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#include <QtCore/QUrl>
#include <QtCore/QVariant>
#include <QtXmlPatterns/QXmlNamePool>
#include "filetree.h"

/*
The model has two types of nodes: elements & attributes.

    <directory name="">
        <file name="">
        </file>
    </directory>

  In QXmlNodeModelIndex we store two values. QXmlNodeIndex::data()
  is treated as a signed int, and it is an index into m_fileInfos
  unless it is -1, in which case it has no meaning and the value
  of QXmlNodeModelIndex::additionalData() is a Type name instead.
 */

/*!
  The constructor passes \a pool to the base class, then loads an
  internal vector with an instance of QXmlName for each of the
  strings "file", "directory", "fileName", "filePath", "size",
  "mimeType", and "suffix".
 */
FileTree::FileTree(const QXmlNamePool& pool) : QSimpleXmlNodeModel(pool)
                                             , m_filterAllowAll(QDir::AllEntries
                                                                | QDir::AllDirs
                                                                | QDir::NoDotAndDotDot
                                                                | QDir::Hidden)
                                             , m_sortFlags(QDir::Name)
{
    QXmlNamePool np = namePool();
    m_names.resize(7);
    m_names[File]               = QXmlName(np, QLatin1String("file"));
    m_names[Directory]          = QXmlName(np, QLatin1String("directory"));
    m_names[AttributeFileName]  = QXmlName(np, QLatin1String("fileName"));
    m_names[AttributeFilePath]  = QXmlName(np, QLatin1String("filePath"));
    m_names[AttributeSize]      = QXmlName(np, QLatin1String("size"));
    m_names[AttributeMIMEType]  = QXmlName(np, QLatin1String("mimeType"));
    m_names[AttributeSuffix]    = QXmlName(np, QLatin1String("suffix"));
}

/*!
 */
QXmlNodeModelIndex FileTree::nodeFor(const QString& dirName) const
{
    /* We call QDir::cleanPath() because a QFileInfo constructed on a
     * path ending with a slash, will return the empty string in fileName(),
     * instead of the directory name. */
    QFileInfo dirInfo(QDir::cleanPath(dirName));
    Q_ASSERT(dirInfo.exists());
    return toNodeIndex(dirInfo);
}

/*!
  Since the value will always be in m_fileInfos, it is safe for
  us to return a const reference to it.
 */
const QFileInfo&
FileTree::toFileInfo(const QXmlNodeModelIndex &nodeIndex) const
{
    return m_fileInfos.at(nodeIndex.data());
}

/*!
 */
QXmlNodeModelIndex
FileTree::toNodeIndex(const QFileInfo &fileInfo, Type attributeName) const
{
    const int indexOf = m_fileInfos.indexOf(fileInfo);

    if (indexOf == -1) {
        m_fileInfos.append(fileInfo);
        return createIndex(m_fileInfos.count()-1, attributeName);
    }
    else
        return createIndex(indexOf, attributeName);
}

/*!
 */
QXmlNodeModelIndex FileTree::toNodeIndex(const QFileInfo &fileInfo) const
{
    return toNodeIndex(fileInfo, fileInfo.isDir() ? Directory : File);
}

/*!
 */
QXmlNodeModelIndex FileTree::nextSibling(const QXmlNodeModelIndex &nodeIndex,
                                         const QFileInfo &fileInfo,
                                         qint8 offset) const
{
    Q_ASSERT(offset == -1 || offset == 1);

    /* First, get our parent. */
    const QXmlNodeModelIndex parent(nextFromSimpleAxis(Parent, nodeIndex));

    if (parent.isNull())
        return QXmlNodeModelIndex();

    /* Now, get all the parent's children. That is, all our siblings. */
    const QFileInfo parentFI(toFileInfo(parent));
    Q_ASSERT(Type(parent.additionalData()) == Directory);
    const QFileInfoList
    siblings(QDir(parentFI.absoluteFilePath()).entryInfoList(QStringList(), m_filterAllowAll, m_sortFlags));
    Q_ASSERT_X(!siblings.isEmpty(),
               Q_FUNC_INFO,
               "This would be a contradiction, there's at least one.");

    const int indexOfMe = siblings.indexOf(fileInfo);
    Q_ASSERT_X(indexOfMe != -1, Q_FUNC_INFO, "We're there, somewhere.");

    const int siblingIndex = indexOfMe + offset;
    if (siblingIndex < 0 || siblingIndex > siblings.count() - 1)
        return QXmlNodeModelIndex();
    else
        return toNodeIndex(siblings.at(siblingIndex));
}

/*!
 */
QXmlNodeModelIndex
FileTree::nextFromSimpleAxis(QSimpleXmlNodeModel::SimpleAxis axis,
                             const QXmlNodeModelIndex &nodeIndex) const
{
    const QFileInfo fi(toFileInfo(nodeIndex));
    const Type type = Type(nodeIndex.additionalData());

    if (type != File && type != Directory) {
        /* We're an attribute. */
        Q_ASSERT_X(axis == Parent,
                   Q_FUNC_INFO,
                   "QSimpleXmlNodeModel guarantees that it only "
                   "asks for Parent for attributes.");
        return toNodeIndex(fi, Directory);
    }

    switch(axis) {
        case Parent:
            return toNodeIndex(QFileInfo(fi.path()), Directory);
        case FirstChild:
        {
            if (type == File) {
                /* This guy doesn't have children. */
                return QXmlNodeModelIndex();
            }
            else {
                Q_ASSERT(type == Directory);
                Q_ASSERT_X(fi.isDir(),
                           Q_FUNC_INFO,
                           "If we're a directory, we really should be one!");

                const QDir dir(fi.absoluteFilePath());
                Q_ASSERT(dir.exists());

                const QFileInfoList children(dir.entryInfoList(QStringList(), m_filterAllowAll, m_sortFlags));

                if (children.isEmpty())
                    return QXmlNodeModelIndex();

                const QFileInfo firstChild(children.first());
                return toNodeIndex(firstChild);
            }
        }
        case PreviousSibling:
            return nextSibling(nodeIndex, fi, -1);
        case NextSibling:
            return nextSibling(nodeIndex, fi, 1);
    }

    Q_ASSERT_X(false, Q_FUNC_INFO, "This line should never be reached.");
    return QXmlNodeModelIndex();
}

/*!
 */
QUrl FileTree::documentUri(const QXmlNodeModelIndex &node) const
{
    /*
      We always have the same document URI,
      regardless of what node it is.
    */
    Q_UNUSED(node);

    /*
      No matter what instance this FileTree represents, it will always
     have file:/// as the root.
    */
    return QUrl("file:///");
}

/*!
 */
QXmlNodeModelIndex::NodeKind
FileTree::kind(const QXmlNodeModelIndex &node) const
{
    switch(Type(node.additionalData())) {
        case Directory:
        /* Fallthrough. */
        case File:
            return QXmlNodeModelIndex::Element;
        default:
            return QXmlNodeModelIndex::Attribute;
    }
}

/*!
 */
QXmlNodeModelIndex::DocumentOrder
FileTree::compareOrder(const QXmlNodeModelIndex&,
                       const QXmlNodeModelIndex&) const
{
    /* There is no order between files, so just return an arbitrary value. */
    return QXmlNodeModelIndex::Precedes;
}

/*!
 */
QXmlName FileTree::name(const QXmlNodeModelIndex &node) const
{
    return m_names.at(node.additionalData());
}

/*!
 */
QXmlNodeModelIndex FileTree::root(const QXmlNodeModelIndex &node) const
{
    /* We always have the same root. */
    Q_UNUSED(node);

    return toNodeIndex(QFileInfo(QLatin1String("/")));
}

/*!
 */
QVariant FileTree::typedValue(const QXmlNodeModelIndex &node) const
{
    const QFileInfo &fi = toFileInfo(node);

    switch(Type(node.additionalData())) {
        case Directory:
        /* Fallthrough. */
        case File:
            return QString();
        case AttributeFileName:
            return fi.fileName();
        case AttributeFilePath:
            return fi.filePath();
        case AttributeSize:
            return fi.size();
        case AttributeMIMEType:
        {
            /* We don't have any MIME detection code currently, so return
             * the most generic one. */
            return QLatin1String("application/octet-stream");
        }
        case AttributeSuffix:
            return fi.suffix();
    }

    Q_ASSERT_X(false, Q_FUNC_INFO, "This line should never be reached.");
    return QString();
}

/*!
 */
QVector<QXmlNodeModelIndex>
FileTree::attributes(const QXmlNodeModelIndex &element) const
{
    QVector<QXmlNodeModelIndex> result;

    /* Both elements has this attribute. */
    const QFileInfo &forElement = toFileInfo(element);
    result.append(toNodeIndex(forElement, AttributeFilePath));
    result.append(toNodeIndex(forElement, AttributeFileName));

    if (Type(element.additionalData() == File)) {
        result.append(toNodeIndex(forElement, AttributeSize));
        result.append(toNodeIndex(forElement, AttributeSuffix));
        result.append(toNodeIndex(forElement, AttributeMIMEType));
    }
    else {
        Q_ASSERT(element.additionalData() == Directory);
    }

    return result;
}