Panda3D
Public Member Functions | List of all members
TiXmlHandle Class Reference

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

Public Member Functions

 __init__ (const TiXmlHandle ref)
 Copy constructor. More...
 
 __init__ (TiXmlNode _node)
 Create a handle from any node (at any depth of the tree.) This can be a null pointer. More...
 
TiXmlHandle Child (str value, int index)
 Return a handle to the "index" child with the given name. More...
 
TiXmlHandle Child (int index)
 Return a handle to the "index" child. More...
 
TiXmlHandle Child (str _value, int index)
 
TiXmlHandle ChildElement (str value, int index)
 Return a handle to the "index" child element with the given name. More...
 
TiXmlHandle ChildElement (int index)
 Return a handle to the "index" child element. More...
 
TiXmlHandle ChildElement (str _value, int index)
 
TiXmlElement Element ()
 
TiXmlHandle FirstChild ()
 Return a handle to the first child node. More...
 
TiXmlHandle FirstChild (str value)
 Return a handle to the first child node with the given name. More...
 
TiXmlHandle FirstChild (str _value)
 
TiXmlHandle FirstChildElement ()
 Return a handle to the first child element. More...
 
TiXmlHandle FirstChildElement (str value)
 Return a handle to the first child element with the given name. More...
 
TiXmlHandle FirstChildElement (str _value)
 
TiXmlNode Node ()
 
TiXmlHandle operator= (const TiXmlHandle ref)
 
TiXmlText Text ()
 
TiXmlElement ToElement ()
 Return the handle as a TiXmlElement. More...
 
TiXmlNode ToNode ()
 Return the handle as a TiXmlNode. More...
 
TiXmlText ToText ()
 Return the handle as a TiXmlText. More...
 
TiXmlUnknown ToUnknown ()
 Return the handle as a TiXmlUnknown. More...
 
TiXmlUnknown Unknown ()
 

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

◆ __init__() [1/2]

__init__ ( const TiXmlHandle  ref)

Copy constructor.

◆ __init__() [2/2]

__init__ ( TiXmlNode  _node)

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

◆ Child() [1/3]

TiXmlHandle Child ( str  value,
int  index 
)

Return a handle to the "index" child with the given name.

The first child is 0, the second 1, etc.

◆ Child() [2/3]

TiXmlHandle Child ( int  index)

Return a handle to the "index" child.

The first child is 0, the second 1, etc.

◆ Child() [3/3]

TiXmlHandle Child ( str  _value,
int  index 
)

◆ ChildElement() [1/3]

TiXmlHandle ChildElement ( str  value,
int  index 
)

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.

◆ ChildElement() [2/3]

TiXmlHandle ChildElement ( int  index)

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.

◆ ChildElement() [3/3]

TiXmlHandle ChildElement ( str  _value,
int  index 
)

◆ Element()

TiXmlElement Element ( )

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

◆ FirstChild() [1/3]

TiXmlHandle FirstChild ( )

Return a handle to the first child node.

◆ FirstChild() [2/3]

TiXmlHandle FirstChild ( str  value)

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

◆ FirstChild() [3/3]

TiXmlHandle FirstChild ( str  _value)

◆ FirstChildElement() [1/3]

TiXmlHandle FirstChildElement ( )

Return a handle to the first child element.

◆ FirstChildElement() [2/3]

TiXmlHandle FirstChildElement ( str  value)

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

◆ FirstChildElement() [3/3]

TiXmlHandle FirstChildElement ( str  _value)

◆ Node()

TiXmlNode Node ( )

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

◆ operator=()

TiXmlHandle operator= ( const TiXmlHandle  ref)

◆ Text()

TiXmlText Text ( )

This may return null.

◆ ToElement()

TiXmlElement ToElement ( )

Return the handle as a TiXmlElement.

This may return null.

◆ ToNode()

TiXmlNode ToNode ( )

Return the handle as a TiXmlNode.

This may return null.

◆ ToText()

TiXmlText ToText ( )

Return the handle as a TiXmlText.

This may return null.

◆ ToUnknown()

TiXmlUnknown ToUnknown ( )

Return the handle as a TiXmlUnknown.

This may return null.

◆ Unknown()

TiXmlUnknown Unknown ( )

This may return null.