1 files changed, 154 insertions, 0 deletions
diff --git a/include/lldb/Utility/Either.h b/include/lldb/Utility/Either.h
new file mode 100644
index 000000000000..ae647363512d
--- /dev/null
+++ b/include/lldb/Utility/Either.h
@@ -0,0 +1,154 @@
+//===-- Either.h -----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_Either_h_
+#define liblldb_Either_h_
+
+#include "llvm/ADT/Optional.h"
+
+#include <functional>
+
+namespace lldb_utility {
+    template <typename T1, typename T2>
+    class Either
+    {
+    private:
+        enum class Selected
+        {
+            One, Two
+        };
+        
+        Selected m_selected;
+        union
+        {
+            T1 m_t1;
+            T2 m_t2;
+        };
+        
+    public:
+        Either (const T1& t1)
+        {
+            m_t1 = t1;
+            m_selected = Selected::One;
+        }
+        
+        Either (const T2& t2)
+        {
+            m_t2 = t2;
+            m_selected = Selected::Two;
+        }
+        
+        Either (const Either<T1,T2>& rhs)
+        {
+            switch (rhs.m_selected)
+            {
+                case Selected::One:
+                    m_t1 = rhs.GetAs<T1>().getValue();
+                    m_selected = Selected::One;
+                    break;
+                case Selected::Two:
+                    m_t2 = rhs.GetAs<T2>().getValue();
+                    m_selected = Selected::Two;
+                    break;
+            }
+        }
+        
+        template <class X, typename std::enable_if<std::is_same<T1,X>::value>::type * = nullptr>
+        llvm::Optional<T1>
+        GetAs() const
+        {
+            switch (m_selected)
+            {
+                case Selected::One:
+                    return m_t1;
+                default:
+                    return llvm::Optional<T1>();
+            }
+        }
+        
+        template <class X, typename std::enable_if<std::is_same<T2,X>::value>::type * = nullptr>
+        llvm::Optional<T2>
+        GetAs() const
+        {
+            switch (m_selected)
+            {
+                case Selected::Two:
+                    return m_t2;
+                default:
+                    return llvm::Optional<T2>();
+            }
+        }
+        
+        template <class ResultType>
+        ResultType
+        Apply (std::function<ResultType(T1)> if_T1,
+               std::function<ResultType(T2)> if_T2) const
+        {
+            switch (m_selected)
+            {
+                case Selected::One:
+                    return if_T1(m_t1);
+                case Selected::Two:
+                    return if_T2(m_t2);
+            }
+        }
+        
+        bool
+        operator == (const Either<T1,T2>& rhs)
+        {
+            return (GetAs<T1>() == rhs.GetAs<T1>()) && (GetAs<T2>() == rhs.GetAs<T2>());
+        }
+        
+        explicit
+        operator bool ()
+        {
+            switch (m_selected)
+            {
+                case Selected::One:
+                    return (bool)m_t1;
+                case Selected::Two:
+                    return (bool)m_t2;
+            }
+        }
+        
+        Either<T1,T2>&
+        operator = (const Either<T1,T2>& rhs)
+        {
+            switch (rhs.m_selected)
+            {
+                case Selected::One:
+                    m_t1 = rhs.GetAs<T1>().getValue();
+                    m_selected = Selected::One;
+                    break;
+                case Selected::Two:
+                    m_t2 = rhs.GetAs<T2>().getValue();
+                    m_selected = Selected::Two;
+                    break;
+            }
+            return *this;
+        }
+        
+        ~Either ()
+        {
+            switch (m_selected)
+            {
+                case Selected::One:
+                    m_t1.T1::~T1();
+                    break;
+                case Selected::Two:
+                    m_t2.T2::~T2();
+                    break;
+            }
+        }
+    };
+    
+} // namespace lldb_utility
+
+#endif // #ifndef liblldb_Either_h_
+