JSObjectLinker.java revision 1483:7cb19fa78763 
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.runtime.JSType.isString;
29
30import java.lang.invoke.MethodHandle;
31import java.lang.invoke.MethodHandles;
32import java.util.Map;
33import javax.script.Bindings;
34import jdk.internal.dynalink.CallSiteDescriptor;
35import jdk.internal.dynalink.StandardOperation;
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.nashorn.api.scripting.JSObject;
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 as well
47 * as ScriptObjects from other Nashorn contexts.
48 */
49final class JSObjectLinker implements TypeBasedGuardingDynamicLinker {
50    private final NashornBeansLinker nashornBeansLinker;
51
52    JSObjectLinker(final NashornBeansLinker nashornBeansLinker) {
53        this.nashornBeansLinker = nashornBeansLinker;
54    }
55
56    @Override
57    public boolean canLinkType(final Class<?> type) {
58        return canLinkTypeStatic(type);
59    }
60
61    static boolean canLinkTypeStatic(final Class<?> type) {
62        // can link JSObject also handles Map, Bindings to make
63        // sure those are not JSObjects.
64        return Map.class.isAssignableFrom(type) ||
65               Bindings.class.isAssignableFrom(type) ||
66               JSObject.class.isAssignableFrom(type);
67    }
68
69    @Override
70    public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception {
71        final Object self = request.getReceiver();
72        final CallSiteDescriptor desc = request.getCallSiteDescriptor();
73
74        GuardedInvocation inv;
75        if (self instanceof JSObject) {
76            inv = lookup(desc, request, linkerServices);
77            inv = inv.replaceMethods(linkerServices.filterInternalObjects(inv.getInvocation()), inv.getGuard());
78        } else if (self instanceof Map || self instanceof Bindings) {
79            // guard to make sure the Map or Bindings does not turn into JSObject later!
80            final GuardedInvocation beanInv = nashornBeansLinker.getGuardedInvocation(request, linkerServices);
81            inv = new GuardedInvocation(beanInv.getInvocation(),
82                NashornGuards.combineGuards(beanInv.getGuard(), NashornGuards.getNotJSObjectGuard()));
83        } else {
84            throw new AssertionError(); // Should never reach here.
85        }
86
87        return Bootstrap.asTypeSafeReturn(inv, linkerServices, desc);
88    }
89
90    private GuardedInvocation lookup(final CallSiteDescriptor desc, final LinkRequest request, final LinkerServices linkerServices) throws Exception {
91        final StandardOperation op = NashornCallSiteDescriptor.getFirstStandardOperation(desc);
92        if (op == null) {
93            return null;
94        }
95        final String name = NashornCallSiteDescriptor.getOperand(desc);
96        switch (op) {
97        case GET_PROPERTY:
98        case GET_ELEMENT:
99        case GET_METHOD:
100            if (name != null) {
101                return findGetMethod(name);
102            }
103            // For indexed get, we want get GuardedInvocation beans linker and pass it.
104            // JSObjectLinker.get uses this fallback getter for explicit signature method access.
105            return findGetIndexMethod(nashornBeansLinker.getGuardedInvocation(request, linkerServices));
106        case SET_PROPERTY:
107        case SET_ELEMENT:
108            return name != null ? findSetMethod(name) : findSetIndexMethod();
109        case CALL:
110            return findCallMethod(desc);
111        case NEW:
112            return findNewMethod(desc);
113        default:
114        }
115        return null;
116    }
117
118    private static GuardedInvocation findGetMethod(final String name) {
119        final MethodHandle getter = MH.insertArguments(JSOBJECT_GETMEMBER, 1, name);
120        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
121    }
122
123    private static GuardedInvocation findGetIndexMethod(final GuardedInvocation inv) {
124        final MethodHandle getter = MH.insertArguments(JSOBJECTLINKER_GET, 0, inv.getInvocation());
125        return inv.replaceMethods(getter, inv.getGuard());
126    }
127
128    private static GuardedInvocation findSetMethod(final String name) {
129        final MethodHandle getter = MH.insertArguments(JSOBJECT_SETMEMBER, 1, name);
130        return new GuardedInvocation(getter, IS_JSOBJECT_GUARD);
131    }
132
133    private static GuardedInvocation findSetIndexMethod() {
134        return new GuardedInvocation(JSOBJECTLINKER_PUT, IS_JSOBJECT_GUARD);
135    }
136
137    private static GuardedInvocation findCallMethod(final CallSiteDescriptor desc) {
138        // TODO: if call site is already a vararg, don't do asCollector
139        MethodHandle mh = JSOBJECT_CALL;
140        if (NashornCallSiteDescriptor.isApplyToCall(desc)) {
141            mh = MH.insertArguments(JSOBJECT_CALL_TO_APPLY, 0, JSOBJECT_CALL);
142        }
143        return new GuardedInvocation(MH.asCollector(mh, Object[].class, desc.getMethodType().parameterCount() - 2), IS_JSOBJECT_GUARD);
144    }
145
146    private static GuardedInvocation findNewMethod(final CallSiteDescriptor desc) {
147        final MethodHandle func = MH.asCollector(JSOBJECT_NEW, Object[].class, desc.getMethodType().parameterCount() - 1);
148        return new GuardedInvocation(func, IS_JSOBJECT_GUARD);
149    }
150
151    @SuppressWarnings("unused")
152    private static boolean isJSObject(final Object self) {
153        return self instanceof JSObject;
154    }
155
156    @SuppressWarnings("unused")
157    private static Object get(final MethodHandle fallback, final Object jsobj, final Object key)
158        throws Throwable {
159        if (key instanceof Integer) {
160            return ((JSObject)jsobj).getSlot((Integer)key);
161        } else if (key instanceof Number) {
162            final int index = getIndex((Number)key);
163            if (index > -1) {
164                return ((JSObject)jsobj).getSlot(index);
165            }
166        } else if (isString(key)) {
167            final String name = key.toString();
168            // get with method name and signature. delegate it to beans linker!
169            if (name.indexOf('(') != -1) {
170                return fallback.invokeExact(jsobj, (Object) name);
171            }
172            return ((JSObject)jsobj).getMember(name);
173        }
174        return null;
175    }
176
177    @SuppressWarnings("unused")
178    private static void put(final Object jsobj, final Object key, final Object value) {
179        if (key instanceof Integer) {
180            ((JSObject)jsobj).setSlot((Integer)key, value);
181        } else if (key instanceof Number) {
182            ((JSObject)jsobj).setSlot(getIndex((Number)key), value);
183        } else if (isString(key)) {
184            ((JSObject)jsobj).setMember(key.toString(), value);
185        }
186    }
187
188    private static int getIndex(final Number n) {
189        final double value = n.doubleValue();
190        return JSType.isRepresentableAsInt(value) ? (int)value : -1;
191    }
192
193    @SuppressWarnings("unused")
194    private static Object callToApply(final MethodHandle mh, final JSObject obj, final Object thiz, final Object... args) {
195        assert args.length >= 2;
196        final Object   receiver  = args[0];
197        final Object[] arguments = new Object[args.length - 1];
198        System.arraycopy(args, 1, arguments, 0, arguments.length);
199        try {
200            return mh.invokeExact(obj, thiz, new Object[] { receiver, arguments });
201        } catch (final RuntimeException | Error e) {
202            throw e;
203        } catch (final Throwable e) {
204            throw new RuntimeException(e);
205        }
206    }
207
208    private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality();
209
210    // method handles of the current class
211    private static final MethodHandle IS_JSOBJECT_GUARD  = findOwnMH_S("isJSObject", boolean.class, Object.class);
212    private static final MethodHandle JSOBJECTLINKER_GET = findOwnMH_S("get", Object.class, MethodHandle.class, Object.class, Object.class);
213    private static final MethodHandle JSOBJECTLINKER_PUT = findOwnMH_S("put", Void.TYPE, Object.class, Object.class, Object.class);
214
215    // method handles of JSObject class
216    private static final MethodHandle JSOBJECT_GETMEMBER     = findJSObjectMH_V("getMember", Object.class, String.class);
217    private static final MethodHandle JSOBJECT_SETMEMBER     = findJSObjectMH_V("setMember", Void.TYPE, String.class, Object.class);
218    private static final MethodHandle JSOBJECT_CALL          = findJSObjectMH_V("call", Object.class, Object.class, Object[].class);
219    private static final MethodHandle JSOBJECT_CALL_TO_APPLY = findOwnMH_S("callToApply", Object.class, MethodHandle.class, JSObject.class, Object.class, Object[].class);
220    private static final MethodHandle JSOBJECT_NEW           = findJSObjectMH_V("newObject", Object.class, Object[].class);
221
222    private static MethodHandle findJSObjectMH_V(final String name, final Class<?> rtype, final Class<?>... types) {
223        return MH.findVirtual(MethodHandles.lookup(), JSObject.class, name, MH.type(rtype, types));
224    }
225
226    private static MethodHandle findOwnMH_S(final String name, final Class<?> rtype, final Class<?>... types) {
227        return MH.findStatic(MethodHandles.lookup(), JSObjectLinker.class, name, MH.type(rtype, types));
228    }
229}
230