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#include <QDir>
#include <QFile>
#include <QDebug>

#include "databasefilewatcher_p.h"

DatabaseFileWatcher::DatabaseFileWatcher(const QString &databasePath, QObject *parent)
    : QObject(parent),
      m_watcher(0),
      m_databasePath(databasePath)
{
}

QString DatabaseFileWatcher::closestExistingParent(const QString &path)
{
    if (QFile::exists(path))
        return path;

    int lastSep = path.lastIndexOf(QDir::separator());
    if (lastSep < 0)
        return QString();
    return closestExistingParent(path.mid(0, lastSep));
}

void DatabaseFileWatcher::restartDirMonitoring(const QString &previousDirPath)
{
    if (m_watcher->files().contains(m_databasePath))
        return;

    QString existing = closestExistingParent(m_databasePath);
    if (existing.isEmpty()) {
        qWarning() << "QServiceManager: can't find existing directory for path to database" << m_databasePath
            << "serviceAdded() and serviceRemoved() will not be emitted";
        return;
    }
    if (existing == m_databasePath) {
            if (!previousDirPath.isEmpty())
                m_watcher->removePath(previousDirPath);

            setEnabled(true);
    } else {
        if (previousDirPath != existing) {
            if (!previousDirPath.isEmpty())
                m_watcher->removePath(previousDirPath);
            if (!m_watcher->directories().contains(existing))
                m_watcher->addPath(existing);
        }
    }
}

void DatabaseFileWatcher::setEnabled(bool enabled)
{
    if (!m_watcher) {
        m_watcher = new QFileSystemWatcher(this);
        connect(m_watcher, SIGNAL(fileChanged(QString)),
            SLOT(databaseChanged(QString)));
        connect(m_watcher, SIGNAL(directoryChanged(QString)),
            SLOT(databaseDirectoryChanged(QString)));
    }

    if (enabled) {
        if (QFile::exists(m_databasePath)) {
            if (!m_watcher->files().contains(m_databasePath))
                    m_watcher->addPath(m_databasePath);
        } else {
            restartDirMonitoring(QString());
        }
    } else {
        m_watcher->removePath(m_databasePath);
    }
}

void DatabaseFileWatcher::databaseDirectoryChanged(const QString &path)
{
    if (m_databasePath.contains(path)) {
        restartDirMonitoring(path);
    }
}

void DatabaseFileWatcher::databaseChanged(const QString &path)
{
    if (!QFile::exists(m_databasePath)) {
        restartDirMonitoring(QString());;
    }

    emit notifyChange();
    // if database was deleted, the path may have been dropped
    if (!m_watcher->files().contains(path) && QFile::exists(path))
        m_watcher->addPath(path);
}