/*

 * Copyright (c) 2015, 2016, 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.incubator.http;

import java.net.SocketPermission;

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.concurrent.Executor;

import jdk.internal.misc.InnocuousThread;

/**

 * Wraps the supplied user Executor

 *

 * when a Security manager set, the correct access control context is used to execute task

 *

 * The access control context is captured at creation time of this object

 */

class ExecutorWrapper {

    final Executor userExecutor; // the undeerlying executor provided by user

    final Executor executor; // the executur which wraps the user's one

    final AccessControlContext acc;

    final ClassLoader ccl;

    public ExecutorWrapper(Executor userExecutor, AccessControlContext acc) {

        this.userExecutor = userExecutor;

        this.acc = acc;

        this.ccl = getCCL();

        if (System.getSecurityManager() == null) {

            this.executor = userExecutor;

        } else {

            this.executor = this::run;

        }

    }

    private ClassLoader getCCL() {

        return AccessController.doPrivileged(

            (PrivilegedAction<ClassLoader>) () -> {

                return Thread.currentThread().getContextClassLoader();

            }

        );

    }

    /**

     * This is only used for the default HttpClient to deal with

     * different application contexts that might be using it.

     * The default client uses InnocuousThreads in its Executor.

     */

    private void prepareThread() {

        final Thread me = Thread.currentThread();

        if (!(me instanceof InnocuousThread))

            return;

        InnocuousThread innocuousMe = (InnocuousThread)me;

        AccessController.doPrivileged(

            (PrivilegedAction<Void>) () -> {

                innocuousMe.setContextClassLoader(ccl);

                innocuousMe.eraseThreadLocals();

                return null;

            }

        );

    }

    void run(Runnable r) {

        prepareThread();

        try {

            userExecutor.execute(r); // all throwables must be caught

        } catch (Throwable t) {

            t.printStackTrace();

        }

    }

    public Executor userExecutor() {

        return userExecutor;

    }

    public Executor executor() {

        return executor;

    }

}