TiXmlHandle Class Reference

#include <tinyxml.h>

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	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

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
}

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.

References TiXmlNode::NextSibling(), and TiXmlHandle().

TiXmlHandle TiXmlHandle::Child

(

int

index

)

const

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

References TiXmlNode::NextSibling(), and TiXmlHandle().

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.

References TiXmlNode::NextSiblingElement(), and TiXmlHandle().

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.

References TiXmlNode::NextSiblingElement(), and TiXmlHandle().

TiXmlElement* TiXmlHandle::Element ( ) const

inline

References ToElement().

TiXmlNode* TiXmlHandle::Node ( ) const

inline

References ToNode().

TiXmlText* TiXmlHandle::Text ( ) const

inline

References ToText().

TiXmlElement* TiXmlHandle::ToElement ( ) const

inline

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

References TiXmlNode::ToElement().

Referenced by Element().

TiXmlNode* TiXmlHandle::ToNode ( ) const

inline

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

Referenced by Node().

TiXmlText* TiXmlHandle::ToText ( ) const

inline

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

References TiXmlNode::ToText().

Referenced by Text().

TiXmlUnknown* TiXmlHandle::ToUnknown ( ) const

inline

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

References TiXmlNode::ToUnknown().

Referenced by Unknown().

TiXmlUnknown* TiXmlHandle::Unknown ( ) const

inline

References ToUnknown().

---

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

• tinyxml.h
• tinyxml.cc