merge -r 122421-124917 viewer-2.0.0-2 -> viewer-2.0.0-3

ignore-dead-branch

1 files changed, 88 insertions, 0 deletions

diff --git a/indra/llui/lllazyvalue.h b/indra/llui/lllazyvalue.h
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+++ b/indra/llui/lllazyvalue.h
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+/** 
+ * @file lllazyvalue.h
+ * @brief generic functor/value abstraction for lazy evaluation of a value
+ * parsing construction parameters from xml and LLSD
+ *
+ * $LicenseInfo:firstyear=2008&license=viewergpl$
+ * 
+ * Copyright (c) 2008-2009, 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_LAZY_VALUE_H
+#define LL_LAZY_VALUE_H
+
+#include <boost/function.hpp>
+
+// Holds on to a value of type T *or* calls a functor to generate a value of type T
+template<typename T>
+class LLLazyValue
+{
+public:
+	typedef typename boost::add_reference<typename boost::add_const<T>::type>::type	T_const_ref;
+	typedef typename boost::function<T_const_ref (void)>							function_type;
+
+public:
+	LLLazyValue(const function_type& value) 
+	:	mValueGetter(value)
+	{} 
+	LLLazyValue(T_const_ref value)
+	:	mValue(value)
+	{}
+	LLLazyValue()
+	:	mValue()
+	{}
+
+	void set(const LLLazyValue& val)
+	{
+		mValueGetter = val.mValueGetter;
+	}
+
+	void set(T_const_ref val)
+	{
+		mValue = val;
+		mValueGetter = NULL;
+	}
+
+	T_const_ref get() const
+	{
+		if (!mValueGetter.empty())
+		{
+			return mValueGetter();
+		}
+		return mValue;
+	}
+
+	bool isUsingFunction() const
+	{
+		return mValueGetter != NULL;
+	}
+
+private:
+	function_type	mValueGetter;
+	T				mValue;
+};
+
+#endif // LL_LAZY_VALUE_H