTableEntry>();
+ public short[] declaredExceptions;
+
+ public MethodInfo(String name, String descriptor, int accessFlags) {
+ this.name = name;
+ this.descriptor = descriptor;
+ this.accessFlags = accessFlags;
+
+ /*
+ * Make sure that constant pool indexes are reserved for the
+ * following items before starting to write the final class file.
+ */
+ cp.getUtf8(name);
+ cp.getUtf8(descriptor);
+ cp.getUtf8("Code");
+ cp.getUtf8("Exceptions");
+ }
+
+ public void write(DataOutputStream out) throws IOException {
+ /*
+ * Write all the items of the "method_info" structure.
+ * See JVMS section 4.6.
+ */
+ // u2 access_flags;
+ out.writeShort(accessFlags);
+ // u2 name_index;
+ out.writeShort(cp.getUtf8(name));
+ // u2 descriptor_index;
+ out.writeShort(cp.getUtf8(descriptor));
+ // u2 attributes_count;
+ out.writeShort(2); // (two method_info attributes:)
+
+ // Write "Code" attribute. See JVMS section 4.7.3.
+
+ // u2 attribute_name_index;
+ out.writeShort(cp.getUtf8("Code"));
+ // u4 attribute_length;
+ out.writeInt(12 + code.size() + 8 * exceptionTable.size());
+ // u2 max_stack;
+ out.writeShort(maxStack);
+ // u2 max_locals;
+ out.writeShort(maxLocals);
+ // u2 code_length;
+ out.writeInt(code.size());
+ // u1 code[code_length];
+ code.writeTo(out);
+ // u2 exception_table_length;
+ out.writeShort(exceptionTable.size());
+ for (ExceptionTableEntry e : exceptionTable) {
+ // u2 start_pc;
+ out.writeShort(e.startPc);
+ // u2 end_pc;
+ out.writeShort(e.endPc);
+ // u2 handler_pc;
+ out.writeShort(e.handlerPc);
+ // u2 catch_type;
+ out.writeShort(e.catchType);
+ }
+ // u2 attributes_count;
+ out.writeShort(0);
+
+ // write "Exceptions" attribute. See JVMS section 4.7.4.
+
+ // u2 attribute_name_index;
+ out.writeShort(cp.getUtf8("Exceptions"));
+ // u4 attributes_length;
+ out.writeInt(2 + 2 * declaredExceptions.length);
+ // u2 number_of_exceptions;
+ out.writeShort(declaredExceptions.length);
+ // u2 exception_index_table[number_of_exceptions];
+ for (short value : declaredExceptions) {
+ out.writeShort(value);
+ }
+ }
+
+ }
+
+ /**
+ * 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 {
+
+ public String methodName;
+ public Class<?>[] parameterTypes;
+ public Class<?> returnType;
+ public Class<?>[] exceptionTypes;
+ public Class<?> fromClass;
+ public String methodFieldName;
+
+ private ProxyMethod(String methodName, Class<?>[] parameterTypes,
+ Class<?> returnType, Class<?>[] exceptionTypes,
+ Class<?> fromClass)
+ {
+ this.methodName = methodName;
+ this.parameterTypes = parameterTypes;
+ this.returnType = returnType;
+ this.exceptionTypes = exceptionTypes;
+ this.fromClass = fromClass;
+ this.methodFieldName = "m" + proxyMethodCount++;
+ }
+
+ /**
+ * Return a MethodInfo object for this method, including generating
+ * the code and exception table entry.
+ */
+ private MethodInfo generateMethod() throws IOException {
+ String desc = getMethodDescriptor(parameterTypes, returnType);
+ MethodInfo minfo = new MethodInfo(methodName, desc,
+ ACC_PUBLIC | ACC_FINAL);
+
+ int[] parameterSlot = new int[parameterTypes.length];
+ int nextSlot = 1;
+ for (int i = 0; i < parameterSlot.length; i++) {
+ parameterSlot[i] = nextSlot;
+ nextSlot += getWordsPerType(parameterTypes[i]);
+ }
+ int localSlot0 = nextSlot;
+ short pc, tryBegin = 0, tryEnd;
+
+ DataOutputStream out = new DataOutputStream(minfo.code);
+
+ code_aload(0, out);
+
+ out.writeByte(opc_getfield);
+ out.writeShort(cp.getFieldRef(
+ superclassName,
+ handlerFieldName, "Ljava/lang/reflect/InvocationHandler;"));
+
+ code_aload(0, out);
+
+ out.writeByte(opc_getstatic);
+ out.writeShort(cp.getFieldRef(
+ dotToSlash(className),
+ methodFieldName, "Ljava/lang/reflect/Method;"));
+
+ if (parameterTypes.length > 0) {
+
+ code_ipush(parameterTypes.length, out);
+
+ out.writeByte(opc_anewarray);
+ out.writeShort(cp.getClass("java/lang/Object"));
+
+ for (int i = 0; i < parameterTypes.length; i++) {
+
+ out.writeByte(opc_dup);
+
+ code_ipush(i, out);
+
+ codeWrapArgument(parameterTypes[i], parameterSlot[i], out);
+
+ out.writeByte(opc_aastore);
+ }
+ } else {
+
+ out.writeByte(opc_aconst_null);
+ }
+
+ out.writeByte(opc_invokeinterface);
+ out.writeShort(cp.getInterfaceMethodRef(
+ "java/lang/reflect/InvocationHandler",
+ "invoke",
+ "(Ljava/lang/Object;Ljava/lang/reflect/Method;" +
+ "[Ljava/lang/Object;)Ljava/lang/Object;"));
+ out.writeByte(4);
+ out.writeByte(0);
+
+ if (returnType == void.class) {
+
+ out.writeByte(opc_pop);
+
+ out.writeByte(opc_return);
+
+ } else {
+
+ codeUnwrapReturnValue(returnType, out);
+ }
+
+ tryEnd = pc = (short) minfo.code.size();
+
+ List<Class<?>> catchList = computeUniqueCatchList(exceptionTypes);
+ if (catchList.size() > 0) {
+
+ for (Class<?> ex : catchList) {
+ minfo.exceptionTable.add(new ExceptionTableEntry(
+ tryBegin, tryEnd, pc,
+ cp.getClass(dotToSlash(ex.getName()))));
+ }
+
+ out.writeByte(opc_athrow);
+
+ pc = (short) minfo.code.size();
+
+ minfo.exceptionTable.add(new ExceptionTableEntry(
+ tryBegin, tryEnd, pc, cp.getClass("java/lang/Throwable")));
+
+ code_astore(localSlot0, out);
+
+ out.writeByte(opc_new);
+ out.writeShort(cp.getClass(
+ "java/lang/reflect/UndeclaredThrowableException"));
+
+ out.writeByte(opc_dup);
+
+ code_aload(localSlot0, out);
+
+ out.writeByte(opc_invokespecial);
+
+ out.writeShort(cp.getMethodRef(
+ "java/lang/reflect/UndeclaredThrowableException",
+ "<init>", "(Ljava/lang/Throwable;)V"));
+
+ out.writeByte(opc_athrow);
+ }
+
+ if (minfo.code.size() > 65535) {
+ throw new IllegalArgumentException("code size limit exceeded");
+ }
+
+ minfo.maxStack = 10;
+ minfo.maxLocals = (short) (localSlot0 + 1);
+ minfo.declaredExceptions = new short[exceptionTypes.length];
+ for (int i = 0; i < exceptionTypes.length; i++) {
+ minfo.declaredExceptions[i] = cp.getClass(
+ dotToSlash(exceptionTypes[i].getName()));
+ }
+
+ return minfo;
+ }
+
+ /**
+ * Generate code for wrapping an argument of the given type
+ * whose value can be found at the specified local variable
+ * index, in order for it to be passed (as an Object) to the
+ * invocation handler's "invoke" method. The code is written
+ * to the supplied stream.
+ */
+ private void codeWrapArgument(Class<?> type, int slot,
+ DataOutputStream out)
+ throws IOException
+ {
+ if (type.isPrimitive()) {
+ PrimitiveTypeInfo prim = PrimitiveTypeInfo.get(type);
+
+ if (type == int.class ||
+ type == boolean.class ||
+ type == byte.class ||
+ type == char.class ||
+ type == short.class)
+ {
+ code_iload(slot, out);
+ } else if (type == long.class) {
+ code_lload(slot, out);
+ } else if (type == float.class) {
+ code_fload(slot, out);
+ } else if (type == double.class) {
+ code_dload(slot, out);
+ } else {
+ throw new AssertionError();
+ }
+
+ out.writeByte(opc_invokestatic);
+ out.writeShort(cp.getMethodRef(
+ prim.wrapperClassName,
+ "valueOf", prim.wrapperValueOfDesc));
+
+ } else {
+
+ code_aload(slot, out);
+ }
+ }
+
+ /**
+ * Generate code for unwrapping a return value of the given
+ * type from the invocation handler's "invoke" method (as type
+ * Object) to its correct type. The code is written to the
+ * supplied stream.
+ */
+ private void codeUnwrapReturnValue(Class<?> type, DataOutputStream out)
+ throws IOException
+ {
+ if (type.isPrimitive()) {
+ PrimitiveTypeInfo prim = PrimitiveTypeInfo.get(type);
+
+ out.writeByte(opc_checkcast);
+ out.writeShort(cp.getClass(prim.wrapperClassName));
+
+ out.writeByte(opc_invokevirtual);
+ out.writeShort(cp.getMethodRef(
+ prim.wrapperClassName,
+ prim.unwrapMethodName, prim.unwrapMethodDesc));
+
+ if (type == int.class ||
+ type == boolean.class ||
+ type == byte.class ||
+ type == char.class ||
+ type == short.class)
+ {
+ out.writeByte(opc_ireturn);
+ } else if (type == long.class) {
+ out.writeByte(opc_lreturn);
+ } else if (type == float.class) {
+ out.writeByte(opc_freturn);
+ } else if (type == double.class) {
+ out.writeByte(opc_dreturn);
+ } else {
+ throw new AssertionError();
+ }
+
+ } else {
+
+ out.writeByte(opc_checkcast);
+ out.writeShort(cp.getClass(dotToSlash(type.getName())));
+
+ out.writeByte(opc_areturn);
+ }
+ }
+
+ /**
+ * Generate code for initializing the static field that stores
+ * the Method object for this proxy method. The code is written
+ * to the supplied stream.
+ */
+ private void codeFieldInitialization(DataOutputStream out)
+ throws IOException
+ {
+ codeClassForName(fromClass, out);
+
+ code_ldc(cp.getString(methodName), out);
+
+ code_ipush(parameterTypes.length, out);
+
+ out.writeByte(opc_anewarray);
+ out.writeShort(cp.getClass("java/lang/Class"));
+
+ for (int i = 0; i < parameterTypes.length; i++) {
+
+ out.writeByte(opc_dup);
+
+ code_ipush(i, out);
+
+ if (parameterTypes[i].isPrimitive()) {
+ PrimitiveTypeInfo prim =
+ PrimitiveTypeInfo.get(parameterTypes[i]);
+
+ out.writeByte(opc_getstatic);
+ out.writeShort(cp.getFieldRef(
+ prim.wrapperClassName, "TYPE", "Ljava/lang/Class;"));
+
+ } else {
+ codeClassForName(parameterTypes[i], out);
+ }
+
+ out.writeByte(opc_aastore);
+ }
+
+ out.writeByte(opc_invokevirtual);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/Class",
+ "getMethod",
+ "(Ljava/lang/String;[Ljava/lang/Class;)" +
+ "Ljava/lang/reflect/Method;"));
+
+ out.writeByte(opc_putstatic);
+ out.writeShort(cp.getFieldRef(
+ dotToSlash(className),
+ methodFieldName, "Ljava/lang/reflect/Method;"));
+ }
+ }
+
+ /**
+ * Generate the constructor method for the proxy class.
+ */
+ private MethodInfo generateConstructor() throws IOException {
+ MethodInfo minfo = new MethodInfo(
+ "<init>", "(Ljava/lang/reflect/InvocationHandler;)V",
+ ACC_PUBLIC);
+
+ DataOutputStream out = new DataOutputStream(minfo.code);
+
+ code_aload(0, out);
+
+ code_aload(1, out);
+
+ out.writeByte(opc_invokespecial);
+ out.writeShort(cp.getMethodRef(
+ superclassName,
+ "<init>", "(Ljava/lang/reflect/InvocationHandler;)V"));
+
+ out.writeByte(opc_return);
+
+ minfo.maxStack = 10;
+ minfo.maxLocals = 2;
+ minfo.declaredExceptions = new short[0];
+
+ return minfo;
+ }
+
+ /**
+ * Generate the static initializer method for the proxy class.
+ */
+ private MethodInfo generateStaticInitializer() throws IOException {
+ MethodInfo minfo = new MethodInfo(
+ "<clinit>", "()V", ACC_STATIC);
+
+ int localSlot0 = 1;
+ short pc, tryBegin = 0, tryEnd;
+
+ DataOutputStream out = new DataOutputStream(minfo.code);
+
+ for (List<ProxyMethod> sigmethods : proxyMethods.values()) {
+ for (ProxyMethod pm : sigmethods) {
+ pm.codeFieldInitialization(out);
+ }
+ }
+
+ out.writeByte(opc_return);
+
+ tryEnd = pc = (short) minfo.code.size();
+
+ minfo.exceptionTable.add(new ExceptionTableEntry(
+ tryBegin, tryEnd, pc,
+ cp.getClass("java/lang/NoSuchMethodException")));
+
+ code_astore(localSlot0, out);
+
+ out.writeByte(opc_new);
+ out.writeShort(cp.getClass("java/lang/NoSuchMethodError"));
+
+ out.writeByte(opc_dup);
+
+ code_aload(localSlot0, out);
+
+ out.writeByte(opc_invokevirtual);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/Throwable", "getMessage", "()Ljava/lang/String;"));
+
+ out.writeByte(opc_invokespecial);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/NoSuchMethodError", "<init>", "(Ljava/lang/String;)V"));
+
+ out.writeByte(opc_athrow);
+
+ pc = (short) minfo.code.size();
+
+ minfo.exceptionTable.add(new ExceptionTableEntry(
+ tryBegin, tryEnd, pc,
+ cp.getClass("java/lang/ClassNotFoundException")));
+
+ code_astore(localSlot0, out);
+
+ out.writeByte(opc_new);
+ out.writeShort(cp.getClass("java/lang/NoClassDefFoundError"));
+
+ out.writeByte(opc_dup);
+
+ code_aload(localSlot0, out);
+
+ out.writeByte(opc_invokevirtual);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/Throwable", "getMessage", "()Ljava/lang/String;"));
+
+ out.writeByte(opc_invokespecial);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/NoClassDefFoundError",
+ "<init>", "(Ljava/lang/String;)V"));
+
+ out.writeByte(opc_athrow);
+
+ if (minfo.code.size() > 65535) {
+ throw new IllegalArgumentException("code size limit exceeded");
+ }
+
+ minfo.maxStack = 10;
+ minfo.maxLocals = (short) (localSlot0 + 1);
+ minfo.declaredExceptions = new short[0];
+
+ return minfo;
+ }
+
+
+ /*
+ * =============== Code Generation Utility Methods ===============
+ */
+
+ /*
+ * The following methods generate code for the load or store operation
+ * indicated by their name for the given local variable. The code is
+ * written to the supplied stream.
+ */
+
+ private void code_iload(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_iload, opc_iload_0, out);
+ }
+
+ private void code_lload(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_lload, opc_lload_0, out);
+ }
+
+ private void code_fload(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_fload, opc_fload_0, out);
+ }
+
+ private void code_dload(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_dload, opc_dload_0, out);
+ }
+
+ private void code_aload(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_aload, opc_aload_0, out);
+ }
+
+// private void code_istore(int lvar, DataOutputStream out)
+// throws IOException
+// {
+// codeLocalLoadStore(lvar, opc_istore, opc_istore_0, out);
+// }
+
+// private void code_lstore(int lvar, DataOutputStream out)
+// throws IOException
+// {
+// codeLocalLoadStore(lvar, opc_lstore, opc_lstore_0, out);
+// }
+
+// private void code_fstore(int lvar, DataOutputStream out)
+// throws IOException
+// {
+// codeLocalLoadStore(lvar, opc_fstore, opc_fstore_0, out);
+// }
+
+// private void code_dstore(int lvar, DataOutputStream out)
+// throws IOException
+// {
+// codeLocalLoadStore(lvar, opc_dstore, opc_dstore_0, out);
+// }
+
+ private void code_astore(int lvar, DataOutputStream out)
+ throws IOException
+ {
+ codeLocalLoadStore(lvar, opc_astore, opc_astore_0, out);
+ }
+
+ /**
+ * Generate code for a load or store instruction for the given local
+ * variable. The code is written to the supplied stream.
+ *
+ * "opcode" indicates the opcode form of the desired load or store
+ * instruction that takes an explicit local variable index, and
+ * "opcode_0" indicates the corresponding form of the instruction
+ * with the implicit index 0.
+ */
+ private void codeLocalLoadStore(int lvar, int opcode, int opcode_0,
+ DataOutputStream out)
+ throws IOException
+ {
+ assert lvar >= 0 && lvar <= 0xFFFF;
+ if (lvar <= 3) {
+ out.writeByte(opcode_0 + lvar);
+ } else if (lvar <= 0xFF) {
+ out.writeByte(opcode);
+ out.writeByte(lvar & 0xFF);
+ } else {
+ /*
+ * Use the "wide" instruction modifier for local variable
+ * indexes that do not fit into an unsigned byte.
+ */
+ out.writeByte(opc_wide);
+ out.writeByte(opcode);
+ out.writeShort(lvar & 0xFFFF);
+ }
+ }
+
+ /**
+ * Generate code for an "ldc" instruction for the given constant pool
+ * index (the "ldc_w" instruction is used if the index does not fit
+ * into an unsigned byte). The code is written to the supplied stream.
+ */
+ private void code_ldc(int index, DataOutputStream out)
+ throws IOException
+ {
+ assert index >= 0 && index <= 0xFFFF;
+ if (index <= 0xFF) {
+ out.writeByte(opc_ldc);
+ out.writeByte(index & 0xFF);
+ } else {
+ out.writeByte(opc_ldc_w);
+ out.writeShort(index & 0xFFFF);
+ }
+ }
+
+ /**
+ * Generate code to push a constant integer value on to the operand
+ * stack, using the "iconst_<i>", "bipush", or "sipush" instructions
+ * depending on the size of the value. The code is written to the
+ * supplied stream.
+ */
+ private void code_ipush(int value, DataOutputStream out)
+ throws IOException
+ {
+ if (value >= -1 && value <= 5) {
+ out.writeByte(opc_iconst_0 + value);
+ } else if (value >= Byte.MIN_VALUE && value <= Byte.MAX_VALUE) {
+ out.writeByte(opc_bipush);
+ out.writeByte(value & 0xFF);
+ } else if (value >= Short.MIN_VALUE && value <= Short.MAX_VALUE) {
+ out.writeByte(opc_sipush);
+ out.writeShort(value & 0xFFFF);
+ } else {
+ throw new AssertionError();
+ }
+ }
+
+ /**
+ * Generate code to invoke the Class.forName with the name of the given
+ * class to get its Class object at runtime. The code is written to
+ * the supplied stream. Note that the code generated by this method
+ * may caused the checked ClassNotFoundException to be thrown.
+ */
+ private void codeClassForName(Class<?> cl, DataOutputStream out)
+ throws IOException
+ {
+ code_ldc(cp.getString(cl.getName()), out);
+
+ out.writeByte(opc_invokestatic);
+ out.writeShort(cp.getMethodRef(
+ "java/lang/Class",
+ "forName", "(Ljava/lang/String;)Ljava/lang/Class;"));
+ }
+
+
+ /*
+ * ==================== 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 "method descriptor" string for a method with the given
+ * parameter types and return type. See JVMS section 4.3.3.
+ */
+ private static String getMethodDescriptor(Class<?>[] parameterTypes,
+ Class<?> returnType)
+ {
+ return getParameterDescriptors(parameterTypes) +
+ ((returnType == void.class) ? "V" : getFieldType(returnType));
+ }
+
+ /**
+ * 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();
+ }
+
+ /**
+ * Return the number of abstract "words", or consecutive local variable
+ * indexes, required to contain a value of the given type. See JVMS
+ * section 3.6.1.
+ *
+ * Note that the original version of the JVMS contained a definition of
+ * this abstract notion of a "word" in section 3.4, but that definition
+ * was removed for the second edition.
+ */
+ private static int getWordsPerType(Class<?> type) {
+ if (type == long.class || type == double.class) {
+ return 2;
+ } else {
+ return 1;
+ }
+ }
+
+ /**
+ * 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<Class<?>> list)
+ {
+ for (Class<?> fc: from) {
+ if (!list.contains(fc)) {
+ for (Class<?> wc: with) {
+ if (wc.isAssignableFrom(fc)) {
+ list.add(fc);
+ break;
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * Given the exceptions declared in the throws clause of a proxy method,
+ * compute the exceptions that need to be caught from the invocation
+ * handler's invoke method and rethrown intact in the method's
+ * implementation before catching other Throwables and wrapping them
+ * in UndeclaredThrowableExceptions.
+ *
+ * The exceptions to be caught are returned in a List object. Each
+ * exception in the returned list is guaranteed to not be a subclass of
+ * any of the other exceptions in the list, so the catch blocks for
+ * these exceptions may be generated in any order relative to each other.
+ *
+ * Error and RuntimeException are each always contained by the returned
+ * list (if none of their superclasses are contained), since those
+ * unchecked exceptions should always be rethrown intact, and thus their
+ * subclasses will never appear in the returned list.
+ *
+ * The returned List will be empty if java.lang.Throwable is in the
+ * given list of declared exceptions, indicating that no exceptions
+ * need to be caught.
+ */
+ private static List<Class<?>> computeUniqueCatchList(Class<?>[] exceptions) {
+ List<Class<?>> uniqueList = new ArrayList<>();
+ // unique exceptions to catch
+
+ uniqueList.add(Error.class); // always catch/rethrow these
+ uniqueList.add(RuntimeException.class);
+
+ nextException:
+ for (Class<?> ex: exceptions) {
+ if (ex.isAssignableFrom(Throwable.class)) {
+ /*
+ * If Throwable is declared to be thrown by the proxy method,
+ * then no catch blocks are necessary, because the invoke
+ * can, at most, throw Throwable anyway.
+ */
+ uniqueList.clear();
+ break;
+ } else if (!Throwable.class.isAssignableFrom(ex)) {
+ /*
+ * Ignore types that cannot be thrown by the invoke method.
+ */
+ continue;
+ }
+ /*
+ * Compare this exception against the current list of
+ * exceptions that need to be caught:
+ */
+ for (int j = 0; j < uniqueList.size();) {
+ Class<?> ex2 = uniqueList.get(j);
+ if (ex2.isAssignableFrom(ex)) {
+ /*
+ * if a superclass of this exception is already on
+ * the list to catch, then ignore this one and continue;
+ */
+ continue nextException;
+ } else if (ex.isAssignableFrom(ex2)) {
+ /*
+ * if a subclass of this exception is on the list
+ * to catch, then remove it;
+ */
+ uniqueList.remove(j);
+ } else {
+ j++; // else continue comparing.
+ }
+ }
+ // This exception is unique (so far): add it to the list to catch.
+ uniqueList.add(ex);
+ }
+ return uniqueList;
+ }
+
+ /**
+ * 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<Class<?>,PrimitiveTypeInfo> 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<Entry> 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<Object,Short> 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(i);
+ }
+
+ /**
+ * Get or assign the index for a CONSTANT_Float entry.
+ */
+ public short getFloat(float f) {
+ return getValue(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, 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, 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 abstract static 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;
+ }
+ }
+ }
+}