Allow showing Nepomuk metadata inside views

Metadata like image-size, rating, comments, tags, ... can be shown
now in the view (e.g. as column in the Details mode).

Still open: The rating-information needs to be shown as stars.

In the context of this feature also the following bugs have been
fixed:
- Fix visual glitches in the header of the Details mode
- Improve the minimum column width calculation to respect also
  the headling and not only the content

BUG: 296782
FIXED-IN: 4.9.0

1 files changed, 66 insertions, 0 deletions

diff --git a/src/kitemviews/knepomukrolesprovider_p.h b/src/kitemviews/knepomukrolesprovider_p.h
new file mode 100644
index 000000000..795509333
--- /dev/null
+++ b/src/kitemviews/knepomukrolesprovider_p.h
@@ -0,0 +1,66 @@
+/***************************************************************************
+ *   Copyright (C) 2012 by Peter Penz <[email protected]>             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
+ ***************************************************************************/
+
+#ifndef KNEPOMUKROLESPROVIDER_H
+#define KNEPOMUKROLESPROVIDER_H
+
+#include <QHash>
+#include <QSet>
+#include <QUrl>
+
+class QUrl;
+
+/**
+ * @brief Allows accessing metadata of a file by providing KFileItemModel roles.
+ *
+ * Is a helper class for KFileItemModelRolesUpdater to retrieve roles that
+ * are only accessible with Nepomuk.
+ */
+class KNepomukRolesProvider
+{
+public:
+    static KNepomukRolesProvider& instance();
+    virtual ~KNepomukRolesProvider();
+
+    /**
+     * @return True if the values of the role can be determined by Nepomuk.
+     */
+    bool isNepomukRole(const QByteArray& role) const;
+
+    /**
+     * @return Values for the roles \a roles that can be determined from the file
+     *         with the URL \a url.
+     */
+    QHash<QByteArray, QVariant> roleValues(const QUrl& url, const QSet<QByteArray>& roles) const;
+
+protected:
+    KNepomukRolesProvider();
+
+private:
+    QString tagsFromValues(const QStringList& values) const;
+
+private:
+    QSet<QByteArray> m_roles;
+    QHash<QUrl, QByteArray> m_roleForUri;
+
+    friend class KNepomukRolesProviderSingleton;
+};
+
+#endif
+