/*

 * Copyright (c) 2008, 2010, 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 sun.dyn;

import java.dyn.*;

import static sun.dyn.MemberName.uncaughtException;

/**

 * Parts of CallSite known to the JVM.

 * @author jrose

 */

public class CallSiteImpl {

    // this implements the upcall from the JVM, MethodHandleNatives.makeDynamicCallSite:

    static CallSite makeSite(MethodHandle bootstrapMethod,

                             // Callee information:

                             String name, MethodType type,

                             // Extra arguments for BSM, if any:

                             Object info,

                             // Caller information:

                             MemberName callerMethod, int callerBCI) {

        Class<?> callerClass = callerMethod.getDeclaringClass();

        Object caller;

        if (bootstrapMethod.type().parameterType(0) == Class.class && TRANSITIONAL_BEFORE_PFD)

            caller = callerClass;  // remove for PFD

        else

            caller = MethodHandleImpl.IMPL_LOOKUP.in(callerClass);

        if (bootstrapMethod == null && TRANSITIONAL_BEFORE_PFD) {

            // If there is no bootstrap method, throw IncompatibleClassChangeError.

            // This is a valid generic error type for resolution (JLS 12.3.3).

            throw new IncompatibleClassChangeError

                ("Class "+callerClass.getName()+" has not declared a bootstrap method for invokedynamic");

        }

        CallSite site;

        try {

            Object binding;

            info = maybeReBox(info);

            if (info == null) {

                binding = bootstrapMethod.invokeGeneric(caller, name, type);

            } else if (!info.getClass().isArray()) {

                binding = bootstrapMethod.invokeGeneric(caller, name, type, info);

            } else {

                Object[] argv = (Object[]) info;

                if (3 + argv.length > 255)

                    new InvokeDynamicBootstrapError("too many bootstrap method arguments");

                MethodType bsmType = bootstrapMethod.type();

                if (bsmType.parameterCount() == 4 && bsmType.parameterType(3) == Object[].class)

                    binding = bootstrapMethod.invokeGeneric(caller, name, type, argv);

                else

                    binding = MethodHandles.spreadInvoker(bsmType, 3)

                        .invokeGeneric(bootstrapMethod, caller, name, type, argv);

            }

            //System.out.println("BSM for "+name+type+" => "+binding);

            if (binding instanceof CallSite) {

                site = (CallSite) binding;

            } else if (binding instanceof MethodHandle && TRANSITIONAL_BEFORE_PFD) {

                // Transitional!

                MethodHandle target = (MethodHandle) binding;

                site = new ConstantCallSite(target);

            } else {

                throw new ClassCastException("bootstrap method failed to produce a CallSite");

            }

            if (TRANSITIONAL_BEFORE_PFD)

                PRIVATE_INITIALIZE_CALL_SITE.invokeExact(site, name, type,

                                                         callerMethod, callerBCI);

            assert(site.getTarget() != null);

            assert(site.getTarget().type().equals(type));

        } catch (Throwable ex) {

            InvokeDynamicBootstrapError bex;

            if (ex instanceof InvokeDynamicBootstrapError)

                bex = (InvokeDynamicBootstrapError) ex;

            else

                bex = new InvokeDynamicBootstrapError("call site initialization exception", ex);

            throw bex;

        }

        return site;

    }

    private static boolean TRANSITIONAL_BEFORE_PFD = true;  // FIXME: remove for PFD

    private static Object maybeReBox(Object x) {

        if (x instanceof Integer) {

            int xi = (int) x;

            if (xi == (byte) xi)

                x = xi;  // must rebox; see JLS 5.1.7

            return x;

        } else if (x instanceof Object[]) {

            Object[] xa = (Object[]) x;

            for (int i = 0; i < xa.length; i++) {

                if (xa[i] instanceof Integer)

                    xa[i] = maybeReBox(xa[i]);

            }

            return xa;

        } else {

            return x;

        }

    }

    // This method is private in CallSite because it touches private fields in CallSite.

    // These private fields (vmmethod, vmindex) are specific to the JVM.

    private static final MethodHandle PRIVATE_INITIALIZE_CALL_SITE;

    static {

        try {

            PRIVATE_INITIALIZE_CALL_SITE =

            !TRANSITIONAL_BEFORE_PFD ? null :

            MethodHandleImpl.IMPL_LOOKUP.findVirtual(CallSite.class, "initializeFromJVM",

                MethodType.methodType(void.class,

                                      String.class, MethodType.class,

                                      MemberName.class, int.class));

            throw uncaughtException(ex);

        }

    }

    public static void setCallSiteTarget(Access token, CallSite site, MethodHandle target) {

        Access.check(token);

        MethodHandleNatives.setCallSiteTarget(site, target);

    }

}