[frameworks/kcompletion] src: KCompletionBox::eventFilter: minimize code executed when filter not hit

Git commit d3aef92ce413cf3a1530653c02ae620013adcf8d by Friedrich W. H. Kossebau.
Committed on 18/07/2026 at 21:52.
Pushed by kossebau into branch 'master'.

KCompletionBox::eventFilter: minimize code executed when filter not hit

As the filter listens to the QApplication events, it will invoked for any
events for all objects. Thus the code better is a bit more optimized for
doing minimal checks:
* check widget pointer only once
* then look at type first, being cached in local var
* use else branches around type, no need to check other types if one hit

Also do not skip base class event filtering on self, perhaps those classes
might need it one day.

M  +147  -144  src/kcompletionbox.cpp

https://invent.kde.org/frameworks/kcompletion/-/commit/d3aef92ce413cf3a1530653c02ae620013adcf8d

diff --git a/src/kcompletionbox.cpp b/src/kcompletionbox.cpp
index 3a14896..a31082d 100644
--- a/src/kcompletionbox.cpp
+++ b/src/kcompletionbox.cpp
@@ -90,159 +90,162 @@ void KCompletionBox::slotActivated(QListWidgetItem *item)
 
 bool KCompletionBox::eventFilter(QObject *o, QEvent *e)
 {
-    int type = e->type();
-    QWidget *wid = qobject_cast<QWidget *>(o);
-
-    if (o == this) {
-        return false;
-    }
-
-    if (wid && wid == d->m_parent //
-        && (type == QEvent::Move || type == QEvent::Resize)) {
-        resizeAndReposition();
-        return false;
-    }
-
-    if (wid && (wid->windowFlags() & Qt::Window) //
-        && type == QEvent::Move && wid == d->m_parent->window()) {
-        hide();
-        return false;
-    }
-
-    if (type == QEvent::MouseButtonPress && (wid && !isAncestorOf(wid))) {
-        if (!d->emitSelected && currentItem() && !qobject_cast<QScrollBar *>(o)) {
-            Q_ASSERT(currentItem());
-            Q_EMIT currentTextChanged(currentItem()->text());
-        }
-        hide();
-        e->accept();
-        return true;
-    }
-
-    if (wid && wid->isAncestorOf(d->m_parent) && isVisible()) {
-        if (type == QEvent::KeyPress) {
-            QKeyEvent *ev = static_cast<QKeyEvent *>(e);
-            switch (ev->key()) {
-            case Qt::Key_Backtab:
-                if (d->tabHandling && (ev->modifiers() == Qt::NoButton || (ev->modifiers() & Qt::ShiftModifier))) {
-                    up();
-                    ev->accept();
-                    return true;
-                }
-                break;
-            case Qt::Key_Tab:
-                if (d->tabHandling && (ev->modifiers() == Qt::NoButton)) {
-                    down();
-                    // #65877: Key_Tab should complete using the first
-                    // (or selected) item, and then offer completions again
-                    if (count() == 1) {
-                        KLineEdit *parent = qobject_cast<KLineEdit *>(d->m_parent);
-                        if (parent) {
-                            parent->doCompletion(currentItem()->text());
-                        } else {
-                            hide();
-                        }
-                    }
-                    ev->accept();
-                    return true;
-                }
-                break;
-            case Qt::Key_Down:
-                down();
-                ev->accept();
-                return true;
-            case Qt::Key_Up:
-                // If there is no selected item and we've popped up above
-                // our parent, select the first item when they press up.
-                if (!selectedItems().isEmpty() //
-                    || mapToGlobal(QPoint(0, 0)).y() > d->m_parent->mapToGlobal(QPoint(0, 0)).y()) {
-                    up();
-                } else {
-                    down();
+    if (o != this) {
+        if (const auto *const wid = qobject_cast<QWidget *>(o)) {
+            const int type = e->type();
+
+            if (type == QEvent::Resize) {
+                if (wid == d->m_parent) {
+                    resizeAndReposition();
+                    return false;
                 }
-                ev->accept();
-                return true;
-            case Qt::Key_PageUp:
-                pageUp();
-                ev->accept();
-                return true;
-            case Qt::Key_PageDown:
-                pageDown();
-                ev->accept();
-                return true;
-            case Qt::Key_Escape:
-                if (!d->cancelText.isNull()) {
-                    Q_EMIT userCancelled(d->cancelText);
+            } else if (type == QEvent::Move) {
+                if (wid == d->m_parent) {
+                    resizeAndReposition();
+                    return false;
                 }
-                if (isVisible()) {
+
+                if ((wid->windowFlags() & Qt::Window) //
+                    && wid == d->m_parent->window()) {
                     hide();
+                    return false;
                 }
-                ev->accept();
-                return true;
-            case Qt::Key_Enter:
-            case Qt::Key_Return:
-                if (ev->modifiers() & Qt::ShiftModifier) {
+            } else if (type == QEvent::MouseButtonPress) {
+                if ((!isAncestorOf(wid))) {
+                    if (!d->emitSelected && currentItem() && !qobject_cast<QScrollBar *>(o)) {
+                        Q_ASSERT(currentItem());
+                        Q_EMIT currentTextChanged(currentItem()->text());
+                    }
                     hide();
-                    ev->accept(); // Consume the Enter event
-                    return true;
-                }
-                break;
-            case Qt::Key_End:
-                if (ev->modifiers() & Qt::ControlModifier) {
-                    end();
-                    ev->accept();
+                    e->accept();
                     return true;
                 }
-                break;
-            case Qt::Key_Home:
-                if (ev->modifiers() & Qt::ControlModifier) {
-                    home();
-                    ev->accept();
-                    return true;
-                }
-                Q_FALLTHROUGH();
-            default:
-                break;
-            }
-        } else if (type == QEvent::ShortcutOverride) {
-            // Override any accelerators that match
-            // the key sequences we use here...
-            QKeyEvent *ev = static_cast<QKeyEvent *>(e);
-            switch (ev->key()) {
-            case Qt::Key_Down:
-            case Qt::Key_Up:
-            case Qt::Key_PageUp:
-            case Qt::Key_PageDown:
-            case Qt::Key_Escape:
-            case Qt::Key_Enter:
-            case Qt::Key_Return:
-                ev->accept();
-                return true;
-            case Qt::Key_Tab:
-            case Qt::Key_Backtab:
-                if (ev->modifiers() == Qt::NoButton || (ev->modifiers() & Qt::ShiftModifier)) {
-                    ev->accept();
-                    return true;
-                }
-                break;
-            case Qt::Key_Home:
-            case Qt::Key_End:
-                if (ev->modifiers() & Qt::ControlModifier) {
-                    ev->accept();
-                    return true;
-                }
-                break;
-            default:
-                break;
-            }
-        } else if (type == QEvent::FocusOut) {
-            QFocusEvent *event = static_cast<QFocusEvent *>(e);
-            if (event->reason() != Qt::PopupFocusReason
+            } else if (wid->isAncestorOf(d->m_parent) && isVisible()) {
+                if (type == QEvent::KeyPress) {
+                    QKeyEvent *ev = static_cast<QKeyEvent *>(e);
+                    switch (ev->key()) {
+                    case Qt::Key_Backtab:
+                        if (d->tabHandling && (ev->modifiers() == Qt::NoButton || (ev->modifiers() & Qt::ShiftModifier))) {
+                            up();
+                            ev->accept();
+                            return true;
+                        }
+                        break;
+                    case Qt::Key_Tab:
+                        if (d->tabHandling && (ev->modifiers() == Qt::NoButton)) {
+                            down();
+                            // #65877: Key_Tab should complete using the first
+                            // (or selected) item, and then offer completions again
+                            if (count() == 1) {
+                                KLineEdit *parent = qobject_cast<KLineEdit *>(d->m_parent);
+                                if (parent) {
+                                    parent->doCompletion(currentItem()->text());
+                                } else {
+                                    hide();
+                                }
+                            }
+                            ev->accept();
+                            return true;
+                        }
+                        break;
+                    case Qt::Key_Down:
+                        down();
+                        ev->accept();
+                        return true;
+                    case Qt::Key_Up:
+                        // If there is no selected item and we've popped up above
+                        // our parent, select the first item when they press up.
+                        if (!selectedItems().isEmpty() //
+                            || mapToGlobal(QPoint(0, 0)).y() > d->m_parent->mapToGlobal(QPoint(0, 0)).y()) {
+                            up();
+                        } else {
+                            down();
+                        }
+                        ev->accept();
+                        return true;
+                    case Qt::Key_PageUp:
+                        pageUp();
+                        ev->accept();
+                        return true;
+                    case Qt::Key_PageDown:
+                        pageDown();
+                        ev->accept();
+                        return true;
+                    case Qt::Key_Escape:
+                        if (!d->cancelText.isNull()) {
+                            Q_EMIT userCancelled(d->cancelText);
+                        }
+                        if (isVisible()) {
+                            hide();
+                        }
+                        ev->accept();
+                        return true;
+                    case Qt::Key_Enter:
+                    case Qt::Key_Return:
+                        if (ev->modifiers() & Qt::ShiftModifier) {
+                            hide();
+                            ev->accept(); // Consume the Enter event
+                            return true;
+                        }
+                        break;
+                    case Qt::Key_End:
+                        if (ev->modifiers() & Qt::ControlModifier) {
+                            end();
+                            ev->accept();
+                            return true;
+                        }
+                        break;
+                    case Qt::Key_Home:
+                        if (ev->modifiers() & Qt::ControlModifier) {
+                            home();
+                            ev->accept();
+                            return true;
+                        }
+                        Q_FALLTHROUGH();
+                    default:
+                        break;
+                    }
+                } else if (type == QEvent::ShortcutOverride) {
+                    // Override any accelerators that match
+                    // the key sequences we use here...
+                    QKeyEvent *ev = static_cast<QKeyEvent *>(e);
+                    switch (ev->key()) {
+                    case Qt::Key_Down:
+                    case Qt::Key_Up:
+                    case Qt::Key_PageUp:
+                    case Qt::Key_PageDown:
+                    case Qt::Key_Escape:
+                    case Qt::Key_Enter:
+                    case Qt::Key_Return:
+                        ev->accept();
+                        return true;
+                    case Qt::Key_Tab:
+                    case Qt::Key_Backtab:
+                        if (ev->modifiers() == Qt::NoButton || (ev->modifiers() & Qt::ShiftModifier)) {
+                            ev->accept();
+                            return true;
+                        }
+                        break;
+                    case Qt::Key_Home:
+                    case Qt::Key_End:
+                        if (ev->modifiers() & Qt::ControlModifier) {
+                            ev->accept();
+                            return true;
+                        }
+                        break;
+                    default:
+                        break;
+                    }
+                } else if (type == QEvent::FocusOut) {
+                    QFocusEvent *event = static_cast<QFocusEvent *>(e);
+                    if (event->reason() != Qt::PopupFocusReason
 #ifdef Q_OS_WIN
-                && (event->reason() != Qt::ActiveWindowFocusReason || QApplication::activeWindow() != this)
+                        && (event->reason() != Qt::ActiveWindowFocusReason || QApplication::activeWindow() != this)
 #endif
-            ) {
-                hide();
+                    ) {
+                        hide();
+                    }
+                }
             }
         }
     }