Make use of incubator to asynchronously instantiate delegates

This has the side effect that map items instantiated by the view are no
longer be added to the map in a deterministic order.

Change-Id: I5933136e8d9dbf0e698353370b9bfc0affe146ac
Reviewed-by: Alex Blasche <alexander.blasche@theqtcompany.com>

5 files changed, 188 insertions, 33 deletions

diff --git a/src/imports/location/location.pro b/src/imports/location/location.pro
index 254802e4..7441fab3 100644
--- a/src/imports/location/location.pro
+++ b/src/imports/location/location.pro
@@ -28,7 +28,8 @@ HEADERS += \
            error_messages.h \
            locationvaluetypehelper_p.h\
            qquickgeomapgesturearea_p.h\
-           ../positioning/qquickgeocoordinateanimation_p.h
+           ../positioning/qquickgeocoordinateanimation_p.h \
+           mapitemviewdelegateincubator.h
 
 SOURCES += \
            location.cpp \
@@ -53,7 +54,8 @@ SOURCES += \
            error_messages.cpp \
            locationvaluetypehelper.cpp \
            qquickgeomapgesturearea.cpp \
-           ../positioning/qquickgeocoordinateanimation.cpp
+           ../positioning/qquickgeocoordinateanimation.cpp \
+           mapitemviewdelegateincubator.cpp
 
 include(declarativeplaces/declarativeplaces.pri)
 
diff --git a/src/imports/location/mapitemviewdelegateincubator.cpp b/src/imports/location/mapitemviewdelegateincubator.cpp
new file mode 100644
index 00000000..2c4ba823
--- /dev/null
+++ b/src/imports/location/mapitemviewdelegateincubator.cpp
@@ -0,0 +1,57 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Jolla Ltd, author: Aaron McCarthy <aaron.mccarthy@jollamobile.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtLocation module 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 "mapitemviewdelegateincubator.h"
+#include "qdeclarativegeomapitemview_p.h"
+
+QT_BEGIN_NAMESPACE
+
+MapItemViewDelegateIncubator::MapItemViewDelegateIncubator(QDeclarativeGeoMapItemView *view)
+:   m_view(view)
+{
+}
+
+void MapItemViewDelegateIncubator::statusChanged(QQmlIncubator::Status status)
+{
+    m_view->incubatorStatusChanged(this, status);
+}
+
+QT_END_NAMESPACE
diff --git a/src/imports/location/mapitemviewdelegateincubator.h b/src/imports/location/mapitemviewdelegateincubator.h
new file mode 100644
index 00000000..7e0813c0
--- /dev/null
+++ b/src/imports/location/mapitemviewdelegateincubator.h
@@ -0,0 +1,65 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Jolla Ltd, author: Aaron McCarthy <aaron.mccarthy@jollamobile.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the QtLocation module 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef MAPITEMVIEWDELEGATEINCUBATOR_H
+#define MAPITEMVIEWDELEGATEINCUBATOR_H
+
+#include <QtQml/QQmlIncubator>
+
+QT_BEGIN_NAMESPACE
+
+class QDeclarativeGeoMapItemView;
+
+class MapItemViewDelegateIncubator : public QQmlIncubator
+{
+public:
+    MapItemViewDelegateIncubator(QDeclarativeGeoMapItemView *view);
+
+protected:
+    void statusChanged(Status status) Q_DECL_OVERRIDE;
+
+private:
+    QDeclarativeGeoMapItemView *m_view;
+};
+
+QT_END_NAMESPACE
+
+#endif // MAPITEMVIEWDELEGATEINCUBATOR_H
diff --git a/src/imports/location/qdeclarativegeomapitemview.cpp b/src/imports/location/qdeclarativegeomapitemview.cpp
index 624d2983..eff03b17 100644
--- a/src/imports/location/qdeclarativegeomapitemview.cpp
+++ b/src/imports/location/qdeclarativegeomapitemview.cpp
@@ -39,9 +39,11 @@
 #include "qdeclarativegeomapitemview_p.h"
 #include "qdeclarativegeomap_p.h"
 #include "qdeclarativegeomapitembase_p.h"
+#include "mapitemviewdelegateincubator.h"
 
 #include <QtCore/QAbstractItemModel>
 #include <QtQml/QQmlContext>
+#include <QtQml/QQmlIncubator>
 #include <QtQml/private/qqmlopenmetaobject_p.h>
 
 QT_BEGIN_NAMESPACE
@@ -92,6 +94,49 @@ void QDeclarativeGeoMapItemView::componentComplete()
     componentCompleted_ = true;
 }
 
+void QDeclarativeGeoMapItemView::incubatorStatusChanged(MapItemViewDelegateIncubator *incubator,
+                                                        QQmlIncubator::Status status)
+{
+    if (status == QQmlIncubator::Loading)
+        return;
+
+    for (int i = 0; i < m_itemData.length(); ++i) {
+        ItemData *itemData = m_itemData.at(i);
+        if (itemData->incubator != incubator)
+            continue;
+
+        switch (status) {
+        case QQmlIncubator::Ready:
+            itemData->item = qobject_cast<QDeclarativeGeoMapItemBase *>(incubator->object());
+            if (!itemData->item) {
+                qWarning() << "QDeclarativeGeoMapItemView map item delegate is of unsupported type.";
+                delete incubator->object();
+            } else {
+                map_->addMapItem(itemData->item);
+                if (fitViewport_)
+                    fitViewport();
+            }
+            delete itemData->incubator;
+            itemData->incubator = 0;
+            break;
+        case QQmlIncubator::Null:
+            // Should never get here
+            delete itemData->incubator;
+            itemData->incubator = 0;
+            break;
+        case QQmlIncubator::Error:
+            qWarning() << "QDeclarativeGeoMapItemView map item creation failed.";
+            delete itemData->incubator;
+            itemData->incubator = 0;
+            break;
+        default:
+            ;
+        }
+
+        break;
+    }
+}
+
 /*!
     \qmlproperty model QtLocation::MapItemView::model
 
@@ -169,12 +214,7 @@ void QDeclarativeGeoMapItemView::itemModelRowsInserted(const QModelIndex &index,
 
     for (int i = start; i <= end; ++i) {
         const QModelIndex insertedIndex = itemModel_->index(i, 0, index);
-        ItemData *itemData = createItemForIndex(insertedIndex);
-        if (!itemData)
-            break;
-
-        m_itemData.insert(i, itemData);
-        map_->addMapItem(itemData->item);
+        createItemForIndex(insertedIndex);
     }
 
     if (fitViewport_)
@@ -335,12 +375,7 @@ void QDeclarativeGeoMapItemView::instantiateAllItems()
 
     for (int i = 0; i < itemModel_->rowCount(); ++i) {
         const QModelIndex index = itemModel_->index(i, 0);
-        ItemData *itemData = createItemForIndex(index);
-        if (!itemData)
-            break;
-
-        m_itemData.append(itemData);
-        map_->addMapItem(itemData->item);
+        createItemForIndex(index);
     }
 
     if (fitViewport_)
@@ -360,7 +395,7 @@ void QDeclarativeGeoMapItemView::repopulate()
 /*!
     \internal
 */
-QDeclarativeGeoMapItemView::ItemData *QDeclarativeGeoMapItemView::createItemForIndex(const QModelIndex &index)
+void QDeclarativeGeoMapItemView::createItemForIndex(const QModelIndex &index)
 {
     // Expected to be already tested by caller.
     Q_ASSERT(delegate_);
@@ -389,27 +424,15 @@ QDeclarativeGeoMapItemView::ItemData *QDeclarativeGeoMapItemView::createItemForI
     itemData->context->setContextProperty(QLatin1String("model"), itemData->modelData);
     itemData->context->setContextProperty(QLatin1String("index"), index.row());
 
-    QObject *object = delegate_->create(itemData->context);
-
-    if (!object) {
-        qWarning() << "QDeclarativeGeoMapItemView map item creation failed.";
-        delete itemData;
-        return 0;
-    }
-
-    itemData->item = qobject_cast<QDeclarativeGeoMapItemBase *>(object);
-    if (!itemData->item) {
-        qWarning() << "QDeclarativeGeoMapItemView map item delegate is of unsupported type.";
-        delete object;
-        delete itemData;
-        return 0;
-    }
+    itemData->incubator = new MapItemViewDelegateIncubator(this);
+    delegate_->create(*itemData->incubator, itemData->context);
 
-    return itemData;
+    m_itemData.insert(index.row(), itemData);
 }
 
 QDeclarativeGeoMapItemView::ItemData::~ItemData()
 {
+    delete incubator;
     delete item;
     delete context;
     delete modelData;
diff --git a/src/imports/location/qdeclarativegeomapitemview_p.h b/src/imports/location/qdeclarativegeomapitemview_p.h
index fa91e3ad..29675295 100644
--- a/src/imports/location/qdeclarativegeomapitemview_p.h
+++ b/src/imports/location/qdeclarativegeomapitemview_p.h
@@ -41,6 +41,7 @@
 
 #include <QtCore/QModelIndex>
 #include <QtQml/QQmlParserStatus>
+#include <QtQml/QQmlIncubator>
 #include <QtQml/qqml.h>
 
 QT_BEGIN_NAMESPACE
@@ -52,6 +53,7 @@ class QDeclarativeGeoMap;
 class QDeclarativeGeoMapItemBase;
 class QQmlOpenMetaObject;
 class QQmlOpenMetaObjectType;
+class MapItemViewDelegateIncubator;
 
 class QDeclarativeGeoMapItemView : public QObject, public QQmlParserStatus
 {
@@ -93,6 +95,10 @@ Q_SIGNALS:
     void delegateChanged();
     void autoFitViewportChanged();
 
+protected:
+    void incubatorStatusChanged(MapItemViewDelegateIncubator *incubator,
+                                QQmlIncubator::Status status);
+
 private Q_SLOTS:
     void itemModelReset();
     void itemModelRowsInserted(const QModelIndex &index, int start, int end);
@@ -105,19 +111,20 @@ private Q_SLOTS:
 private:
     struct ItemData {
         ItemData()
-        :   item(0), context(0), modelData(0), modelDataMeta(0)
+        :   incubator(0), item(0), context(0), modelData(0), modelDataMeta(0)
         {
         }
 
         ~ItemData();
 
+        MapItemViewDelegateIncubator *incubator;
         QDeclarativeGeoMapItemBase *item;
         QQmlContext *context;
         QObject *modelData;
         QQmlOpenMetaObject *modelDataMeta;
     };
 
-    ItemData *createItemForIndex(const QModelIndex &index);
+    void createItemForIndex(const QModelIndex &index);
     void fitViewport();
 
     bool componentCompleted_;
@@ -130,6 +137,7 @@ private:
     QQmlOpenMetaObjectType *m_metaObjectType;
 
     friend class QTypeInfo<ItemData>;
+    friend class MapItemViewDelegateIncubator;
 };
 
 Q_DECLARE_TYPEINFO(QDeclarativeGeoMapItemView::ItemData, Q_MOVABLE_TYPE);