NashornBottomLinker.java revision 1369:a3c6abd88eb4 
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
26package jdk.nashorn.internal.runtime.linker;
27
28import static jdk.nashorn.internal.lookup.Lookup.MH;
29import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
30import static jdk.nashorn.internal.runtime.JSType.GET_UNDEFINED;
31import static jdk.nashorn.internal.runtime.JSType.TYPE_OBJECT_INDEX;
32import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
33
34import java.lang.invoke.MethodHandle;
35import java.util.HashMap;
36import java.util.Map;
37import jdk.internal.dynalink.CallSiteDescriptor;
38import jdk.internal.dynalink.beans.BeansLinker;
39import jdk.internal.dynalink.linker.GuardedInvocation;
40import jdk.internal.dynalink.linker.GuardedTypeConversion;
41import jdk.internal.dynalink.linker.GuardingDynamicLinker;
42import jdk.internal.dynalink.linker.GuardingTypeConverterFactory;
43import jdk.internal.dynalink.linker.LinkRequest;
44import jdk.internal.dynalink.linker.LinkerServices;
45import jdk.internal.dynalink.support.Guards;
46import jdk.nashorn.internal.codegen.types.Type;
47import jdk.nashorn.internal.runtime.JSType;
48import jdk.nashorn.internal.runtime.ScriptRuntime;
49import jdk.nashorn.internal.runtime.UnwarrantedOptimismException;
50
51/**
52 * Nashorn bottom linker; used as a last-resort catch-all linker for all linking requests that fall through all other
53 * linkers (see how {@link Bootstrap} class configures the dynamic linker in its static initializer). It will throw
54 * appropriate ECMAScript errors for attempts to invoke operations on {@code null}, link no-op property getters and
55 * setters for Java objects that couldn't be linked by any other linker, and throw appropriate ECMAScript errors for
56 * attempts to invoke arbitrary Java objects as functions or constructors.
57 */
58final class NashornBottomLinker implements GuardingDynamicLinker, GuardingTypeConverterFactory {
59
60    @Override
61    public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices)
62            throws Exception {
63        final Object self = linkRequest.getReceiver();
64
65        if (self == null) {
66            return linkNull(linkRequest);
67        }
68
69        // None of the objects that can be linked by NashornLinker should ever reach here. Basically, anything below
70        // this point is a generic Java bean. Therefore, reaching here with a ScriptObject is a Nashorn bug.
71        assert isExpectedObject(self) : "Couldn't link " + linkRequest.getCallSiteDescriptor() + " for " + self.getClass().getName();
72
73        return linkBean(linkRequest, linkerServices);
74    }
75
76    private static final MethodHandle EMPTY_PROP_GETTER =
77            MH.dropArguments(MH.constant(Object.class, UNDEFINED), 0, Object.class);
78    private static final MethodHandle EMPTY_ELEM_GETTER =
79            MH.dropArguments(EMPTY_PROP_GETTER, 0, Object.class);
80    private static final MethodHandle EMPTY_PROP_SETTER =
81            MH.asType(EMPTY_ELEM_GETTER, EMPTY_ELEM_GETTER.type().changeReturnType(void.class));
82    private static final MethodHandle EMPTY_ELEM_SETTER =
83            MH.dropArguments(EMPTY_PROP_SETTER, 0, Object.class);
84
85    private static GuardedInvocation linkBean(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception {
86        final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
87        final Object self = linkRequest.getReceiver();
88        final String operator = desc.getFirstOperator();
89        switch (operator) {
90        case "new":
91            if(BeansLinker.isDynamicConstructor(self)) {
92                throw typeError("no.constructor.matches.args", ScriptRuntime.safeToString(self));
93            }
94            if(BeansLinker.isDynamicMethod(self)) {
95                throw typeError("method.not.constructor", ScriptRuntime.safeToString(self));
96            }
97            throw typeError("not.a.function", desc.getFunctionErrorMessage(self));
98        case "call":
99            if(BeansLinker.isDynamicConstructor(self)) {
100                throw typeError("constructor.requires.new", ScriptRuntime.safeToString(self));
101            }
102            if(BeansLinker.isDynamicMethod(self)) {
103                throw typeError("no.method.matches.args", ScriptRuntime.safeToString(self));
104            }
105            throw typeError("not.a.function", desc.getFunctionErrorMessage(self));
106        case "callMethod":
107            throw typeError("no.such.function", getArgument(linkRequest), ScriptRuntime.safeToString(self));
108        case "getMethod":
109            // evaluate to undefined, later on Undefined will take care of throwing TypeError
110            return getInvocation(MH.dropArguments(GET_UNDEFINED.get(TYPE_OBJECT_INDEX), 0, Object.class), self, linkerServices, desc);
111        case "getProp":
112        case "getElem":
113            if(NashornCallSiteDescriptor.isOptimistic(desc)) {
114                throw new UnwarrantedOptimismException(UNDEFINED, NashornCallSiteDescriptor.getProgramPoint(desc), Type.OBJECT);
115            }
116            if (desc.getOperand() != null) {
117                return getInvocation(EMPTY_PROP_GETTER, self, linkerServices, desc);
118            }
119            return getInvocation(EMPTY_ELEM_GETTER, self, linkerServices, desc);
120        case "setProp":
121        case "setElem": {
122            final boolean strict = NashornCallSiteDescriptor.isStrict(desc);
123            if (strict) {
124                throw typeError("cant.set.property", getArgument(linkRequest), ScriptRuntime.safeToString(self));
125            }
126            if (desc.getOperand() != null) {
127                return getInvocation(EMPTY_PROP_SETTER, self, linkerServices, desc);
128            }
129            return getInvocation(EMPTY_ELEM_SETTER, self, linkerServices, desc);
130        }
131        default:
132            break;
133        }
134        throw new AssertionError("unknown call type " + desc);
135    }
136
137    @Override
138    public GuardedTypeConversion convertToType(final Class<?> sourceType, final Class<?> targetType) throws Exception {
139        final GuardedInvocation gi = convertToTypeNoCast(sourceType, targetType);
140        return gi == null ? null : new GuardedTypeConversion(gi.asType(MH.type(targetType, sourceType)), true);
141    }
142
143    /**
144     * Main part of the implementation of {@link GuardingTypeConverterFactory#convertToType(Class, Class)} that doesn't
145     * care about adapting the method signature; that's done by the invoking method. Returns conversion from Object to String/number/boolean (JS primitive types).
146     * @param sourceType the source type
147     * @param targetType the target type
148     * @return a guarded invocation that converts from the source type to the target type.
149     * @throws Exception if something goes wrong
150     */
151    private static GuardedInvocation convertToTypeNoCast(final Class<?> sourceType, final Class<?> targetType) throws Exception {
152        final MethodHandle mh = CONVERTERS.get(targetType);
153        if (mh != null) {
154            return new GuardedInvocation(mh);
155        }
156
157        return null;
158    }
159
160    private static GuardedInvocation getInvocation(final MethodHandle handle, final Object self, final LinkerServices linkerServices, final CallSiteDescriptor desc) {
161        return Bootstrap.asTypeSafeReturn(new GuardedInvocation(handle, Guards.getClassGuard(self.getClass())), linkerServices, desc);
162    }
163
164    // Used solely in an assertion to figure out if the object we get here is something we in fact expect. Objects
165    // linked by NashornLinker should never reach here.
166    private static boolean isExpectedObject(final Object obj) {
167        return !(NashornLinker.canLinkTypeStatic(obj.getClass()));
168    }
169
170    private static GuardedInvocation linkNull(final LinkRequest linkRequest) {
171        final NashornCallSiteDescriptor desc = (NashornCallSiteDescriptor)linkRequest.getCallSiteDescriptor();
172        final String operator = desc.getFirstOperator();
173        switch (operator) {
174        case "new":
175        case "call":
176            throw typeError("not.a.function", "null");
177        case "callMethod":
178        case "getMethod":
179            throw typeError("no.such.function", getArgument(linkRequest), "null");
180        case "getProp":
181        case "getElem":
182            throw typeError("cant.get.property", getArgument(linkRequest), "null");
183        case "setProp":
184        case "setElem":
185            throw typeError("cant.set.property", getArgument(linkRequest), "null");
186        default:
187            break;
188        }
189        throw new AssertionError("unknown call type " + desc);
190    }
191
192    private static final Map<Class<?>, MethodHandle> CONVERTERS = new HashMap<>();
193    static {
194        CONVERTERS.put(boolean.class, JSType.TO_BOOLEAN.methodHandle());
195        CONVERTERS.put(double.class, JSType.TO_NUMBER.methodHandle());
196        CONVERTERS.put(int.class, JSType.TO_INTEGER.methodHandle());
197        CONVERTERS.put(long.class, JSType.TO_LONG.methodHandle());
198        CONVERTERS.put(String.class, JSType.TO_STRING.methodHandle());
199    }
200
201    private static String getArgument(final LinkRequest linkRequest) {
202        final CallSiteDescriptor desc = linkRequest.getCallSiteDescriptor();
203        if (desc.getNameTokenCount() > 2) {
204            return desc.getNameToken(2);
205        }
206        return ScriptRuntime.safeToString(linkRequest.getArguments()[1]);
207    }
208}
209