/*

 * 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

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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:

 */

/*

   Copyright 2009-2013 Attila Szegedi

*/

package jdk.dynalink.linker.support;

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.Field;

import java.lang.reflect.Method;

/**

 * A wrapper around {@link java.lang.invoke.MethodHandles.Lookup} that masks

 * checked exceptions. It is useful in those cases when you're looking up

 * methods within your own codebase (therefore it is an error if they are not

 * present).

 */

public final class Lookup {

    private final MethodHandles.Lookup lookup;

    /**

     * Creates a new instance, bound to an instance of

     * {@link java.lang.invoke.MethodHandles.Lookup}.

     *

     * @param lookup the {@link java.lang.invoke.MethodHandles.Lookup} it delegates to.

     */

    public Lookup(final MethodHandles.Lookup lookup) {

        this.lookup = lookup;

    }

    /**

     * A canonical Lookup object that wraps {@link MethodHandles#publicLookup()}.

     */

    public static final Lookup PUBLIC = new Lookup(MethodHandles.publicLookup());

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflect(Method)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError}.

     *

     * @param m the method to unreflect

     * @return the unreflected method handle.

     * @throws IllegalAccessError if the method is inaccessible.

     */

    public MethodHandle unreflect(final Method m) {

        return unreflect(lookup, m);

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflect(Method)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError}.

     *

     * @param lookup the lookup used to unreflect

     * @param m the method to unreflect

     * @return the unreflected method handle.

     * @throws IllegalAccessError if the method is inaccessible.

     */

    public static MethodHandle unreflect(final MethodHandles.Lookup lookup, final Method m) {

        try {

            return lookup.unreflect(m);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to unreflect method " + m);

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflectGetter(Field)},

     * converting any encountered {@link IllegalAccessException} into an {@link IllegalAccessError}.

     *

     * @param f the field for which a getter is unreflected

     * @return the unreflected field getter handle.

     * @throws IllegalAccessError if the getter is inaccessible.

     */

    public MethodHandle unreflectGetter(final Field f) {

        try {

            return lookup.unreflectGetter(f);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to unreflect getter for field " + f);

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#findGetter(Class, String, Class)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError} and {@link NoSuchFieldException} into a

     * {@link NoSuchFieldError}.

     *

     * @param refc the class declaring the field

     * @param name the name of the field

     * @param type the type of the field

     * @return the unreflected field getter handle.

     * @throws IllegalAccessError if the field is inaccessible.

     * @throws NoSuchFieldError if the field does not exist.

     */

    public MethodHandle findGetter(final Class<?>refc, final String name, final Class<?> type) {

        try {

            return lookup.findGetter(refc, name, type);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to access getter for field " + refc.getName() +

                    "." + name + " of type " + type.getName());

            ee.initCause(e);

            throw ee;

        } catch(final NoSuchFieldException e) {

            final NoSuchFieldError ee = new NoSuchFieldError("Failed to find getter for field " + refc.getName() +

                    "." + name + " of type " + type.getName());

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflectSetter(Field)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError}.

     *

     * @param f the field for which a setter is unreflected

     * @return the unreflected field setter handle.

     * @throws IllegalAccessError if the field is inaccessible.

     * @throws NoSuchFieldError if the field does not exist.

     */

    public MethodHandle unreflectSetter(final Field f) {

        try {

            return lookup.unreflectSetter(f);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to unreflect setter for field " + f);

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflectConstructor(Constructor)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError}.

     *

     * @param c the constructor to unreflect

     * @return the unreflected constructor handle.

     * @throws IllegalAccessError if the constructor is inaccessible.

     */

    public MethodHandle unreflectConstructor(final Constructor<?> c) {

        return unreflectConstructor(lookup, c);

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#unreflectConstructor(Constructor)},

     * converting any encountered {@link IllegalAccessException} into an

     * {@link IllegalAccessError}.

     *

     * @param lookup the lookup used to unreflect

     * @param c the constructor to unreflect

     * @return the unreflected constructor handle.

     * @throws IllegalAccessError if the constructor is inaccessible.

     */

    public static MethodHandle unreflectConstructor(final MethodHandles.Lookup lookup, final Constructor<?> c) {

        try {

            return lookup.unreflectConstructor(c);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to unreflect constructor " + c);

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#findSpecial(Class, String, MethodType, Class)}

     * on the underlying lookup. Converts any encountered

     * {@link IllegalAccessException} into an {@link IllegalAccessError} and

     * {@link NoSuchMethodException} into a {@link NoSuchMethodError}.

     *

     * @param declaringClass class declaring the method

     * @param name the name of the method

     * @param type the type of the method

     * @return a method handle for the method

     * @throws IllegalAccessError if the method is inaccessible.

     * @throws NoSuchMethodError if the method does not exist.

     */

    public MethodHandle findSpecial(final Class<?> declaringClass, final String name, final MethodType type) {

        try {

            return lookup.findSpecial(declaringClass, name, type, declaringClass);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to access special method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        } catch(final NoSuchMethodException e) {

            final NoSuchMethodError ee = new NoSuchMethodError("Failed to find special method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        }

    }

    private static String methodDescription(final Class<?> declaringClass, final String name, final MethodType type) {

        return declaringClass.getName() + "#" + name + type;

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#findStatic(Class, String, MethodType)}

     * on the underlying lookup. Converts any encountered

     * {@link IllegalAccessException} into an {@link IllegalAccessError} and

     * {@link NoSuchMethodException} into a {@link NoSuchMethodError}.

     *

     * @param declaringClass class declaring the method

     * @param name the name of the method

     * @param type the type of the method

     * @return a method handle for the method

     * @throws IllegalAccessError if the method is inaccessible.

     * @throws NoSuchMethodError if the method does not exist.

     */

    public MethodHandle findStatic(final Class<?> declaringClass, final String name, final MethodType type) {

        try {

            return lookup.findStatic(declaringClass, name, type);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to access static method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        } catch(final NoSuchMethodException e) {

            final NoSuchMethodError ee = new NoSuchMethodError("Failed to find static method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Performs a {@link java.lang.invoke.MethodHandles.Lookup#findVirtual(Class, String, MethodType)}

     * on the underlying lookup. Converts any encountered

     * {@link IllegalAccessException} into an {@link IllegalAccessError} and

     * {@link NoSuchMethodException} into a {@link NoSuchMethodError}.

     *

     * @param declaringClass class declaring the method

     * @param name the name of the method

     * @param type the type of the method

     * @return a method handle for the method

     * @throws IllegalAccessError if the method is inaccessible.

     * @throws NoSuchMethodError if the method does not exist.

     */

    public MethodHandle findVirtual(final Class<?> declaringClass, final String name, final MethodType type) {

        try {

            return lookup.findVirtual(declaringClass, name, type);

        } catch(final IllegalAccessException e) {

            final IllegalAccessError ee = new IllegalAccessError("Failed to access virtual method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        } catch(final NoSuchMethodException e) {

            final NoSuchMethodError ee = new NoSuchMethodError("Failed to find virtual method " + methodDescription(

                    declaringClass, name, type));

            ee.initCause(e);

            throw ee;

        }

    }

    /**

     * Given a lookup, finds using {@link #findSpecial(Class, String, MethodType)}

     * a method on that lookup's class. Useful in classes' code for convenient

     * linking to their own privates.

     * @param lookup the lookup for the class

     * @param name the name of the method

     * @param rtype the return type of the method

     * @param ptypes the parameter types of the method

     * @return the method handle for the method

     */

    public static MethodHandle findOwnSpecial(final MethodHandles.Lookup lookup, final String name, final Class<?> rtype, final Class<?>... ptypes) {

        return new Lookup(lookup).findOwnSpecial(name, rtype, ptypes);

    }

    /**

     * Finds using {@link #findSpecial(Class, String, MethodType)} a method on

     * that lookup's class. Useful in classes' code for convenient linking to

     * their own privates. It's also more convenient than {@code findSpecial}

     * in that you can just list the parameter types, and don't have to specify

     * lookup class.

     * @param name the name of the method

     * @param rtype the return type of the method

     * @param ptypes the parameter types of the method

     * @return the method handle for the method

     */

    public MethodHandle findOwnSpecial(final String name, final Class<?> rtype, final Class<?>... ptypes) {

        return findSpecial(lookup.lookupClass(), name, MethodType.methodType(rtype, ptypes));

    }

    /**

     * Given a lookup, finds using {@link #findStatic(Class, String, MethodType)}

     * a method on that lookup's class. Useful in classes' code for convenient

     * linking to their own privates. It's easier to use than {@code findStatic}

     * in that you can just list the parameter types, and don't have to specify

     * lookup class.

     * @param lookup the lookup for the class

     * @param name the name of the method

     * @param rtype the return type of the method

     * @param ptypes the parameter types of the method

     * @return the method handle for the method

     */

    public static MethodHandle findOwnStatic(final MethodHandles.Lookup lookup, final String name, final Class<?> rtype, final Class<?>... ptypes) {

        return new Lookup(lookup).findOwnStatic(name, rtype, ptypes);

    }

    /**

     * Finds using {@link #findStatic(Class, String, MethodType)} a method on

     * that lookup's class. Useful in classes' code for convenient linking to

     * their own privates. It's easier to use than {@code findStatic}

     * in that you can just list the parameter types, and don't have to specify

     * lookup class.

     * @param name the name of the method

     * @param rtype the return type of the method

     * @param ptypes the parameter types of the method

     * @return the method handle for the method

     */

    public MethodHandle findOwnStatic(final String name, final Class<?> rtype, final Class<?>... ptypes) {

        return findStatic(lookup.lookupClass(), name, MethodType.methodType(rtype, ptypes));

    }

}