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 "dolphin_export.h"
  24 #include "kitemviews/kitemmodelbase.h"
  25
  26 #include <KFileItem>
  27 #include <config-baloo.h>
  28
  29 #include <QObject>
  30 #include <QSet>
  31 #include <QSize>
  32 #include <QStringList>
  33
  34 class KDirectoryContentsCounter;
  35 class KFileItemModel;
  36 class QPixmap;
  37 class QTimer;
  38 class KOverlayIconPlugin;
  39
  40 namespace KIO {
  41     class PreviewJob;
  42 }
  43
  44 #ifdef HAVE_BALOO
  45     namespace Baloo
  46     {
  47         class FileMonitor;
  48     }
  49     #include <Baloo/IndexerConfig>
  50 #endif
  51
  52 /**
  53  * @brief Resolves expensive roles asynchronously and applies them to the KFileItemModel.
  54  *
  55  * KFileItemModel only resolves roles that are inexpensive like e.g. the file name or
  56  * the permissions. Creating previews or determining the MIME-type can be quite expensive
  57  * and KFileItemModelRolesUpdater takes care to update such roles asynchronously.
  58  *
  59  * To prevent a huge CPU and I/O load, these roles are not updated for all
  60  * items, but only for the visible items, some items around the visible area,
  61  * and the items on the first and last pages of the view. This is a compromise
  62  * that aims to minimize the risk that the user sees items with unknown icons
  63  * in the view when scrolling or pressing Home or End.
  64  *
  65  * Determining the roles is done in several phases:
  66  *
  67  * 1.   If the sort role is "slow", it is determined for all items. If this
  68  *      cannot be finished synchronously in 200 ms, the remaining items are
  69  *      handled asynchronously by \a resolveNextSortRole().
  70  *
  71  * 2.   The function startUpdating(), which is called if either the sort role
  72  *      has been successfully determined for all items, or items are inserted
  73  *      in the view, or the visible items might have changed because items
  74  *      were removed or moved, tries to determine the icons for all visible
  75  *      items synchronously for 200 ms. Then:
  76  *
  77  *      (a) If previews are disabled, icons and all other roles are determined
  78  *          asynchronously for the interesting items. This is done by the
  79  *          function \a resolveNextPendingRoles().
  80  *
  81  *      (b) If previews are enabled, a \a KIO::PreviewJob is started that loads
  82  *          the previews for the interesting items. At the same time, the icons
  83  *          for these items are determined asynchronously as fast as possible
  84  *          by \a resolveNextPendingRoles(). This minimizes the risk that the
  85  *          user sees "unknown" icons when scrolling before the previews have
  86  *          arrived.
  87  *
  88  * 3.   Finally, the entire process is repeated for any items that might have
  89  *      changed in the mean time.
  90  */
  91 class DOLPHIN_EXPORT KFileItemModelRolesUpdater : public QObject
  92 {
  93     Q_OBJECT
  94
  95 public:
  96     explicit KFileItemModelRolesUpdater(KFileItemModel* model, QObject* parent = nullptr);
  97     ~KFileItemModelRolesUpdater() override;
  98
  99     void setIconSize(const QSize& size);
 100     QSize iconSize() const;
 101
 102     /**
 103      * Sets the range of items that are visible currently. The roles
 104      * of visible items are resolved first.
 105      */
 106     void setVisibleIndexRange(int index, int count);
 107
 108     void setMaximumVisibleItems(int count);
 109
 110     /**
 111      * If \a show is set to true, the "iconPixmap" role will be filled with a preview
 112      * of the file. If \a show is false the MIME type icon will be used for the "iconPixmap"
 113      * role.
 114      */
 115     void setPreviewsShown(bool show);
 116     bool previewsShown() const;
 117
 118     /**
 119      * If enabled a small preview gets upscaled to the icon size in case where
 120      * the icon size is larger than the preview. Per default enlarging is
 121      * enabled.
 122      */
 123     void setEnlargeSmallPreviews(bool enlarge);
 124     bool enlargeSmallPreviews() const;
 125
 126     /**
 127      * If \a paused is set to true the asynchronous resolving of roles will be paused.
 128      * State changes during pauses like changing the icon size or the preview-shown
 129      * will be remembered and handled after unpausing.
 130      */
 131     void setPaused(bool paused);
 132     bool isPaused() const;
 133
 134     /**
 135      * Sets the roles that should be resolved asynchronously.
 136      */
 137     void setRoles(const QSet<QByteArray>& roles);
 138     QSet<QByteArray> roles() const;
 139
 140     /**
 141      * Sets the list of enabled thumbnail plugins that are used for previews.
 142      * Per default all plugins enabled in the KConfigGroup "PreviewSettings"
 143      * are used.
 144      *
 145      * For a list of available plugins, call KServiceTypeTrader::self()->query("ThumbCreator").
 146      *
 147      * @see enabledPlugins
 148      */
 149     void setEnabledPlugins(const QStringList& list);
 150
 151     /**
 152      * Returns the list of enabled thumbnail plugins.
 153      * @see setEnabledPlugins
 154      */
 155     QStringList enabledPlugins() const;
 156
 157 private slots:
 158     void slotItemsInserted(const KItemRangeList& itemRanges);
 159     void slotItemsRemoved(const KItemRangeList& itemRanges);
 160     void slotItemsMoved(const KItemRange& itemRange, const QList<int> &movedToIndexes);
 161     void slotItemsChanged(const KItemRangeList& itemRanges,
 162                           const QSet<QByteArray>& roles);
 163     void slotSortRoleChanged(const QByteArray& current,
 164                              const QByteArray& previous);
 165
 166     /**
 167      * Is invoked after a preview has been received successfully.
 168      * @see startPreviewJob()
 169      */
 170     void slotGotPreview(const KFileItem& item, const QPixmap& pixmap);
 171
 172     /**
 173      * Is invoked after generating a preview has failed.
 174      * @see startPreviewJob()
 175      */
 176     void slotPreviewFailed(const KFileItem& item);
 177
 178     /**
 179      * Is invoked when the preview job has been finished. Starts a new preview
 180      * job if there are any interesting items without previews left, or updates
 181      * the changed items otherwise.     *
 182      * @see startPreviewJob()
 183      */
 184     void slotPreviewJobFinished();
 185
 186     /**
 187      * Is invoked when one of the KOverlayIconPlugin emit the signal that an overlay has changed
 188      */
 189     void slotOverlaysChanged(const QUrl& url, const QStringList&);
 190
 191     /**
 192      * Resolves the sort role of the next item in m_pendingSortRole, applies it
 193      * to the model, and invokes itself if there are any pending items left. If
 194      * that is not the case, \a startUpdating() is called.
 195      */
 196     void resolveNextSortRole();
 197
 198     /**
 199      * Resolves the icon name and (if previews are disabled) all other roles
 200      * for the next interesting item. If there are no pending items left, any
 201      * changed items are updated.
 202      */
 203     void resolveNextPendingRoles();
 204
 205     /**
 206      * Resolves items that have not been resolved yet after the change has been
 207      * notified by slotItemsChanged(). Is invoked if the m_changedItemsTimer
 208      * expires.
 209      */
 210     void resolveRecentlyChangedItems();
 211
 212     void applyChangedBalooRoles(const QString& file);
 213     void applyChangedBalooRolesForItem(const KFileItem& file);
 214
 215     void slotDirectoryContentsCountReceived(const QString& path, int count);
 216
 217 private:
 218     /**
 219      * Starts the updating of all roles. The visible items are handled first.
 220      */
 221     void startUpdating();
 222
 223     /**
 224      * Loads the icons for the visible items. After 200 ms, the function
 225      * stops determining mime types and only loads preliminary icons.
 226      * This is a compromise that prevents that
 227      * (a) the GUI is blocked for more than 200 ms, and
 228      * (b) "unknown" icons could be shown in the view.
 229      */
 230     void updateVisibleIcons();
 231
 232     /**
 233      * Creates previews for the items starting from the first item in
 234      * m_pendingPreviewItems.
 235      * @see slotGotPreview()
 236      * @see slotPreviewFailed()
 237      * @see slotPreviewJobFinished()
 238      */
 239     void startPreviewJob();
 240
 241     /**
 242      * Ensures that icons, previews, and other roles are determined for any
 243      * items that have been changed.
 244      */
 245     void updateChangedItems();
 246
 247     /**
 248      * Resolves the sort role of the item and applies it to the model.
 249      */
 250     void applySortRole(int index);
 251
 252     void applySortProgressToModel();
 253
 254     enum ResolveHint {
 255         ResolveFast,
 256         ResolveAll
 257     };
 258     bool applyResolvedRoles(int index, ResolveHint hint);
 259     QHash<QByteArray, QVariant> rolesData(const KFileItem& item);
 260
 261     /**
 262      * @return The number of items of the path \a path.
 263      */
 264     int subItemsCount(const QString& path) const;
 265
 266     /**
 267      * Must be invoked if a property has been changed that affects
 268      * the look of the preview. Takes care to update all previews.
 269      */
 270     void updateAllPreviews();
 271
 272     void killPreviewJob();
 273
 274     QList<int> indexesToResolve() const;
 275
 276 private:
 277     enum State {
 278         Idle,
 279         Paused,
 280         ResolvingSortRole,
 281         ResolvingAllRoles,
 282         PreviewJobRunning
 283     };
 284
 285     State m_state;
 286
 287     // Property changes during pausing must be remembered to be able
 288     // to react when unpausing again:
 289     bool m_previewChangedDuringPausing;
 290     bool m_iconSizeChangedDuringPausing;
 291     bool m_rolesChangedDuringPausing;
 292
 293     // Property for setPreviewsShown()/previewsShown().
 294     bool m_previewShown;
 295
 296     // Property for setEnlargeSmallPreviews()/enlargeSmallPreviews()
 297     bool m_enlargeSmallPreviews;
 298
 299     // True if the role "iconPixmap" should be cleared when resolving the next
 300     // role with resolveRole(). Is necessary if the preview gets disabled
 301     // during the roles-updater has been paused by setPaused().
 302     bool m_clearPreviews;
 303
 304     // Remembers which items have been handled already, to prevent that
 305     // previews and other expensive roles are determined again.
 306     QSet<KFileItem> m_finishedItems;
 307
 308     KFileItemModel* m_model;
 309     QSize m_iconSize;
 310     int m_firstVisibleIndex;
 311     int m_lastVisibleIndex;
 312     int m_maximumVisibleItems;
 313     QSet<QByteArray> m_roles;
 314     QSet<QByteArray> m_resolvableRoles;
 315     QStringList m_enabledPlugins;
 316
 317     // Items for which the sort role still has to be determined.
 318     QSet<KFileItem> m_pendingSortRoleItems;
 319
 320     // Indexes of items which still have to be handled by
 321     // resolveNextPendingRoles().
 322     QList<int> m_pendingIndexes;
 323
 324     // Items which have been left over from the last call of startPreviewJob().
 325     // A new preview job will be started from them once the first one finishes.
 326     KFileItemList m_pendingPreviewItems;
 327
 328     KIO::PreviewJob* m_previewJob;
 329
 330     // When downloading or copying large files, the slot slotItemsChanged()
 331     // will be called periodically within a quite short delay. To prevent
 332     // a high CPU-load by generating e.g. previews for each notification, the update
 333     // will be postponed until no file change has been done within a longer period
 334     // of time.
 335     QTimer* m_recentlyChangedItemsTimer;
 336     QSet<KFileItem> m_recentlyChangedItems;
 337
 338     // Items which have not been changed repeatedly recently.
 339     QSet<KFileItem> m_changedItems;
 340
 341     KDirectoryContentsCounter* m_directoryContentsCounter;
 342
 343     QList<KOverlayIconPlugin*> m_overlayIconsPlugin;
 344
 345 #ifdef HAVE_BALOO
 346     Baloo::FileMonitor* m_balooFileMonitor;
 347     Baloo::IndexerConfig m_balooConfig;
 348 #endif
 349 };
 350
 351 #endif
 352
 353