db2/include/cxx_int.h

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 1997
   5  *      Sleepycat Software.  All rights reserved.
   6  *
   7  *      @(#)cxx_int.h   10.4 (Sleepycat) 8/22/97
   8  */
   9
  10 #ifndef _CXX_INT_H_
  11 #define _CXX_INT_H_
  12
  13 // private data structures known to the implementation only
  14
  15 #include <assert.h>             // used by defines below
  16
  17 //
  18 // Using FooImp classes will allow the implementation to change in the
  19 // future without any modification to user code or even to header files
  20 // that the user includes. FooImp * is just like void * except that it
  21 // provides a little extra protection, since you cannot randomly assign
  22 // any old pointer to a FooImp* as you can with void *.  Currently, a
  23 // pointer to such an opaque class is always just a pointer to the
  24 // appropriate underlying implementation struct.  These are converted
  25 // back and forth using the various overloaded wrap()/unwrap() methods.
  26 // This is essentially a use of the "Bridge" Design Pattern.
  27 //
  28 // WRAPPED_CLASS implements the appropriate wrap() and unwrap() methods
  29 // for a wrapper class that has an underlying pointer representation.
  30 //
  31 #define WRAPPED_CLASS(_WRAPPER_CLASS, _IMP_CLASS, _WRAPPED_TYPE)           \
  32                                                                            \
  33         class _IMP_CLASS {};                                               \
  34                                                                            \
  35         inline _WRAPPED_TYPE unwrap(_WRAPPER_CLASS *val)                   \
  36         {                                                                  \
  37             if (!val) return 0;                                            \
  38             return (_WRAPPED_TYPE)(val->imp());                            \
  39         }                                                                  \
  40                                                                            \
  41         inline const _WRAPPED_TYPE unwrapConst(const _WRAPPER_CLASS *val)  \
  42         {                                                                  \
  43             if (!val) return 0;                                            \
  44             return (const _WRAPPED_TYPE)(val->imp());                      \
  45         }                                                                  \
  46                                                                            \
  47         inline _IMP_CLASS *wrap(_WRAPPED_TYPE val)                         \
  48         {                                                                  \
  49             return (_IMP_CLASS*)val;                                       \
  50         }
  51
  52 WRAPPED_CLASS(DbLockTab, DbLockTabImp, DB_LOCKTAB*)
  53 WRAPPED_CLASS(DbLog, DbLogImp, DB_LOG*)
  54 WRAPPED_CLASS(DbMpool, DbMpoolImp, DB_MPOOL*)
  55 WRAPPED_CLASS(DbMpoolFile, DbMpoolFileImp, DB_MPOOLFILE*)
  56 WRAPPED_CLASS(Db, DbImp, DB*)
  57 WRAPPED_CLASS(DbTxn, DbTxnImp, DB_TXN*)
  58 WRAPPED_CLASS(DbTxnMgr, DbTxnMgrImp, DB_TXNMGR*)
  59
  60 // Macros that handle detected errors, in case we want to
  61 // change the default behavior.  runtime_error() throws an
  62 // exception by default.
  63 //
  64 // Since it's unusual to throw an exception in a destructor,
  65 // we have a separate macro.  For now, we silently ignore such
  66 // detected errors.
  67 //
  68 #define DB_ERROR(caller, ecode) \
  69     DbEnv::runtime_error(caller, ecode)
  70
  71 #define DB_DESTRUCTOR_ERROR(caller, ecode) \
  72     DbEnv::runtime_error(caller, ecode, 1)
  73
  74
  75 ////////////////////////////////////////////////////////////////
  76 ////////////////////////////////////////////////////////////////
  77 //
  78 // These defines are for tedious flag or field set/get access methods.
  79 //
  80
  81 // Define setName() and getName() methods that twiddle
  82 // the _flags field.
  83 //
  84 #define DB_FLAG_METHODS(_class, _flags, _cxx_name, _flag_name) \
  85                                                                \
  86 void _class::set##_cxx_name(int onOrOff)                       \
  87 {                                                              \
  88     if (onOrOff)                                               \
  89         _flags |= _flag_name;                                  \
  90     else                                                       \
  91         _flags &= ~(_flag_name);                               \
  92 }                                                              \
  93                                                                \
  94 int _class::get##_cxx_name() const                             \
  95 {                                                              \
  96     return (_flags & _flag_name) ? 1 : 0;                      \
  97 }
  98
  99
 100 #define DB_RO_ACCESS(_class, _type, _cxx_name, _field)         \
 101                                                                \
 102 _type _class::get_##_cxx_name() const                          \
 103 {                                                              \
 104     return _field;                                             \
 105 }
 106
 107 #define DB_WO_ACCESS(_class, _type, _cxx_name, _field)         \
 108                                                                \
 109 void _class::set_##_cxx_name(_type value)                      \
 110 {                                                              \
 111     _field = value;                                            \
 112 }                                                              \
 113
 114 #define DB_RW_ACCESS(_class, _type, _cxx_name, _field)         \
 115         DB_RO_ACCESS(_class, _type, _cxx_name, _field)         \
 116         DB_WO_ACCESS(_class, _type, _cxx_name, _field)
 117
 118 #endif /* !_CXX_INT_H_ */