TiXmlHandle Class Reference

#include <tinyxml.h>

Collaboration diagram for TiXmlHandle:

List of all members.

Public Member Functions
	TiXmlHandle (TiXmlNode *_node)
	Create a handle from any node (at any depth of the tree.) This can be a null pointer.
	TiXmlHandle (const TiXmlHandle &ref)
	Copy constructor.
TiXmlHandle	operator= (const TiXmlHandle &ref)
TiXmlHandle	FirstChild () const
	Return a handle to the first child node.
TiXmlHandle	FirstChild (const char *value) const
	Return a handle to the first child node with the given name.
TiXmlHandle	FirstChildElement () const
	Return a handle to the first child element.
TiXmlHandle	FirstChildElement (const char *value) const
	Return a handle to the first child element with the given name.
TiXmlHandle	Child (const char *value, int index) const
TiXmlHandle	Child (int index) const
TiXmlHandle	ChildElement (const char *value, int index) const
TiXmlHandle	ChildElement (int index) const
TiXmlNode *	ToNode () const
TiXmlElement *	ToElement () const
TiXmlText *	ToText () const
TiXmlUnknown *	ToUnknown () const
TiXmlNode *	Node () const
TiXmlElement *	Element () const
TiXmlText *	Text () const
TiXmlUnknown *	Unknown () const
Private Attributes
TiXmlNode *	node

---

Detailed Description

A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. Note that TiXmlHandle is not part of the TinyXml DOM structure. It is a separate utility class.

Take an example:

	<Document>
		<Element attributeA = "valueA">
			<Child attributeB = "value1" />
			<Child attributeB = "value2" />
		</Element>
	<Document>
	

Assuming you want the value of "attributeB" in the 2nd "Child" element, it's very easy to write a *lot* of code that looks like:

	TiXmlElement* root = document.FirstChildElement( "Document" );
	if ( root )
	{
		TiXmlElement* element = root->FirstChildElement( "Element" );
		if ( element )
		{
			TiXmlElement* child = element->FirstChildElement( "Child" );
			if ( child )
			{
				TiXmlElement* child2 = child->NextSiblingElement( "Child" );
				if ( child2 )
				{
					// Finally do something useful.
	

And that doesn't even cover "else" cases. TiXmlHandle addresses the verbosity of such code. A TiXmlHandle checks for null pointers so it is perfectly safe and correct to use:

	TiXmlHandle docHandle( &document );
	TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).ToElement();
	if ( child2 )
	{
		// do something useful
	

Which is MUCH more concise and useful.

It is also safe to copy handles - internally they are nothing more than node pointers.

	TiXmlHandle handleCopy = handle;
	

What they should not be used for is iteration:

	int i=0; 
	while ( true )
	{
		TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).ToElement();
		if ( !child )
			break;
		// do something
		++i;
	}
	

It seems reasonable, but it is in fact two embedded while loops. The Child method is a linear walk to find the element, so this code would iterate much more than it needs to. Instead, prefer:

	TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).ToElement();

	for( child; child; child=child->NextSiblingElement() )
	{
		// do something
	}
	

Definition at line 1631 of file tinyxml.h.

---

Constructor & Destructor Documentation

TiXmlHandle::TiXmlHandle

(

TiXmlNode *

_node

)

[inline]

Create a handle from any node (at any depth of the tree.) This can be a null pointer.

Definition at line 1635 of file tinyxml.h.

{ this->node = _node; }

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TiXmlHandle::TiXmlHandle

(

const TiXmlHandle &

ref

)

[inline]

Copy constructor.

Definition at line 1637 of file tinyxml.h.

{ this->node = ref.node; }

---

Member Function Documentation

TiXmlHandle TiXmlHandle::Child	(	const char *	value,
		int	index
	)		const

Return a handle to the "index" child with the given name. The first child is 0, the second 1, etc.

Definition at line 1652 of file tinyxml.cpp.

{
        if ( node )
        {
                int i;
                TiXmlNode* child = node->FirstChild( value );
                for (   i=0;
                                child && i<count;
                                child = child->NextSibling( value ), ++i )
                {
                        // nothing
                }
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::Child

(

int

index

)

const

Return a handle to the "index" child. The first child is 0, the second 1, etc.

Definition at line 1633 of file tinyxml.cpp.

{
        if ( node )
        {
                int i;
                TiXmlNode* child = node->FirstChild();
                for (   i=0;
                                child && i<count;
                                child = child->NextSibling(), ++i )
                {
                        // nothing
                }
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::ChildElement	(	const char *	value,
		int	index
	)		const

Return a handle to the "index" child element with the given name. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.

Definition at line 1690 of file tinyxml.cpp.

{
        if ( node )
        {
                int i;
                TiXmlElement* child = node->FirstChildElement( value );
                for (   i=0;
                                child && i<count;
                                child = child->NextSiblingElement( value ), ++i )
                {
                        // nothing
                }
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::ChildElement

(

int

index

)

const

Return a handle to the "index" child element. The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.

Definition at line 1671 of file tinyxml.cpp.

{
        if ( node )
        {
                int i;
                TiXmlElement* child = node->FirstChildElement();
                for (   i=0;
                                child && i<count;
                                child = child->NextSiblingElement(), ++i )
                {
                        // nothing
                }
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlElement* TiXmlHandle::Element

(

)

const [inline]

Deprecated:

use ToElement. Return the handle as a TiXmlElement. This may return null.

Definition at line 1696 of file tinyxml.h.

{ return ToElement(); }

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TiXmlHandle TiXmlHandle::FirstChild

(

const char *

value

)

const

Return a handle to the first child node with the given name.

Definition at line 1597 of file tinyxml.cpp.

{
        if ( node )
        {
                TiXmlNode* child = node->FirstChild( value );
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::FirstChild

(

)

const

Return a handle to the first child node.

Definition at line 1585 of file tinyxml.cpp.

{
        if ( node )
        {
                TiXmlNode* child = node->FirstChild();
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::FirstChildElement

(

)

const

Return a handle to the first child element.

Definition at line 1609 of file tinyxml.cpp.

{
        if ( node )
        {
                TiXmlElement* child = node->FirstChildElement();
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlHandle TiXmlHandle::FirstChildElement

(

const char *

value

)

const

Return a handle to the first child element with the given name.

Definition at line 1621 of file tinyxml.cpp.

{
        if ( node )
        {
                TiXmlElement* child = node->FirstChildElement( value );
                if ( child )
                        return TiXmlHandle( child );
        }
        return TiXmlHandle( 0 );
}

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TiXmlNode* TiXmlHandle::Node

(

)

const [inline]

Deprecated:

use ToNode. Return the handle as a TiXmlNode. This may return null.

Definition at line 1692 of file tinyxml.h.

{ return ToNode(); } 

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TiXmlHandle TiXmlHandle::operator=

(

const TiXmlHandle &

ref

)

[inline]

Definition at line 1638 of file tinyxml.h.

{ this->node = ref.node; return *this; }

TiXmlText* TiXmlHandle::Text

(

)

const [inline]

Deprecated:

use ToText() Return the handle as a TiXmlText. This may return null.

Definition at line 1700 of file tinyxml.h.

{ return ToText(); }

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TiXmlElement* TiXmlHandle::ToElement

(

)

const [inline]

Return the handle as a TiXmlElement. This may return null.

Definition at line 1681 of file tinyxml.h.

{ return ( ( node && node->ToElement() ) ? node->ToElement() : 0 ); }

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TiXmlNode* TiXmlHandle::ToNode

(

)

const [inline]

Return the handle as a TiXmlNode. This may return null.

Definition at line 1678 of file tinyxml.h.

{ return node; } 

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TiXmlText* TiXmlHandle::ToText

(

)

const [inline]

Return the handle as a TiXmlText. This may return null.

Definition at line 1684 of file tinyxml.h.

{ return ( ( node && node->ToText() ) ? node->ToText() : 0 ); }

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TiXmlUnknown* TiXmlHandle::ToUnknown

(

)

const [inline]

Return the handle as a TiXmlUnknown. This may return null.

Definition at line 1687 of file tinyxml.h.

{ return ( ( node && node->ToUnknown() ) ? node->ToUnknown() : 0 ); }

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TiXmlUnknown* TiXmlHandle::Unknown

(

)

const [inline]

Deprecated:

use ToUnknown() Return the handle as a TiXmlUnknown. This may return null.

Definition at line 1704 of file tinyxml.h.

{ return ToUnknown(); }

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Member Data Documentation

TiXmlNode* TiXmlHandle::node [private]

Definition at line 1707 of file tinyxml.h.

---

The documentation for this class was generated from the following files:

• /home/cube/sources/osgearth/src/osgEarth/tinyxml.h
• /home/cube/sources/osgearth/src/osgEarth/tinyxml.cpp