service_runtime/linux/lock.h

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
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  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
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  13  * in the documentation and/or other materials provided with the
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  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
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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_LINUX_LOCK_H_
  37 #define NATIVE_CLIENT_SERVICE_RUNTIME_LINUX_LOCK_H_
  38
  39 #include <pthread.h>
  40 #include "native_client/include/base/basictypes.h"
  41 #include "native_client/service_runtime/nacl_sync.h"
  42
  43 // This class implements the underlying platform-specific spin-lock mechanism
  44 // used for the Lock class.  Most users should not use LockImpl directly, but
  45 // should instead use Lock.
  46 class Lock {
  47  friend class ConditionVariable;
  48  public:
  49   Lock();
  50   ~Lock();
  51   void Acquire();
  52   void Release();
  53   bool Try();
  54
  55  private:
  56   pthread_mutex_t mutex_;
  57
  58   DISALLOW_EVIL_CONSTRUCTORS(Lock);
  59 };
  60
  61 // A helper class that acquires the given Lock while the AutoLock is in scope.
  62 class AutoLock {
  63  public:
  64   AutoLock(Lock& lock) : lock_(lock) {
  65     lock_.Acquire();
  66   }
  67
  68   ~AutoLock() {
  69     lock_.Release();
  70   }
  71
  72  private:
  73   Lock& lock_;
  74   DISALLOW_EVIL_CONSTRUCTORS(AutoLock);
  75 };
  76
  77 // A helper macro to perform a single operation (expressed by expr)
  78 // in a lock
  79 #define LOCKED_EXPRESSION(lock, expr) \
  80   do { \
  81     AutoLock _auto_lock(lock);  \
  82     (expr); \
  83   } while (0)
  84
  85 #endif  // NATIVE_CLIENT_SERVICE_RUNTIME_LINUX_LOCK_H_