icuSources/common/mutex.h

   1 /*
   2 ******************************************************************************
   3 *
   4 *   Copyright (C) 1997-2003, International Business Machines
   5 *   Corporation and others.  All Rights Reserved.
   6 *
   7 ******************************************************************************
   8 */
   9 //----------------------------------------------------------------------------
  10 // File:     mutex.h
  11 //
  12 // Lightweight C++ wrapper for umtx_ C mutex functions
  13 //
  14 // Author:   Alan Liu  1/31/97
  15 // History:
  16 // 06/04/97   helena         Updated setImplementation as per feedback from 5/21 drop.
  17 // 04/07/1999  srl               refocused as a thin wrapper
  18 //
  19 //----------------------------------------------------------------------------
  20 #ifndef MUTEX_H
  21 #define MUTEX_H
  22
  23 #include "unicode/utypes.h"
  24 #include "unicode/uobject.h"
  25 #include "umutex.h"
  26
  27 U_NAMESPACE_BEGIN
  28
  29 //----------------------------------------------------------------------------
  30 // Code within that accesses shared static or global data should
  31 // should instantiate a Mutex object while doing so. You should make your own
  32 // private mutex where possible.
  33
  34 // For example:
  35 //
  36 // UMTX myMutex;
  37 //
  38 // int InitializeMyMutex()
  39 // {
  40 //    umtx_init( &myMutex );
  41 //    return 0;
  42 // }
  43 //
  44 // static int initializeMyMutex = InitializeMyMutex();
  45 //
  46 // void Function(int arg1, int arg2)
  47 // {
  48 //    static Object* foo;     // Shared read-write object
  49 //    Mutex mutex(&myMutex);  // or no args for the global lock
  50 //    foo->Method();
  51 //    // When 'mutex' goes out of scope and gets destroyed here, the lock is released
  52 // }
  53 //
  54 // Note:  Do NOT use the form 'Mutex mutex();' as that merely forward-declares a function
  55 //        returning a Mutex. This is a common mistake which silently slips through the
  56 //        compiler!!
  57 //
  58
  59 class U_COMMON_API Mutex : public UMemory {
  60 public:
  61   inline Mutex(UMTX *mutex = NULL);
  62   inline ~Mutex();
  63
  64 private:
  65   UMTX   *fMutex;
  66
  67   Mutex(const Mutex &other); // forbid copying of this class
  68   Mutex &operator=(const Mutex &other); // forbid copying of this class
  69 };
  70
  71 inline Mutex::Mutex(UMTX *mutex)
  72   : fMutex(mutex)
  73 {
  74   umtx_lock(fMutex);
  75 }
  76
  77 inline Mutex::~Mutex()
  78 {
  79   umtx_unlock(fMutex);
  80 }
  81
  82 U_NAMESPACE_END
  83
  84 #endif //_MUTEX_
  85 //eof