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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package jdk.nashorn.internal.runtime.linker;

import static jdk.nashorn.internal.runtime.JSType.isString;
import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_CALL;
import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETMEMBER;
import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_GETSLOT;
import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETMEMBER;
import static jdk.nashorn.internal.runtime.linker.BrowserJSObjectLinker.JSObjectHandles.JSOBJECT_SETSLOT;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.linker.GuardedInvocation;
import jdk.dynalink.linker.LinkRequest;
import jdk.dynalink.linker.LinkerServices;
import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
import jdk.nashorn.internal.lookup.MethodHandleFactory;
import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
import jdk.nashorn.internal.runtime.JSType;

A Dynalink linker to handle web browser built-in JS (DOM etc.) objects.
/** * A Dynalink linker to handle web browser built-in JS (DOM etc.) objects. */
final class BrowserJSObjectLinker implements TypeBasedGuardingDynamicLinker { private static final String JSOBJECT_CLASS = "netscape.javascript.JSObject"; private static final Class<?> jsObjectClass = findBrowserJSObjectClass(); private final NashornBeansLinker nashornBeansLinker; BrowserJSObjectLinker(final NashornBeansLinker nashornBeansLinker) { this.nashornBeansLinker = nashornBeansLinker; } @Override public boolean canLinkType(final Class<?> type) { return canLinkTypeStatic(type); } static boolean canLinkTypeStatic(final Class<?> type) { return jsObjectClass != null && jsObjectClass.isAssignableFrom(type); } private static void checkJSObjectClass() { assert jsObjectClass != null : JSOBJECT_CLASS + " not found!"; } @Override public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception { final Object self = request.getReceiver(); final CallSiteDescriptor desc = request.getCallSiteDescriptor(); checkJSObjectClass(); assert jsObjectClass.isInstance(self); GuardedInvocation inv = lookup(desc, request, linkerServices); inv = inv.replaceMethods(linkerServices.filterInternalObjects(inv.getInvocation()), inv.getGuard()); return Bootstrap.asTypeSafeReturn(inv, linkerServices, desc); } private GuardedInvocation lookup(final CallSiteDescriptor desc, final LinkRequest request, final LinkerServices linkerServices) throws Exception { GuardedInvocation inv; try { inv = nashornBeansLinker.getGuardedInvocation(request, linkerServices); } catch (final Throwable th) { inv = null; } final String name = NashornCallSiteDescriptor.getOperand(desc); switch (NashornCallSiteDescriptor.getStandardOperation(desc)) { case GET: return name != null ? findGetMethod(name, inv) : findGetIndexMethod(inv); case SET: return name != null ? findSetMethod(name, inv) : findSetIndexMethod(); case CALL: return findCallMethod(desc); default: return null; } } private static GuardedInvocation findGetMethod(final String name, final GuardedInvocation inv) { if (inv != null) { return inv; } final MethodHandle getter = MH.insertArguments(JSOBJECT_GETMEMBER, 1, name); return new GuardedInvocation(getter, IS_JSOBJECT_GUARD); } private static GuardedInvocation findGetIndexMethod(final GuardedInvocation inv) { final MethodHandle getter = MH.insertArguments(JSOBJECTLINKER_GET, 0, inv.getInvocation()); return inv.replaceMethods(getter, inv.getGuard()); } private static GuardedInvocation findSetMethod(final String name, final GuardedInvocation inv) { if (inv != null) { return inv; } final MethodHandle getter = MH.insertArguments(JSOBJECT_SETMEMBER, 1, name); return new GuardedInvocation(getter, IS_JSOBJECT_GUARD); } private static GuardedInvocation findSetIndexMethod() { return new GuardedInvocation(JSOBJECTLINKER_PUT, IS_JSOBJECT_GUARD); } private static GuardedInvocation findCallMethod(final CallSiteDescriptor desc) { final MethodHandle call = MH.insertArguments(JSOBJECT_CALL, 1, "call"); return new GuardedInvocation(MH.asCollector(call, Object[].class, desc.getMethodType().parameterCount() - 1), IS_JSOBJECT_GUARD); } @SuppressWarnings("unused") private static boolean isJSObject(final Object self) { return jsObjectClass.isInstance(self); } @SuppressWarnings("unused") private static Object get(final MethodHandle fallback, final Object jsobj, final Object key) throws Throwable { if (key instanceof Integer) { return JSOBJECT_GETSLOT.invokeExact(jsobj, (int)key); } else if (key instanceof Number) { final int index = getIndex((Number)key); if (index > -1) { return JSOBJECT_GETSLOT.invokeExact(jsobj, index); } } else if (isString(key)) { final String name = key.toString(); if (name.indexOf('(') != -1) { return fallback.invokeExact(jsobj, (Object) name); } return JSOBJECT_GETMEMBER.invokeExact(jsobj, name); } return null; } @SuppressWarnings("unused") private static void put(final Object jsobj, final Object key, final Object value) throws Throwable { if (key instanceof Integer) { JSOBJECT_SETSLOT.invokeExact(jsobj, (int)key, value); } else if (key instanceof Number) { JSOBJECT_SETSLOT.invokeExact(jsobj, getIndex((Number)key), value); } else if (isString(key)) { JSOBJECT_SETMEMBER.invokeExact(jsobj, key.toString(), value); } } private static int getIndex(final Number n) { final double value = n.doubleValue(); return JSType.isRepresentableAsInt(value) ? (int)value : -1; } private static final MethodHandleFunctionality MH = MethodHandleFactory.getFunctionality(); // method handles of the current class private static final MethodHandle IS_JSOBJECT_GUARD = findOwnMH_S("isJSObject", boolean.class, Object.class); private static final MethodHandle JSOBJECTLINKER_GET = findOwnMH_S("get", Object.class, MethodHandle.class, Object.class, Object.class); private static final MethodHandle JSOBJECTLINKER_PUT = findOwnMH_S("put", Void.TYPE, Object.class, Object.class, Object.class); private static MethodHandle findOwnMH_S(final String name, final Class<?> rtype, final Class<?>... types) { return MH.findStatic(MethodHandles.lookup(), BrowserJSObjectLinker.class, name, MH.type(rtype, types)); } // method handles of netscape.javascript.JSObject class // These are in separate class as we lazily initialize these // method handles when we hit a subclass of JSObject first time. static class JSObjectHandles { // method handles of JSObject class static final MethodHandle JSOBJECT_GETMEMBER = findJSObjectMH_V("getMember", Object.class, String.class).asType(MH.type(Object.class, Object.class, String.class)); static final MethodHandle JSOBJECT_GETSLOT = findJSObjectMH_V("getSlot", Object.class, int.class).asType(MH.type(Object.class, Object.class, int.class)); 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)); 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)); 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)); private static MethodHandle findJSObjectMH_V(final String name, final Class<?> rtype, final Class<?>... types) { checkJSObjectClass(); return MH.findVirtual(MethodHandles.publicLookup(), jsObjectClass, name, MH.type(rtype, types)); } } private static Class<?> findBrowserJSObjectClass() { ClassLoader extLoader; extLoader = BrowserJSObjectLinker.class.getClassLoader(); // in case nashorn is loaded as bootstrap! if (extLoader == null) { extLoader = ClassLoader.getSystemClassLoader().getParent(); } try { return Class.forName(JSOBJECT_CLASS, false, extLoader); } catch (final ClassNotFoundException e) { return null; } } }