src/jdk.dynalink/share/classes/jdk/dynalink/beans/CallerSensitiveDynamicMethod.java

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/*
 * This file is available under and governed by the GNU General Public
 * License version 2 only, as published by the Free Software Foundation.
 * However, the following notice accompanied the original version of this
 * file, and Oracle licenses the original version of this file under the BSD
 * license:
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/*
   Copyright 2009-2013 Attila Szegedi

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions are
   met:
   * Redistributions of source code must retain the above copyright
     notice, this list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above copyright
     notice, this list of conditions and the following disclaimer in the
     documentation and/or other materials provided with the distribution.
   * Neither the name of the copyright holder nor the names of
     contributors may be used to endorse or promote products derived from
     this software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER
   BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
   BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
   OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package jdk.dynalink.beans;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import java.lang.invoke.MethodType;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
import jdk.dynalink.CallSiteDescriptor;
import jdk.dynalink.SecureLookupSupplier;
import jdk.dynalink.internal.AccessControlContextFactory;
import jdk.dynalink.linker.support.Lookup;

/**
 * A dynamic method bound to exactly one Java method or constructor that is caller sensitive. Since the target method is
 * caller sensitive, it doesn't cache a method handle but rather uses the passed lookup object in
 * {@link #getTarget(CallSiteDescriptor)} to unreflect a method handle from the reflective member on
 * every request.
 */
class CallerSensitiveDynamicMethod extends SingleDynamicMethod {
    @SuppressWarnings("removal")
    private static final AccessControlContext GET_LOOKUP_CONTEXT =
            AccessControlContextFactory.createAccessControlContext(
                    SecureLookupSupplier.GET_LOOKUP_PERMISSION_NAME);

    private final Executable target;
    private final MethodType type;

    CallerSensitiveDynamicMethod(final Executable target) {
        super(getName(target));
        this.target = target;
        this.type = getMethodType(target);
    }

    private static String getName(final Executable m) {
        final boolean constructor = m instanceof Constructor;
        return getMethodNameWithSignature(getMethodType(m), constructor ? m.getName() :
            getClassAndMethodName(m.getDeclaringClass(), m.getName()), !constructor);
    }

    @Override
    MethodType getMethodType() {
        return type;
    }

    private static MethodType getMethodType(final Executable m) {
        final boolean isMethod = m instanceof Method;
        final Class<?> rtype = isMethod ? ((Method)m).getReturnType() : ((Constructor<?>)m).getDeclaringClass();
        final Class<?>[] ptypes = m.getParameterTypes();
        final MethodType type = MethodType.methodType(rtype, ptypes);
        return type.insertParameterTypes(0,
                isMethod ?
                        Modifier.isStatic(m.getModifiers()) ?
                                Object.class :
                                m.getDeclaringClass() :
                        StaticClass.class);
    }

    @Override
    boolean isVarArgs() {
        return target.isVarArgs();
    }

    @Override
    MethodHandle getTarget(final CallSiteDescriptor desc) {
        @SuppressWarnings("removal")
        final MethodHandles.Lookup lookup = AccessController.doPrivileged(
                (PrivilegedAction<MethodHandles.Lookup>)desc::getLookup,
                GET_LOOKUP_CONTEXT);

        if(target instanceof Method) {
            final MethodHandle mh = unreflect(lookup, (Method)target);
            if(Modifier.isStatic(target.getModifiers())) {
                return StaticClassIntrospector.editStaticMethodHandle(mh);
            }
            return mh;
        }
        return StaticClassIntrospector.editConstructorMethodHandle(unreflectConstructor(lookup,
                (Constructor<?>)target));
    }

    @Override
    boolean isConstructor() {
        return target instanceof Constructor;
    }

    private static MethodHandle unreflect(final MethodHandles.Lookup lookup, final Method m) {
        return Lookup.unreflect(lookup, m);
    }

    private static MethodHandle unreflectConstructor(final MethodHandles.Lookup lookup, final Constructor<?> c) {
        return Lookup.unreflectConstructor(lookup, c);
    }
}