Fix performance bottleneck in QQuickWindow::mouseMoveEvent().

When a mouse move event is received, a lot of time is spent looking
for items with cursors, recursively.

With this patch, it will only recur into item hierarchies that
contain cursors.

Not having cursors is much more common than having them.

Benchmark included:
Before: 15 msecs per iteration (total: 62, iterations: 4)
After: 0.000064 msecs per iteration (total: 68, iterations: 1048576)

Task-number: QTBUG-27054
Change-Id: I3a5441652ca1c0b8d2cbc5683013562174f5af4a
Reviewed-by: Alan Alpert <416365416c@gmail.com>

3 files changed, 104 insertions, 1 deletions

diff --git a/tests/benchmarks/qml/qml.pro b/tests/benchmarks/qml/qml.pro
index 7a75c69dd1..3fbf130969 100644
--- a/tests/benchmarks/qml/qml.pro
+++ b/tests/benchmarks/qml/qml.pro
@@ -11,7 +11,8 @@ SUBDIRS += \
            qqmlmetaproperty \
            script \
            qmltime \
-           js
+           js \
+           qquickwindow
 
 contains(QT_CONFIG, opengl): SUBDIRS += painting
 
diff --git a/tests/benchmarks/qml/qquickwindow/qquickwindow.pro b/tests/benchmarks/qml/qquickwindow/qquickwindow.pro
new file mode 100644
index 0000000000..76aecf9d13
--- /dev/null
+++ b/tests/benchmarks/qml/qquickwindow/qquickwindow.pro
@@ -0,0 +1,11 @@
+CONFIG += testcase
+TARGET = tst_qquickwindow
+SOURCES += tst_qquickwindow.cpp
+macx:CONFIG -= app_bundle
+
+testDataFiles.files = data
+testDataFiles.path = .
+DEPLOYMENT += testDataFiles
+
+QT += core-private gui-private v8-private qml-private quick-private opengl-private testlib
+DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0
\ No newline at end of file
diff --git a/tests/benchmarks/qml/qquickwindow/tst_qquickwindow.cpp b/tests/benchmarks/qml/qquickwindow/tst_qquickwindow.cpp
new file mode 100644
index 0000000000..01ddd70838
--- /dev/null
+++ b/tests/benchmarks/qml/qquickwindow/tst_qquickwindow.cpp
@@ -0,0 +1,91 @@
+/***************************************************************************
+**
+** Copyright (C) 2011 - 2012 Research In Motion
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtQuick/QQuickWindow>
+#include <QtQuick/private/qquickrectangle_p.h>
+#include <QtQuick/private/qquickwindow_p.h>
+
+#include <qtest.h>
+#include <QtTest/QtTest>
+
+class tst_qquickwindow : public QObject
+{
+    Q_OBJECT
+public:
+    tst_qquickwindow();
+
+private slots:
+    void tst_updateCursor();
+    void cleanupTestCase();
+private:
+    QQuickWindow* window;
+};
+
+tst_qquickwindow::tst_qquickwindow()
+{
+    window = new QQuickWindow;
+    window->resize(250, 250);
+    window->setPos(100, 100);
+    for ( int i=0; i<8000; i++ ) {
+        QQuickRectangle *r =new QQuickRectangle(window->rootItem());
+        for ( int j=0; j<10; ++j ) {
+            new QQuickRectangle(r);
+        }
+    }
+    window->show();
+    QVERIFY(QTest::qWaitForWindowExposed(window));
+}
+
+void tst_qquickwindow::cleanupTestCase()
+{
+    delete window;
+}
+
+void tst_qquickwindow::tst_updateCursor()
+{
+    QBENCHMARK {
+        QQuickWindowPrivate::get(window)->updateCursor(QPoint(100,100));
+    }
+}
+
+QTEST_MAIN(tst_qquickwindow);
+
+#include "tst_qquickwindow.moc"