ComboBox: use deferred execution

As a special case, ComboBox defers the execution of the popup until
the popup is either accessed or made visible. This gives a nice boost
in creation time benchmarks (20->25, ~25%). The old optimization of
setting the delegate model only when the popup is visible is no longer
needed.

Task-number: QTBUG-50992
Change-Id: Ifeaceb759ab676bb54c6bc09dc97810eade72ca1
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

1 files changed, 49 insertions, 0 deletions

diff --git a/tests/auto/customization/tst_customization.cpp b/tests/auto/customization/tst_customization.cpp
index 20914b61..51ae3650 100644
--- a/tests/auto/customization/tst_customization.cpp
+++ b/tests/auto/customization/tst_customization.cpp
@@ -39,6 +39,8 @@
 #include <QtCore/qregularexpression.h>
 #include <QtQml/qqmlengine.h>
 #include <QtQml/qqmlcomponent.h>
+#include <QtQuick/qquickitem.h>
+#include <QtQuick/qquickwindow.h>
 #include <QtQuickControls2/qquickstyle.h>
 #include "../shared/visualtestutil.h"
 
@@ -55,6 +57,8 @@ private slots:
     void creation_data();
     void creation();
 
+    void comboPopup();
+
 private:
     void reset();
     void addHooks();
@@ -131,6 +135,7 @@ void tst_customization::creation_data()
     QTest::newRow("empty:ApplicationWindow") << "empty" << "ApplicationWindow"<< (QStringList() << "applicationwindow-empty");
     QTest::newRow("empty:Button") << "empty" << "Button"<< (QStringList() << "button-empty");
     QTest::newRow("empty:CheckBox") << "empty" << "CheckBox" << (QStringList() << "checkbox-empty");
+    QTest::newRow("empty:ComboBox") << "empty" << "ComboBox" << (QStringList() << "combobox-empty");
     QTest::newRow("empty:Dial") << "empty" << "Dial" << (QStringList() << "dial-empty");
     QTest::newRow("empty:Label") << "empty" << "Label"<< (QStringList() << "label-empty");
     QTest::newRow("empty:RadioButton") << "empty" << "RadioButton" << (QStringList() << "radiobutton-empty");
@@ -142,6 +147,7 @@ void tst_customization::creation_data()
     // the "incomplete" style is missing most delegates
     QTest::newRow("incomplete:Button") << "incomplete" << "Button" << (QStringList() << "button-incomplete" << "button-background-incomplete");
     QTest::newRow("incomplete:CheckBox") << "incomplete" << "CheckBox" << (QStringList() << "checkbox-incomplete" << "checkbox-contentItem-incomplete");
+    QTest::newRow("incomplete:ComboBox") << "incomplete" << "ComboBox" << (QStringList() << "combobox-incomplete" << "combobox-contentItem-incomplete");
     QTest::newRow("incomplete:Dial") << "incomplete" << "Dial" << (QStringList() << "dial-incomplete" << "dial-handle-incomplete");
     QTest::newRow("incomplete:RadioButton") << "incomplete" << "RadioButton" << (QStringList() << "radiobutton-incomplete" << "radiobutton-indicator-incomplete");
     QTest::newRow("incomplete:RangeSlider") << "incomplete" << "RangeSlider" << (QStringList() << "rangeslider-incomplete" << "rangeslider-first-handle-incomplete" << "rangeslider-second-handle-incomplete");
@@ -151,6 +157,7 @@ void tst_customization::creation_data()
     QTest::newRow("simple:ApplicationWindow") << "simple" << "ApplicationWindow" << (QStringList() << "applicationwindow-simple" << "applicationwindow-background-simple");
     QTest::newRow("simple:Button") << "simple" << "Button" << (QStringList() << "button-simple" << "button-background-simple" << "button-contentItem-simple");
     QTest::newRow("simple:CheckBox") << "simple" << "CheckBox" << (QStringList() << "checkbox-simple" << "checkbox-contentItem-simple" << "checkbox-indicator-simple");
+    QTest::newRow("simple:ComboBox") << "simple" << "ComboBox" << (QStringList() << "combobox-simple" << "combobox-background-simple" << "combobox-contentItem-simple" << "combobox-indicator-simple");
     QTest::newRow("simple:Dial") << "simple" << "Dial" << (QStringList() << "dial-simple" << "dial-background-simple" << "dial-handle-simple");
     QTest::newRow("simple:Label") << "simple" << "Label" << (QStringList() << "label-simple" << "label-background-simple");
     QTest::newRow("simple:RadioButton") << "simple" << "RadioButton" << (QStringList() << "radiobutton-simple" << "radiobutton-contentItem-simple" << "radiobutton-indicator-simple");
@@ -163,6 +170,7 @@ void tst_customization::creation_data()
     QTest::newRow("override:ApplicationWindow") << "override" << "ApplicationWindow" << (QStringList() << "applicationwindow-override" << "applicationwindow-background-override" << "applicationwindow-simple"); // overrides "simple"
     QTest::newRow("override:Button") << "override" << "Button" << (QStringList() << "button-override" << "button-background-override" << "button-contentItem-override" << "button-empty"); // overrides "empty"
     QTest::newRow("override:CheckBox") << "override" << "CheckBox" << (QStringList() << "checkbox-override" << "checkbox-background-override" << "checkbox-contentItem-incomplete" << "checkbox-incomplete"); // overrides "incomplete"
+    QTest::newRow("override:ComboBox") << "override" << "ComboBox" << (QStringList() << "combobox-override" << "combobox-background-override" << "combobox-contentItem-simple"  << "combobox-indicator-simple" << "combobox-simple"); // overrides "simple"
     QTest::newRow("override:Dial") << "override" << "Dial" << (QStringList() << "dial-override"  << "dial-background-override" << "dial-handle-override" << "dial-incomplete"); // overrides "incomplete"
     QTest::newRow("override:Label") << "override" << "Label" << (QStringList() << "label-override" << "label-background-override" << "label-simple"); // overrides "simple"
     QTest::newRow("override:RadioButton") << "override" << "RadioButton" << (QStringList() << "radiobutton-override"  << "radiobutton-background-override" << "radiobutton-contentItem-simple" << "radiobutton-indicator-override" << "radiobutton-simple"); // overrides "simple"
@@ -190,6 +198,47 @@ void tst_customization::creation()
     QVERIFY2(qt_destroyedQObjects()->isEmpty(), qPrintable("unexpectedly destroyed: " + qt_destroyedQObjects->join(", ") + " were unexpectedly destroyed"));
 }
 
+void tst_customization::comboPopup()
+{
+    QQuickStyle::setStyle(testFile("styles/simple"));
+
+    {
+        // test that ComboBox::popup is created when accessed
+        QQmlComponent component(engine);
+        component.setData("import QtQuick.Controls 2.2; ComboBox { }", QUrl());
+        QScopedPointer<QQuickItem> comboBox(qobject_cast<QQuickItem *>(component.create()));
+        QVERIFY(comboBox);
+
+        QVERIFY(!qt_createdQObjects()->contains("combobox-popup-simple"));
+
+        QObject *popup = comboBox->property("popup").value<QObject *>();
+        QVERIFY(popup);
+        QVERIFY(qt_createdQObjects()->contains("combobox-popup-simple"));
+    }
+
+    reset();
+
+    {
+        // test that ComboBox::popup is created when it becomes visible
+        QQuickWindow window;
+        window.resize(300, 300);
+        window.show();
+        window.requestActivate();
+        QVERIFY(QTest::qWaitForWindowActive(&window));
+
+        QQmlComponent component(engine);
+        component.setData("import QtQuick.Controls 2.2; ComboBox { }", QUrl());
+        QScopedPointer<QQuickItem> comboBox(qobject_cast<QQuickItem *>(component.create()));
+        QVERIFY(comboBox);
+
+        comboBox->setParentItem(window.contentItem());
+        QVERIFY(!qt_createdQObjects()->contains("combobox-popup-simple"));
+
+        QTest::mouseClick(&window, Qt::LeftButton, Qt::NoModifier, QPoint(1, 1));
+        QVERIFY(qt_createdQObjects()->contains("combobox-popup-simple"));
+    }
+}
+
 QTEST_MAIN(tst_customization)
 
 #include "tst_customization.moc"