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#include "ResourceProxyModel.h"
#include <QItemSelectionRange>
#include "Resource.h"
#include "ResourceObserver.h"
class ModelResourceObserver : public ResourceObserver
{
public:
explicit ModelResourceObserver(const QModelIndex &index, const int role)
: m_index(index), m_role(role)
{
qRegisterMetaType<QVector<int>>("QVector<int>");
}
void resourceUpdated() override
{
if (m_index.isValid())
{
// the resource changed, pretend to be the model and notify the views of the update. they will re-poll the model which will return the new resource value
QMetaObject::invokeMethod(const_cast<QAbstractItemModel *>(m_index.model()),
"dataChanged", Qt::QueuedConnection,
Q_ARG(QModelIndex, m_index), Q_ARG(QModelIndex, m_index), Q_ARG(QVector<int>, QVector<int>() << m_role));
}
}
private:
QPersistentModelIndex m_index;
int m_role;
};
ResourceProxyModel::ResourceProxyModel(const int resultTypeId, QObject *parent)
: QIdentityProxyModel(parent), m_resultTypeId(resultTypeId)
{
}
QVariant ResourceProxyModel::data(const QModelIndex &proxyIndex, int role) const
{
const QModelIndex mapped = mapToSource(proxyIndex);
// valid cell that's a Qt::DecorationRole and that contains a non-empty string
if (mapped.isValid() && role == Qt::DecorationRole && !mapToSource(proxyIndex).data(role).toString().isEmpty())
{
// do we already have a resource for this index?
if (!m_resources.contains(mapped))
{
Resource::Ptr placeholder;
const QVariant placeholderIdentifier = mapped.data(PlaceholderRole);
if (!placeholderIdentifier.isNull() && placeholderIdentifier.type() == QVariant::String)
{
placeholder = Resource::create(placeholderIdentifier.toString());
}
// create the Resource and apply the observer for models
Resource::Ptr res = Resource::create(mapToSource(proxyIndex).data(role).toString(), placeholder)
->applyTo(new ModelResourceObserver(proxyIndex, role));
m_resources.insert(mapped, res);
}
return m_resources.value(mapped)->getResourceInternal(m_resultTypeId);
}
// otherwise fall back to the source model
return mapped.data(role);
}
void ResourceProxyModel::setSourceModel(QAbstractItemModel *model)
{
if (sourceModel())
{
disconnect(sourceModel(), 0, this, 0);
}
if (model)
{
connect(model, &QAbstractItemModel::dataChanged, this, [this](const QModelIndex &tl, const QModelIndex &br, const QVector<int> &roles)
{
// invalidate resources so that they will be re-created
if (roles.contains(Qt::DecorationRole) || roles.contains(PlaceholderRole) || roles.isEmpty())
{
const QItemSelectionRange range(tl, br);
for (const QModelIndex &index : range.indexes())
{
m_resources.remove(index);
}
}
});
}
QIdentityProxyModel::setSourceModel(model);
}
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