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     void setDevicePixelRatio(qreal devicePixelRatio);
  93     qreal devicePixelRatio() const;
  94
  95     /**
  96      * Sets the range of items that are visible currently. The roles
  97      * of visible items are resolved first.
  98      */
  99     void setVisibleIndexRange(int index, int count);
 100
 101     void setMaximumVisibleItems(int count);
 102
 103     /**
 104      * If \a show is set to true, the "iconPixmap" role will be filled with a preview
 105      * of the file. If \a show is false the MIME type icon will be used for the "iconPixmap"
 106      * role.
 107      */
 108     void setPreviewsShown(bool show);
 109     bool previewsShown() const;
 110
 111     /**
 112      * If enabled a small preview gets upscaled to the icon size in case where
 113      * the icon size is larger than the preview. Per default enlarging is
 114      * enabled.
 115      */
 116     void setEnlargeSmallPreviews(bool enlarge);
 117     bool enlargeSmallPreviews() const;
 118
 119     /**
 120      * If \a paused is set to true the asynchronous resolving of roles will be paused.
 121      * State changes during pauses like changing the icon size or the preview-shown
 122      * will be remembered and handled after unpausing.
 123      */
 124     void setPaused(bool paused);
 125     bool isPaused() const;
 126
 127     /**
 128      * Sets the roles that should be resolved asynchronously.
 129      */
 130     void setRoles(const QSet<QByteArray> &roles);
 131     QSet<QByteArray> roles() const;
 132
 133     /**
 134      * Sets the list of enabled thumbnail plugins that are used for previews.
 135      * Per default all plugins enabled in the KConfigGroup "PreviewSettings"
 136      * are used.
 137      *
 138      * For a list of available plugins, call KIO::PreviewJob::availableThumbnailerPlugins().
 139      *
 140      * @see enabledPlugins
 141      */
 142     void setEnabledPlugins(const QStringList &list);
 143
 144     /**
 145      * Returns the list of enabled thumbnail plugins.
 146      * @see setEnabledPlugins
 147      */
 148     QStringList enabledPlugins() const;
 149
 150     /**
 151      * Sets the maximum file size of local files for which
 152      * previews will be generated (if enabled). A value of 0
 153      * indicates no file size limit.
 154      * Per default the value from KConfigGroup "PreviewSettings"
 155      * MaximumSize is used, 0 otherwise.
 156      * @param size
 157      */
 158     void setLocalFileSizePreviewLimit(qlonglong size);
 159     qlonglong localFileSizePreviewLimit() const;
 160
 161     /**
 162      * If set to true, directories contents are scanned to determine their size
 163      * Default true
 164      */
 165     void setScanDirectories(bool enabled);
 166     bool scanDirectories() const;
 167
 168     /**
 169      * Notifies the updater of a change in the hover state on an item.
 170      *
 171      * This will trigger asynchronous loading of the next few thumb sequence images
 172      * using a PreviewJob.
 173      *
 174      * @param item URL of the item that is hovered, or an empty URL if no item is hovered.
 175      * @param seqIdx The current hover sequence index. While an item is hovered,
 176      *               this method will be called repeatedly with increasing values
 177      *               for this parameter.
 178      */
 179     void setHoverSequenceState(const QUrl &itemUrl, int seqIdx);
 180
 181 private Q_SLOTS:
 182     void slotItemsInserted(const KItemRangeList &itemRanges);
 183     void slotItemsRemoved(const KItemRangeList &itemRanges);
 184     void slotItemsMoved(KItemRange itemRange, const QList<int> &movedToIndexes);
 185     void slotItemsChanged(const KItemRangeList &itemRanges, const QSet<QByteArray> &roles);
 186     void slotSortRoleChanged(const QByteArray &current, const QByteArray &previous);
 187
 188     /**
 189      * Is invoked after a preview has been received successfully.
 190      *
 191      * Note that this is not called for hover sequence previews.
 192      *
 193      * @see startPreviewJob()
 194      */
 195     void slotGotPreview(const KFileItem &item, const QPixmap &pixmap);
 196
 197     /**
 198      * Is invoked after generating a preview has failed.
 199      *
 200      * Note that this is not called for hover sequence previews.
 201      *
 202      * @see startPreviewJob()
 203      */
 204     void slotPreviewFailed(const KFileItem &item);
 205
 206     /**
 207      * Is invoked when the preview job has been finished. Starts a new preview
 208      * job if there are any interesting items without previews left, or updates
 209      * the changed items otherwise.
 210      *
 211      * Note that this is not called for hover sequence previews.
 212      *
 213      * @see startPreviewJob()
 214      */
 215     void slotPreviewJobFinished();
 216
 217     /**
 218      * Is invoked after a hover sequence preview has been received successfully.
 219      */
 220     void slotHoverSequenceGotPreview(const KFileItem &item, const QPixmap &pixmap);
 221
 222     /**
 223      * Is invoked after generating a hover sequence preview has failed.
 224      */
 225     void slotHoverSequencePreviewFailed(const KFileItem &item);
 226
 227     /**
 228      * Is invoked when a hover sequence preview job is finished. May start another
 229      * job for the next sequence index right away by calling
 230      * \a loadNextHoverSequencePreview().
 231      *
 232      * Note that a PreviewJob will only ever generate a single sequence image, due
 233      * to limitations of the PreviewJob API.
 234      */
 235     void slotHoverSequencePreviewJobFinished();
 236
 237     /**
 238      * Is invoked when one of the KOverlayIconPlugin emit the signal that an overlay has changed
 239      */
 240     void slotOverlaysChanged(const QUrl &url, const QStringList &);
 241
 242     /**
 243      * Resolves the sort role of the next item in m_pendingSortRole, applies it
 244      * to the model, and invokes itself if there are any pending items left. If
 245      * that is not the case, \a startUpdating() is called.
 246      */
 247     void resolveNextSortRole();
 248
 249     /**
 250      * Resolves the icon name and (if previews are disabled) all other roles
 251      * for the next interesting item. If there are no pending items left, any
 252      * changed items are updated.
 253      */
 254     void resolveNextPendingRoles();
 255
 256     /**
 257      * Resolves items that have not been resolved yet after the change has been
 258      * notified by slotItemsChanged(). Is invoked if the m_changedItemsTimer
 259      * expires.
 260      */
 261     void resolveRecentlyChangedItems();
 262
 263     void applyChangedBalooRoles(const QString &file);
 264     void applyChangedBalooRolesForItem(const KFileItem &file);
 265
 266     void slotDirectoryContentsCountReceived(const QString &path, int count, long long size);
 267
 268 private:
 269     /**
 270      * Starts the updating of all roles. The visible items are handled first.
 271      */
 272     void startUpdating();
 273
 274     /**
 275      * Loads the icons for the visible items. After 200 ms, the function
 276      * stops determining mime types and only loads preliminary icons.
 277      * This is a compromise that prevents that
 278      * (a) the GUI is blocked for more than 200 ms, and
 279      * (b) "unknown" icons could be shown in the view.
 280      */
 281     void updateVisibleIcons();
 282
 283     /**
 284      * Creates previews for the items starting from the first item in
 285      * m_pendingPreviewItems.
 286      * @see slotGotPreview()
 287      * @see slotPreviewFailed()
 288      * @see slotPreviewJobFinished()
 289      */
 290     void startPreviewJob();
 291
 292     /**
 293      * Transforms a raw preview image, applying scale and frame.
 294      *
 295      * @param pixmap A raw preview image from a PreviewJob.
 296      * @return The scaled and decorated preview image.
 297      */
 298     QPixmap transformPreviewPixmap(const QPixmap &pixmap);
 299
 300     /**
 301      * Starts a PreviewJob for loading the next hover sequence image.
 302      */
 303     void loadNextHoverSequencePreview();
 304
 305     /**
 306      * Aborts the currently running hover sequence PreviewJob (if any).
 307      */
 308     void killHoverSequencePreviewJob();
 309
 310     /**
 311      * Ensures that icons, previews, and other roles are determined for any
 312      * items that have been changed.
 313      */
 314     void updateChangedItems();
 315
 316     /**
 317      * Resolves the sort role of the item and applies it to the model.
 318      * Despite the name, this handles both sorting and grouping, as
 319      * regrouping never happens without resorting at the same time.
 320      */
 321     void applySortRole(int index);
 322
 323     void applySortProgressToModel();
 324
 325     enum ResolveHint { ResolveFast, ResolveAll };
 326     bool applyResolvedRoles(int index, ResolveHint hint);
 327     QHash<QByteArray, QVariant> rolesData(const KFileItem &item, int index);
 328
 329     /**
 330      * Must be invoked if a property has been changed that affects
 331      * the look of the preview. Takes care to update all previews.
 332      */
 333     void updateAllPreviews();
 334
 335     void killPreviewJob();
 336
 337     QList<int> indexesToResolve() const;
 338
 339     void trimHoverSequenceLoadedItems();
 340
 341 private:
 342     /**
 343      * enqueue directory size counting for KFileItem item at index
 344      */
 345     void startDirectorySizeCounting(const KFileItem &item, int index);
 346
 347     enum State { Idle, Paused, ResolvingSortRole, ResolvingAllRoles, PreviewJobRunning };
 348
 349     State m_state;
 350
 351     // Property changes during pausing must be remembered to be able
 352     // to react when unpausing again:
 353     bool m_previewChangedDuringPausing;
 354     bool m_iconSizeChangedDuringPausing;
 355     bool m_rolesChangedDuringPausing;
 356
 357     // Property for setPreviewsShown()/previewsShown().
 358     bool m_previewShown;
 359
 360     // Property for setEnlargeSmallPreviews()/enlargeSmallPreviews()
 361     bool m_enlargeSmallPreviews;
 362
 363     // True if the role "iconPixmap" should be cleared when resolving the next
 364     // role with resolveRole(). Is necessary if the preview gets disabled
 365     // during the roles-updater has been paused by setPaused().
 366     bool m_clearPreviews;
 367
 368     // Remembers which items have been handled already, to prevent that
 369     // previews and other expensive roles are determined again.
 370     QSet<KFileItem> m_finishedItems;
 371
 372     KFileItemModel *m_model;
 373     QSize m_iconSize;
 374     qreal m_devicePixelRatio;
 375     int m_firstVisibleIndex;
 376     int m_lastVisibleIndex;
 377     int m_maximumVisibleItems;
 378     QSet<QByteArray> m_roles;
 379     QSet<QByteArray> m_resolvableRoles;
 380     QStringList m_enabledPlugins;
 381     qulonglong m_localFileSizePreviewLimit;
 382
 383     // Items for which the sort role still has to be determined.
 384     QSet<KFileItem> m_pendingSortRoleItems;
 385
 386     // Indexes of items which still have to be handled by
 387     // resolveNextPendingRoles().
 388     QList<int> m_pendingIndexes;
 389
 390     // Items which have been left over from the last call of startPreviewJob().
 391     // A new preview job will be started from them once the first one finishes.
 392     KFileItemList m_pendingPreviewItems;
 393
 394     KIO::PreviewJob *m_previewJob;
 395
 396     // Info about the item that the user currently hovers, and the current sequence
 397     // index for thumb generation.
 398     KFileItem m_hoverSequenceItem;
 399     int m_hoverSequenceIndex;
 400     KIO::PreviewJob *m_hoverSequencePreviewJob;
 401     int m_hoverSequenceNumSuccessiveFailures;
 402     std::list<KFileItem> m_hoverSequenceLoadedItems;
 403
 404     // When downloading or copying large files, the slot slotItemsChanged()
 405     // will be called periodically within a quite short delay. To prevent
 406     // a high CPU-load by generating e.g. previews for each notification, the update
 407     // will be postponed until no file change has been done within a longer period
 408     // of time.
 409     QTimer *m_recentlyChangedItemsTimer;
 410     QSet<KFileItem> m_recentlyChangedItems;
 411
 412     // Items which have not been changed repeatedly recently.
 413     QSet<KFileItem> m_changedItems;
 414
 415     KDirectoryContentsCounter *m_directoryContentsCounter;
 416
 417     QList<KOverlayIconPlugin *> m_overlayIconsPlugin;
 418
 419 #if HAVE_BALOO
 420     Baloo::FileMonitor *m_balooFileMonitor;
 421     Baloo::IndexerConfig m_balooConfig;
 422 #endif
 423 };
 424
 425 #endif