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TiXmlHandle Class Reference

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 *_node)
 Create a handle from any node (at any depth of the tree.) This can be a null pointer. More...
 
 TiXmlHandle (const TiXmlHandle &ref)
 Copy constructor. More...
 
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...
 
TiXmlElementElement () 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...
 
TiXmlNodeNode () const
 
TiXmlHandle operator= (const TiXmlHandle &ref)
 
TiXmlTextText () const
 
TiXmlElementToElement () const
 Return the handle as a TiXmlElement. More...
 
TiXmlNodeToNode () const
 Return the handle as a TiXmlNode. More...
 
TiXmlTextToText () const
 Return the handle as a TiXmlText. More...
 
TiXmlUnknownToUnknown () const
 Return the handle as a TiXmlUnknown. More...
 
TiXmlUnknownUnknown () 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
}

Definition at line 1631 of file tinyxml.h.

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.

Definition at line 1635 of file tinyxml.h.

Referenced by FirstChild(), and FirstChildElement().

◆ TiXmlHandle() [2/2]

TiXmlHandle::TiXmlHandle ( const TiXmlHandle ref)
inline

Copy constructor.

Definition at line 1637 of file tinyxml.h.

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.

Definition at line 1674 of file tinyxml.cpp.

◆ 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.

Definition at line 1655 of file tinyxml.cpp.

◆ 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.

Definition at line 1712 of file tinyxml.cpp.

◆ 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.

Definition at line 1693 of file tinyxml.cpp.

◆ Element()

TiXmlElement* TiXmlHandle::Element ( ) const
inline

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

Definition at line 1696 of file tinyxml.h.

References ToElement().

◆ FirstChild() [1/2]

TiXmlHandle TiXmlHandle::FirstChild ( ) const

Return a handle to the first child node.

Definition at line 1607 of file tinyxml.cpp.

References TiXmlHandle().

◆ FirstChild() [2/2]

TiXmlHandle TiXmlHandle::FirstChild ( const char *  value) const

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

Definition at line 1619 of file tinyxml.cpp.

References TiXmlHandle().

◆ FirstChildElement() [1/2]

TiXmlHandle TiXmlHandle::FirstChildElement ( ) const

Return a handle to the first child element.

Definition at line 1631 of file tinyxml.cpp.

References TiXmlHandle().

◆ FirstChildElement() [2/2]

TiXmlHandle TiXmlHandle::FirstChildElement ( const char *  value) const

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

Definition at line 1643 of file tinyxml.cpp.

References TiXmlHandle().

◆ Node()

TiXmlNode* TiXmlHandle::Node ( ) const
inline

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

Definition at line 1692 of file tinyxml.h.

References ToNode().

◆ Text()

TiXmlText* TiXmlHandle::Text ( ) const
inline

This may return null.

Definition at line 1700 of file tinyxml.h.

References ToText().

◆ ToElement()

TiXmlElement* TiXmlHandle::ToElement ( ) const
inline

Return the handle as a TiXmlElement.

This may return null.

Definition at line 1681 of file tinyxml.h.

Referenced by Element().

◆ ToNode()

TiXmlNode* TiXmlHandle::ToNode ( ) const
inline

Return the handle as a TiXmlNode.

This may return null.

Definition at line 1678 of file tinyxml.h.

Referenced by Node().

◆ ToText()

TiXmlText* TiXmlHandle::ToText ( ) const
inline

Return the handle as a TiXmlText.

This may return null.

Definition at line 1684 of file tinyxml.h.

Referenced by Text().

◆ ToUnknown()

TiXmlUnknown* TiXmlHandle::ToUnknown ( ) const
inline

Return the handle as a TiXmlUnknown.

This may return null.

Definition at line 1687 of file tinyxml.h.

Referenced by Unknown().

◆ Unknown()

TiXmlUnknown* TiXmlHandle::Unknown ( ) const
inline

This may return null.

Definition at line 1704 of file tinyxml.h.

References ToUnknown().


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