Performance boost for previews that are already available in the cache: apply the...

svn path=/trunk/KDE/kdebase/apps/; revision=789009

diff --git a/src/iconmanager.cpp b/src/iconmanager.cpp
index dcfa9befea3a5c1ec8ca4f7d28206e5f5cc8f980..cde15b00b01757785fcdba1e4a3d91e00726725f 100644 (file)
--- a/src/iconmanager.cpp
+++ b/src/iconmanager.cpp
@@ -38,10 +38,12 @@ IconManager::IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel*
     QObject(parent),
     m_showPreview(false),
     m_view(parent),
+    m_previewTimer(0),
     m_previewJobs(),
     m_dolphinModel(0),
     m_proxyModel(model),
-    m_cutItemsCache()
+    m_cutItemsCache(),
+    m_previews()
 {
     Q_ASSERT(m_view->iconSize().isValid());  // each view must provide its current icon size
 
@@ -52,6 +54,9 @@ IconManager::IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel*
     QClipboard* clipboard = QApplication::clipboard();
     connect(clipboard, SIGNAL(dataChanged()),
             this, SLOT(updateCutItems()));
+
+    m_previewTimer = new QTimer(this);
+    connect(m_previewTimer, SIGNAL(timeout()), this, SLOT(dispatchPreviewQueue()));
 }
 
 IconManager::~IconManager()
@@ -98,49 +103,12 @@ void IconManager::updateIcons(const KFileItemList& items)
     }
 }
 
-void IconManager::replaceIcon(const KFileItem& item, const QPixmap& pixmap)
+void IconManager::addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap)
 {
-    Q_ASSERT(!item.isNull());
-    if (!m_showPreview) {
-        // the preview has been canceled in the meantime
-        return;
-    }
-
-    // check whether the item is part of the directory lister (it is possible
-    // that a preview from an old directory lister is received)
-    KDirLister* dirLister = m_dolphinModel->dirLister();
-    bool isOldPreview = true;
-    const KUrl::List dirs = dirLister->directories();
-    const QString itemDir = item.url().directory();
-    foreach (KUrl url, dirs) {
-        if (url.path() == itemDir) {
-            isOldPreview = false;
-            break;
-        }
-    }
-    if (isOldPreview) {
-        return;
-    }
-
-    const QModelIndex idx = m_dolphinModel->indexForItem(item);
-    if (idx.isValid() && (idx.column() == 0)) {
-        QPixmap icon = pixmap;
-
-        const QString mimeType = item.mimetype();
-        const QString mimeTypeGroup = mimeType.left(mimeType.indexOf('/'));
-        if ((mimeTypeGroup != "image") || !applyImageFrame(icon)) {
-            limitToSize(icon, m_view->iconSize());
-        }
-
-        const QMimeData* mimeData = QApplication::clipboard()->mimeData();
-        if (KonqMimeData::decodeIsCutSelection(mimeData) && isCutItem(item)) {
-            KIconEffect iconEffect;
-            icon = iconEffect.apply(icon, KIconLoader::Desktop, KIconLoader::DisabledState);
-            m_dolphinModel->setData(idx, QIcon(icon), Qt::DecorationRole);
-        } else {
-            m_dolphinModel->setData(idx, QIcon(icon), Qt::DecorationRole);
-        }
-    }
+    Preview preview;
+    preview.item = item;
+    preview.pixmap = pixmap;
+    m_previews.append(preview);
 }
 
 void IconManager::slotPreviewJobFinished(KJob* job)
@@ -165,6 +133,37 @@ void IconManager::updateCutItems()
     applyCutItemEffect();
 }
 
+void IconManager::dispatchPreviewQueue()
+{
+    const int previewsCount = m_previews.count();
+    if (previewsCount == 0) {
+        return;
+    }
+
+    // Applying the previews to the model must be done step by step
+    // in larger blocks: Applying a preview immediately when getting the signal
+    // 'gotPreview()' from the PreviewJob is too expensive, as a relayout
+    // of the view would be triggered for each single preview.
+
+    int dispatchCount = 30;
+    if (dispatchCount > previewsCount) {
+        dispatchCount = previewsCount;
+    }
+
+    for (int i = 0; i < dispatchCount; ++i) {
+        const Preview& preview = m_previews.first();
+        replaceIcon(preview.item, preview.pixmap);
+        m_previews.pop_front();
+    }
+
+    if (m_previews.count() > 0) {
+        // there are still pending previews; if no preview job is
+        // working, poll more aggressively:
+        const int timeout = (m_previewJobs.count() > 0) ? 200 : 10;
+        m_previewTimer->start(timeout);
+    }
+}
+
 void IconManager::generatePreviews(const KFileItemList &items)
 {
     Q_ASSERT(m_showPreview);
@@ -187,11 +186,57 @@ void IconManager::generatePreviews(const KFileItemList &items)
     const QSize size = m_view->iconSize();
     KIO::PreviewJob* job = KIO::filePreview(orderedItems, 128, 128);
     connect(job, SIGNAL(gotPreview(const KFileItem&, const QPixmap&)),
-            this, SLOT(replaceIcon(const KFileItem&, const QPixmap&)));
+            this, SLOT(addToPreviewQueue(const KFileItem&, const QPixmap&)));
     connect(job, SIGNAL(finished(KJob*)),
             this, SLOT(slotPreviewJobFinished(KJob*)));
 
     m_previewJobs.append(job);
+    m_previewTimer->start(200);
+}
+
+void IconManager::replaceIcon(const KFileItem& item, const QPixmap& pixmap)
+{
+    Q_ASSERT(!item.isNull());
+    if (!m_showPreview) {
+        // the preview has been canceled in the meantime
+        return;
+    }
+
+    // check whether the item is part of the directory lister (it is possible
+    // that a preview from an old directory lister is received)
+    KDirLister* dirLister = m_dolphinModel->dirLister();
+    bool isOldPreview = true;
+    const KUrl::List dirs = dirLister->directories();
+    const QString itemDir = item.url().directory();
+    foreach (KUrl url, dirs) {
+        if (url.path() == itemDir) {
+            isOldPreview = false;
+            break;
+        }
+    }
+    if (isOldPreview) {
+        return;
+    }
+
+    const QModelIndex idx = m_dolphinModel->indexForItem(item);
+    if (idx.isValid() && (idx.column() == 0)) {
+        QPixmap icon = pixmap;
+
+        const QString mimeType = item.mimetype();
+        const QString mimeTypeGroup = mimeType.left(mimeType.indexOf('/'));
+        if ((mimeTypeGroup != "image") || !applyImageFrame(icon)) {
+            limitToSize(icon, m_view->iconSize());
+        }
+
+        const QMimeData* mimeData = QApplication::clipboard()->mimeData();
+        if (KonqMimeData::decodeIsCutSelection(mimeData) && isCutItem(item)) {
+            KIconEffect iconEffect;
+            icon = iconEffect.apply(icon, KIconLoader::Desktop, KIconLoader::DisabledState);
+            m_dolphinModel->setData(idx, QIcon(icon), Qt::DecorationRole);
+        } else {
+            m_dolphinModel->setData(idx, QIcon(icon), Qt::DecorationRole);
+        }
+    }
 }
 
 bool IconManager::isCutItem(const KFileItem& item) const

diff --git a/src/iconmanager.h b/src/iconmanager.h
index 888fb42ee8bd09b50f118f1833050d83b32d7b00..ed74946e6d6fdf94bad5d73576a1fdfd339bf51a 100644 (file)
--- a/src/iconmanager.h
+++ b/src/iconmanager.h
@@ -59,10 +59,11 @@ private slots:
     void updateIcons(const KFileItemList& items);
 
     /**
-     * Replaces the icon of the item \a item by the preview pixmap
-     * \a pixmap.
+     * Adds the preview \a pixmap for the item \a item to the preview
+     * queue and starts a timer which will dispatch the preview queue
+     * later.
      */
-    void replaceIcon(const KFileItem& item, const QPixmap& pixmap);
+    void addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap);
 
     /**
      * Is invoked when the preview job has been finished and
@@ -73,9 +74,21 @@ private slots:
     /** Synchronizes the item icon with the clipboard of cut items. */
     void updateCutItems();
 
+    /**
+     * Dispatches the preview queue m_previews block by block within
+     * time slices.
+     */
+    void dispatchPreviewQueue();
+
 private:
     void generatePreviews(const KFileItemList &items);
 
+    /**
+     * Replaces the icon of the item \a item by the preview pixmap
+     * \a pixmap.
+     */
+    void replaceIcon(const KFileItem& item, const QPixmap& pixmap);
+
     /**
      * Returns true, if the item \a item has been cut into
      * the clipboard.
@@ -112,14 +125,25 @@ private:
         QPixmap pixmap;
     };
 
+    /**
+     * Remembers the received preview pixmap for an item.
+     */
+    struct Preview
+    {
+        KFileItem item;
+        QPixmap pixmap;
+    };
+
     bool m_showPreview;
 
     QAbstractItemView* m_view;
+    QTimer* m_previewTimer;
     QList<KJob*> m_previewJobs;
     DolphinModel* m_dolphinModel;
     DolphinSortFilterProxyModel* m_proxyModel;
 
     QList<CutItem> m_cutItemsCache;
+    QList<Preview> m_previews;
 };
 
 inline bool IconManager::showPreview() const