Add a Flush() method to IOStream to read and discard all remaining data,

and a SelfFlushingStream class which can be used to ensure that protocol 
streams are always flushed, to avoid breaking protocol.

3 files changed, 92 insertions, 0 deletions

diff --git a/lib/common/IOStream.cpp b/lib/common/IOStream.cpp
index 3c7be561..76fb7fed 100644
--- a/lib/common/IOStream.cpp
+++ b/lib/common/IOStream.cpp
@@ -238,4 +238,24 @@ bool IOStream::CopyStreamTo(IOStream &rCopyTo, int Timeout, int BufferSize)
 	return true;	// completed
 }
 
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    IOStream::Flush(int Timeout)
+//		Purpose: Read and discard all remaining data in stream.
+//			 Useful for protocol streams which must be flushed
+//			 to avoid breaking the protocol.
+//		Created: 2008/08/20
+//
+// --------------------------------------------------------------------------
+void IOStream::Flush(int Timeout)
+{
+	char buffer[4096];
+
+	while(StreamDataLeft())
+	{
+		Read(buffer, sizeof(buffer), Timeout);
+	}
+}
+
 
diff --git a/lib/common/IOStream.h b/lib/common/IOStream.h
index 042ccca4..fc9f8a97 100644
--- a/lib/common/IOStream.h
+++ b/lib/common/IOStream.h
@@ -57,6 +57,7 @@ public:
 	// Utility functions
 	bool ReadFullBuffer(void *pBuffer, int NBytes, int *pNBytesRead, int Timeout = IOStream::TimeOutInfinite);
 	bool CopyStreamTo(IOStream &rCopyTo, int Timeout = IOStream::TimeOutInfinite, int BufferSize = 1024);
+	void Flush(int Timeout = IOStream::TimeOutInfinite);
 	
 	static int ConvertSeekTypeToOSWhence(int SeekType);
 };
diff --git a/lib/common/SelfFlushingStream.h b/lib/common/SelfFlushingStream.h
new file mode 100644
index 00000000..36e9a4d3
--- /dev/null
+++ b/lib/common/SelfFlushingStream.h
@@ -0,0 +1,71 @@
+// --------------------------------------------------------------------------
+//
+// File
+//		Name:    SelfFlushingStream.h
+//		Purpose: A stream wrapper that always flushes the underlying
+//			 stream, to ensure protocol safety.
+//		Created: 2008/08/20
+//
+// --------------------------------------------------------------------------
+
+#ifndef SELFFLUSHINGSTREAM__H
+#define SELFFLUSHINGSTREAM__H
+
+#include "IOStream.h"
+
+// --------------------------------------------------------------------------
+//
+// Class
+//		Name:    SelfFlushingStream
+//		Purpose: A stream wrapper that always flushes the underlying
+//			 stream, to ensure protocol safety.
+//		Created: 2008/08/20
+//
+// --------------------------------------------------------------------------
+class SelfFlushingStream : public IOStream
+{
+public:
+	SelfFlushingStream(IOStream &rSource)
+	: mrSource(rSource) { }
+
+	SelfFlushingStream(const SelfFlushingStream &rToCopy)
+	: mrSource(rToCopy.mrSource) { }
+	
+	~SelfFlushingStream()
+	{
+		Flush();
+	}
+
+private:
+	// no copying from IOStream allowed
+	SelfFlushingStream(const IOStream& rToCopy);
+	
+public:
+	virtual int Read(void *pBuffer, int NBytes,
+		int Timeout = IOStream::TimeOutInfinite)
+	{
+		return mrSource.Read(pBuffer, NBytes, Timeout);
+	}
+	virtual pos_type BytesLeftToRead()
+	{
+		return mrSource.BytesLeftToRead();
+	}
+	virtual void Write(const void *pBuffer, int NBytes)
+	{
+		mrSource.Write(pBuffer, NBytes);
+	}
+	virtual bool StreamDataLeft()
+	{
+		return mrSource.StreamDataLeft();
+	}
+	virtual bool StreamClosed()
+	{
+		return mrSource.StreamClosed();
+	}
+
+private:
+	IOStream &mrSource;
+};
+
+#endif // SELFFLUSHINGSTREAM__H
+