Slider: use deferred execution

Note: It is important to repeat the names of the deferred properties
in base classes. The QML engine ask for the class info from the meta-
object. A class info declaration in a sub-class overshadows the class
info declaration by the same name in the base class.

Task-number: QTBUG-50992
Change-Id: Ib674b943db2f0bf196c9386ea22b511715c0a98f
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

7 files changed, 285 insertions, 4 deletions

diff --git a/src/quicktemplates2/qquickslider.cpp b/src/quicktemplates2/qquickslider.cpp
index da2f402f..d4cbf61c 100644
--- a/src/quicktemplates2/qquickslider.cpp
+++ b/src/quicktemplates2/qquickslider.cpp
@@ -36,6 +36,7 @@
 
 #include "qquickslider_p.h"
 #include "qquickcontrol_p_p.h"
+#include "qquickdeferredexecute_p_p.h"
 
 #include <QtQuick/private/qquickwindow_p.h>
 
@@ -112,6 +113,8 @@ public:
     void handleRelease(const QPointF &point) override;
     void handleUngrab() override;
 
+    void executeHandle(bool complete = false);
+
     qreal from;
     qreal to;
     qreal value;
@@ -122,7 +125,7 @@ public:
     QPointF pressPoint;
     Qt::Orientation orientation;
     QQuickSlider::SnapMode snapMode;
-    QQuickItem *handle;
+    QQuickDeferredPointer<QQuickItem> handle;
 };
 
 qreal QQuickSliderPrivate::snapPosition(qreal position) const
@@ -235,6 +238,20 @@ void QQuickSliderPrivate::handleUngrab()
     q->setPressed(false);
 }
 
+static inline QString handleName() { return QStringLiteral("handle"); }
+
+void QQuickSliderPrivate::executeHandle(bool complete)
+{
+    Q_Q(QQuickSlider);
+    if (handle.wasExecuted())
+        return;
+
+    if (!handle)
+        quickBeginDeferred(q, handleName(), handle);
+    if (complete)
+        quickCompleteDeferred(q, handleName(), handle);
+}
+
 QQuickSlider::QQuickSlider(QQuickItem *parent)
     : QQuickControl(*(new QQuickSliderPrivate), parent)
 {
@@ -485,7 +502,9 @@ void QQuickSlider::setOrientation(Qt::Orientation orientation)
 */
 QQuickItem *QQuickSlider::handle() const
 {
-    Q_D(const QQuickSlider);
+    QQuickSliderPrivate *d = const_cast<QQuickSliderPrivate *>(d_func());
+    if (!d->handle)
+        d->executeHandle();
     return d->handle;
 }
 
@@ -495,11 +514,12 @@ void QQuickSlider::setHandle(QQuickItem *handle)
     if (d->handle == handle)
         return;
 
-    QQuickControlPrivate::destroyDelegate(d->handle, this);
+    delete d->handle;
     d->handle = handle;
     if (handle && !handle->parentItem())
         handle->setParentItem(this);
-    emit handleChanged();
+    if (!d->handle.isExecuting())
+        emit handleChanged();
 }
 
 /*!
@@ -704,6 +724,8 @@ void QQuickSlider::mirrorChange()
 void QQuickSlider::componentComplete()
 {
     Q_D(QQuickSlider);
+    d->executeHandle(true);
+    d->executeBackground(true);
     QQuickControl::componentComplete();
     setValue(d->value);
     d->updatePosition();
diff --git a/src/quicktemplates2/qquickslider_p.h b/src/quicktemplates2/qquickslider_p.h
index f33c330a..377e853a 100644
--- a/src/quicktemplates2/qquickslider_p.h
+++ b/src/quicktemplates2/qquickslider_p.h
@@ -68,6 +68,7 @@ class Q_QUICKTEMPLATES2_PRIVATE_EXPORT QQuickSlider : public QQuickControl
     Q_PROPERTY(Qt::Orientation orientation READ orientation WRITE setOrientation NOTIFY orientationChanged FINAL)
     Q_PROPERTY(QQuickItem *handle READ handle WRITE setHandle NOTIFY handleChanged FINAL)
     Q_PROPERTY(bool live READ live WRITE setLive NOTIFY liveChanged FINAL REVISION 2)
+    Q_CLASSINFO("DeferredPropertyNames", "background,handle")
 
 public:
     explicit QQuickSlider(QQuickItem *parent = nullptr);
diff --git a/tests/auto/customization/data/styles/empty/Slider.qml b/tests/auto/customization/data/styles/empty/Slider.qml
new file mode 100644
index 00000000..ec2bacf8
--- /dev/null
+++ b/tests/auto/customization/data/styles/empty/Slider.qml
@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.9
+import QtQuick.Templates 2.2 as T
+
+T.Slider {
+    id: control
+    objectName: "slider-empty"
+}
diff --git a/tests/auto/customization/data/styles/incomplete/Slider.qml b/tests/auto/customization/data/styles/incomplete/Slider.qml
new file mode 100644
index 00000000..e26a2d53
--- /dev/null
+++ b/tests/auto/customization/data/styles/incomplete/Slider.qml
@@ -0,0 +1,61 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.9
+import QtQuick.Templates 2.2 as T
+
+T.Slider {
+    id: control
+    objectName: "slider-incomplete"
+
+    handle: Item {
+        objectName: "slider-handle-incomplete"
+    }
+}
diff --git a/tests/auto/customization/data/styles/override/Slider.qml b/tests/auto/customization/data/styles/override/Slider.qml
new file mode 100644
index 00000000..c416d2c6
--- /dev/null
+++ b/tests/auto/customization/data/styles/override/Slider.qml
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.9
+import "../incomplete" as Incomplete
+
+Incomplete.Slider {
+    id: control
+    objectName: "slider-override"
+
+    handle: Rectangle {
+        objectName: "slider-handle-override"
+    }
+
+    background: Rectangle {
+        objectName: "slider-background-override"
+    }
+}
diff --git a/tests/auto/customization/data/styles/simple/Slider.qml b/tests/auto/customization/data/styles/simple/Slider.qml
new file mode 100644
index 00000000..ba81a518
--- /dev/null
+++ b/tests/auto/customization/data/styles/simple/Slider.qml
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** 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 The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.9
+import QtQuick.Templates 2.2 as T
+
+T.Slider {
+    id: control
+    objectName: "slider-simple"
+
+    implicitWidth: Math.max(handle.implicitWidth, background.implicitWidth)
+    implicitHeight: Math.max(handle.implicitHeight, background.implicitHeight)
+
+    handle: Rectangle {
+        objectName: "slider-handle-simple"
+        color: control.pressed ? "red" : "green"
+    }
+
+    background: Rectangle {
+        objectName: "slider-background-simple"
+        implicitWidth: 200
+        implicitHeight: 20
+    }
+}
diff --git a/tests/auto/customization/tst_customization.cpp b/tests/auto/customization/tst_customization.cpp
index 3da13628..2fd42987 100644
--- a/tests/auto/customization/tst_customization.cpp
+++ b/tests/auto/customization/tst_customization.cpp
@@ -128,21 +128,25 @@ void tst_customization::creation_data()
     QTest::newRow("empty:Button") << "empty" << "Button"<< (QStringList() << "button-empty");
     QTest::newRow("empty:CheckBox") << "empty" << "CheckBox" << (QStringList() << "checkbox-empty");
     QTest::newRow("empty:RadioButton") << "empty" << "RadioButton" << (QStringList() << "radiobutton-empty");
+    QTest::newRow("empty:Slider") << "empty" << "Slider" << (QStringList() << "slider-empty");
 
     // 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:RadioButton") << "incomplete" << "RadioButton" << (QStringList() << "radiobutton-incomplete" << "radiobutton-indicator-incomplete");
+    QTest::newRow("incomplete:Slider") << "incomplete" << "Slider" << (QStringList() << "slider-incomplete" << "slider-handle-incomplete");
 
     // the "simple" style simulates a proper style and contains most delegates
     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:RadioButton") << "simple" << "RadioButton" << (QStringList() << "radiobutton-simple" << "radiobutton-contentItem-simple" << "radiobutton-indicator-simple");
+    QTest::newRow("simple:Slider") << "simple" << "Slider" << (QStringList() << "slider-simple" << "slider-background-simple" << "slider-handle-simple");
 
     // the "override" style overrides various delegates in the above styles
     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:RadioButton") << "override" << "RadioButton" << (QStringList() << "radiobutton-override"  << "radiobutton-background-override" << "radiobutton-contentItem-simple" << "radiobutton-indicator-override" << "radiobutton-simple"); // overrides "simple"
+    QTest::newRow("override:Slider") << "override" << "Slider" << (QStringList() << "slider-override"  << "slider-background-override" << "slider-handle-override" << "slider-incomplete"); // overrides "incomplete"
 }
 
 void tst_customization::creation()