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package jdk.nashorn.internal.runtime.linker;

import static jdk.nashorn.internal.runtime.JSType.isString;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.util.Map;
import java.util.Objects;
import jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.Operation;
import jdk.dynalink.StandardOperation;
import jdk.dynalink.linker.GuardedInvocation;
import jdk.dynalink.linker.LinkRequest;
import jdk.dynalink.linker.LinkerServices;
import jdk.dynalink.linker.TypeBasedGuardingDynamicLinker;
import jdk.nashorn.api.scripting.JSObject;
import jdk.nashorn.api.scripting.ScriptObjectMirror;
import jdk.nashorn.internal.lookup.MethodHandleFactory;
import jdk.nashorn.internal.lookup.MethodHandleFunctionality;
import jdk.nashorn.internal.runtime.Context;
import jdk.nashorn.internal.runtime.JSType;
import jdk.nashorn.internal.runtime.ScriptRuntime;
import jdk.nashorn.internal.objects.Global;

A Dynalink linker to handle web browser built-in JS (DOM etc.) objects as well as ScriptObjects from other Nashorn contexts.
/** * A Dynalink linker to handle web browser built-in JS (DOM etc.) objects as well * as ScriptObjects from other Nashorn contexts. */
final class JSObjectLinker implements TypeBasedGuardingDynamicLinker { private final NashornBeansLinker nashornBeansLinker; JSObjectLinker(final NashornBeansLinker nashornBeansLinker) { this.nashornBeansLinker = nashornBeansLinker; } @Override public boolean canLinkType(final Class<?> type) { return canLinkTypeStatic(type); } private static boolean canLinkTypeStatic(final Class<?> type) { // can link JSObject also handles Map (this includes Bindings) to make // sure those are not JSObjects. return Map.class.isAssignableFrom(type) || JSObject.class.isAssignableFrom(type); } @Override public GuardedInvocation getGuardedInvocation(final LinkRequest request, final LinkerServices linkerServices) throws Exception { final Object self = request.getReceiver(); final CallSiteDescriptor desc = request.getCallSiteDescriptor(); if (self == null || !canLinkTypeStatic(self.getClass())) { return null; } GuardedInvocation inv; if (self instanceof JSObject) { inv = lookup(desc, request, linkerServices); inv = inv.replaceMethods(linkerServices.filterInternalObjects(inv.getInvocation()), inv.getGuard()); } else if (self instanceof Map) { // guard to make sure the Map or Bindings does not turn into JSObject later! final GuardedInvocation beanInv = nashornBeansLinker.getGuardedInvocation(request, linkerServices); inv = new GuardedInvocation(beanInv.getInvocation(), NashornGuards.combineGuards(beanInv.getGuard(), NashornGuards.getNotJSObjectGuard())); } else { throw new AssertionError("got instanceof: " + self.getClass()); // Should never reach here. } return Bootstrap.asTypeSafeReturn(inv, linkerServices, desc); } private GuardedInvocation lookup(final CallSiteDescriptor desc, final LinkRequest request, final LinkerServices linkerServices) throws Exception { final Operation op = NashornCallSiteDescriptor.getBaseOperation(desc); if (op instanceof StandardOperation) { final String name = NashornCallSiteDescriptor.getOperand(desc); switch ((StandardOperation)op) { case GET: if (NashornCallSiteDescriptor.hasStandardNamespace(desc)) { if (name != null) { return findGetMethod(name); } // For indexed get, we want get GuardedInvocation beans linker and pass it. // JSObjectLinker.get uses this fallback getter for explicit signature method access. return findGetIndexMethod(nashornBeansLinker.getGuardedInvocation(request, linkerServices)); } break; case SET: if (NashornCallSiteDescriptor.hasStandardNamespace(desc)) { return name != null ? findSetMethod(name) : findSetIndexMethod(); } break; case REMOVE: if (NashornCallSiteDescriptor.hasStandardNamespace(desc)) { return new GuardedInvocation( name == null ? JSOBJECTLINKER_DEL : MH.insertArguments(JSOBJECTLINKER_DEL, 1, name), IS_JSOBJECT_GUARD); } break; case CALL: return findCallMethod(desc); case NEW: return findNewMethod(desc); default: } } return null; } private static GuardedInvocation findGetMethod(final String name) { 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 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) { MethodHandle mh = NashornCallSiteDescriptor.isScope(desc)? JSOBJECT_SCOPE_CALL : JSOBJECT_CALL; if (NashornCallSiteDescriptor.isApplyToCall(desc)) { mh = MH.insertArguments(JSOBJECT_CALL_TO_APPLY, 0, mh); } final MethodType type = desc.getMethodType(); mh = type.parameterType(type.parameterCount() - 1) == Object[].class ? mh : MH.asCollector(mh, Object[].class, type.parameterCount() - 2); return new GuardedInvocation(mh, IS_JSOBJECT_GUARD); } private static GuardedInvocation findNewMethod(final CallSiteDescriptor desc) { final MethodHandle func = MH.asCollector(JSOBJECT_NEW, Object[].class, desc.getMethodType().parameterCount() - 1); return new GuardedInvocation(func, IS_JSOBJECT_GUARD); } @SuppressWarnings("unused") private static boolean isJSObject(final Object self) { return self instanceof JSObject; } @SuppressWarnings("unused") private static Object get(final MethodHandle fallback, final Object jsobj, final Object key) throws Throwable { if (key instanceof Integer) { return ((JSObject)jsobj).getSlot((Integer)key); } else if (key instanceof Number) { final int index = getIndex((Number)key); if (index > -1) { return ((JSObject)jsobj).getSlot(index); } else { return ((JSObject)jsobj).getMember(JSType.toString(key)); } } else if (isString(key)) { final String name = key.toString(); // get with method name and signature. delegate it to beans linker! if (name.indexOf('(') != -1) { return fallback.invokeExact(jsobj, (Object) name); } return ((JSObject)jsobj).getMember(name); } return null; } @SuppressWarnings("unused") private static void put(final Object jsobj, final Object key, final Object value) { if (key instanceof Integer) { ((JSObject)jsobj).setSlot((Integer)key, value); } else if (key instanceof Number) { final int index = getIndex((Number)key); if (index > -1) { ((JSObject)jsobj).setSlot(index, value); } else { ((JSObject)jsobj).setMember(JSType.toString(key), value); } } else if (isString(key)) { ((JSObject)jsobj).setMember(key.toString(), value); } } @SuppressWarnings("unused") private static boolean del(final Object jsobj, final Object key) { if (jsobj instanceof ScriptObjectMirror) { return ((ScriptObjectMirror)jsobj).delete(key); } ((JSObject) jsobj).removeMember(Objects.toString(key)); return true; } private static int getIndex(final Number n) { final double value = n.doubleValue(); return JSType.isRepresentableAsInt(value) ? (int)value : -1; } @SuppressWarnings("unused") private static Object callToApply(final MethodHandle mh, final JSObject obj, final Object thiz, final Object... args) { assert args.length >= 1; final Object receiver = args[0]; final Object[] arguments = new Object[args.length - 1]; System.arraycopy(args, 1, arguments, 0, arguments.length); try { return mh.invokeExact(obj, thiz, new Object[] { receiver, arguments }); } catch (final RuntimeException | Error e) { throw e; } catch (final Throwable e) { throw new RuntimeException(e); } } // This is used when a JSObject is called as scope call to do undefined -> Global this translation. @SuppressWarnings("unused") private static Object jsObjectScopeCall(final JSObject jsObj, final Object thiz, final Object[] args) { final Object modifiedThiz; if (thiz == ScriptRuntime.UNDEFINED && !jsObj.isStrictFunction()) { final Global global = Context.getGlobal(); modifiedThiz = ScriptObjectMirror.wrap(global, global); } else { modifiedThiz = thiz; } return jsObj.call(modifiedThiz, args); } 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 final MethodHandle JSOBJECTLINKER_DEL = findOwnMH_S("del", boolean.class, Object.class, Object.class); // method handles of JSObject class private static final MethodHandle JSOBJECT_GETMEMBER = findJSObjectMH_V("getMember", Object.class, String.class); private static final MethodHandle JSOBJECT_SETMEMBER = findJSObjectMH_V("setMember", Void.TYPE, String.class, Object.class); private static final MethodHandle JSOBJECT_CALL = findJSObjectMH_V("call", Object.class, Object.class, Object[].class); private static final MethodHandle JSOBJECT_SCOPE_CALL = findOwnMH_S("jsObjectScopeCall", Object.class, JSObject.class, Object.class, Object[].class); private static final MethodHandle JSOBJECT_CALL_TO_APPLY = findOwnMH_S("callToApply", Object.class, MethodHandle.class, JSObject.class, Object.class, Object[].class); private static final MethodHandle JSOBJECT_NEW = findJSObjectMH_V("newObject", Object.class, Object[].class); private static MethodHandle findJSObjectMH_V(final String name, final Class<?> rtype, final Class<?>... types) { return MH.findVirtual(MethodHandles.lookup(), JSObject.class, name, MH.type(rtype, types)); } private static MethodHandle findOwnMH_S(final String name, final Class<?> rtype, final Class<?>... types) { return MH.findStatic(MethodHandles.lookup(), JSObjectLinker.class, name, MH.type(rtype, types)); } }