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, 153 insertions, 0 deletions

diff --git a/src/kitemviews/knepomukrolesprovider.cpp b/src/kitemviews/knepomukrolesprovider.cpp
new file mode 100644
index 000000000..1612d57b6
--- /dev/null
+++ b/src/kitemviews/knepomukrolesprovider.cpp
@@ -0,0 +1,153 @@
+/***************************************************************************
+ *   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            *
+ ***************************************************************************/
+
+#include "knepomukrolesprovider_p.h"
+
+#include <KDebug>
+#include <KGlobal>
+
+#include <Nepomuk/Resource>
+#include <Nepomuk/Tag>
+#include <Nepomuk/Types/Property>
+#include <Nepomuk/Variant>
+
+struct KNepomukRolesProviderSingleton
+{
+    KNepomukRolesProvider instance;
+};
+K_GLOBAL_STATIC(KNepomukRolesProviderSingleton, s_nepomukRolesProvider)
+
+
+KNepomukRolesProvider& KNepomukRolesProvider::instance()
+{
+    return s_nepomukRolesProvider->instance;
+}
+
+KNepomukRolesProvider::~KNepomukRolesProvider()
+{
+}
+
+bool KNepomukRolesProvider::isNepomukRole(const QByteArray& role) const
+{
+    return m_roles.contains(role);
+}
+
+QHash<QByteArray, QVariant> KNepomukRolesProvider::roleValues(const QUrl& url,
+                                                              const QSet<QByteArray>& roles) const
+{
+    const Nepomuk::Resource resource(url);
+    if (!resource.isValid()) {
+        return QHash<QByteArray, QVariant>();
+    }
+
+    QHash<QByteArray, QVariant> values;
+
+    int width = -1;
+    int height = -1;
+
+    QHashIterator<QUrl, Nepomuk::Variant> it(resource.properties());
+    while (it.hasNext()) {
+        it.next();
+
+        const Nepomuk::Types::Property property = it.key();
+        const QByteArray role = m_roleForUri.value(property.uri());
+        if (role.isEmpty() || !roles.contains(role)) {
+            continue;
+        }
+
+        const Nepomuk::Variant value = it.value();
+
+        if (role == "imageSize") {
+            // Merge the two Nepomuk properties for width and height
+            // as one string into the "imageSize" role
+            const QString uri = property.uri().toString();
+            if (uri.endsWith("#width")) {
+                width = value.toInt();
+            } else if (uri.endsWith("#height")) {
+                height = value.toInt();
+            }
+
+            if (width >= 0 && height >= 0) {
+                const QString widthAndHeight = QString::number(width) +
+                                               QLatin1String(" x ") +
+                                               QString::number(height);
+                values.insert(role, widthAndHeight);
+            }
+        } else if (role == "tags") {
+            const QString tags = tagsFromValues(value.toStringList());
+            values.insert(role, tags);
+        } else {
+            values.insert(role, value.toString());
+        }
+    }
+
+    return values;
+}
+
+KNepomukRolesProvider::KNepomukRolesProvider() :
+    m_roles(),
+    m_roleForUri()
+{
+    struct UriInfo
+    {
+        const char* const uri;
+        const char* const role;
+    };
+
+    // Mapping from the URIs to the KFileItemModel roles. Note that this must not be
+    // a 1:1 mapping: One role may contain several URI-values (e.g. the URIs for height and
+    // width of an image are mapped to the role "imageSize")
+    static const UriInfo uriInfoList[] = {
+        { "http://www.semanticdesktop.org/ontologies/2007/08/15/nao#numericRating", "rating" },
+        { "http://www.semanticdesktop.org/ontologies/2007/08/15/nao#hasTag",        "tags" },
+        { "http://www.semanticdesktop.org/ontologies/2007/08/15/nao#description",   "comment" },
+        { "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#wordCount",     "wordCount" },
+        { "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#lineCount",     "lineCount" },
+        { "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#width",         "imageSize" },
+        { "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#height",        "imageSize" },
+        { "http://www.semanticdesktop.org/ontologies/2007/05/10/nexif#orientation", "orientation", },
+        { "http://www.semanticdesktop.org/ontologies/2009/02/19/nmm#performer",     "artist" },
+        { "http://www.semanticdesktop.org/ontologies/2009/02/19/nmm#musicAlbum",    "album" },
+        { "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#duration",      "duration" },
+        { "http://www.semanticdesktop.org/ontologies/2009/02/19/nmm#trackNumber",   "track" },
+        { "http://www.semanticdesktop.org/ontologies/2010/04/30/ndo#copiedFrom",    "copiedFrom" }
+    };
+
+    for (unsigned int i = 0; i < sizeof(uriInfoList) / sizeof(UriInfo); ++i) {
+        m_roleForUri.insert(QUrl(uriInfoList[i].uri), uriInfoList[i].role);
+        m_roles.insert(uriInfoList[i].role);
+    }
+}
+
+QString KNepomukRolesProvider::tagsFromValues(const QStringList& values) const
+{
+    QString tags;
+
+    for (int i = 0; i < values.count(); ++i) {
+        if (i > 0) {
+            tags.append(QLatin1String(", "));
+        }
+
+        const Nepomuk::Tag tag(values[i]);
+        tags += tag.genericLabel();
+    }
+
+    return tags;
+}
+