Hi,
kdiff3 is a tool i regularly use to compare folder hierarchies, but
what always troubled me a bit was the performance issues when
traversing the tree or showing/hiding a subset of items (equal,
orphans in A/B).. when i did a valgrind --tool=callgrind run on it
yesterday i finally saw where all this time is spent - within the
QTreeWidget::isItemHidden function! That is maintaining a list of
hidden items and traverses that each and every time to find out wheter
an individual item actually is hidden. Comparing two folder
hierarchies with a total of ~8000 items thus results in over 150
million iterations within that loop! The simple hack which is attached
obviously cut that down massively, but i'm not sure wether it might
break any functionality that is provided by iterating over that list..
Does it?
rgds marcel.
--
"Obstacles are those frightful things you see when you take
your eyes off your goal." -- Henry Ford (1863-1947)
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--- ./src/gui/itemviews/qtreewidget.h.orig 2009-01-29 02:00:43.000000000
+0100
+++ ./src/gui/itemviews/qtreewidget.h 2009-02-02 01:52:36.841835741 +0100
@@ -202,6 +202,8 @@
protected:
void emitDataChanged();
+ bool hideFlag;
+
private:
void sortChildren(int column, Qt::SortOrder order, bool climb);
QVariant childrenCheckState(int column) const;
@@ -395,7 +397,7 @@
{ return (view ? view->isItemSelected(this) : false); }
inline void QTreeWidgetItem::setHidden(bool ahide)
-{ if (view) view->setItemHidden(this, ahide); }
+{ if (view) hideFlag = ahide; }
inline bool QTreeWidgetItem::isHidden() const
{ return (view ? view->isItemHidden(this) : false); }
--- ./src/gui/itemviews/qtreewidget.cpp.orig 2009-01-29 02:00:43.000000000
+0100
+++ ./src/gui/itemviews/qtreewidget.cpp 2009-02-02 01:54:43.106085102 +0100
@@ -1302,6 +1302,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
}
@@ -1321,6 +1322,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
for (int i = 0; i < strings.count(); ++i)
setText(i, strings.at(i));
}
@@ -1342,6 +1344,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
if (view && view->model()) {
QTreeModel *model = qobject_cast<QTreeModel*>(view->model());
model->rootItem->addChild(this);
@@ -1367,6 +1370,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
for (int i = 0; i < strings.count(); ++i)
setText(i, strings.at(i));
if (view && view->model()) {
@@ -1392,6 +1396,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
if (view) {
QTreeModel *model = qobject_cast<QTreeModel*>(view->model());
if (model) {
@@ -1415,6 +1420,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
if (parent)
parent->addChild(this);
}
@@ -1433,6 +1439,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
for (int i = 0; i < strings.count(); ++i)
setText(i, strings.at(i));
if (parent)
@@ -1455,6 +1462,7 @@
|Qt::ItemIsDragEnabled
|Qt::ItemIsDropEnabled)
{
+ hideFlag = false;
if (parent) {
int i = parent->children.indexOf(after) + 1;
parent->insertChild(i, this);
@@ -1838,6 +1846,7 @@
d(new QTreeWidgetItemPrivate(this)), par(0),
itemFlags(other.itemFlags)
{
+ hideFlag = false;
d->display = other.d->display;
}
@@ -3048,6 +3057,7 @@
Q_D(const QTreeWidget);
if (item == d->model()->headerItem)
return header()->isHidden();
+ return (item->hideFlag);
if (d->hiddenIndexes.isEmpty())
return false;
foreach (const QPersistentModelIndex &idx, d->hiddenIndexes)
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