source: trunk/src/xmlpatterns/api/qxmlname.cpp@ 751

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/*
 * QXmlName is conceptually identical to QPatternist::QName. The
 * difference is that the latter is elegant, powerful and fast.
 *
 * However, it is too powerful and too open and not at all designed
 * for being public. QXmlName, in contrast, is only a public marker,
 * that for instance uses a qint64 instead of qint32, such that we in
 * the future can use that, if needed.
 */

#include "qnamepool_p.h"
#include "qxmlname.h"
#include "qxmlnamepool.h"
#include "qxpathhelper_p.h"
#include "private/qxmlutils_p.h"

QT_BEGIN_NAMESPACE

/*!
  \class QXmlName
  \brief The QXmlName class represents the name of an XML node, in an efficient, namespace-aware way.
  \reentrant
  \since 4.4
  \ingroup xml-tools

  QXmlName represents the name of an XML node in a way that
  is both efficient and safe for comparing names. Normally,
  an XML node represents an XML element or attribute, but
  QXmlName can also represent the names of other kinds of
  nodes, e.g., QAbstractXmlReceiver::processingInstruction()
  and QAbstractXmlReceiver::namespaceBinding().

  The name of an XML node has three components: The \e {namespace
  URI}, the \e {local name}, and the \e {prefix}. To see what these
  refer to in XML, consider the following snippet.

  \quotefile doc/src/snippets/patternist/mobeyDick.xml

  For the element named \e book, localName() returns \e book,
  namespaceUri() returns \e http://example.com/MyDefault,
  and prefix() returns an empty string. For the element named
  \e title, localName() returns \e title, namespaceUri() returns
  \e http://purl.org/dc/elements/1.1, and prefix() returns \e dc.

  To ensure that operations with QXmlName are efficient, e.g.,
  copying names and comparing them, each instance of QXmlName is
  associated with a \l {QXmlNamePool} {name pool}, which must be
  specified at QXmlName construction time. The three components
  of the QXmlName, i.e., the namespace URI, the local name, and
  the prefix, are stored in the name pool mapped to identifiers
  so they can be shared. For this reason, the only way to create
  a valid instance of QXmlName is to use the class constructor,
  where the \l {QXmlNamePool} {name pool}, local name, namespace
  URI, and prefix must all be specified.

  Note that QXmlName's default constructor constructs a null
  instance. It is typically used for allocating unused entries
  in collections of QXmlName.

  A side effect of associating each instance of QXmlName with
  a \l {QXmlNamePool} {name pool} is that each instance of
  QXmlName is tied to the QXmlNamePool with which it was created.
  However, the QXmlName class does not keep track of the name pool,
  so all the accessor functions, e.g., namespaceUri(), prefix(),
  localName(), and toClarkName() require that the correct name
  pool be passed to them. Failure to provide the correct name
  pool to these accessor functions results in undefined behavior.

  Note that a \l {QXmlNamePool} {name pool} is \e not an XML
  namespace. One \l {QXmlNamePool} {name pool} can represent
  instances of QXmlName from different XML namespaces, and the