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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_RUNTIME_SEMAPHORE_HPP
  26 #define SHARE_VM_RUNTIME_SEMAPHORE_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 
  30 #if defined(LINUX) || defined(SOLARIS) || defined(AIX)
  31 # include "semaphore_posix.hpp"
  32 #elif defined(BSD)
  33 # include "semaphore_bsd.hpp"
  34 #elif defined(_WINDOWS)
  35 # include "semaphore_windows.hpp"
  36 #else
  37 # error "No semaphore implementation provided for this OS"
  38 #endif
  39 
  40 class JavaThread;
  41 
  42 // Implements the limited, platform independent Semaphore API.
  43 class Semaphore : public CHeapObj<mtInternal> {
  44   SemaphoreImpl _impl;
  45 
  46   // Prevent copying and assignment of Semaphore instances.
  47   Semaphore(const Semaphore&);
  48   Semaphore& operator=(const Semaphore&);
  49 
  50  public:
  51   Semaphore(uint value = 0) : _impl(value) {}
  52   ~Semaphore() {}
  53 
  54   void signal(uint count = 1) { _impl.signal(count); }
  55 
  56   void wait()                 { _impl.wait(); }
  57 
  58   bool trywait()              { return _impl.trywait(); }
  59 
  60   void wait_with_safepoint_check(JavaThread* thread);
  61 };
  62 
  63 #endif // SHARE_VM_RUNTIME_SEMAPHORE_HPP