contrib/llvm/tools/lldb/include/lldb/Utility/PriorityPointerPair.h

   1 //===-- PriorityPointerPair.h ----------------------------------------*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef liblldb_PriorityPointerPair_h_
  11 #define liblldb_PriorityPointerPair_h_
  12
  13 #include "lldb/lldb-public.h"
  14 #include "lldb/Utility/SharingPtr.h"
  15
  16 namespace lldb_utility {
  17
  18 //----------------------------------------------------------------------
  19 // A prioritized pair of SharedPtr<T>. One of the two pointers is high
  20 // priority, the other is low priority.
  21 // The Get() method always returns high, if *high != NULL,
  22 // otherwise, low is returned (even if *low == NULL)
  23 //----------------------------------------------------------------------
  24
  25 template<typename T>
  26 class PriorityPointerPair
  27 {
  28 public:
  29
  30     typedef T& reference_type;
  31     typedef T* pointer_type;
  32
  33     typedef typename std::shared_ptr<T> T_SP;
  34
  35     PriorityPointerPair() :
  36     m_high(),
  37     m_low()
  38     {}
  39
  40     PriorityPointerPair(pointer_type high,
  41                         pointer_type low) :
  42     m_high(high),
  43     m_low(low)
  44     {}
  45
  46     PriorityPointerPair(pointer_type low) :
  47     m_high(),
  48     m_low(low)
  49     {}
  50
  51     PriorityPointerPair(T_SP& high,
  52                         T_SP& low) :
  53     m_high(high),
  54     m_low(low)
  55     {}
  56
  57     PriorityPointerPair(T_SP& low) :
  58     m_high(),
  59     m_low(low)
  60     {}
  61
  62     void
  63     SwapLow(pointer_type l)
  64     {
  65         m_low.swap(l);
  66     }
  67
  68     void
  69     SwapHigh(pointer_type h)
  70     {
  71         m_high.swap(h);
  72     }
  73
  74     void
  75     SwapLow(T_SP l)
  76     {
  77         m_low.swap(l);
  78     }
  79
  80     void
  81     SwapHigh(T_SP h)
  82     {
  83         m_high.swap(h);
  84     }
  85
  86     T_SP
  87     GetLow()
  88     {
  89         return m_low;
  90     }
  91
  92     T_SP
  93     GetHigh()
  94     {
  95         return m_high;
  96     }
  97
  98     T_SP
  99     Get()
 100     {
 101         if (m_high.get())
 102             return m_high;
 103         return m_low;
 104     }
 105
 106     void
 107     ResetHigh()
 108     {
 109         m_high.reset();
 110     }
 111
 112     void
 113     ResetLow()
 114     {
 115         m_low.reset();
 116     }
 117
 118     void
 119     Reset()
 120     {
 121         ResetLow();
 122         ResetHigh();
 123     }
 124
 125     reference_type
 126     operator*() const
 127     {
 128         return Get().operator*();
 129     }
 130
 131     pointer_type
 132     operator->() const
 133     {
 134         return Get().operator->();
 135     }
 136
 137     ~PriorityPointerPair();
 138
 139 private:
 140
 141     T_SP m_high;
 142     T_SP m_low;
 143
 144     DISALLOW_COPY_AND_ASSIGN (PriorityPointerPair);
 145
 146 };
 147
 148 } // namespace lldb_utility
 149
 150 #endif // #ifndef liblldb_PriorityPointerPair_h_