src/kitemviews/kfileitemmodelrolesupdater.h

   1 /*
   2  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-or-later
   5  */
   6
   7 #ifndef KFILEITEMMODELROLESUPDATER_H
   8 #define KFILEITEMMODELROLESUPDATER_H
   9
  10 #include "dolphin_export.h"
  11 #include "kitemviews/kitemmodelbase.h"
  12
  13 #include <list>
  14
  15 #include "config-dolphin.h"
  16 #include <KFileItem>
  17
  18 #include <QObject>
  19 #include <QSet>
  20 #include <QSize>
  21 #include <QStringList>
  22
  23 class KDirectoryContentsCounter;
  24 class KFileItemModel;
  25 class QPixmap;
  26 class QTimer;
  27 class KOverlayIconPlugin;
  28
  29 namespace KIO
  30 {
  31 class PreviewJob;
  32 }
  33
  34 #if HAVE_BALOO
  35 namespace Baloo
  36 {
  37 class FileMonitor;
  38 }
  39 #include <Baloo/IndexerConfig>
  40 #endif
  41
  42 /**
  43  * @brief Resolves expensive roles asynchronously and applies them to the KFileItemModel.
  44  *
  45  * KFileItemModel only resolves roles that are inexpensive like e.g. the file name or
  46  * the permissions. Creating previews or determining the MIME-type can be quite expensive
  47  * and KFileItemModelRolesUpdater takes care to update such roles asynchronously.
  48  *
  49  * To prevent a huge CPU and I/O load, these roles are not updated for all
  50  * items, but only for the visible items, some items around the visible area,
  51  * and the items on the first and last pages of the view. This is a compromise
  52  * that aims to minimize the risk that the user sees items with unknown icons
  53  * in the view when scrolling or pressing Home or End.
  54  *
  55  * Determining the roles is done in several phases:
  56  *
  57  * 1.   If the sort role is "slow", it is determined for all items. If this
  58  *      cannot be finished synchronously in 200 ms, the remaining items are
  59  *      handled asynchronously by \a resolveNextSortRole().
  60  *
  61  * 2.   The function startUpdating(), which is called if either the sort role
  62  *      has been successfully determined for all items, or items are inserted
  63  *      in the view, or the visible items might have changed because items
  64  *      were removed or moved, tries to determine the icons for all visible
  65  *      items synchronously for 200 ms. Then:
  66  *
  67  *      (a) If previews are disabled, icons and all other roles are determined
  68  *          asynchronously for the interesting items. This is done by the
  69  *          function \a resolveNextPendingRoles().
  70  *
  71  *      (b) If previews are enabled, a \a KIO::PreviewJob is started that loads
  72  *          the previews for the interesting items. At the same time, the icons
  73  *          for these items are determined asynchronously as fast as possible
  74  *          by \a resolveNextPendingRoles(). This minimizes the risk that the
  75  *          user sees "unknown" icons when scrolling before the previews have
  76  *          arrived.
  77  *
  78  * 3.   Finally, the entire process is repeated for any items that might have
  79  *      changed in the mean time.
  80  */
  81 class DOLPHIN_EXPORT KFileItemModelRolesUpdater : public QObject
  82 {
  83     Q_OBJECT
  84
  85 public:
  86     explicit KFileItemModelRolesUpdater(KFileItemModel *model, QObject *parent = nullptr);
  87     ~KFileItemModelRolesUpdater() override;
  88
  89     void setIconSize(const QSize &size);
  90     QSize iconSize() const;
  91
  92     /**
  93      * Sets the range of items that are visible currently. The roles
  94      * of visible items are resolved first.
  95      */
  96     void setVisibleIndexRange(int index, int count);
  97
  98     void setMaximumVisibleItems(int count);
  99
 100     /**
 101      * If \a show is set to true, the "iconPixmap" role will be filled with a preview
 102      * of the file. If \a show is false the MIME type icon will be used for the "iconPixmap"
 103      * role.
 104      */
 105     void setPreviewsShown(bool show);
 106     bool previewsShown() const;
 107
 108     /**
 109      * If enabled a small preview gets upscaled to the icon size in case where
 110      * the icon size is larger than the preview. Per default enlarging is
 111      * enabled.
 112      */
 113     void setEnlargeSmallPreviews(bool enlarge);
 114     bool enlargeSmallPreviews() const;
 115
 116     /**
 117      * If \a paused is set to true the asynchronous resolving of roles will be paused.
 118      * State changes during pauses like changing the icon size or the preview-shown
 119      * will be remembered and handled after unpausing.
 120      */
 121     void setPaused(bool paused);
 122     bool isPaused() const;
 123
 124     /**
 125      * Sets the roles that should be resolved asynchronously.
 126      */
 127     void setRoles(const QSet<QByteArray> &roles);
 128     QSet<QByteArray> roles() const;
 129
 130     /**
 131      * Sets the list of enabled thumbnail plugins that are used for previews.
 132      * Per default all plugins enabled in the KConfigGroup "PreviewSettings"
 133      * are used.
 134      *
 135      * For a list of available plugins, call KIO::PreviewJob::availableThumbnailerPlugins().
 136      *
 137      * @see enabledPlugins
 138      */
 139     void setEnabledPlugins(const QStringList &list);
 140
 141     /**
 142      * Returns the list of enabled thumbnail plugins.
 143      * @see setEnabledPlugins
 144      */
 145     QStringList enabledPlugins() const;
 146
 147     /**
 148      * Sets the maximum file size of local files for which
 149      * previews will be generated (if enabled). A value of 0
 150      * indicates no file size limit.
 151      * Per default the value from KConfigGroup "PreviewSettings"
 152      * MaximumSize is used, 0 otherwise.
 153      * @param size
 154      */
 155     void setLocalFileSizePreviewLimit(qlonglong size);
 156     qlonglong localFileSizePreviewLimit() const;
 157
 158     /**
 159      * If set to true, directories contents are scanned to determine their size
 160      * Default true
 161      */
 162     void setScanDirectories(bool enabled);
 163     bool scanDirectories() const;
 164
 165     /**
 166      * Notifies the updater of a change in the hover state on an item.
 167      *
 168      * This will trigger asynchronous loading of the next few thumb sequence images
 169      * using a PreviewJob.
 170      *
 171      * @param item URL of the item that is hovered, or an empty URL if no item is hovered.
 172      * @param seqIdx The current hover sequence index. While an item is hovered,
 173      *               this method will be called repeatedly with increasing values
 174      *               for this parameter.
 175      */
 176     void setHoverSequenceState(const QUrl &itemUrl, int seqIdx);
 177
 178 private Q_SLOTS:
 179     void slotItemsInserted(const KItemRangeList &itemRanges);
 180     void slotItemsRemoved(const KItemRangeList &itemRanges);
 181     void slotItemsMoved(KItemRange itemRange, const QList<int> &movedToIndexes);
 182     void slotItemsChanged(const KItemRangeList &itemRanges, const QSet<QByteArray> &roles);
 183     void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous);
 184
 185     /**
 186      * Is invoked after a preview has been received successfully.
 187      *
 188      * Note that this is not called for hover sequence previews.
 189      *
 190      * @see startPreviewJob()
 191      */
 192     void slotGotPreview(const KFileItem &item, const QPixmap &pixmap);
 193
 194     /**
 195      * Is invoked after generating a preview has failed.
 196      *
 197      * Note that this is not called for hover sequence previews.
 198      *
 199      * @see startPreviewJob()
 200      */
 201     void slotPreviewFailed(const KFileItem &item);
 202
 203     /**
 204      * Is invoked when the preview job has been finished. Starts a new preview
 205      * job if there are any interesting items without previews left, or updates
 206      * the changed items otherwise.
 207      *
 208      * Note that this is not called for hover sequence previews.
 209      *
 210      * @see startPreviewJob()
 211      */
 212     void slotPreviewJobFinished();
 213
 214     /**
 215      * Is invoked after a hover sequence preview has been received successfully.
 216      */
 217     void slotHoverSequenceGotPreview(const KFileItem &item, const QPixmap &pixmap);
 218
 219     /**
 220      * Is invoked after generating a hover sequence preview has failed.
 221      */
 222     void slotHoverSequencePreviewFailed(const KFileItem &item);
 223
 224     /**
 225      * Is invoked when a hover sequence preview job is finished. May start another
 226      * job for the next sequence index right away by calling
 227      * \a loadNextHoverSequencePreview().
 228      *
 229      * Note that a PreviewJob will only ever generate a single sequence image, due
 230      * to limitations of the PreviewJob API.
 231      */
 232     void slotHoverSequencePreviewJobFinished();
 233
 234     /**
 235      * Is invoked when one of the KOverlayIconPlugin emit the signal that an overlay has changed
 236      */
 237     void slotOverlaysChanged(const QUrl &url, const QStringList &);
 238
 239     /**
 240      * Resolves the sort role of the next item in m_pendingSortRole, applies it
 241      * to the model, and invokes itself if there are any pending items left. If
 242      * that is not the case, \a startUpdating() is called.
 243      */
 244     void resolveNextSortRole();
 245
 246     /**
 247      * Resolves the icon name and (if previews are disabled) all other roles
 248      * for the next interesting item. If there are no pending items left, any
 249      * changed items are updated.
 250      */
 251     void resolveNextPendingRoles();
 252
 253     /**
 254      * Resolves items that have not been resolved yet after the change has been
 255      * notified by slotItemsChanged(). Is invoked if the m_changedItemsTimer
 256      * expires.
 257      */
 258     void resolveRecentlyChangedItems();
 259
 260     void applyChangedBalooRoles(const QString &file);
 261     void applyChangedBalooRolesForItem(const KFileItem &file);
 262
 263     void slotDirectoryContentsCountReceived(const QString &path, int count, long size);
 264
 265 private:
 266     /**
 267      * Starts the updating of all roles. The visible items are handled first.
 268      */
 269     void startUpdating();
 270
 271     /**
 272      * Loads the icons for the visible items. After 200 ms, the function
 273      * stops determining mime types and only loads preliminary icons.
 274      * This is a compromise that prevents that
 275      * (a) the GUI is blocked for more than 200 ms, and
 276      * (b) "unknown" icons could be shown in the view.
 277      */
 278     void updateVisibleIcons();
 279
 280     /**
 281      * Creates previews for the items starting from the first item in
 282      * m_pendingPreviewItems.
 283      * @see slotGotPreview()
 284      * @see slotPreviewFailed()
 285      * @see slotPreviewJobFinished()
 286      */
 287     void startPreviewJob();
 288
 289     /**
 290      * Transforms a raw preview image, applying scale and frame.
 291      *
 292      * @param pixmap A raw preview image from a PreviewJob.
 293      * @return The scaled and decorated preview image.
 294      */
 295     QPixmap transformPreviewPixmap(const QPixmap &pixmap);
 296
 297     /**
 298      * Starts a PreviewJob for loading the next hover sequence image.
 299      */
 300     void loadNextHoverSequencePreview();
 301
 302     /**
 303      * Aborts the currently running hover sequence PreviewJob (if any).
 304      */
 305     void killHoverSequencePreviewJob();
 306
 307     /**
 308      * Ensures that icons, previews, and other roles are determined for any
 309      * items that have been changed.
 310      */
 311     void updateChangedItems();
 312
 313     /**
 314      * Resolves the sort role of the item and applies it to the model.
 315      */
 316     void applySortRole(int index);
 317
 318     void applySortProgressToModel();
 319
 320     enum ResolveHint { ResolveFast, ResolveAll };
 321     bool applyResolvedRoles(int index, ResolveHint hint);
 322     QHash<QByteArray, QVariant> rolesData(const KFileItem &item, int index);
 323
 324     /**
 325      * Must be invoked if a property has been changed that affects
 326      * the look of the preview. Takes care to update all previews.
 327      */
 328     void updateAllPreviews();
 329
 330     void killPreviewJob();
 331
 332     QList<int> indexesToResolve() const;
 333
 334     void trimHoverSequenceLoadedItems();
 335
 336 private:
 337     void startDirectorySizeCounting(const KFileItem &item, int index);
 338
 339     enum State { Idle, Paused, ResolvingSortRole, ResolvingAllRoles, PreviewJobRunning };
 340
 341     State m_state;
 342
 343     // Property changes during pausing must be remembered to be able
 344     // to react when unpausing again:
 345     bool m_previewChangedDuringPausing;
 346     bool m_iconSizeChangedDuringPausing;
 347     bool m_rolesChangedDuringPausing;
 348
 349     // Property for setPreviewsShown()/previewsShown().
 350     bool m_previewShown;
 351
 352     // Property for setEnlargeSmallPreviews()/enlargeSmallPreviews()
 353     bool m_enlargeSmallPreviews;
 354
 355     // True if the role "iconPixmap" should be cleared when resolving the next
 356     // role with resolveRole(). Is necessary if the preview gets disabled
 357     // during the roles-updater has been paused by setPaused().
 358     bool m_clearPreviews;
 359
 360     // Remembers which items have been handled already, to prevent that
 361     // previews and other expensive roles are determined again.
 362     QSet<KFileItem> m_finishedItems;
 363
 364     KFileItemModel *m_model;
 365     QSize m_iconSize;
 366     int m_firstVisibleIndex;
 367     int m_lastVisibleIndex;
 368     int m_maximumVisibleItems;
 369     QSet<QByteArray> m_roles;
 370     QSet<QByteArray> m_resolvableRoles;
 371     QStringList m_enabledPlugins;
 372     qulonglong m_localFileSizePreviewLimit;
 373     bool m_scanDirectories;
 374
 375     // Items for which the sort role still has to be determined.
 376     QSet<KFileItem> m_pendingSortRoleItems;
 377
 378     // Indexes of items which still have to be handled by
 379     // resolveNextPendingRoles().
 380     QList<int> m_pendingIndexes;
 381
 382     // Items which have been left over from the last call of startPreviewJob().
 383     // A new preview job will be started from them once the first one finishes.
 384     KFileItemList m_pendingPreviewItems;
 385
 386     KIO::PreviewJob *m_previewJob;
 387
 388     // Info about the item that the user currently hovers, and the current sequence
 389     // index for thumb generation.
 390     KFileItem m_hoverSequenceItem;
 391     int m_hoverSequenceIndex;
 392     KIO::PreviewJob *m_hoverSequencePreviewJob;
 393     int m_hoverSequenceNumSuccessiveFailures;
 394     std::list<KFileItem> m_hoverSequenceLoadedItems;
 395
 396     // When downloading or copying large files, the slot slotItemsChanged()
 397     // will be called periodically within a quite short delay. To prevent
 398     // a high CPU-load by generating e.g. previews for each notification, the update
 399     // will be postponed until no file change has been done within a longer period
 400     // of time.
 401     QTimer *m_recentlyChangedItemsTimer;
 402     QSet<KFileItem> m_recentlyChangedItems;
 403
 404     // Items which have not been changed repeatedly recently.
 405     QSet<KFileItem> m_changedItems;
 406
 407     KDirectoryContentsCounter *m_directoryContentsCounter;
 408
 409     QList<KOverlayIconPlugin *> m_overlayIconsPlugin;
 410
 411 #if HAVE_BALOO
 412     Baloo::FileMonitor *m_balooFileMonitor;
 413     Baloo::IndexerConfig m_balooConfig;
 414 #endif
 415 };
 416
 417 #endif