MMgc/GCSpinLock.h

   1 /* -*- Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 4 -*- */
   2 /* vi: set ts=4 sw=4 expandtab: (add to ~/.vimrc: set modeline modelines=5) */
   3 /* ***** BEGIN LICENSE BLOCK *****
   4  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   5  *
   6  * The contents of this file are subject to the Mozilla Public License Version
   7  * 1.1 (the "License"); you may not use this file except in compliance with
   8  * the License. You may obtain a copy of the License at
   9  * http://www.mozilla.org/MPL/
  10  *
  11  * Software distributed under the License is distributed on an "AS IS" basis,
  12  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  13  * for the specific language governing rights and limitations under the
  14  * License.
  15  *
  16  * The Original Code is [Open Source Virtual Machine.].
  17  *
  18  * The Initial Developer of the Original Code is
  19  * Adobe System Incorporated.
  20  * Portions created by the Initial Developer are Copyright (C) 2004-2006
  21  * the Initial Developer. All Rights Reserved.
  22  *
  23  * Contributor(s):
  24  *   Adobe AS3 Team
  25  *
  26  * Alternatively, the contents of this file may be used under the terms of
  27  * either the GNU General Public License Version 2 or later (the "GPL"), or
  28  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  29  * in which case the provisions of the GPL or the LGPL are applicable instead
  30  * of those above. If you wish to allow use of your version of this file only
  31  * under the terms of either the GPL or the LGPL, and not to allow others to
  32  * use your version of this file under the terms of the MPL, indicate your
  33  * decision by deleting the provisions above and replace them with the notice
  34  * and other provisions required by the GPL or the LGPL. If you do not delete
  35  * the provisions above, a recipient may use your version of this file under
  36  * the terms of any one of the MPL, the GPL or the LGPL.
  37  *
  38  * ***** END LICENSE BLOCK ***** */
  39
  40 #ifndef __GCSpinLock__
  41 #define __GCSpinLock__
  42
  43 namespace MMgc
  44 {
  45     /**
  46      * GCAcquireSpinlock is a convenience class which acquires
  47      * the specified spinlock at construct time, then releases
  48      * the spinlock at desruct time.  The single statement
  49      *
  50      *    GCAcquireSpinlock acquire(spinlock);
  51      *
  52      * ... will acquire the spinlock at the top of the function
  53      * and release it at the end.  This makes for less error-prone
  54      * code than explicit acquire/release.
  55      */
  56     class GCAcquireSpinlock
  57     {
  58     public:
  59         REALLY_INLINE explicit GCAcquireSpinlock(vmpi_spin_lock_t *spinlock) :
  60             m_spinlock(spinlock)
  61         {
  62         #ifdef _DEBUG
  63             bool r =
  64         #endif
  65             VMPI_lockAcquire(m_spinlock);
  66
  67             GCAssert(r);
  68         }
  69
  70         REALLY_INLINE ~GCAcquireSpinlock()
  71         {
  72         #ifdef _DEBUG
  73             bool r =
  74         #endif
  75             VMPI_lockRelease(m_spinlock);
  76
  77             GCAssert(r);
  78         }
  79
  80     private:
  81         vmpi_spin_lock_t *m_spinlock;
  82
  83     private: // not implemented
  84         GCAcquireSpinlock();
  85         GCAcquireSpinlock(const GCAcquireSpinlock&);
  86         GCAcquireSpinlock& operator=(const GCAcquireSpinlock&);
  87     };
  88
  89     class GCAcquireSpinlockWithRecursion
  90     {
  91     public:
  92         REALLY_INLINE explicit GCAcquireSpinlockWithRecursion(vmpi_spin_lock_t *sl, vmpi_thread_t owner)
  93             : m_spinlock(sl)
  94         {
  95             if(!VMPI_lockTestAndAcquire(sl)) {
  96                 if(VMPI_currentThread() == owner) {
  97                     m_spinlock = NULL;
  98                 } else {
  99                     VMPI_lockAcquire(sl);
 100                 }
 101             }
 102         }
 103
 104         ~GCAcquireSpinlockWithRecursion()
 105         {
 106             if(m_spinlock)
 107                 VMPI_lockRelease(m_spinlock);
 108         }
 109
 110     private:
 111         vmpi_spin_lock_t *m_spinlock;
 112
 113     private: // not implemented
 114         GCAcquireSpinlockWithRecursion();
 115         GCAcquireSpinlockWithRecursion(const GCAcquireSpinlockWithRecursion&);
 116         GCAcquireSpinlockWithRecursion& operator=(const GCAcquireSpinlockWithRecursion&);
 117     };
 118 }
 119
 120 #endif /* __GCSpinLock__ */