From 9ec432034dc3c45d7ce763eb02dae4cc7f6b8da8 Mon Sep 17 00:00:00 2001
From: Steven Bennetts <steve@lindenlab.com>
Date: Sun, 21 Jun 2009 08:04:56 +0000
Subject: merge -r 122421-124917 viewer-2.0.0-2 -> viewer-2.0.0-3
 ignore-dead-branch

---
 indra/llcommon/llsafehandle.h | 167 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 167 insertions(+)
 create mode 100644 indra/llcommon/llsafehandle.h

(limited to 'indra/llcommon/llsafehandle.h')

diff --git a/indra/llcommon/llsafehandle.h b/indra/llcommon/llsafehandle.h
new file mode 100644
index 0000000000..1f7c682fd1
--- /dev/null
+++ b/indra/llcommon/llsafehandle.h
@@ -0,0 +1,167 @@
+/** 
+ * @file llsafehandle.h
+ * @brief Reference-counted object where Object() is valid, not NULL.
+ *
+ * $LicenseInfo:firstyear=2002&license=viewergpl$
+ * 
+ * Copyright (c) 2002-2009, 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 LLSAFEHANDLE_H
+#define LLSAFEHANDLE_H
+
+#include "llerror.h"	// *TODO: consider eliminating this
+
+// Expands LLPointer to return a pointer to a special instance of class Type instead of NULL.
+// This is useful in instances where operations on NULL pointers are semantically safe and/or
+// when error checking occurs at a different granularity or in a different part of the code
+// than when referencing an object via a LLSafeHandle.
+
+template <class Type> 
+class LLSafeHandle
+{
+public:
+	LLSafeHandle() :
+		mPointer(NULL)
+	{
+	}
+
+	LLSafeHandle(Type* ptr) : 
+		mPointer(NULL)
+	{
+		assign(ptr);
+	}
+
+	LLSafeHandle(const LLSafeHandle<Type>& ptr) : 
+		mPointer(NULL)
+	{
+		assign(ptr.mPointer);
+	}
+
+	// support conversion up the type hierarchy.  See Item 45 in Effective C++, 3rd Ed.
+	template<typename Subclass>
+	LLSafeHandle(const LLSafeHandle<Subclass>& ptr) : 
+		mPointer(NULL)
+	{
+		assign(ptr.get());
+	}
+
+	~LLSafeHandle()								
+	{
+		unref();
+	}
+
+	const Type*	operator->() const				{ return nonNull(mPointer); }
+	Type*	operator->()						{ return nonNull(mPointer); }
+
+	Type*	get() const							{ return mPointer; }
+	// we disallow these operations as they expose our null objects to direct manipulation
+	// and bypass the reference counting semantics
+	//const Type&	operator*() const			{ return *nonNull(mPointer); }
+	//Type&	operator*()							{ return *nonNull(mPointer); }
+
+	operator BOOL()  const						{ return mPointer != NULL; }
+	operator bool()  const						{ return mPointer != NULL; }
+	bool operator!() const						{ return mPointer == NULL; }
+	bool isNull() const							{ return mPointer == NULL; }
+	bool notNull() const						{ return mPointer != NULL; }
+
+
+	operator Type*()       const				{ return mPointer; }
+	operator const Type*() const				{ return mPointer; }
+	bool operator !=(Type* ptr) const           { return (mPointer != ptr); 	}
+	bool operator ==(Type* ptr) const           { return (mPointer == ptr); 	}
+	bool operator ==(const LLSafeHandle<Type>& ptr) const           { return (mPointer == ptr.mPointer); 	}
+	bool operator < (const LLSafeHandle<Type>& ptr) const           { return (mPointer < ptr.mPointer); 	}
+	bool operator > (const LLSafeHandle<Type>& ptr) const           { return (mPointer > ptr.mPointer); 	}
+
+	LLSafeHandle<Type>& operator =(Type* ptr)                   
+	{ 
+		assign(ptr);
+		return *this; 
+	}
+
+	LLSafeHandle<Type>& operator =(const LLSafeHandle<Type>& ptr)  
+	{ 
+		assign(ptr.mPointer);
+		return *this; 
+	}
+
+	// support assignment up the type hierarchy. See Item 45 in Effective C++, 3rd Ed.
+	template<typename Subclass>
+	LLSafeHandle<Type>& operator =(const LLSafeHandle<Subclass>& ptr)  
+	{ 
+		assign(ptr.get());
+		return *this; 
+	}
+
+public:
+	typedef Type* (*NullFunc)();
+	static const NullFunc sNullFunc;
+
+protected:
+	void ref()                             
+	{ 
+		if (mPointer)
+		{
+			mPointer->ref();
+		}
+	}
+
+	void unref()
+	{
+		if (mPointer)
+		{
+			Type *tempp = mPointer;
+			mPointer = NULL;
+			tempp->unref();
+			if (mPointer != NULL)
+			{
+				llwarns << "Unreference did assignment to non-NULL because of destructor" << llendl;
+				unref();
+			}
+		}
+	}
+
+	void assign(Type* ptr)
+	{
+		if( mPointer != ptr )
+		{
+			unref(); 
+			mPointer = ptr; 
+			ref();
+		}
+	}
+
+	static Type* nonNull(Type* ptr)
+	{
+		return ptr == NULL ? sNullFunc() : ptr;
+	}
+
+protected:
+	Type*	mPointer;
+};
+
+#endif
-- 
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