TiXmlHandle Class Reference

#include <tinyxml.h>

Collaboration diagram for TiXmlHandle:

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

Constructor & Destructor Documentation

TiXmlHandle() [1/2]

TiXmlHandle::TiXmlHandle ( TiXmlNode *  _node )

inline

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

{ this->node = _node; }

TiXmlHandle() [2/2]

TiXmlHandle::TiXmlHandle ( const TiXmlHandle &  ref )

inline

Copy constructor.

{ this->node = ref.node; }

Member Function Documentation

Child() [1/2]

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.

{
    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 );
}

Child() [2/2]

TiXmlHandle TiXmlHandle::Child

(

int

index

)

const

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

{
    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 );
}

ChildElement() [1/2]

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.

{
    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 );
}

ChildElement() [2/2]

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.

{
    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 );
}

Element()

TiXmlElement* TiXmlHandle::Element ( ) const

inline

Deprecated:

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

{ return ToElement(); }

FirstChild() [1/2]

TiXmlHandle TiXmlHandle::FirstChild

(

)

const

Return a handle to the first child node.

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

FirstChild() [2/2]

TiXmlHandle TiXmlHandle::FirstChild

(

const char *

value

)

const

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

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

FirstChildElement() [1/2]

TiXmlHandle TiXmlHandle::FirstChildElement

(

)

const

Return a handle to the first child element.

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

FirstChildElement() [2/2]

TiXmlHandle TiXmlHandle::FirstChildElement

(

const char *

value

)

const

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

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

Node()

TiXmlNode* TiXmlHandle::Node ( ) const

inline

Deprecated:

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

{ return ToNode(); } 

operator=()

TiXmlHandle TiXmlHandle::operator= ( const TiXmlHandle &  ref )

inline

{ if ( &ref != this ) this->node = ref.node; return *this; }

Text()

TiXmlText* TiXmlHandle::Text ( ) const

inline

Deprecated:

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

{ return ToText(); }

ToElement()

TiXmlElement* TiXmlHandle::ToElement ( ) const

inline

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

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

ToNode()

TiXmlNode* TiXmlHandle::ToNode ( ) const

inline

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

{ return node; } 

ToText()

TiXmlText* TiXmlHandle::ToText ( ) const

inline

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

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

ToUnknown()

TiXmlUnknown* TiXmlHandle::ToUnknown ( ) const

inline

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

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

Unknown()

TiXmlUnknown* TiXmlHandle::Unknown ( ) const

inline

Deprecated:

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

{ return ToUnknown(); }

Member Data Documentation

node

TiXmlNode* TiXmlHandle::node

private

---

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

• src/libScan/tinyxml.h
• src/libScan/tinyxml.cpp