1 files changed, 177 insertions, 0 deletions
diff --git a/include/lldb/Core/History.h b/include/lldb/Core/History.h
new file mode 100644
index 000000000000..b3626882f843
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+++ b/include/lldb/Core/History.h
@@ -0,0 +1,177 @@
+//===-- History.h -----------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef lldb_History_h_
+#define lldb_History_h_
+
+// C Includes
+#include <stdint.h>
+
+// C++ Includes
+#include <stack>
+#include <string>
+
+// Other libraries and framework includes
+// Project includes
+#include "lldb/lldb-public.h"
+#include "lldb/Host/Mutex.h"
+
+namespace lldb_private {
+
+//----------------------------------------------------------------------
+/// @class HistorySource History.h "lldb/Core/History.h"
+/// @brief A class that defines history events.
+//----------------------------------------------------------------------
+    
+class HistorySource
+{
+public:
+    typedef const void * HistoryEvent;
+
+    HistorySource () :
+        m_mutex (Mutex::eMutexTypeRecursive),
+        m_events ()
+    {
+    }
+
+    virtual 
+    ~HistorySource()
+    {
+    }
+
+    // Create a new history event. Subclasses should use any data or members
+    // in the subclass of this class to produce a history event and push it
+    // onto the end of the history stack.
+
+    virtual HistoryEvent
+    CreateHistoryEvent () = 0; 
+    
+    virtual void
+    DeleteHistoryEvent (HistoryEvent event) = 0;
+    
+    virtual void
+    DumpHistoryEvent (Stream &strm, HistoryEvent event) = 0;
+
+    virtual size_t
+    GetHistoryEventCount() = 0;
+    
+    virtual HistoryEvent
+    GetHistoryEventAtIndex (uint32_t idx) = 0;
+    
+    virtual HistoryEvent
+    GetCurrentHistoryEvent () = 0;
+
+    // Return 0 when lhs == rhs, 1 if lhs > rhs, or -1 if lhs < rhs.
+    virtual int
+    CompareHistoryEvents (const HistoryEvent lhs, 
+                          const HistoryEvent rhs) = 0;
+    
+    virtual bool
+    IsCurrentHistoryEvent (const HistoryEvent event) = 0;
+
+private:
+    typedef std::stack<HistoryEvent> collection;
+
+    Mutex m_mutex;
+    collection m_events;
+    
+    DISALLOW_COPY_AND_ASSIGN (HistorySource);
+
+};
+    
+//----------------------------------------------------------------------
+/// @class HistorySourceUInt History.h "lldb/Core/History.h"
+/// @brief A class that defines history events that are represented by
+/// unsigned integers.
+///
+/// Any history event that is defined by a unique monotonically 
+/// increasing unsigned integer
+//----------------------------------------------------------------------
+
+class HistorySourceUInt : public HistorySource
+{
+    HistorySourceUInt (const char *id_name, uintptr_t start_value = 0u) :
+        HistorySource(),
+        m_name (id_name),
+        m_curr_id (start_value)
+    {
+    }
+    
+    virtual 
+    ~HistorySourceUInt()
+    {
+    }
+    
+    // Create a new history event. Subclasses should use any data or members
+    // in the subclass of this class to produce a history event and push it
+    // onto the end of the history stack.
+    
+    virtual HistoryEvent
+    CreateHistoryEvent ()
+    {
+        ++m_curr_id;
+        return (HistoryEvent)m_curr_id;
+    }
+    
+    virtual void
+    DeleteHistoryEvent (HistoryEvent event)
+    {
+        // Nothing to delete, the event contains the integer
+    }
+    
+    virtual void
+    DumpHistoryEvent (Stream &strm, HistoryEvent event);
+    
+    virtual size_t
+    GetHistoryEventCount()
+    {
+        return m_curr_id;
+    }
+    
+    virtual HistoryEvent
+    GetHistoryEventAtIndex (uint32_t idx)
+    {
+        return (HistoryEvent)((uintptr_t)idx);
+    }
+    
+    virtual HistoryEvent
+    GetCurrentHistoryEvent ()
+    {
+        return (HistoryEvent)m_curr_id;
+    }
+    
+    // Return 0 when lhs == rhs, 1 if lhs > rhs, or -1 if lhs < rhs.
+    virtual int
+    CompareHistoryEvents (const HistoryEvent lhs, 
+                          const HistoryEvent rhs)
+    {
+        uintptr_t lhs_uint = (uintptr_t)lhs;
+        uintptr_t rhs_uint = (uintptr_t)rhs;
+        if (lhs_uint < rhs_uint)
+            return -1;
+        if (lhs_uint > rhs_uint)
+            return +1;
+        return 0;
+    }
+    
+    virtual bool
+    IsCurrentHistoryEvent (const HistoryEvent event)
+    {
+        return (uintptr_t)event == m_curr_id;
+    }
+
+protected:
+    std::string m_name; // The name of the history unsigned integer
+    uintptr_t m_curr_id; // The current value of the history unsigned unteger
+};
+
+
+} // namespace lldb_private
+
+#endif	// lldb_History_h_