A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. More...

#include <tinyxml.h>

Public Member Functions
	TiXmlHandle (TiXmlNode *aNode)
	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
	Return a handle to the "index" child with the given name. More...

TiXmlHandle	Child (int index) const
	Return a handle to the "index" child. More...

TiXmlHandle	ChildElement (const char *value, int index) const
	Return a handle to the "index" child element with the given name. More...

TiXmlHandle	ChildElement (int index) const
	Return a handle to the "index" child element. More...

TiXmlHandle	FirstChild (const std::string &_value) const

TiXmlHandle	FirstChildElement (const std::string &_value) const

TiXmlHandle	Child (const std::string &_value, int index) const

TiXmlHandle	ChildElement (const std::string &_value, int index) const

TiXmlNode *	Node () const
	Return the handle as a TiXmlNode. This may return null.

TiXmlElement *	Element () const
	Return the handle as a TiXmlElement. This may return null.

TiXmlText *	Text () const
	Return the handle as a TiXmlText. This may return null.

TiXmlUnknown *	Unknown () const
	Return the handle as a TiXmlUnknown. This may return null;.

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 ).Element();
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 ).Element();
        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" ).Element();

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

Definition at line 1376 of file tinyxml.h.