1 /*
   2  * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.net.http;
  27 
  28 import java.security.AccessControlContext;
  29 import java.security.AccessController;
  30 import java.security.PrivilegedAction;
  31 import java.util.concurrent.Executor;
  32 import java.util.concurrent.ExecutorService;
  33 import java.util.function.Supplier;
  34 
  35 /**
  36  * Wraps the supplied user ExecutorService.
  37  *
  38  * 1) when a Security manager set, the correct access control context
  39  *    is used to execute task
  40  *
  41  * 2) memory fence implemented
  42  */
  43 class ExecutorWrapper {
  44 
  45     final ExecutorService userExecutor; // the actual executor service used
  46     final Executor executor;
  47 
  48     public static ExecutorWrapper wrap(ExecutorService userExecutor) {
  49         return new ExecutorWrapper(userExecutor);
  50     }
  51 
  52     /**
  53      * Returns a dummy ExecutorWrapper which uses the calling thread
  54      */
  55     public static ExecutorWrapper callingThread() {
  56         return new ExecutorWrapper();
  57     }
  58 
  59     private ExecutorWrapper(ExecutorService userExecutor) {
  60         // used for executing in calling thread
  61         this.userExecutor = userExecutor;
  62         this.executor = userExecutor;
  63     }
  64 
  65     private ExecutorWrapper() {
  66         this.userExecutor = null;
  67         this.executor = (Runnable command) -> {
  68             command.run();
  69         };
  70     }
  71 
  72     public ExecutorService userExecutor() {
  73         return userExecutor;
  74     }
  75 
  76     public synchronized void synchronize() {}
  77 
  78     public void execute(Runnable r, Supplier<AccessControlContext> ctxSupplier) {
  79         synchronize();
  80         Runnable r1 = () -> {
  81             try {
  82                 r.run();
  83             } catch (Throwable t) {
  84                 Log.logError(t);
  85             }
  86         };
  87 
  88         if (ctxSupplier != null && System.getSecurityManager() != null) {
  89             AccessControlContext acc = ctxSupplier.get();
  90             if (acc == null) {
  91                 throw new InternalError();
  92             }
  93             AccessController.doPrivilegedWithCombiner(
  94                 (PrivilegedAction<Void>)() -> {
  95                     executor.execute(r1); // all throwables must be caught
  96                     return null;
  97                 }, acc);
  98         } else {
  99             executor.execute(r1); // all throwables must be caught
 100         }
 101     }
 102 }