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DataDirector API
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#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 * | 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;. | |
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
}
| 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.
| TiXmlHandle Child | ( | int | index | ) | const |
Return a handle to the "index" child. The first child is 0, the second 1, etc.
| 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.
| 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.
1.8.10