edelib
2.1.0
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Wraps a node pointer. More...
#include <edelib/TiXml.h>
Public Member Functions | |
TiXmlHandle (TiXmlNode *_node) | |
TiXmlHandle (const TiXmlHandle &ref) | |
TiXmlHandle | operator= (const TiXmlHandle &ref) |
TiXmlHandle | FirstChild () const |
TiXmlHandle | FirstChild (const char *value) const |
TiXmlHandle | FirstChildElement () const |
TiXmlHandle | FirstChildElement (const char *value) const |
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 * | ToNode () const |
TiXmlElement * | ToElement () const |
TiXmlText * | ToText () const |
TiXmlUnknown * | ToUnknown () const |
TiXmlNode * | Node () const |
TiXmlElement * | Element () const |
TiXmlText * | Text () const |
TiXmlUnknown * | Unknown () const |
Wraps a node pointer.
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 * } *
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Create a handle from any node (at any depth of the tree.) This can be a null pointer.
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Copy constructor
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.
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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.
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Assignement from TiXmlHandle
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Return the handle as a TiXmlElement. This may return null.
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Return the handle as a TiXmlUnknown. This may return null.
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