fix linking

[dolphin.git] / src / iconmanager.cpp

diff --git a/src/iconmanager.cpp b/src/iconmanager.cpp
index 002f4e86d5fba26cb333ff2d957173b5be683865..97dac53b7b269440e8a6a37ba7d84174e4495889 100644 (file)
--- a/src/iconmanager.cpp
+++ b/src/iconmanager.cpp
@@ -32,10 +32,55 @@
 #include <QAbstractItemView>
 #include <QClipboard>
 #include <QColor>
 #include <QAbstractItemView>
 #include <QClipboard>
 #include <QColor>

+#include <QListView>

 #include <QPainter>
 #include <QScrollBar>
 #include <QIcon>
 
 #include <QPainter>
 #include <QScrollBar>
 #include <QIcon>
 

+/**
+ * If the passed item view is an instance of QListView, expensive
+ * layout operations are blocked in the constructor and are unblocked
+ * again in the destructor.
+ *
+ * This helper class is a workaround for the following huge performance
+ * problem when having directories with several 1000 items:
+ * - each change of an icon emits a dataChanged() signal from the model
+ * - QListView iterates through all items on each dataChanged() signal
+ *   and invokes QItemDelegate::sizeHint()
+ * - the sizeHint() implementation of KFileItemDelegate is quite complex,
+ *   invoking it 1000 times for each icon change might block the UI
+ *
+ * QListView does not invoke QItemDelegate::sizeHint() when the
+ * uniformItemSize property has been set to true, so this property is
+ * set before exchanging a block of icons. It is important to reset
+ * it again before the event loop is entered, otherwise QListView
+ * would not get the correct size hints after dispatching the layoutChanged()
+ * signal.
+ */
+class LayoutBlocker {
+public:
+    LayoutBlocker(QAbstractItemView* view) :
+        m_uniformSizes(false),
+        m_view(qobject_cast<QListView*>(view))
+    {
+        if (m_view != 0) {
+            m_uniformSizes = m_view->uniformItemSizes();
+            m_view->setUniformItemSizes(true);
+        }
+    }
+
+    ~LayoutBlocker()
+    {
+        if (m_view != 0) {
+            m_view->setUniformItemSizes(m_uniformSizes);
+        }
+    }
+
+private:
+    bool m_uniformSizes;
+    QListView* m_view;
+};
+

 IconManager::IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel* model) :
     QObject(parent),
     m_showPreview(false),
 IconManager::IconManager(QAbstractItemView* parent, DolphinSortFilterProxyModel* model) :
     QObject(parent),
     m_showPreview(false),


@@ -154,28 +199,11 @@ void IconManager::generatePreviews(const KFileItemList& items)
         return;
     }
 
         return;
     }
 

-    // Order the items in a way that the preview for the visible items
-    // is generated first, as this improves the feeled performance a lot.
-    // Implementation note: using KDirModel::itemForUrl() would lead to a more
-    // readable code, but it is a lot slower in comparison to itemListContains().
-    const QRect visibleArea = m_view->viewport()->rect();
-    KFileItemList orderedItems;
-    const int rowCount = m_proxyModel->rowCount();
-    for (int row = 0; row < rowCount; ++row) {
-        const QModelIndex proxyIndex = m_proxyModel->index(row, 0);
-        const QRect itemRect = m_view->visualRect(proxyIndex);
-        const QModelIndex dirIndex = m_proxyModel->mapToSource(proxyIndex);
-        KFileItem item = m_dolphinModel->itemForIndex(dirIndex);
-        const KUrl url = item.url();
-        if (itemListContains(items, url)) {
-            if (itemRect.intersects(visibleArea)) {
-                orderedItems.insert(0, item);
-                m_pendingItems.insert(0, url);
-            } else {
-                orderedItems.append(item);
-                m_pendingItems.append(url);
-            }
-        }
+    KFileItemList orderedItems = items;
+    orderItems(orderedItems);
+
+    foreach (const KFileItem& item, orderedItems) {
+        m_pendingItems.append(item);

     }
 
     startPreviewJob(orderedItems);
     }
 
     startPreviewJob(orderedItems);


@@ -188,7 +216,7 @@ void IconManager::addToPreviewQueue(const KFileItem& item, const QPixmap& pixmap
     preview.pixmap = pixmap;
     m_previews.append(preview);
 
     preview.pixmap = pixmap;
     m_previews.append(preview);
 

-    m_dispatchedItems.append(item.url());
+    m_dispatchedItems.append(item);

 }
 
 void IconManager::slotPreviewJobFinished(KJob* job)
 }
 
 void IconManager::slotPreviewJobFinished(KJob* job)


@@ -232,6 +260,7 @@ void IconManager::dispatchPreviewQueue()
             dispatchCount = previewsCount;
         }
 
             dispatchCount = previewsCount;
         }
 

+        LayoutBlocker blocker(m_view);

         for (int i = 0; i < dispatchCount; ++i) {
             const ItemInfo& preview = m_previews.first();
             replaceIcon(preview.url, preview.pixmap);
         for (int i = 0; i < dispatchCount; ++i) {
             const ItemInfo& preview = m_previews.first();
             replaceIcon(preview.url, preview.pixmap);


@@ -269,11 +298,11 @@ void IconManager::resumePreviews()
     // queue is usually equal. So even when having a lot of elements the
     // nested loop is no performance bottle neck, as the inner loop is only
     // entered once in most cases.
     // queue is usually equal. So even when having a lot of elements the
     // nested loop is no performance bottle neck, as the inner loop is only
     // entered once in most cases.

-    foreach (const KUrl& url, m_dispatchedItems) {
-        QList<KUrl>::iterator begin = m_pendingItems.begin();
-        QList<KUrl>::iterator end   = m_pendingItems.end();
-        for (QList<KUrl>::iterator it = begin; it != end; ++it) {
-            if ((*it) == url) {
+    foreach (const KFileItem& item, m_dispatchedItems) {
+        KFileItemList::iterator begin = m_pendingItems.begin();
+        KFileItemList::iterator end   = m_pendingItems.end();
+        for (KFileItemList::iterator it = begin; it != end; ++it) {
+            if ((*it).url() == item.url()) {

                 m_pendingItems.erase(it);
                 break;
             }
                 m_pendingItems.erase(it);
                 break;
             }


@@ -281,30 +310,8 @@ void IconManager::resumePreviews()
     }
     m_dispatchedItems.clear();
 
     }
     m_dispatchedItems.clear();
 

-    // Create a new preview job for the remaining items.
-    // Order the items in a way that the preview for the visible items
-    // is generated first, as this improves the feeled performance a lot.
-    // Implementation note: using KDirModel::itemForUrl() would lead to a more
-    // readable code, but it is a lot slower in comparison
-    // to m_pendingItems.contains().
-    const QRect visibleArea = m_view->viewport()->rect();
-    KFileItemList orderedItems;
-
-    const int rowCount = m_proxyModel->rowCount();
-    for (int row = 0; row < rowCount; ++row) {
-        const QModelIndex proxyIndex = m_proxyModel->index(row, 0);
-        const QRect itemRect = m_view->visualRect(proxyIndex);
-        const QModelIndex dirIndex = m_proxyModel->mapToSource(proxyIndex);
-        KFileItem item = m_dolphinModel->itemForIndex(dirIndex);
-        const KUrl url = item.url();
-        if (m_pendingItems.contains(url)) {
-            if (itemRect.intersects(visibleArea)) {
-                orderedItems.insert(0, item);
-            } else {
-                orderedItems.append(item);
-            }
-        }
-    }
+    KFileItemList orderedItems = m_pendingItems;
+    orderItems(orderedItems);

 
     // Kill all suspended preview jobs. Usually when a preview job
     // has been finished, slotPreviewJobFinished() clears all item queues.
 
     // Kill all suspended preview jobs. Usually when a preview job
     // has been finished, slotPreviewJobFinished() clears all item queues.


@@ -520,14 +527,67 @@ void IconManager::killPreviewJobs()
     m_previewJobs.clear();
 }
 
     m_previewJobs.clear();
 }
 

-bool IconManager::itemListContains(const KFileItemList& items, const KUrl& url) const
+void IconManager::orderItems(KFileItemList& items)

 {
 {

-    foreach (const KFileItem& item, items) {
-        if (url == item.url()) {
-            return true;
+    // Order the items in a way that the preview for the visible items
+    // is generated first, as this improves the feeled performance a lot.
+    //
+    // Implementation note: 2 different algorithms are used for the sorting.
+    // Algorithm 1 is faster when having a lot of items in comparison
+    // to the number of rows in the model. Algorithm 2 is faster
+    // when having quite less items in comparison to the number of rows in
+    // the model. Choosing the right algorithm is important when having directories
+    // with several hundreds or thousands of items.
+
+    const int itemCount = items.count();
+    const int rowCount = m_proxyModel->rowCount();
+    const QRect visibleArea = m_view->viewport()->rect();
+
+    if (itemCount * 10 > rowCount) {
+        // Algorithm 1: The number of items is > 10 % of the row count. Parse all rows
+        // and check whether the received row is part of the item list.
+        for (int row = 0; row < rowCount; ++row) {
+            const QModelIndex proxyIndex = m_proxyModel->index(row, 0);
+            const QRect itemRect = m_view->visualRect(proxyIndex);
+            const QModelIndex dirIndex = m_proxyModel->mapToSource(proxyIndex);
+
+            KFileItem item = m_dolphinModel->itemForIndex(dirIndex);  // O(1)
+            const KUrl url = item.url();
+
+            // check whether the item is part of the item list 'items'
+            int index = -1;
+            for (int i = 0; i < itemCount; ++i) {
+                if (items[i].url() == url) {
+                    index = i;
+                    break;
+                }
+            }
+
+            if ((index > 0) && itemRect.intersects(visibleArea)) {
+                // The current item is (at least partly) visible. Move it
+                // to the front of the list, so that the preview is
+                // generated earlier.
+                items.removeAt(index);
+                items.insert(0, item);
+            }
+        }
+    } else {
+        // Algorithm 2: The number of items is <= 10 % of the row count. In this case iterate
+        // all items and receive the corresponding row from the item.
+        for (int i = 0; i < itemCount; ++i) {
+            const QModelIndex dirIndex = m_dolphinModel->indexForItem(items[i]); // O(n) (n = number of rows)
+            const QModelIndex proxyIndex = m_proxyModel->mapFromSource(dirIndex);
+            const QRect itemRect = m_view->visualRect(proxyIndex);
+
+            if (itemRect.intersects(visibleArea)) {
+                // The current item is (at least partly) visible. Move it
+                // to the front of the list, so that the preview is
+                // generated earlier.
+                items.insert(0, items[i]);
+                items.removeAt(i + 1);
+            }

         }
     }
         }
     }

-    return false;

 }
 
 #include "iconmanager.moc"
 }
 
 #include "iconmanager.moc"