src/kitemviews/kfileitemmodelrolesupdater.h

   1 /***************************************************************************
   2  *   Copyright (C) 2011 by Peter Penz <peter.penz19@gmail.com>             *
   3  *                                                                         *
   4  *   This program is free software; you can redistribute it and/or modify  *
   5  *   it under the terms of the GNU General Public License as published by  *
   6  *   the Free Software Foundation; either version 2 of the License, or     *
   7  *   (at your option) any later version.                                   *
   8  *                                                                         *
   9  *   This program is distributed in the hope that it will be useful,       *
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  12  *   GNU General Public License for more details.                          *
  13  *                                                                         *
  14  *   You should have received a copy of the GNU General Public License     *
  15  *   along with this program; if not, write to the                         *
  16  *   Free Software Foundation, Inc.,                                       *
  17  *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
  18  ***************************************************************************/
  19
  20 #ifndef KFILEITEMMODELROLESUPDATER_H
  21 #define KFILEITEMMODELROLESUPDATER_H
  22
  23 #include <libdolphin_export.h>
  24
  25 #include <KFileItem>
  26 #include <kitemviews/kitemmodelbase.h>
  27
  28 #include <QObject>
  29 #include <QSet>
  30 #include <QSize>
  31 #include <QStringList>
  32
  33 class KFileItemModel;
  34 class KJob;
  35 class QPixmap;
  36 class QTimer;
  37
  38 /**
  39  * @brief Resolves expensive roles asynchronously and applies them to the KFileItemModel.
  40  *
  41  * KFileItemModel only resolves roles that are inexpensive like e.g. the file name or
  42  * the permissions. Creating previews or determining the MIME-type can be quite expensive
  43  * and KFileItemModelRolesUpdater takes care to update such roles asynchronously.
  44  */
  45 class LIBDOLPHINPRIVATE_EXPORT KFileItemModelRolesUpdater : public QObject
  46 {
  47     Q_OBJECT
  48
  49 public:
  50     explicit KFileItemModelRolesUpdater(KFileItemModel* model, QObject* parent = 0);
  51     virtual ~KFileItemModelRolesUpdater();
  52
  53     void setIconSize(const QSize& size);
  54     QSize iconSize() const;
  55
  56     /**
  57      * Sets the range of items that are visible currently. The roles
  58      * of visible items are resolved first.
  59      */
  60     void setVisibleIndexRange(int index, int count);
  61
  62     /**
  63      * If \a show is set to true, the "iconPixmap" role will be filled with a preview
  64      * of the file. If \a show is false the MIME type icon will be used for the "iconPixmap"
  65      * role.
  66      */
  67     void setPreviewShown(bool show);
  68     bool isPreviewShown() const;
  69
  70     /**
  71      * If \a paused is set to true the asynchronous resolving of roles will be paused.
  72      * State changes during pauses like changing the icon size or the preview-shown
  73      * will be remembered and handled after unpausing.
  74      */
  75     void setPaused(bool paused);
  76     bool isPaused() const;
  77
  78     /**
  79      * Sets the roles that should be resolved asynchronously.
  80      */
  81     void setRoles(const QSet<QByteArray>& roles);
  82     QSet<QByteArray> roles() const;
  83
  84     /**
  85      * Sets the list of enabled thumbnail plugins that are used for previews.
  86      * Per default all plugins enabled in the KConfigGroup "PreviewSettings"
  87      * are used.
  88      *
  89      * For a list of available plugins, call KServiceTypeTrader::self()->query("ThumbCreator").
  90      *
  91      * @see enabledPlugins
  92      */
  93     void setEnabledPlugins(const QStringList& list);
  94
  95     /**
  96      * Returns the list of enabled thumbnail plugins.
  97      * @see setEnabledPlugins
  98      */
  99     QStringList enabledPlugins() const;
 100
 101 private slots:
 102     void slotItemsInserted(const KItemRangeList& itemRanges);
 103     void slotItemsRemoved(const KItemRangeList& itemRanges);
 104     void slotItemsChanged(const KItemRangeList& itemRanges,
 105                           const QSet<QByteArray>& roles);
 106
 107     /**
 108      * Is invoked after a preview has been received successfully.
 109      * @see startPreviewJob()
 110      */
 111     void slotGotPreview(const KFileItem& item, const QPixmap& pixmap);
 112
 113     /**
 114      * Is invoked after generating a preview has failed.
 115      * @see startPreviewJob()
 116      */
 117     void slotPreviewFailed(const KFileItem& item);
 118
 119     /**
 120      * Is invoked when the preview job has been finished and
 121      * removes the job from the m_previewJobs list.
 122      * @see startPreviewJob()
 123      */
 124     void slotPreviewJobFinished(KJob* job);
 125
 126     void resolvePendingRoles();
 127     void resolveNextPendingRoles();
 128
 129     /**
 130      * Resolves items that have not been resolved yet after the change has been
 131      * notified by slotItemsChanged(). Is invoked if the m_changedItemsTimer
 132      * exceeds.
 133      */
 134     void resolveChangedItems();
 135
 136 private:
 137     /**
 138      * Updates the roles for the given item ranges. The roles for the currently
 139      * visible items will get updated first.
 140      */
 141     void startUpdating(const KItemRangeList& itemRanges);
 142
 143     /**
 144      * Creates previews for the items starting from the first item of the
 145      * given list.
 146      * @see slotGotPreview()
 147      * @see slotPreviewFailed()
 148      * @see slotPreviewJobFinished()
 149      */
 150     void startPreviewJob(const KFileItemList& items);
 151
 152     bool hasPendingRoles() const;
 153     void resetPendingRoles();
 154     void triggerPendingRolesResolving(int count);
 155     void sortAndResolveAllRoles();
 156     void sortAndResolvePendingRoles();
 157
 158     enum ResolveHint {
 159         ResolveFast,
 160         ResolveAll
 161     };
 162     bool applyResolvedRoles(const KFileItem& item, ResolveHint hint);
 163     QHash<QByteArray, QVariant> rolesData(const KFileItem& item) const;
 164
 165     KFileItemList sortedItems(const QSet<KFileItem>& items) const;
 166
 167     /**
 168      * @return The number of items of the path \a path.
 169      */
 170     int subItemsCount(const QString& path) const;
 171
 172 private:
 173     // Property for setPaused()/isPaused().
 174     bool m_paused;
 175
 176     // Property changes during pausing must be remembered to be able
 177     // to react when unpausing again:
 178     bool m_previewChangedDuringPausing;
 179     bool m_iconSizeChangedDuringPausing;
 180     bool m_rolesChangedDuringPausing;
 181
 182     // Property for setPreviewShown()/previewShown().
 183     bool m_previewShown;
 184
 185     // True if the role "iconPixmap" should be cleared when resolving the next
 186     // role with resolveRole(). Is necessary if the preview gets disabled
 187     // during the roles-updater has been paused by setPaused().
 188     bool m_clearPreviews;
 189
 190     KFileItemModel* m_model;
 191     QSize m_iconSize;
 192     int m_firstVisibleIndex;
 193     int m_lastVisibleIndex;
 194     QSet<QByteArray> m_roles;
 195     QStringList m_enabledPlugins;
 196
 197     QSet<KFileItem> m_pendingVisibleItems;
 198     QSet<KFileItem> m_pendingInvisibleItems;
 199     QList<KJob*> m_previewJobs;
 200
 201     QTimer* m_resolvePendingRolesTimer;
 202
 203     // When downloading or copying large files, the slot slotItemsChanged()
 204     // will be called periodically within a quite short delay. To prevent
 205     // a high CPU-load by generating e.g. previews for each notification, the update
 206     // will be postponed until no file change has been done within a longer period
 207     // of time.
 208     QTimer* m_changedItemsTimer;
 209     QSet<KFileItem> m_changedItems;
 210 };
 211
 212 #endif
 213
 214