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nux  3.0.0
Public Member Functions | Private Attributes
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>

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List of all members.

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 operator= (const TiXmlHandle &ref)
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
 Return a handle to the "index" child with the given name.
TiXmlHandle Child (int index) const
 Return a handle to the "index" child.
TiXmlHandle ChildElement (const char *value, int index) const
 Return a handle to the "index" child element with the given name.
TiXmlHandle ChildElement (int index) const
 Return a handle to the "index" child element.
TiXmlNodeToNode () const
 Return the handle as a TiXmlNode.
TiXmlElementToElement () const
 Return the handle as a TiXmlElement.
TiXmlTextToText () const
 Return the handle as a TiXmlText.
TiXmlUnknownToUnknown () const
 Return the handle as a TiXmlUnknown.
TiXmlNodeNode () const
TiXmlElementElement () const
TiXmlTextText () const
TiXmlUnknownUnknown () const

Private Attributes

TiXmlNodenode

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 2025 of file tinyxml.h.


Constructor & Destructor Documentation

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 2029 of file tinyxml.h.

  {
    this->node = _node;
  }

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TiXmlHandle::TiXmlHandle ( const TiXmlHandle ref) [inline]

Copy constructor.

Definition at line 2034 of file tinyxml.h.

  {
    this->node = ref.node;
  }

Member Function Documentation

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 1901 of file tinyxml.cpp.

{
  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 );
}

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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 1879 of file tinyxml.cpp.

{
  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 );
}

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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 1945 of file tinyxml.cpp.

{
  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 );
}

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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 1923 of file tinyxml.cpp.

{
  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 );
}

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TiXmlElement* TiXmlHandle::Element ( ) const [inline]
Deprecated:
use ToElement.

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

Definition at line 2127 of file tinyxml.h.

  {
    return ToElement();
  }

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Return a handle to the first child node.

Definition at line 1823 of file tinyxml.cpp.

{
  if ( node )
  {
    TiXmlNode *child = node->FirstChild();

    if ( child )
      return TiXmlHandle ( child );
  }

  return TiXmlHandle ( 0 );
}

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

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

Definition at line 1837 of file tinyxml.cpp.

{
  if ( node )
  {
    TiXmlNode *child = node->FirstChild ( value );

    if ( child )
      return TiXmlHandle ( child );
  }

  return TiXmlHandle ( 0 );
}

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Return a handle to the first child element.

Definition at line 1851 of file tinyxml.cpp.

{
  if ( node )
  {
    TiXmlElement *child = node->FirstChildElement();

    if ( child )
      return TiXmlHandle ( child );
  }

  return TiXmlHandle ( 0 );
}

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

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

Definition at line 1865 of file tinyxml.cpp.

{
  if ( node )
  {
    TiXmlElement *child = node->FirstChildElement ( value );

    if ( child )
      return TiXmlHandle ( child );
  }

  return TiXmlHandle ( 0 );
}

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TiXmlNode* TiXmlHandle::Node ( ) const [inline]
Deprecated:
use ToNode.

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

Definition at line 2120 of file tinyxml.h.

  {
    return ToNode();
  }

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TiXmlHandle TiXmlHandle::operator= ( const TiXmlHandle ref) [inline]

Definition at line 2038 of file tinyxml.h.

  {
    this->node = ref.node;
    return *this;
  }
TiXmlText* TiXmlHandle::Text ( ) const [inline]
Deprecated:
use ToText() Return the handle as a TiXmlText.

This may return null.

Definition at line 2134 of file tinyxml.h.

  {
    return ToText();
  }

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TiXmlElement* TiXmlHandle::ToElement ( ) const [inline]

Return the handle as a TiXmlElement.

This may return null.

Definition at line 2100 of file tinyxml.h.

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

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TiXmlNode* TiXmlHandle::ToNode ( ) const [inline]

Return the handle as a TiXmlNode.

This may return null.

Definition at line 2094 of file tinyxml.h.

  {
    return node;
  }

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TiXmlText* TiXmlHandle::ToText ( ) const [inline]

Return the handle as a TiXmlText.

This may return null.

Definition at line 2106 of file tinyxml.h.

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

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TiXmlUnknown* TiXmlHandle::ToUnknown ( ) const [inline]

Return the handle as a TiXmlUnknown.

This may return null.

Definition at line 2112 of file tinyxml.h.

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

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TiXmlUnknown* TiXmlHandle::Unknown ( ) const [inline]
Deprecated:
use ToUnknown() Return the handle as a TiXmlUnknown.

This may return null.

Definition at line 2141 of file tinyxml.h.

  {
    return ToUnknown();
  }

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Member Data Documentation

Definition at line 2147 of file tinyxml.h.


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