service_runtime/win/lock_impl.h

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
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  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32
  33 // NOTE: changed the Windows implementation to use mutex instead
  34 // of CRITICAL_SECTION
  35
  36 #ifndef NATIVE_CLIENT_SERVICE_RUNTIME_WIN_LOCK_IMPL_H_
  37 #define NATIVE_CLIENT_SERVICE_RUNTIME_WIN_LOCK_IMPL_H_
  38
  39 #include <Windows.h>
  40 #include "native_client/include/base/basictypes.h"
  41
  42 // This class implements the underlying platform-specific spin-lock mechanism
  43 // used for the Lock class.  Most users should not use LockImpl directly, but
  44 // should instead use Lock.
  45 class LockImpl {
  46  public:
  47   LockImpl();
  48   ~LockImpl();
  49
  50   // If the lock is not held, take it and return true.  If the lock is already
  51   // held by something else, immediately return false.
  52   bool Try();
  53
  54   // Take the lock, blocking until it is available if necessary.
  55   void Lock();
  56
  57   // Release the lock.  This must only be called by the lock's holder: after
  58   // a successful call to Try, or a call to Lock.
  59   void Unlock();
  60
  61  private:
  62 #if defined(WIN32)
  63   HANDLE mutex_;
  64 #elif defined(__APPLE__)
  65   OSSpinLock spin_lock_;
  66 #endif
  67
  68   DISALLOW_EVIL_CONSTRUCTORS(LockImpl);
  69 };
  70
  71 class AutoLockImpl {
  72  public:
  73   AutoLockImpl(LockImpl* lock_impl)
  74       : lock_impl_(lock_impl) {
  75     lock_impl_->Lock();
  76   }
  77
  78   ~AutoLockImpl() {
  79     lock_impl_->Unlock();
  80   }
  81
  82  private:
  83   LockImpl* lock_impl_;
  84   DISALLOW_EVIL_CONSTRUCTORS(AutoLockImpl);
  85 };
  86
  87 #endif  // NATIVE_CLIENT_SERVICE_RUNTIME_WIN_LOCK_IMPL_H_