gwenview/lib/semanticinfo/abstractsemanticinfobackend.h

   1 // vim: set tabstop=4 shiftwidth=4 noexpandtab:
   2 /*
   3 Gwenview: an image viewer
   4 Copyright 2008 Aurélien Gâteau <aurelien.gateau@free.fr>
   5
   6 This program is free software; you can redistribute it and/or
   7 modify it under the terms of the GNU General Public License
   8 as published by the Free Software Foundation; either version 2
   9 of the License, or (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin Street, Fifth Floor, Cambridge, MA 02110-1301, USA.
  19
  20 */
  21 #ifndef ABSTRACTSEMANTICINFOBACKEND_H
  22 #define ABSTRACTSEMANTICINFOBACKEND_H
  23
  24 #include <lib/gwenviewlib_export.h>
  25
  26 // Qt
  27 #include <QObject>
  28 #include <QSet>
  29
  30 // KDE
  31
  32 // Local
  33
  34 class KUrl;
  35
  36 namespace Gwenview {
  37
  38
  39 typedef QString SemanticInfoTag;
  40
  41
  42 /**
  43  * This class represents the set of tags associated to an url.
  44  *
  45  * It provides convenience methods to convert to and from QVariant, which are
  46  * useful to communicate with SemanticInfoDirModel.
  47  */
  48 class GWENVIEWLIB_EXPORT TagSet : public QSet<SemanticInfoTag> {
  49 public:
  50         TagSet();
  51         TagSet(const QSet<SemanticInfoTag>&);
  52
  53         QVariant toVariant() const;
  54         static TagSet fromVariant(const QVariant&);
  55 };
  56
  57
  58 /**
  59  * A POD struct used by AbstractSemanticInfoBackEnd to store the metadata
  60  * associated to an url.
  61  */
  62 struct SemanticInfo {
  63         int mRating;
  64         QString mDescription;
  65         TagSet mTags;
  66 };
  67
  68
  69 /**
  70  * An abstract class, used by SemanticInfoDirModel to store and retrieve metadata.
  71  */
  72 class AbstractSemanticInfoBackEnd : public QObject {
  73         Q_OBJECT
  74 public:
  75         AbstractSemanticInfoBackEnd(QObject* parent);
  76
  77         virtual TagSet allTags() const = 0;
  78
  79         virtual void refreshAllTags() = 0;
  80
  81         virtual void storeSemanticInfo(const KUrl&, const SemanticInfo&) = 0;
  82
  83         virtual void retrieveSemanticInfo(const KUrl&) = 0;
  84
  85         virtual QString labelForTag(const SemanticInfoTag&) const = 0;
  86
  87         /**
  88          * Return a tag for a label. Will emit tagAdded() if the tag had to be
  89          * created.
  90          */
  91         virtual SemanticInfoTag tagForLabel(const QString&) = 0;
  92
  93 Q_SIGNALS:
  94         void semanticInfoRetrieved(const KUrl&, const SemanticInfo&);
  95
  96         /**
  97          * Emitted whenever a new tag is added to allTags()
  98          */
  99         void tagAdded(const SemanticInfoTag&, const QString& label);
 100 };
 101
 102
 103 } // namespace
 104
 105 #endif /* ABSTRACTSEMANTICINFOBACKEND_H */