1 /*
2 * Copyright (c) 2010, 2013, 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 jdk.nashorn.internal.runtime.linker;
27
28 import static jdk.nashorn.internal.lookup.Lookup.MH;
29 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
30 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
31
32 import java.lang.invoke.MethodHandle;
33 import java.lang.invoke.MethodType;
34 import java.lang.reflect.Method;
35 import java.lang.reflect.Modifier;
36 import java.util.HashMap;
37 import java.util.Map;
38 import jdk.internal.dynalink.CallSiteDescriptor;
39 import jdk.internal.dynalink.beans.BeansLinker;
40 import jdk.internal.dynalink.linker.GuardedInvocation;
41 import jdk.internal.dynalink.linker.GuardedTypeConversion;
42 import jdk.internal.dynalink.linker.GuardingDynamicLinker;
43 import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
44 import jdk.internal.dynalink.linker.LinkRequest;
45 import jdk.internal.dynalink.linker.LinkerServices;
46 import jdk.internal.dynalink.support.Guards;
47 import jdk.nashorn.internal.codegen.types.Type;
48 import jdk.nashorn.internal.runtime.Context;
49 import jdk.nashorn.internal.runtime.JSType;
50 import jdk.nashorn.internal.runtime.ScriptRuntime;
51 import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;
52
53 /**
54 * Nashorn bottom linker; used as a last-resort catch-all linker for all linking requests that fall through all other
55 * linkers (see how {@link Bootstrap} class configures the dynamic linker in its static initializer). It will throw
56 * appropriate ECMAScript errors for attempts to invoke operations on {@code null}, link no-op property getters and
57 * setters for Java objects that couldn't be linked by any other linker, and throw appropriate ECMAScript errors for
58 * attempts to invoke arbitrary Java objects as functions or constructors.
59 */
60 final class NashornBottomLinker implements GuardingDynamicLinker, GuardingTypeConverterFactory {
61
62 @Override
63 public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices)
64 throws Exception {
65 final Object self = linkRequest.getReceiver();
66
67 if (self == null) {
68 return linkNull(linkRequest);
69 }
70
71 // None of the objects that can be linked by NashornLinker should ever reach here. Basically, anything below
72 // this point is a generic Java bean. Therefore, reaching here with a ScriptObject is a Nashorn bug.
73 assert isExpectedObject(self) : "Couldn't link " + linkRequest.getCallSiteDescriptor() + " for " + self.getClass().getName();
74
75 return linkBean(linkRequest, linkerServices);
76 }
77
78 private static final MethodHandle EMPTY_PROP_GETTER =
79 MH.dropArguments(MH.constant(Object.class, UNDEFINED), 0, Object.class);
80 private static final MethodHandle EMPTY_ELEM_GETTER =
81 MH.dropArguments(EMPTY_PROP_GETTER, 0, Object.class);
82 private static final MethodHandle EMPTY_PROP_SETTER =
83 MH.asType(EMPTY_ELEM_GETTER, EMPTY_ELEM_GETTER.type().changeReturnType(void.class));
84 private static final MethodHandle EMPTY_ELEM_SETTER =
85 MH.dropArguments(EMPTY_PROP_SETTER, 0, Object.class);
86
87 private static GuardedInvocation linkBean(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
88 final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
89 final Object self = linkRequest.getReceiver();
90 final String operator = desc.getFirstOperator();
91 switch (operator) {
92 case "new":
93 if(BeansLinker.isDynamicMethod(self)) {
94 throw typeError("method.not.constructor", ScriptRuntime.safeToString(self));
95 }
96 throw typeError("not.a.function", ScriptRuntime.safeToString(self));
97 case "call":
98 // Support dyn:call on any object that supports some @FunctionalInterface
99 // annotated interface. This way Java method, constructor references or
100 // implementations of java.util.function.* interfaces can be called as though
101 // those are script functions.
102 final Method m = getFunctionalInterfaceMethod(self.getClass());
103 if (m != null) {
104 final MethodType callType = desc.getMethodType();
105 // 'callee' and 'thiz' passed from script + actual arguments
106 if (callType.parameterCount() != m.getParameterCount() + 2) {
107 throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
108 }
109 return Bootstrap.asTypeSafeReturn(new GuardedInvocation(
110 // drop 'thiz' passed from the script.
111 MH.dropArguments(desc.getLookup().unreflect(m), 1, callType.parameterType(1)),
112 Guards.getInstanceOfGuard(m.getDeclaringClass())), linkerServices, desc);
113 }
114 if(BeansLinker.isDynamicConstructor(self)) {
115 throw typeError("constructor.requires.new", ScriptRuntime.safeToString(self));
116 }
117 if(BeansLinker.isDynamicMethod(self)) {
118 throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
119 }
120 throw typeError("not.a.function", ScriptRuntime.safeToString(self));
121 case "callMethod":
122 case "getMethod":
123 throw typeError("no.such.function", getArgument(linkRequest), ScriptRuntime.safeToString(self));
124 case "getProp":
125 case "getElem":
126 if(NashornCallSiteDescriptor.isOptimistic(desc)) {
127 throw new UnwarrantedOptimismException(UNDEFINED, NashornCallSiteDescriptor.getProgramPoint(desc), Type.OBJECT);
128 }
129 if (desc.getOperand() != null) {
130 return getInvocation(EMPTY_PROP_GETTER, self, linkerServices, desc);
131 }
132 return getInvocation(EMPTY_ELEM_GETTER, self, linkerServices, desc);
133 case "setProp":
134 case "setElem":
135 if (desc.getOperand() != null) {
136 return getInvocation(EMPTY_PROP_SETTER, self, linkerServices, desc);
137 }
138 return getInvocation(EMPTY_ELEM_SETTER, self, linkerServices, desc);
139 default:
140 break;
141 }
142 throw new AssertionError("unknown call type " + desc);
143 }
144
145 @Override
146 public GuardedTypeConversion convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception {
147 final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType);
148 return gi == null ? null : new GuardedTypeConversion(gi.asType(MH.type(targetType, sourceType)), true);
149 }
150
151 /**
152 * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't
153 * care about adapting the method signature; that's done by the invoking method. Returns conversion from Object to String/number/boolean (JS primitive types).
154 * @param sourceType the source type
155 * @param targetType the target type
156 * @return a guarded invocation that converts from the source type to the target type.
157 * @throws Exception if something goes wrong
158 */
159 private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception {
160 final MethodHandle mh = CONVERTERS.get(targetType);
161 if (mh != null) {
162 return new GuardedInvocation(mh);
163 }
164
165 return null;
166 }
167
168 private static GuardedInvocation getInvocation(final MethodHandle handle, final Object self, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
169 return Bootstrap.asTypeSafeReturn(new GuardedInvocation(handle, Guards.getClassGuard(self.getClass())), linkerServices, desc);
170 }
171
172 // Used solely in an assertion to figure out if the object we get here is something we in fact expect. Objects
173 // linked by NashornLinker should never reach here.
174 private static boolean isExpectedObject(final Object obj) {
175 return !(NashornLinker.canLinkTypeStatic(obj.getClass()));
176 }
177
178 private static GuardedInvocation linkNull(final LinkRequest linkRequest) {
179 final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
180 final String operator = desc.getFirstOperator();
181 switch (operator) {
182 case "new":
183 case "call":
184 throw typeError("not.a.function", "null");
185 case "callMethod":
186 case "getMethod":
187 throw typeError("no.such.function", getArgument(linkRequest), "null");
188 case "getProp":
189 case "getElem":
190 throw typeError("cant.get.property", getArgument(linkRequest), "null");
191 case "setProp":
192 case "setElem":
193 throw typeError("cant.set.property", getArgument(linkRequest), "null");
194 default:
195 break;
196 }
197 throw new AssertionError("unknown call type " + desc);
198 }
199
200 private static final Map<Class<?>, MethodHandle> CONVERTERS = new HashMap<>();
201 static {
202 CONVERTERS.put(boolean.class, JSType.TO_BOOLEAN.methodHandle());
203 CONVERTERS.put(double.class, JSType.TO_NUMBER.methodHandle());
204 CONVERTERS.put(int.class, JSType.TO_INTEGER.methodHandle());
205 CONVERTERS.put(long.class, JSType.TO_LONG.methodHandle());
206 CONVERTERS.put(String.class, JSType.TO_STRING.methodHandle());
207 }
208
209 private static String getArgument(final LinkRequest linkRequest) {
210 final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
211 if (desc.getNameTokenCount() > 2) {
212 return desc.getNameToken(2);
213 }
214 return ScriptRuntime.safeToString(linkRequest.getArguments()[1]);
215 }
216
217 // cache of @FunctionalInterface method of implementor classes
218 private static final ClassValue<Method> FUNCTIONAL_IFACE_METHOD = new ClassValue<Method>() {
219 @Override
220 protected Method computeValue(final Class<?> type) {
221 return findFunctionalInterfaceMethod(type);
222 }
223
224 private Method findFunctionalInterfaceMethod(final Class<?> clazz) {
225 if (clazz == null) {
226 return null;
227 }
228
229 for (final Class<?> iface : clazz.getInterfaces()) {
230 // check accessiblity up-front
231 if (! Context.isAccessibleClass(iface)) {
232 continue;
233 }
234
235 // check for @FunctionalInterface
236 if (iface.isAnnotationPresent(FunctionalInterface.class)) {
237 // return the first abstract method
238 for (final Method m : iface.getMethods()) {
239 if (Modifier.isAbstract(m.getModifiers())) {
240 return m;
241 }
242 }
243 }
244 }
245
246 // did not find here, try super class
247 return findFunctionalInterfaceMethod(clazz.getSuperclass());
248 }
249 };
250
251 // Returns @FunctionalInterface annotated interface's single abstract
252 // method. If not found, returns null.
253 static Method getFunctionalInterfaceMethod(final Class<?> clazz) {
254 return FUNCTIONAL_IFACE_METHOD.get(clazz);
255 }
256 }