BrowserJSObjectLinker.java revision 1138:5cda82fecbc5 
1/*
2 * Copyright (c) 2014, 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.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETMEMBER;
29import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETSLOT;
30import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETMEMBER;
31import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETSLOT;
32import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_CALL;
33import java.lang.invoke.MethodHandle;
34import java.lang.invoke.MethodHandles;
35import jdk.internal.dynalink.CallSiteDescriptor;
36import jdk.internal.dynalink.linker.GuardedInvocation;
37import jdk.internal.dynalink.linker.LinkRequest;
38import jdk.internal.dynalink.linker.LinkerServices;
39import jdk.internal.dynalink.linker.TypeBasedGuardingDynamicLinker;
40import jdk.internal.dynalink.support.CallSiteDescriptorFactory;
41import jdk.nashorn.internal.lookup.MethodHandleFactory;
42import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
43import jdk.nashorn.internal.runtime.JSType;
44
45/**
46 * A Dynalink linker to handle web browser built-in JS (DOM etc.) objects.
47 */
48final class BrowserJSObjectLinker implements TypeBasedGuardingDynamicLinker {
49    private static ClassLoader extLoader;
50    static {
51        extLoader = BrowserJSObjectLinker.class.getClassLoader();
52        // in case nashorn is loaded as bootstrap!
53        if (extLoader == null) {
54            extLoader = ClassLoader.getSystemClassLoader().getParent();
55        }
56    }
57
58    private static final String JSOBJECT_CLASS = "netscape.javascript.JSObject";
59    // not final because this is lazily initialized
60    // when we hit a subclass for the first time.
61    private static volatile Class<?> jsObjectClass;
62    private final NashornBeansLinker nashornBeansLinker;
63
64    BrowserJSObjectLinker(final NashornBeansLinker nashornBeansLinker) {
65        this.nashornBeansLinker = nashornBeansLinker;
66    }
67
68    @Override
69    public boolean canLinkType(final Class<?> type) {
70        return canLinkTypeStatic(type);
71    }
72
73    static boolean canLinkTypeStatic(final Class<?> type) {
74        if (jsObjectClass != null && jsObjectClass.isAssignableFrom(type)) {
75            return true;
76        }
77
78        // check if this class is a subclass of JSObject
79        Class<?> clazz = type;
80        while (clazz != null) {
81            if (clazz.getClassLoader() == extLoader &&
82                clazz.getName().equals(JSOBJECT_CLASS)) {
83                jsObjectClass = clazz;
84                return true;
85            }
86            clazz = clazz.getSuperclass();
87        }
88
89        return false;
90    }
91
92    private static void checkJSObjectClass() {
93        assert jsObjectClass != null : JSOBJECT_CLASS + " not found!";
94    }
95
96    @Override
97    public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception {
98        final LinkRequest requestWithoutContext = request.withoutRuntimeContext(); // Nashorn has no runtime context
99        final Object self = requestWithoutContext.getReceiver();
100        final CallSiteDescriptor desc = requestWithoutContext.getCallSiteDescriptor();
101        checkJSObjectClass();
102
103        if (desc.getNameTokenCount() < 2 || !"dyn".equals(desc.getNameToken(CallSiteDescriptor.SCHEME))) {
104            // We only support standard "dyn:*[:*]" operations
105            return null;
106        }
107
108        final GuardedInvocation inv;
109        if (jsObjectClass.isInstance(self)) {
110            inv = lookup(desc, request, linkerServices);
111        } else {
112            throw new AssertionError(); // Should never reach here.
113        }
114
115        return Bootstrap.asTypeSafeReturn(inv, linkerServices, desc);
116    }
117
118    private GuardedInvocation lookup(final CallSiteDescriptor desc, final LinkRequest request, final LinkerServices linkerServices) throws Exception {
119        final String operator = CallSiteDescriptorFactory.tokenizeOperators(desc).get(0);
120        final int c = desc.getNameTokenCount();
121
122        switch (operator) {
123            case "getProp":
124            case "getElem":
125            case "getMethod":
126                if (c > 2) {
127                    return findGetMethod(desc);
128                }
129            // For indexed get, we want GuardedInvocation from beans linker and pass it.
130            // BrowserJSObjectLinker.get uses this fallback getter for explicit signature method access.
131            return findGetIndexMethod(nashornBeansLinker.getGuardedInvocation(request, linkerServices));
132            case "setProp":
133            case "setElem":
134                return c > 2 ? findSetMethod(desc) : findSetIndexMethod();
135            case "call":
136                return findCallMethod(desc);
137            default:
138                return null;
139        }
140    }
141
142    private static GuardedInvocation findGetMethod(final CallSiteDescriptor desc) {
143        final String name = desc.getNameToken(CallSiteDescriptor.NAME_OPERAND);
144        final MethodHandle getter = MH.insertArguments(JSOBJECT_GETMEMBER, 1, name);
145        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
146    }
147
148    private static GuardedInvocation findGetIndexMethod(final GuardedInvocation inv) {
149        final MethodHandle getter = MH.insertArguments(JSOBJECTLINKER_GET, 0, inv.getInvocation());
150        return inv.replaceMethods(getter, inv.getGuard());
151    }
152
153    private static GuardedInvocation findSetMethod(final CallSiteDescriptor desc) {
154        final MethodHandle getter = MH.insertArguments(JSOBJECT_SETMEMBER, 1, desc.getNameToken(2));
155        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
156    }
157
158    private static GuardedInvocation findSetIndexMethod() {
159        return new GuardedInvocation(JSOBJECTLINKER_PUT, IS_JSOBJECT_GUARD);
160    }
161
162    private static GuardedInvocation findCallMethod(final CallSiteDescriptor desc) {
163        final MethodHandle call = MH.insertArguments(JSOBJECT_CALL, 1, "call");
164        return new GuardedInvocation(MH.asCollector(call, Object[].class, desc.getMethodType().parameterCount() - 1), IS_JSOBJECT_GUARD);
165    }
166
167    @SuppressWarnings("unused")
168    private static boolean isJSObject(final Object self) {
169        return jsObjectClass.isInstance(self);
170    }
171
172    @SuppressWarnings("unused")
173    private static Object get(final MethodHandle fallback, final Object jsobj, final Object key) throws Throwable {
174        if (key instanceof Integer) {
175            return JSOBJECT_GETSLOT.invokeExact(jsobj, (int)key);
176        } else if (key instanceof Number) {
177            final int index = getIndex((Number)key);
178            if (index > -1) {
179                return JSOBJECT_GETSLOT.invokeExact(jsobj, index);
180            }
181        } else if (key instanceof String) {
182            final String name = (String)key;
183            if (name.indexOf('(') != -1) {
184                return fallback.invokeExact(jsobj, key);
185            }
186            return JSOBJECT_GETMEMBER.invokeExact(jsobj, (String)key);
187        }
188        return null;
189    }
190
191    @SuppressWarnings("unused")
192    private static void put(final Object jsobj, final Object key, final Object value) throws Throwable {
193        if (key instanceof Integer) {
194            JSOBJECT_SETSLOT.invokeExact(jsobj, (int)key, value);
195        } else if (key instanceof Number) {
196            JSOBJECT_SETSLOT.invokeExact(jsobj, getIndex((Number)key), value);
197        } else if (key instanceof String) {
198            JSOBJECT_SETMEMBER.invokeExact(jsobj, (String)key, value);
199        }
200    }
201
202    private static int getIndex(final Number n) {
203        final double value = n.doubleValue();
204        return JSType.isRepresentableAsInt(value) ? (int)value : -1;
205    }
206
207    private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality();
208    // method handles of the current class
209    private static final MethodHandle IS_JSOBJECT_GUARD  = findOwnMH_S("isJSObject", boolean.class, Object.class);
210    private static final MethodHandle JSOBJECTLINKER_GET = findOwnMH_S("get", Object.class, MethodHandle.class, Object.class, Object.class);
211    private static final MethodHandle JSOBJECTLINKER_PUT = findOwnMH_S("put", Void.TYPE, Object.class, Object.class, Object.class);
212
213    private static MethodHandle findOwnMH_S(final String name, final Class<?> rtype, final Class<?>... types) {
214            return MH.findStatic(MethodHandles.lookup(), BrowserJSObjectLinker.class, name, MH.type(rtype, types));
215    }
216
217    // method handles of netscape.javascript.JSObject class
218    // These are in separate class as we lazily initialize these
219    // method handles when we hit a subclass of JSObject first time.
220    static class JSObjectHandles {
221        // method handles of JSObject class
222        static final MethodHandle JSOBJECT_GETMEMBER     = findJSObjectMH_V("getMember", Object.class, String.class).asType(MH.type(Object.class, Object.class, String.class));
223        static final MethodHandle JSOBJECT_GETSLOT       = findJSObjectMH_V("getSlot", Object.class, int.class).asType(MH.type(Object.class, Object.class, int.class));
224        static final MethodHandle JSOBJECT_SETMEMBER     = findJSObjectMH_V("setMember", Void.TYPE, String.class, Object.class).asType(MH.type(Void.TYPE, Object.class, String.class, Object.class));
225        static final MethodHandle JSOBJECT_SETSLOT       = findJSObjectMH_V("setSlot", Void.TYPE, int.class, Object.class).asType(MH.type(Void.TYPE, Object.class, int.class, Object.class));
226        static final MethodHandle JSOBJECT_CALL          = findJSObjectMH_V("call", Object.class, String.class, Object[].class).asType(MH.type(Object.class, Object.class, String.class, Object[].class));
227
228        private static MethodHandle findJSObjectMH_V(final String name, final Class<?> rtype, final Class<?>... types) {
229            checkJSObjectClass();
230            return MH.findVirtual(MethodHandles.publicLookup(), jsObjectClass, name, MH.type(rtype, types));
231        }
232    }
233}
234