| /* |
| * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * 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. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package jdk.nashorn.internal.runtime.linker; |
| |
| import java.lang.invoke.MethodHandle; |
| import java.lang.invoke.MethodHandles; |
| import java.lang.invoke.MethodType; |
| import java.util.Arrays; |
| import jdk.internal.dynalink.CallSiteDescriptor; |
| import jdk.internal.dynalink.linker.GuardedInvocation; |
| import jdk.internal.dynalink.linker.LinkRequest; |
| import jdk.internal.dynalink.linker.LinkerServices; |
| import jdk.internal.dynalink.linker.TypeBasedGuardingDynamicLinker; |
| import jdk.internal.dynalink.support.Guards; |
| |
| /** |
| * Links {@link BoundCallable} objects. Passes through to linker services for linking a callable (for either |
| * "dyn:call" or "dyn:new"), and modifies the returned invocation to deal with the receiver and argument binding. |
| */ |
| final class BoundCallableLinker implements TypeBasedGuardingDynamicLinker { |
| @Override |
| public boolean canLinkType(final Class<?> type) { |
| return type == BoundCallable.class; |
| } |
| |
| @Override |
| public GuardedInvocation getGuardedInvocation(final LinkRequest linkRequest, final LinkerServices linkerServices) throws Exception { |
| final Object objBoundCallable = linkRequest.getReceiver(); |
| if(!(objBoundCallable instanceof BoundCallable)) { |
| return null; |
| } |
| |
| final CallSiteDescriptor descriptor = linkRequest.getCallSiteDescriptor(); |
| if (descriptor.getNameTokenCount() < 2 || !"dyn".equals(descriptor.getNameToken(CallSiteDescriptor.SCHEME))) { |
| return null; |
| } |
| final String operation = descriptor.getNameToken(CallSiteDescriptor.OPERATOR); |
| // We need to distinguish "dyn:new" from "dyn:call" because "dyn:call" sites have parameter list of the form |
| // "callee, this, args", while "dyn:call" sites have "callee, args" -- they lack the "this" parameter. |
| final boolean isCall; |
| if ("new".equals(operation)) { |
| isCall = false; |
| } else if ("call".equals(operation)) { |
| isCall = true; |
| } else { |
| // Only dyn:call and dyn:new are supported. |
| return null; |
| } |
| final BoundCallable boundCallable = (BoundCallable)objBoundCallable; |
| final Object callable = boundCallable.getCallable(); |
| final Object boundThis = boundCallable.getBoundThis(); |
| |
| // We need to ask the linker services for a delegate invocation on the target callable. |
| |
| // Replace arguments (boundCallable[, this], args) => (callable[, boundThis], boundArgs, args) when delegating |
| final Object[] args = linkRequest.getArguments(); |
| final Object[] boundArgs = boundCallable.getBoundArgs(); |
| final int argsLen = args.length; |
| final int boundArgsLen = boundArgs.length; |
| final Object[] newArgs = new Object[argsLen + boundArgsLen]; |
| newArgs[0] = callable; |
| final int firstArgIndex; |
| if (isCall) { |
| newArgs[1] = boundThis; |
| firstArgIndex = 2; |
| } else { |
| firstArgIndex = 1; |
| } |
| System.arraycopy(boundArgs, 0, newArgs, firstArgIndex, boundArgsLen); |
| System.arraycopy(args, firstArgIndex, newArgs, firstArgIndex + boundArgsLen, argsLen - firstArgIndex); |
| |
| // Use R(T0, T1, T2, ...) => R(callable.class, boundThis.class, boundArg0.class, ..., boundArgn.class, T2, ...) |
| // call site type when delegating to underlying linker (for dyn:new, there's no this). |
| final MethodType type = descriptor.getMethodType(); |
| // Use R(T0, ...) => R(callable.class, ...) |
| MethodType newMethodType = descriptor.getMethodType().changeParameterType(0, callable.getClass()); |
| if (isCall) { |
| // R(callable.class, T1, ...) => R(callable.class, boundThis.class, ...) |
| newMethodType = newMethodType.changeParameterType(1, boundThis == null? Object.class : boundThis.getClass()); |
| } |
| // R(callable.class[, boundThis.class], T2, ...) => R(callable.class[, boundThis.class], boundArg0.class, ..., boundArgn.class, T2, ...) |
| for(int i = boundArgs.length; i-- > 0;) { |
| newMethodType = newMethodType.insertParameterTypes(firstArgIndex, boundArgs[i] == null ? Object.class : boundArgs[i].getClass()); |
| } |
| final CallSiteDescriptor newDescriptor = descriptor.changeMethodType(newMethodType); |
| |
| // Delegate to target's linker |
| final GuardedInvocation inv = linkerServices.getGuardedInvocation(linkRequest.replaceArguments(newDescriptor, newArgs)); |
| if(inv == null) { |
| return null; |
| } |
| |
| // Bind (callable[, boundThis], boundArgs) to the delegate handle |
| final MethodHandle boundHandle = MethodHandles.insertArguments(inv.getInvocation(), 0, |
| Arrays.copyOf(newArgs, firstArgIndex + boundArgs.length)); |
| final Class<?> p0Type = type.parameterType(0); |
| final MethodHandle droppingHandle; |
| if (isCall) { |
| // Ignore incoming boundCallable and this |
| droppingHandle = MethodHandles.dropArguments(boundHandle, 0, p0Type, type.parameterType(1)); |
| } else { |
| // Ignore incoming boundCallable |
| droppingHandle = MethodHandles.dropArguments(boundHandle, 0, p0Type); |
| } |
| // Identity guard on boundCallable object |
| final MethodHandle newGuard = Guards.getIdentityGuard(boundCallable); |
| return inv.replaceMethods(droppingHandle, newGuard.asType(newGuard.type().changeParameterType(0, p0Type))); |
| } |
| } |