BrowserJSObjectLinker.java revision 1483:7cb19fa78763 
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.JSType.isString;
29import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_CALL;
30import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETMEMBER;
31import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETSLOT;
32import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETMEMBER;
33import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETSLOT;
34
35import java.lang.invoke.MethodHandle;
36import java.lang.invoke.MethodHandles;
37import jdk.internal.dynalink.CallSiteDescriptor;
38import jdk.internal.dynalink.StandardOperation;
39import jdk.internal.dynalink.linker.GuardedInvocation;
40import jdk.internal.dynalink.linker.LinkRequest;
41import jdk.internal.dynalink.linker.LinkerServices;
42import jdk.internal.dynalink.linker.TypeBasedGuardingDynamicLinker;
43import jdk.nashorn.internal.lookup.MethodHandleFactory;
44import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
45import jdk.nashorn.internal.runtime.JSType;
46
47/**
48 * A Dynalink linker to handle web browser built-in JS (DOM etc.) objects.
49 */
50final class BrowserJSObjectLinker implements TypeBasedGuardingDynamicLinker {
51    private static ClassLoader extLoader;
52    static {
53        extLoader = BrowserJSObjectLinker.class.getClassLoader();
54        // in case nashorn is loaded as bootstrap!
55        if (extLoader == null) {
56            extLoader = ClassLoader.getSystemClassLoader().getParent();
57        }
58    }
59
60    private static final String JSOBJECT_CLASS = "netscape.javascript.JSObject";
61    // not final because this is lazily initialized
62    // when we hit a subclass for the first time.
63    private static volatile Class<?> jsObjectClass;
64    private final NashornBeansLinker nashornBeansLinker;
65
66    BrowserJSObjectLinker(final NashornBeansLinker nashornBeansLinker) {
67        this.nashornBeansLinker = nashornBeansLinker;
68    }
69
70    @Override
71    public boolean canLinkType(final Class<?> type) {
72        return canLinkTypeStatic(type);
73    }
74
75    static boolean canLinkTypeStatic(final Class<?> type) {
76        if (jsObjectClass != null && jsObjectClass.isAssignableFrom(type)) {
77            return true;
78        }
79
80        // check if this class is a subclass of JSObject
81        Class<?> clazz = type;
82        while (clazz != null) {
83            if (clazz.getClassLoader() == extLoader &&
84                clazz.getName().equals(JSOBJECT_CLASS)) {
85                jsObjectClass = clazz;
86                return true;
87            }
88            clazz = clazz.getSuperclass();
89        }
90
91        return false;
92    }
93
94    private static void checkJSObjectClass() {
95        assert jsObjectClass != null : JSOBJECT_CLASS + " not found!";
96    }
97
98    @Override
99    public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception {
100        final Object self = request.getReceiver();
101        final CallSiteDescriptor desc = request.getCallSiteDescriptor();
102        checkJSObjectClass();
103
104        GuardedInvocation inv;
105        if (jsObjectClass.isInstance(self)) {
106            inv = lookup(desc, request, linkerServices);
107            inv = inv.replaceMethods(linkerServices.filterInternalObjects(inv.getInvocation()), inv.getGuard());
108        } else {
109            throw new AssertionError(); // Should never reach here.
110        }
111
112        return Bootstrap.asTypeSafeReturn(inv, linkerServices, desc);
113    }
114
115    private GuardedInvocation lookup(final CallSiteDescriptor desc, final LinkRequest request, final LinkerServices linkerServices) throws Exception {
116        GuardedInvocation inv;
117        try {
118            inv = nashornBeansLinker.getGuardedInvocation(request, linkerServices);
119        } catch (final Throwable th) {
120            inv = null;
121        }
122
123        final StandardOperation op = NashornCallSiteDescriptor.getFirstStandardOperation(desc);
124        if (op == null) {
125            return null;
126        }
127        final String name = NashornCallSiteDescriptor.getOperand(desc);
128        switch (op) {
129        case GET_PROPERTY:
130        case GET_ELEMENT:
131        case GET_METHOD:
132            return name != null ? findGetMethod(name, inv) : findGetIndexMethod(inv);
133        case SET_PROPERTY:
134        case SET_ELEMENT:
135            return name != null ? findSetMethod(name, inv) : findSetIndexMethod();
136        case CALL:
137            return findCallMethod(desc);
138        default:
139        }
140        return null;
141    }
142
143    private static GuardedInvocation findGetMethod(final String name, final GuardedInvocation inv) {
144        if (inv != null) {
145            return inv;
146        }
147        final MethodHandle getter = MH.insertArguments(JSOBJECT_GETMEMBER, 1, name);
148        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
149    }
150
151    private static GuardedInvocation findGetIndexMethod(final GuardedInvocation inv) {
152        final MethodHandle getter = MH.insertArguments(JSOBJECTLINKER_GET, 0, inv.getInvocation());
153        return inv.replaceMethods(getter, inv.getGuard());
154    }
155
156    private static GuardedInvocation findSetMethod(final String name, final GuardedInvocation inv) {
157        if (inv != null) {
158            return inv;
159        }
160        final MethodHandle getter = MH.insertArguments(JSOBJECT_SETMEMBER, 1, name);
161        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
162    }
163
164    private static GuardedInvocation findSetIndexMethod() {
165        return new GuardedInvocation(JSOBJECTLINKER_PUT, IS_JSOBJECT_GUARD);
166    }
167
168    private static GuardedInvocation findCallMethod(final CallSiteDescriptor desc) {
169        final MethodHandle call = MH.insertArguments(JSOBJECT_CALL, 1, "call");
170        return new GuardedInvocation(MH.asCollector(call, Object[].class, desc.getMethodType().parameterCount() - 1), IS_JSOBJECT_GUARD);
171    }
172
173    @SuppressWarnings("unused")
174    private static boolean isJSObject(final Object self) {
175        return jsObjectClass.isInstance(self);
176    }
177
178    @SuppressWarnings("unused")
179    private static Object get(final MethodHandle fallback, final Object jsobj, final Object key) throws Throwable {
180        if (key instanceof Integer) {
181            return JSOBJECT_GETSLOT.invokeExact(jsobj, (int)key);
182        } else if (key instanceof Number) {
183            final int index = getIndex((Number)key);
184            if (index > -1) {
185                return JSOBJECT_GETSLOT.invokeExact(jsobj, index);
186            }
187        } else if (isString(key)) {
188            final String name = key.toString();
189            if (name.indexOf('(') != -1) {
190                return fallback.invokeExact(jsobj, (Object) name);
191            }
192            return JSOBJECT_GETMEMBER.invokeExact(jsobj, name);
193        }
194        return null;
195    }
196
197    @SuppressWarnings("unused")
198    private static void put(final Object jsobj, final Object key, final Object value) throws Throwable {
199        if (key instanceof Integer) {
200            JSOBJECT_SETSLOT.invokeExact(jsobj, (int)key, value);
201        } else if (key instanceof Number) {
202            JSOBJECT_SETSLOT.invokeExact(jsobj, getIndex((Number)key), value);
203        } else if (isString(key)) {
204            JSOBJECT_SETMEMBER.invokeExact(jsobj, key.toString(), value);
205        }
206    }
207
208    private static int getIndex(final Number n) {
209        final double value = n.doubleValue();
210        return JSType.isRepresentableAsInt(value) ? (int)value : -1;
211    }
212
213    private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality();
214    // method handles of the current class
215    private static final MethodHandle IS_JSOBJECT_GUARD  = findOwnMH_S("isJSObject", boolean.class, Object.class);
216    private static final MethodHandle JSOBJECTLINKER_GET = findOwnMH_S("get", Object.class, MethodHandle.class, Object.class, Object.class);
217    private static final MethodHandle JSOBJECTLINKER_PUT = findOwnMH_S("put", Void.TYPE, Object.class, Object.class, Object.class);
218
219    private static MethodHandle findOwnMH_S(final String name, final Class<?> rtype, final Class<?>... types) {
220            return MH.findStatic(MethodHandles.lookup(), BrowserJSObjectLinker.class, name, MH.type(rtype, types));
221    }
222
223    // method handles of netscape.javascript.JSObject class
224    // These are in separate class as we lazily initialize these
225    // method handles when we hit a subclass of JSObject first time.
226    static class JSObjectHandles {
227        // method handles of JSObject class
228        static final MethodHandle JSOBJECT_GETMEMBER     = findJSObjectMH_V("getMember", Object.class, String.class).asType(MH.type(Object.class, Object.class, String.class));
229        static final MethodHandle JSOBJECT_GETSLOT       = findJSObjectMH_V("getSlot", Object.class, int.class).asType(MH.type(Object.class, Object.class, int.class));
230        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));
231        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));
232        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));
233
234        private static MethodHandle findJSObjectMH_V(final String name, final Class<?> rtype, final Class<?>... types) {
235            checkJSObjectClass();
236            return MH.findVirtual(MethodHandles.publicLookup(), jsObjectClass, name, MH.type(rtype, types));
237        }
238    }
239}
240