include/osl/conditn.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
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  19
  20 #ifndef INCLUDED_OSL_CONDITN_HXX
  21 #define INCLUDED_OSL_CONDITN_HXX
  22
  23 #include <osl/time.h>
  24
  25 #include <osl/conditn.h>
  26
  27
  28 namespace osl
  29 {
  30     /**
  31      * Warning: the Condition abstraction is inadequate for any
  32      * situation where there may be multiple threads setting,
  33      * waiting, and resetting the same condition. It can only be
  34      * used to synchronise interactions between two threads
  35      * cf. lost wakeups in:
  36      *    http://www.cs.wustl.edu/~schmidt/win32-cv-1.html
  37      */
  38     class Condition
  39     {
  40     public:
  41
  42         enum Result
  43         {
  44             result_ok      = osl_cond_result_ok,
  45             result_error   = osl_cond_result_error,
  46             result_timeout = osl_cond_result_timeout
  47         };
  48
  49         /* Create a condition.
  50          */
  51         Condition()
  52         {
  53             condition = osl_createCondition();
  54         }
  55
  56         /* Release the OS-structures and free condition data-structure.
  57          */
  58         ~Condition()
  59         {
  60             osl_destroyCondition(condition);
  61         }
  62
  63         /* Release all waiting threads, check returns true.
  64          */
  65         void set()
  66         {
  67             osl_setCondition(condition);
  68         }
  69
  70         /* Reset condition to false: wait() will block, check() returns false.
  71          */
  72         void reset() {
  73             osl_resetCondition(condition);
  74         }
  75
  76         /** Blocks the calling thread until condition is set.
  77          */
  78         Result wait(const TimeValue *pTimeout = 0)
  79         {
  80             return (Result) osl_waitCondition(condition, pTimeout);
  81         }
  82
  83         /** Checks if the condition is set without blocking.
  84          */
  85         bool check()
  86         {
  87             return osl_checkCondition(condition);
  88         }
  89
  90
  91     private:
  92         oslCondition condition;
  93
  94         /** The underlying oslCondition has no reference count.
  95
  96         Since the underlying oslCondition is not a reference counted object, copy
  97         constructed Condition may work on an already destructed oslCondition object.
  98
  99         */
 100         Condition(const Condition&) SAL_DELETED_FUNCTION;
 101
 102         /** This assignment operator is deleted for the same reason as
 103             the copy constructor.
 104         */
 105         Condition& operator= (const Condition&) SAL_DELETED_FUNCTION;
 106     };
 107
 108 }
 109
 110 #endif // INCLUDED_OSL_CONDITN_HXX
 111
 112 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */