1 /*
2 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.reflect.code.op;
27
28 import java.lang.annotation.ElementType;
29 import java.lang.annotation.Retention;
30 import java.lang.annotation.RetentionPolicy;
31 import java.lang.annotation.Target;
32 import java.lang.invoke.MethodHandle;
33 import java.lang.invoke.MethodHandles;
34 import java.lang.reflect.Constructor;
35 import java.lang.reflect.Method;
36 import java.lang.reflect.Modifier;
37 import java.lang.reflect.code.Op;
38 import java.util.HashMap;
39 import java.util.Map;
40 import java.util.function.Function;
41
42 /**
43 * An operation factory for constructing an {@link Op operation} from its
44 * {@link ExternalizableOp.ExternalizedOp external content}.
45 */
46 @FunctionalInterface
47 public interface OpFactory {
48
49 /**
50 * An operation declaration annotation.
51 * <p>
52 * This annotation may be declared on a concrete class implementing an {@link Op operation} whose name is a constant
53 * that can be declared as this attribute's value.
54 * <p>
55 * Tooling can process declarations of this annotation to build a factory for constructing operations from their name.
56 */
57 @Retention(RetentionPolicy.RUNTIME)
58 @Target(ElementType.TYPE)
59 @interface OpDeclaration {
60 /**
61 * {@return the operation name}
62 */
63 String value();
64 }
65
66 /**
67 * A class value for lazily computing an operation factory for {@link Op operation} classes
68 * annotated with {@link OpDeclaration} and enclosed within a given class to compute over.
69 * <p>
70 * Each enclosed class annotated with {@code OpDeclaration} must declare a public static method named {@code create}
71 * with one parameter type of {@link ExternalizableOp.ExternalizedOp} and return type that is the concrete class type.
72 * Alternatively, the concrete class must declare public constructor with one parameter type of
73 * {@link ExternalizableOp.ExternalizedOp}.
74 */
75 ClassValue<OpFactory> OP_FACTORY = new ClassValue<>() {
76 @Override
77 protected OpFactory computeValue(Class<?> c) {
78 // @@@ See https://bugs.openjdk.org/browse/JDK-8321207
79 final Map<String, Class<? extends Op>> opMapping = createOpMapping(c);
80
81 return def -> {
82 var opClass = opMapping.get(def.name());
83 if (opClass == null) {
84 return null;
85 }
86
87 return constructOp(opClass, def);
88 };
89 }
90 };
91
92 /**
93 * Constructs an {@link Op operation} from its external content.
94 * <p>
95 * If there is no mapping from the operation's name to a concrete
96 * class of an {@code Op} then this method returns null.
97 *
98 * @param def the operation's external content
99 * @return the operation, otherwise null
100 */
101 Op constructOp(ExternalizableOp.ExternalizedOp def);
102
103 /**
104 * Constructs an {@link Op operation} from its external content.
105 * <p>
106 * If there is no mapping from the operation's name to a concrete
107 * class of an {@code Op} then this method throws UnsupportedOperationException.
108 *
109 * @param def the operation's external content
110 * @return the operation, otherwise null
111 * @throws UnsupportedOperationException if there is no mapping from the operation's
112 * name to a concrete class of an {@code Op}
113 */
114 default Op constructOpOrFail(ExternalizableOp.ExternalizedOp def) {
115 Op op = constructOp(def);
116 if (op == null) {
117 throw new UnsupportedOperationException("Unsupported operation: " + def.name());
118 }
119
120 return op;
121 }
122
123 /**
124 * Compose this operation factory with another operation factory.
125 * <p>
126 * If there is no mapping in this operation factory then the result
127 * of the other operation factory is returned.
128 *
129 * @param after the other operation factory.
130 * @return the composed operation factory.
131 */
132 default OpFactory andThen(OpFactory after) {
133 return def -> {
134 Op op = constructOp(def);
135 return op != null ? op : after.constructOp(def);
136 };
137 }
138
139 private static Map<String, Class<? extends Op>> createOpMapping(Class<?> opClasses) {
140 Map<String, Class<? extends Op>> mapping = new HashMap<>();
141 for (Class<?> opClass : opClasses.getNestMembers()) {
142 if (opClass.isAnnotationPresent(OpDeclaration.class)) {
143 if (!Modifier.isPublic(opClass.getModifiers())) {
144 throw new InternalError("Operation class not public: " + opClass.getName());
145 }
146
147 if (!Op.class.isAssignableFrom(opClass)) {
148 throw new InternalError("Operation class is not assignable to Op: " + opClass);
149 }
150
151 MethodHandle handle = getOpConstructorMethodHandle(opClass);
152 if (handle == null) {
153 throw new InternalError("Operation constructor for operation class not found: " + opClass.getName());
154 }
155
156 if (!Op.class.isAssignableFrom(handle.type().returnType())) {
157 throw new InternalError("Operation constructor does not return an Op: " + handle);
158 }
159
160 String opName = opClass.getAnnotation(OpDeclaration.class).value();
161 @SuppressWarnings("unchecked")
162 var opClassCast = (Class<Op>) opClass;
163 mapping.put(opName, opClassCast);
164 }
165 }
166 return mapping;
167 }
168
169 private static MethodHandle getOpConstructorMethodHandle(Class<?> opClass) {
170 Method method = null;
171 try {
172 method = opClass.getMethod("create", ExternalizableOp.ExternalizedOp.class);
173 } catch (NoSuchMethodException e) {
174 }
175
176 if (method != null) {
177 if (!Modifier.isStatic(method.getModifiers())) {
178 throw new InternalError("Operation constructor is not a static method: " + method);
179 }
180
181 try {
182 /*__return MethodHandles.lookup().unreflect(method);__*/ return MethodHandles.publicLookup().unreflect(method);
183 } catch (IllegalAccessException e) {
184 throw new InternalError("Inaccessible operation constructor for operation: " +
185 method);
186 }
187 }
188
189 Constructor<?> constructor;
190 try {
191 constructor = opClass.getConstructor(ExternalizableOp.ExternalizedOp.class);
192 } catch (NoSuchMethodException e) {
193 return null;
194 }
195
196 try {
197 /*__return MethodHandles.lookup().unreflectConstructor(constructor);__*/ return MethodHandles.publicLookup().unreflectConstructor(constructor);
198 } catch (IllegalAccessException e) {
199 throw new InternalError("Inaccessible operation constructor for operation: " +
200 constructor);
201 }
202 }
203
204 private static Op constructOp(Class<? extends Op> opClass, ExternalizableOp.ExternalizedOp opDef) {
205 class Enclosed {
206 private static final ClassValue<Function<ExternalizableOp.ExternalizedOp, Op>> OP_CONSTRUCTOR = new ClassValue<>() {
207 @Override
208 protected Function<ExternalizableOp.ExternalizedOp, Op> computeValue(Class<?> opClass) {
209 final MethodHandle opConstructorMH = getOpConstructorMethodHandle(opClass);
210 assert opConstructorMH != null;
211
212 return operationDefinition -> {
213 try {
214 return (Op) opConstructorMH.invoke(operationDefinition);
215 } catch (RuntimeException | Error e) {
216 throw e;
217 } catch (Throwable t) {
218 throw new RuntimeException(t);
219 }
220 };
221 }
222 };
223 }
224 return Enclosed.OP_CONSTRUCTOR.get(opClass).apply(opDef);
225 }
226 }