Imported existing code

indra/llmessage/llchainio.h

@@ -0,0 +1,141 @@
+/** 
+ * @file llchainio.h
+ * @author Phoenix
+ * @date 2005-08-04
+ * @brief This class declares the interface for constructing io chains.
+ *
+ * $LicenseInfo:firstyear=2005&license=viewergpl$
+ * 
+ * Copyright (c) 2005-2009, Linden Research, Inc.
+ * 
+ * Second Life Viewer Source Code
+ * The source code in this file ("Source Code") is provided by Linden Lab
+ * to you under the terms of the GNU General Public License, version 2.0
+ * ("GPL"), unless you have obtained a separate licensing agreement
+ * ("Other License"), formally executed by you and Linden Lab.  Terms of
+ * the GPL can be found in doc/GPL-license.txt in this distribution, or
+ * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
+ * 
+ * There are special exceptions to the terms and conditions of the GPL as
+ * it is applied to this Source Code. View the full text of the exception
+ * in the file doc/FLOSS-exception.txt in this software distribution, or
+ * online at
+ * http://secondlifegrid.net/programs/open_source/licensing/flossexception
+ * 
+ * By copying, modifying or distributing this software, you acknowledge
+ * that you have read and understood your obligations described above,
+ * and agree to abide by those obligations.
+ * 
+ * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
+ * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
+ * COMPLETENESS OR PERFORMANCE.
+ * $/LicenseInfo$
+ */
+
+#ifndef LL_LLCHAINIO_H
+#define LL_LLCHAINIO_H
+
+#include "llpumpio.h"
+
+/** 
+ * @class LLDeferredChain
+ * @brief This class allows easy addition of a chain which will sleep
+ * and then process another chain.
+ */
+class LLDeferredChain
+{
+public:
+	/**
+	 * @brief Add a chain to a pump in a finite # of seconds
+	 *
+	 * @prarm pump The pump to work on.
+	 * @prarm in_seconds The number of seconds from now when chain should start.
+	 * @prarm chain The chain to add in in_seconds seconds.
+	 * @prarm chain_timeout timeout for chain on the pump.
+	 * @return Returns true if the operation was queued.
+	 */
+	static bool addToPump(
+		LLPumpIO* pump,
+		F32 in_seconds,
+		const LLPumpIO::chain_t& chain,
+		F32 chain_timeout);
+};
+
+/** 
+ * @class LLChainIOFactory
+ * @brief This class is an abstract base class for building io chains.
+ *
+ * This declares an abstract base class for a chain factory. The
+ * factory is used to connect an input pipe to the first pipe in the
+ * chain, and an output pipe to the last pipe in the chain. This will
+ * allow easy construction for buffer based io like services to for
+ * API centered IO while abstracting the input and output to simple
+ * data passing.
+ * To use this class, you should derive a class which implements the
+ * <code>build</code> method.
+ */
+class LLChainIOFactory
+{
+public:
+	// Constructor
+	LLChainIOFactory();
+
+	// Destructor
+	virtual ~LLChainIOFactory();
+
+	/** 
+	 * @brief Build the chian with in as the first and end as the last
+	 *
+	 * The caller of the LLChainIOFactory is responsible for managing
+	 * the memory of the in pipe. All of the chains generated by the
+	 * factory will be ref counted as usual, so the caller will also
+	 * need to break the links in the chain.
+	 * @param chain The chain which will have new pipes appended
+	 * @param context A context for use by this factory if you choose
+	 * @retrun Returns true if the call was successful.
+	 */
+	virtual bool build(LLPumpIO::chain_t& chain, LLSD context) const = 0;
+
+protected:
+};
+
+/** 
+ * @class LLSimpleIOFactory
+ * @brief Basic implementation for making a factory that returns a
+ * 'chain' of one object
+ */
+template<class Pipe>
+class LLSimpleIOFactory : public LLChainIOFactory
+{
+public:
+	virtual bool build(LLPumpIO::chain_t& chain, LLSD context) const
+	{
+		chain.push_back(LLIOPipe::ptr_t(new Pipe));
+		return true;
+	}
+};
+
+/** 
+ * @class LLCloneIOFactory
+ * @brief Implementation for a facory which copies a particular pipe.
+ */
+template<class Pipe>
+class LLCloneIOFactory : public LLChainIOFactory
+{
+public:
+	LLCloneIOFactory(Pipe* original) :
+		mHandle(original),
+		mOriginal(original) {}
+
+	virtual bool build(LLPumpIO::chain_t& chain, LLSD context) const
+	{
+		chain.push_back(LLIOPipe::ptr_t(new Pipe(*mOriginal)));
+		return true;
+	}
+
+protected:
+	LLIOPipe::ptr_t mHandle;
+	Pipe* mOriginal;
+};
+
+#endif // LL_LLCHAINIO_H