QQuickItemParticle: Only delete owned particles

A common pattern for ItemParticle (as shown in the particleview.qml
example) is to use it to manage movement of a model's delegates. In such
a case item management is handled by the user code (which bridges the
needs of the Model and the View) and deleting the items in ItemParticle
quickly leads to crashes.

This change maintains (and improves, due to handling resets) the
deletion of delegates created by the ItemParticles, as shown in
delegates.qml. This example was expanded with a click to reset feature
so as to more clearly see the impact of resets.

Task-number: QTBUG-37486
Change-Id: I9de935034c11a7dd2abdd60e7b3bd42867dede9c
Reviewed-by: Robin Burchell <robin.burchell@viroteck.net>

3 files changed, 165 insertions, 0 deletions

diff --git a/tests/auto/particles/qquickitemparticle/data/managed.qml b/tests/auto/particles/qquickitemparticle/data/managed.qml
new file mode 100644
index 0000000000..f8f231dc55
--- /dev/null
+++ b/tests/auto/particles/qquickitemparticle/data/managed.qml
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Particles 2.0
+
+Rectangle {
+    color: "black"
+    width: 320
+    height: 320
+
+    ParticleSystem {
+        id: sys
+        objectName: "system"
+        anchors.fill: parent
+        property int acc: 0
+
+        ItemParticle {
+            delegate: Image {
+                Component.onCompleted: sys.acc = sys.acc + 1;
+                Component.onDestruction: sys.acc = sys.acc - 1;
+                source: "../../shared/star.png"
+            }
+        }
+
+        Emitter{
+            //0,0 position
+            size: 32
+            emitRate: 1000
+            lifeSpan: 100
+        }
+    }
+}
diff --git a/tests/auto/particles/qquickitemparticle/data/unmanaged.qml b/tests/auto/particles/qquickitemparticle/data/unmanaged.qml
new file mode 100644
index 0000000000..c9b66b9d4f
--- /dev/null
+++ b/tests/auto/particles/qquickitemparticle/data/unmanaged.qml
@@ -0,0 +1,77 @@
+/****************************************************************************
+**
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL21$
+** 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 or version 3 as published by the Free
+** Software Foundation and appearing in the file LICENSE.LGPLv21 and
+** LICENSE.LGPLv3 included in the packaging of this file. Please review the
+** following information to ensure the GNU Lesser General Public License
+** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
+** 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.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.0
+import QtQuick.Particles 2.0
+
+Rectangle {
+    color: "black"
+    width: 320
+    height: 320
+
+    Repeater {
+        model: 100
+        delegate: Image {
+            id: img
+            Component.onCompleted: {
+                sys.acc = sys.acc + 1;
+                ip.take(img);
+            }
+            Component.onDestruction: sys.acc = sys.acc - 1;
+
+            //Test uses the recycling case because it's most realistic
+            //Attempts by ItemParticle to delete the delegate should lead to a segfault
+            ItemParticle.onDetached: ip.take(img);
+
+            source: "../../shared/star.png"
+        }
+    }
+
+    ParticleSystem {
+        id: sys
+        objectName: "system"
+        anchors.fill: parent
+        property int acc: 0
+
+        ItemParticle {
+            id: ip
+        }
+
+        Emitter{
+            //0,0 position
+            size: 32
+            emitRate: 1000
+            lifeSpan: 100
+        }
+    }
+}
diff --git a/tests/auto/particles/qquickitemparticle/tst_qquickitemparticle.cpp b/tests/auto/particles/qquickitemparticle/tst_qquickitemparticle.cpp
index c019f2e3bb..c825591972 100644
--- a/tests/auto/particles/qquickitemparticle/tst_qquickitemparticle.cpp
+++ b/tests/auto/particles/qquickitemparticle/tst_qquickitemparticle.cpp
@@ -48,6 +48,8 @@ public:
 private slots:
     void initTestCase();
     void test_basic();
+    void test_deletion();
+    void test_noDeletion();
 };
 
 void tst_qquickitemparticle::initTestCase()
@@ -87,6 +89,29 @@ void tst_qquickitemparticle::test_basic()
     delete view;
 }
 
+void tst_qquickitemparticle::test_deletion()
+{
+    QQuickView* view = createView(testFileUrl("managed.qml"), 500);
+    QQuickParticleSystem* system = view->rootObject()->findChild<QQuickParticleSystem*>("system");
+    ensureAnimTime(500, system->m_animation);
+
+    QVERIFY(extremelyFuzzyCompare(system->groupData[0]->size(), 100, 10));
+    //qDebug() << system->property("acc").toInt(); Seems to be around +15 due to the one frame delay in cleanup compared to creation
+    QVERIFY(extremelyFuzzyCompare(system->property("acc").toInt(), 100, 20));
+    delete view;
+}
+
+void tst_qquickitemparticle::test_noDeletion()
+{
+    QQuickView* view = createView(testFileUrl("unmanaged.qml"), 500);
+    QQuickParticleSystem* system = view->rootObject()->findChild<QQuickParticleSystem*>("system");
+    ensureAnimTime(500, system->m_animation);
+
+    QVERIFY(extremelyFuzzyCompare(system->groupData[0]->size(), 100, 10));
+    QVERIFY(extremelyFuzzyCompare(system->property("acc").toInt(), 100, 10));
+    delete view;
+}
+
 QTEST_MAIN(tst_qquickitemparticle);
 
 #include "tst_qquickitemparticle.moc"