qabstractitemmodel.cpp

奇趣公司比较新的qt/emd版本

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#include "qabstractitemmodel.h"
#include <private/qabstractitemmodel_p.h>
#include <qdatastream.h>
#include <qstringlist.h>
#include <qsize.h>
#include <qmimedata.h>
#include <qdebug.h>
#include <qvector.h>
#include <qstack.h>
#include <qbitarray.h>

#include <limits.h>

class QPersistentModelIndexDataLessThan
{
public:
    inline bool operator()(const QPersistentModelIndexData *left,
                           const QPersistentModelIndexData *right) const
    { return (left->index < right->index); }
};

QPersistentModelIndexData *QPersistentModelIndexData::create(const QModelIndex &index)
{
    Q_ASSERT(index.isValid()); // we will _never_ insert an invalid index in the list
    QPersistentModelIndexData *d = 0;
    const QAbstractItemModelPrivate *p = index.model()->d_func();
    const QPersistentModelIndexData *previous = p->persistent.previous;
    if (previous && previous->index == index) {
        d = p->persistent.previous;
    } else { // do a binary search, or sorted insert
        const QPersistentModelIndexData tmp(index);
        QAbstractItemModel *model = const_cast<QAbstractItemModel*>(index.model());
        QVector<QPersistentModelIndexData*> *indexes = &(model->d_func()->persistent.indexes);
        QVector<QPersistentModelIndexData*>::iterator begin = indexes->begin();
        QVector<QPersistentModelIndexData*>::iterator end = indexes->end();
        QVector<QPersistentModelIndexData*>::iterator it =
            qLowerBound(begin, end, &tmp, QPersistentModelIndexDataLessThan());
        if (it != end && (*it)->index == index) {
            d = (*it);
        } else {
            d = new QPersistentModelIndexData();
            d->model = index.model();
            d->index = index;
            model->d_func()->persistent.indexes.insert(it, d);
            model->d_func()->addPersistentIndexData(d);
        }
        model->d_func()->persistent.previous = d;
    }
    Q_ASSERT(d);
    return d;
}

void QPersistentModelIndexData::destroy(QPersistentModelIndexData *data)
{
    Q_ASSERT(data);
    Q_ASSERT(data->ref == 0);
    QAbstractItemModel *model = const_cast<QAbstractItemModel*>(data->model);
    // a valid persistent model index with a null model pointer can only happen if the model was destroyed
    if (model) {
        QAbstractItemModelPrivate *p = model->d_func();
        Q_ASSERT(p);
        p->removePersistentIndexData(data);
    }
    delete data;
}

/*!
  \class QPersistentModelIndex

  \brief The QPersistentModelIndex class is used to locate data in a data model.

  \ingroup model-view

  A QPersistentModelIndex is a model index that can be stored by an
  application, and later used to access information in a model.
  Unlike the QModelIndex class, it is safe to store a
  QPersistentModelIndex since the model will ensure that references
  to items will continue to be valid as long as they can be accessed
  by the model.

  It is good practice to check that persistent model indexes are valid
  before using them.

  \sa {Model/View Programming}, QModelIndex, QAbstractItemModel
*/


/*!
  \fn QPersistentModelIndex::QPersistentModelIndex()

  \internal
*/

QPersistentModelIndex::QPersistentModelIndex()
    : d(0)
{
}

/*!
  \fn QPersistentModelIndex::QPersistentModelIndex(const QPersistentModelIndex &other)

  Creates a new QPersistentModelIndex that is a copy of the \a other persistent
  model index.
*/

QPersistentModelIndex::QPersistentModelIndex(const QPersistentModelIndex &other)
    : d(other.d)
{
    if (d) d->ref.ref();
}

/*!
    Creates a new QPersistentModelIndex that is a copy of the model \a index.
*/

QPersistentModelIndex::QPersistentModelIndex(const QModelIndex &index)
    : d(0)
{
    if (index.isValid()) {
        d = QPersistentModelIndexData::create(index);
        d->ref.ref();
    }
}

/*!
    \fn QPersistentModelIndex::~QPersistentModelIndex()

    \internal
*/

QPersistentModelIndex::~QPersistentModelIndex()
{
    if (d && !d->ref.deref()) {
        QPersistentModelIndexData::destroy(d);
        d = 0;
    }
}

/*!
  Returns true if this persistent model index is equal to the \a other
  persistent model index; otherwise returns false.

  All values in the persistent model index are used when comparing
  with another persistent model index.
*/

bool QPersistentModelIndex::operator==(const QPersistentModelIndex &other) const
{
    if (d && other.d)
        return d->index == other.d->index;
    return d == other.d;
}

/*!
    \since 4.1

    Returns true if this persistent model index is smaller than the \a other
    persistent model index; otherwise returns false.

    All values in the persistent model index are used when comparing
    with another persistent model index.
*/

bool QPersistentModelIndex::operator<(const QPersistentModelIndex &other) const
{
    if (d && other.d)
        return d->index < other.d->index;
    return d < other.d;
}

/*!
    \fn bool QPersistentModelIndex::operator!=(const QPersistentModelIndex &other) const
    \since 4.2

    Returns true if this persistent model index is not equal to the \a
    other persistent model index; otherwise returns false.
*/

/*!
    Sets the persistent model index to refer to the same item in a model
    as the \a other persistent model index.
*/

QPersistentModelIndex &QPersistentModelIndex::operator=(const QPersistentModelIndex &other)
{
    if (d == other.d)
        return *this;
    if (d && !d->ref.deref())
        QPersistentModelIndexData::destroy(d);
    d = other.d;
    if (d) d->ref.ref();
    return *this;
}

/*!
    Sets the persistent model index to refer to the same item in a model
    as the \a other model index.
*/

QPersistentModelIndex &QPersistentModelIndex::operator=(const QModelIndex &other)
{
    if (d && !d->ref.deref())
        QPersistentModelIndexData::destroy(d);
    if (other.isValid()) {
        d = QPersistentModelIndexData::create(other);
        if (d) d->ref.ref();
    } else {
        d = 0;
    }
    return *this;
}

/*!
  \fn QPersistentModelIndex::operator const QModelIndex&() const

  Cast operator that returns a const QModelIndex&.
*/

QPersistentModelIndex::operator const QModelIndex&() const
{
    static const QModelIndex invalid;
    if (d)
        return d->index;
    return invalid;
}

/*!
    \fn bool QPersistentModelIndex::operator==(const QModelIndex &other) const

    Returns true if this persistent model index refers to the same location as
    the \a other model index; otherwise returns false.
    Note that all values in the persistent model index are used when comparing
    with another model index.
*/

bool QPersistentModelIndex::operator==(const QModelIndex &other) const
{
    if (d)
        return d->index == other;
    return !other.isValid();
}

/*!
    \fn bool QPersistentModelIndex::operator!=(const QModelIndex &other) const

    Returns true if this persistent model index does not refer to the same
    location as the \a other model index; otherwise returns false.
*/

bool QPersistentModelIndex::operator!=(const QModelIndex &other) const
{
    if (d)
        return d->index != other;
    return other.isValid();
}

/*!
    \fn int QPersistentModelIndex::row() const

    Returns the row this persistent model index refers to.
*/

int QPersistentModelIndex::row() const
{
    if (d)
        return d->index.row();
    return -1;
}

/*!
    \fn int QPersistentModelIndex::column() const

    Returns the column this persistent model index refers to.
*/

int QPersistentModelIndex::column() const
{
    if (d)
        return d->index.column();
    return -1;
}

/*!
    \fn void *QPersistentModelIndex::internalPointer() const

    \internal

    Returns a \c{void} \c{*} pointer used by the model to associate the index with
    the internal data structure.
*/

void *QPersistentModelIndex::internalPointer() const
{
    if (d)
        return d->index.internalPointer();
    return 0;
}

/*!
    \fn void *QPersistentModelIndex::internalId() const

    \internal

    Returns a \c{qint64} used by the model to associate the index with
    the internal data structure.
*/

qint64 QPersistentModelIndex::internalId() const
{
    if (d)
        return d->index.internalId();
    return 0;
}

/*!
  Returns the parent QModelIndex for this persistent index, or
  QModelIndex() if it has no parent.

  \sa child() sibling() model()
*/
QModelIndex QPersistentModelIndex::parent() const
{
    if (d)
        return d->index.parent();
    return QModelIndex();
}

/*!
  Returns the sibling at \a row and \a column or an invalid
  QModelIndex if there is no sibling at this position.

  \sa parent() child()
*/

QModelIndex QPersistentModelIndex::sibling(int row, int column) const
{
    if (d)
        return d->index.sibling(row, column);
    return QModelIndex();
}

/*!
  Returns the child of the model index that is stored in the given
  \a row and \a column.

  \sa parent() sibling()
*/

QModelIndex QPersistentModelIndex::child(int row, int column) const
{
    if (d)
        return d->index.child(row, column);
    return QModelIndex();
}