1 files changed, 109 insertions, 0 deletions
diff --git a/src/vm/eventpipebuffer.h b/src/vm/eventpipebuffer.h
new file mode 100644
index 0000000000..f279a2865c
--- /dev/null
+++ b/src/vm/eventpipebuffer.h
@@ -0,0 +1,109 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#ifndef __EVENTPIPE_BUFFER_H__
+#define __EVENTPIPE_BUFFER_H__
+
+#ifdef FEATURE_PERFTRACING
+
+#include "eventpipeevent.h"
+#include "eventpipeeventinstance.h"
+
+class EventPipeBuffer
+{
+
+    friend class EventPipeBufferList;
+    friend class EventPipeBufferManager;
+
+private:
+
+    // A pointer to the actual buffer.
+    BYTE *m_pBuffer;
+
+    // The current write pointer.
+    BYTE *m_pCurrent;
+
+    // The max write pointer (end of the buffer).
+    BYTE *m_pLimit;
+
+    // The timestamp of the most recent event in the buffer.
+    LARGE_INTEGER m_mostRecentTimeStamp;
+
+    // Used by PopNext as input to GetNext.
+    // If NULL, no events have been popped.
+    // The event will still remain in the buffer after it is popped, but PopNext will not return it again.
+    EventPipeEventInstance *m_pLastPoppedEvent;
+
+    // Each buffer will become part of a per-thread linked list of buffers.
+    // The linked list is invasive, thus we declare the pointers here.
+    EventPipeBuffer *m_pPrevBuffer;
+    EventPipeBuffer *m_pNextBuffer;
+
+    unsigned int GetSize() const
+    {
+        LIMITED_METHOD_CONTRACT;
+        return (unsigned int)(m_pLimit - m_pBuffer);
+    }
+
+    EventPipeBuffer* GetPrevious() const
+    {
+        LIMITED_METHOD_CONTRACT;
+        return m_pPrevBuffer;
+    }
+
+    EventPipeBuffer* GetNext() const
+    {
+        LIMITED_METHOD_CONTRACT;
+        return m_pNextBuffer;
+    }
+
+    void SetPrevious(EventPipeBuffer *pBuffer)
+    {
+        LIMITED_METHOD_CONTRACT;
+        m_pPrevBuffer = pBuffer;
+    }
+
+    void SetNext(EventPipeBuffer *pBuffer)
+    {
+        LIMITED_METHOD_CONTRACT;
+        m_pNextBuffer = pBuffer;
+    }
+
+public:
+
+    EventPipeBuffer(unsigned int bufferSize);
+    ~EventPipeBuffer();
+
+    // Write an event to the buffer.
+    // An optional stack trace can be provided for sample profiler events.
+    // Otherwise, if a stack trace is needed, one will be automatically collected.
+    // Returns:
+    //  - true: The write succeeded.
+    //  - false: The write failed.  In this case, the buffer should be considered full.
+    bool WriteEvent(Thread *pThread, EventPipeEvent &event, BYTE *pData, unsigned int dataLength, LPCGUID pActivityId, LPCGUID pRelatedActivityId, StackContents *pStack = NULL);
+
+    // Get the timestamp of the most recent event in the buffer.
+    LARGE_INTEGER GetMostRecentTimeStamp() const;
+
+    // Clear the buffer.
+    void Clear();
+
+    // Get the next event from the buffer as long as it is before the specified timestamp.
+    // Input of NULL gets the first event.
+    EventPipeEventInstance* GetNext(EventPipeEventInstance *pEvent, LARGE_INTEGER beforeTimeStamp);
+
+    // Get the next event from the buffer, but don't mark it read.
+    EventPipeEventInstance* PeekNext(LARGE_INTEGER beforeTimeStamp);
+
+    // Get the next event from the buffer and mark it as read.
+    EventPipeEventInstance* PopNext(LARGE_INTEGER beforeTimeStamp);
+
+#ifdef _DEBUG
+    bool EnsureConsistency();
+#endif // _DEBUG
+};
+
+#endif // FEATURE_PERFTRACING
+
+#endif // __EVENTPIPE_BUFFER_H__