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#include <QVector>

#include "qabstractxmlnodemodel_p.h"

#include "qabstractxmlreceiver.h"

#include "qcommonvalues_p.h"

#include "qemptyiterator_p.h"

#include "qitemmappingiterator_p.h"

#include "qitem_p.h"

#include "qnamespaceresolver_p.h"

#include "qsequencemappingiterator_p.h"

#include "qsingletoniterator_p.h"

#include "qabstractxmlnodemodel.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

typedef QExplicitlySharedDataPointer<QAbstractXmlForwardIterator<QXmlNodeModelIndex> > QXmlNodeModelIndexIteratorPointer;

/**

 * @file

 * @short Contains the implementation of QAbstractXmlNodeModel.

 */

bool QAbstractXmlNodeModel::isIgnorableInDeepEqual(const QXmlNodeModelIndex &n)

{

    Q_ASSERT(!n.isNull());

    const QXmlNodeModelIndex::NodeKind nk = n.kind();

    return nk == QXmlNodeModelIndex::ProcessingInstruction ||

           nk == QXmlNodeModelIndex::Comment;

}

/*!

  \class QAbstractXmlNodeModel

  \brief The QAbstractXmlNodeModel class is an abstract base class for modeling non-XML data to look like XML for QXmlQuery.

  \threadsafe

  \since 4.4

  \ingroup xml-tools

  The QAbstractXmlNodeModel specifies the interface that a node model

  must implement for that node model be accessible to the query engine

  for processing XQuery queries.  A node model represents data as a

  structure that can be queried as if the data were XML.

  The node model represented by a subclass of QAbstractXmlNodeModel is

  meant to be accessed by the QtXmlPatterns query engine. If the API

  seems a little strange in a few places, it is because the member

  functions are called by the query engine as it evaluates an

  XQuery. They aren't meant to be used programatically.

  \section1 Usage

  QAbstractXmlNodeModel bridges the gap between the arbitrary structure

  of the non-XML data to be queried and the well-defined structure of

  XML data understood by QXmlQuery.

  Consider a chemistry application that reads the file \c

  chemistryData, which contains non-XML data that represents a

  chemical structure composed of molecules and atoms. The application

  will query this chemistry data with an XQuery it reads from file \c

  queryFile. We write a custom subclass of QAbstractXmlNodeModel (\c

  ChemistryNodeModel) that reads \c chemistryData and builds a data

  structure, perhaps composed of objects of our own classes \c

  molecule and \c atom.  Clearly, this data structure is not XML. Our

  custom subclass will know how to traverse this non-XML structure and

  present it through the \l

  {http://www.w3.org/TR/xpath-datamodel/}{XPath Data Model interface}.

  \snippet doc/src/snippets/code/src_xmlpatterns_api_qabstractxmlnodemodel.cpp 1

  The application first creates an instance of QXmlQuery and calls \l

  {QXmlQuery::setQuery()}{setQuery()} to read \c queryFile containing

  the XQuery we want to run. Then it creates an instance of our custom

  node model class, \c ChemistryNodeModel, which is a subclass of

  QAbstractXmlNodeModel. Its constructor is called with the \l

  {QXmlNamePool} {name pool} obtained from our QXmlQuery, and with the

  \c chemistryFile containing the structure of molecules and atoms to

  be queried. The \l {QXmlNamePool} {name pool} is required because

  our custom node model has the member function \l

  {QAbstractXmlNodeModel::name()} {name()}, which returns the \l

  {QXmlName} {name} of any node in the model. The \l {QXmlQuery}

  {query} and the custom node model must use the same name pool for

  constructing these \l {QXmlName} {names}. The constructor would then

  read \c chemistryFile and build the custom node model structure.

  To connect the \c query to the custom node model, we must bind a

  variable name used in the query to a node in the model. The variable

  can then be used in the query as a starting node. First, an \l

  {QXmlNodeModelIndex} {index} for the desired starting node is

  retrieved by calling QAbstractXmlNodeModel::createIndex(). Then the

  index is bound to a variable name, in this case \c queryRoot, by

  passing the name and the index to QXmlQuery::bindVariable(). The

  query can then use a variable reference \c $queryRoot to refer to

  the starting node. Note that if the \l {QXmlQuery} {query} uses

  multiple variable references, a call to QXmlQuery::bindVariable()

  is required to bind each different variable name to a node in the

  model.

  The query is executed when the application calls one of the

  QXmlQuery evaluation functions. The application uses

  QXmlQuery::evaluateTo(QAbstractXmlReceiver *), because it then uses

  a \l {QXmlSerializer} {serializer} to out the query result as XML to

  \c stdout. We could have used QXmlQuery::evaluateTo(QXmlResultItems

  *) to get a list of result items, or

  QXmlQuery::evaluateTo(QStringList *) if the query evaluated to a

  sequence of \c {xs:string} values.

  During query execution, the engine iterates over the node model

  using nextFromSimpleAxis() to get the \l {QXmlNodeModelIndex}

  {index} of the next node to be visited. The engine can get the name

  of a node by calling name() with the node's \l {QXmlNodeModelIndex}

  {index}. stringValue(), baseUri(), documentUri() and kind() are also

  called as needed with a node \l {QXmlNodeModelIndex} {index}.

  The example demonstrates the standard pattern for using a subclass

  of QAbstractXmlNodeModel in combination with QXmlQuery to perform

  an XQuery.

  \list 1

    \o Instantiate QXmlQuery and give it the XQuery to be run;

    \o Instantiate a subclass of QAbstractXmlNodeModel or

    QSimpleXmlNodeModel;

    \o Retrieve a QXmlNodeModelIndex for the node in the model where

    the QXmlQuery should start the query;

    \o Use QXmlQuery::bindVariable() to bind the QXmlNodeModelIndex

    to \c {$variable name};

    \o Call one of the QXmlQuery evaluation functions to run the

    query.

  \endlist

  \section1 Subclassing

  Because the \l {http://www.w3.org/TR/xpath-datamodel/}{XPath Data Model

  interface} presented by QAbstractXmlNodeModel allows QXmlQuery to

  operate on non-XML data as if it were XML, implementing subclasses

  of QAbstractXmlNodeModel can involve a significant amount of

  work. The QSimpleXmlNodeModel class is provided to simplify the

  implementation for many common use cases.

  \section1 Thread Safety

  Because the node model can be accessed concurrently by threads in

  the QtXmlPatterns module, subclasses of QAbstractXmlNodeModel must

  be written to be \l{Reentrancy and Thread-Safety}{thread-safe}.

  Classes that simplify implementing thread-safety include QReadLocker

  and QWriteLocker.

  See the example \l{File System Example} for a demonstration.

 */

/*!

  \enum QXmlNodeModelIndex::Constants

  \value ForwardAxis All forward axes include this flag.

  \value ReverseAxis All reverse axes include this flag.

 */

/*!

  \enum QXmlNodeModelIndex::DocumentOrder

  Identifies the specific node comparison operator that should be

  used.

  \value Precedes Signifies the \c \<\< operator. Test whether the

         first operand precedes the second in the document.

  \value Follows Signifies the \c \>\> operator. Test whether the

                 first operand follows the second in the document.

  \value Is Signifies the \c is operator. Test whether two nodes have

  the same node identity.

 */

/*!

  \enum QAbstractXmlNodeModel::SimpleAxis

  Four axes that each contain one node only.

  \value Parent The parent of the context node

  \value FirstChild The first child of the context node

  \value PreviousSibling The previous child of the context node

  \value NextSibling The next child of the context node

*/

/*!

 \enum QXmlNodeModelIndex::Axis

 \internal

   Identify the axes emanating from a node.

   The axes AxisChild, AxisDescendant, AxisAttribute, AxisSelf,

   AxisDescendantOrSelf, AxisFollowingSibling, and AxisFollowing are

   forward axes.

   The axes AxisParent, AxisAncestor, AxisPrecedingSibling,

   AxisPreceding and AxisAncestorOrSelf are reverse axes.

   \sa {http://www.w3.org/TR/xquery/#axes}{XQuery 1.0: An XML Query Language, 3.2.1.1 Axes}

   \value AxisChild                The \c child axis.

   \value AxisDescendant           The \c descendant axis.

   \value AxisAttribute            The \c attribute axis. Note: There

                                   is a node kind named \c{Attribute}.

   \value AxisSelf                 The \c self axis.

   \value AxisDescendantOrSelf     The \c descendant-or-self axis.

   \value AxisFollowingSibling     The \c following-sibling axis.

   \value AxisNamespace            The \c namespace axis. Note: Does

                                   not exist in XQuery; deprecated in

                                   XPath 2.0 (optionally supported);

                                   mandatory in XPath 1.0.

   \value AxisFollowing            The \c following axis.

   \value AxisParent               The \c parent axis.

   \value AxisAncestor             The \c ancestor axis.

   \value AxisPrecedingSibling     The \c preceding-sibling axis.

   \value AxisPreceding            The \c preceding axis.

   \value AxisAncestorOrSelf       The \c ancestor-or-self axis.

*/

using namespace QPatternist;

/*!

  Default constructor.

 */

QAbstractXmlNodeModel::QAbstractXmlNodeModel() : d_ptr(0)

{

}

/*!

 \internal

 Takes the d-pointer.

 */

QAbstractXmlNodeModel::QAbstractXmlNodeModel(QAbstractXmlNodeModelPrivate *d) : d_ptr(d)

{

}

/*!

  Destructor.

 */

QAbstractXmlNodeModel::~QAbstractXmlNodeModel()

{

}

/*!

  \typedef QAbstractXmlNodeModel::List

  A \l{QList}{list} of \l{QExplicitlySharedDataPointer} {smart

  pointers} to instances of QAbstractXmlNodeModel.

  \sa QExplicitlySharedDataPointer

 */

/*!

  \typedef QAbstractXmlNodeModel::Ptr

  A \l {QExplicitlySharedDataPointer} {smart pointer} to an

  instance of QAbstractXmlNodeModel.

  \sa QExplicitlySharedDataPointer

 */

/*!

  \fn QUrl QAbstractXmlNodeModel::baseUri(const QXmlNodeModelIndex &n) const

  Returns the base URI for the node whose index is \a n. The caller

  guarantees that \a n is not \c null and that it belongs to a node

  in this node model.

  The base URI of a node can be extracted using the \c fn:base-uri()

  function. The base URI is typically used for resolving relative URIs

  that appear in the node or its children. It is conformant to just

  return the document URI, although that might not properly reflect

  the underlying data.

  This function maps to the \c dm:base-uri accessor, which returns

  a base URI according to the following:

  \list

  \o For document nodes, the base URI and the document URI are the same.

  \o For elements, the base URI is the URI appearing in the element's

     \c xml:base attribute, if present, or it is resolved to the

     parent element's base URI.

  \o Namespace nodes have no base URI.

  \o The base URI for a processing instruction, comment, attribute,

  or text node is the base URI of the node's parent element.

  \endlist

  The implementation guarantees to return a valid QUrl, or a default

  constructed QUrl. If a node has no base URI, as in the case where a

  comment has no parent, a default constructed QUrl is returned.

   \sa {http://www.w3.org/TR/xpath-datamodel/#dm-base-uri}{XQuery 1.0 and XPath 2.0 Data Model (XDM), 5.2 base-uri Accessor}

 */

/*!

  \fn QUrl QAbstractXmlNodeModel::documentUri(const QXmlNodeModelIndex &n) const

  Returns the document URI of \a n. The document URI identifies the

  resource which is the document. For example, the document could be a

  regular file, e.g., \c{file:/}, or it could be the \c{http://} URL of

  the location of a file. The document URI is used for resolving URIs

  and to simply know where the document is.

  If the node model maps to a URI in a natural way, return that URI.

  Otherwise, return the company or product URI. The document URI can

  be any URI as long as its valid and absolute.

  The caller guarantees that \a n is not \c null and that it belongs

  to this QAbstractXmlNodeModel.

  This function maps to the \c dm:document-uri accessor, which

  returns a document URI according to the following:

  \list

  \o If \a n is a document node, return an absolute QUrl containing

     the document URI, or a default constructed QUrl. The latter

     signals that no document URI is available for the document node.

  \o For all other nodes, return a default constructed QUrl.

  \endlist

  \sa {http://www.w3.org/TR/xpath-datamodel/#dm-document-uri}{XQuery 1.0 and XPath 2.0 Data Model (XDM), 5.4 document-uri Accessor}

  \sa QUrl::isValid(), QUrl::isRelative()

 */

/*

### Qt 5:

Add the function:

    virtual QSourceLocation sourceLocation(const QXmlNodeModelIndex &nodeIndex) const = 0;

Such that the data model can communicate back source locations.

 */

/*!

  \fn QXmlNodeModelIndex::NodeKind QAbstractXmlNodeModel::kind(const QXmlNodeModelIndex &ni) const

  Returns a value indicating the kind of node identified by \a ni.

  The caller guarantees that \a ni is not null and that it identifies

  a node in this node model. This function maps to the \c

  dm:node-kind() accessor.

  \sa {http://www.w3.org/TR/xpath-datamodel/#dm-node-kind}{XQuery 1.0 and XPath 2.0 Data Model (XDM), 5.10 node-kind Accessor}

 */

/*!

  \fn QXmlNodeModelIndex::DocumentOrder QAbstractXmlNodeModel::compareOrder(const QXmlNodeModelIndex &ni1, const QXmlNodeModelIndex &ni2) const

  This function returns the relative document order for the

  nodes indexed by \a ni1 and \a ni2. It is used for the \c Is

  operator and for sorting nodes in document order.

  The caller guarantees that \a ni1 and \a ni2 are not \c null and

  that both identify nodes in this node model.

  If \a ni1 is identical to \a ni2, QXmlNodeModelIndex::Is is returned.

  If \a ni1 precedes \a ni2 in document order, QXmlNodeModelIndex::Precedes

  is returned. If \a ni1 follows \a ni2 in document order,

  QXmlNodeModelIndex::Follows is returned.

  \sa {http://www.w3.org/TR/xpath-datamodel/#document-order}{XQuery 1.0 and XPath 2.0 Data Model (XDM), 2.4 Document Order}

 */

/*!

  \fn QXmlNodeModelIndex QAbstractXmlNodeModel::root(const QXmlNodeModelIndex &n) const

  Returns the root node of the tree that contains the node whose index

  is \a n. The caller guarantees that \a n is not \c null and that it

  identifies a node in this node model.

  If \a n identifies a node that is a direct child of the root,

  parent() would return the same QXmlNodeModelIndex returned by

  this function.

 */

namespace QPatternist

{

    class MergeIterator

    {

    public:

        inline MergeIterator()

        {

        }

        inline

        QXmlNodeModelIndexIteratorPointer

        mapToSequence(const QXmlNodeModelIndexIteratorPointer &it,

                      const DynamicContext::Ptr &) const

        {

            return it;

        }

    private:

        Q_DISABLE_COPY(MergeIterator)

    };

    static const MergeIterator mergeIterator;

    /**

     * One might wonder, why not use makeVectorIterator() directly on a QVector

     * with iterators?

     *

     * A problem emerges QAbstractXmlForwardIterator::copy(). All "meta

     * iterators" that contain other iterators and so forth, propagate the

     * copy() call such that all involved iterators are copied. However, if we

     * have a ListIterator of iterators it isn't aware of that it contains

     * iterators. Hence, we have this class which is specialized(not in the

     * template sense) on iterators, and hence copies them appropriately.

     */

    class IteratorVector : public ListIterator<QXmlNodeModelIndexIteratorPointer, QVector<QXmlNodeModelIndexIteratorPointer> >

    {

        typedef QVector<QXmlNodeModelIndexIteratorPointer> ItVector;

    public:

        typedef QAbstractXmlForwardIterator<QXmlNodeModelIndexIteratorPointer>::Ptr Ptr;

        IteratorVector(const ItVector &in) : ListIterator<QXmlNodeModelIndexIteratorPointer, QVector<QXmlNodeModelIndexIteratorPointer> >(in)

        {

        }

        virtual QAbstractXmlForwardIterator<QXmlNodeModelIndexIteratorPointer>::Ptr copy() const

        {

            ItVector result;

            for(int i = 0; i < m_list.count(); ++i)

                result.append(m_list.at(i)->copy());

            return Ptr(new IteratorVector(result));

        }

    };

}

/*!

 \internal

 This function is not a private member of QAbstractXmlNodeModel

 because it would be messy to forward declare the required types.

*/

static inline QXmlNodeModelIndexIteratorPointer mergeIterators(const QXmlNodeModelIndex &node,

                                                               const QXmlNodeModelIndexIteratorPointer &it2)

{

    QVector<QXmlNodeModelIndexIteratorPointer> iterators;

    iterators.append(makeSingletonIterator(node));

    iterators.append(it2);

    return makeSequenceMappingIterator<QXmlNodeModelIndex>(&mergeIterator,

                                                           IteratorVector::Ptr(new IteratorVector(iterators)),

                                                           DynamicContext::Ptr());

}

inline QAbstractXmlForwardIterator<QXmlNodeModelIndex>::Ptr

QAbstractXmlNodeModel::mapToSequence(const QXmlNodeModelIndex &ni,

                                     const DynamicContext::Ptr &) const

{

    Q_ASSERT(!ni.isNull());

    /* Since we pass in this here, mapToSequence is used recursively. */

    return mergeIterators(ni, makeSequenceMappingIterator<QXmlNodeModelIndex>(this,

                                                                              ni.iterate(QXmlNodeModelIndex::AxisChild),

                                                                              DynamicContext::Ptr()));

}