From b273e586b045c5114e52bc51d80dde9a7276d9ae Mon Sep 17 00:00:00 2001
From: Paolo Angelelli <paolo.angelelli@qt.io>
Date: Sun, 20 May 2018 16:44:39 +0200
Subject: Fix MapItemView deleting wrong items

Asynchronous incubation caused messing up with internal index.

Task-number: QTBUG-68366
Change-Id: I9d9edbe42b7ace488c1a7f8728214ae1061caa26
Reviewed-by: Peter Staab <peter.staab76@gmail.com>
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>
---
 .../declarativemaps/qdeclarativegeomapitemview.cpp | 45 ++++++++++++++++++----
 1 file changed, 37 insertions(+), 8 deletions(-)

(limited to 'src/location/declarativemaps/qdeclarativegeomapitemview.cpp')

diff --git a/src/location/declarativemaps/qdeclarativegeomapitemview.cpp b/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
index b49e675c..21402130 100644
--- a/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
+++ b/src/location/declarativemaps/qdeclarativegeomapitemview.cpp
@@ -140,6 +140,8 @@ void QDeclarativeGeoMapItemView::createdItem(int index, QObject */*object*/)
             qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(index, QQmlIncubator::Asynchronous));
     if (item)
         addItemToMap(item, index);
+    else
+        qWarning() << "createdItem for " << index << " produced a null item";
 }
 
 void QDeclarativeGeoMapItemView::modelUpdated(const QQmlChangeSet &changeSet, bool reset)
@@ -167,8 +169,7 @@ void QDeclarativeGeoMapItemView::modelUpdated(const QQmlChangeSet &changeSet, bo
         for (int idx = c.start(); idx < c.end(); idx++) {
             QDeclarativeGeoMapItemBase *item =
                     qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(idx, QQmlIncubator::Asynchronous));
-            if (item) // if not, a createdItem signal will be emitted.
-                addItemToMap(item, idx);
+            addItemToMap(item, idx); // if not item, a createdItem signal will be emitted.
         }
     }
 
@@ -296,8 +297,7 @@ void QDeclarativeGeoMapItemView::instantiateAllItems()
     for (int i = 0; i < m_delegateModel->count(); i++) {
         QDeclarativeGeoMapItemBase *item =
                 qobject_cast<QDeclarativeGeoMapItemBase *>(m_delegateModel->object(i, QQmlIncubator::Asynchronous));
-        if (item) // else createdItem will be emitted.
-            addItemToMap(item, i);
+        addItemToMap(item, i); // if not item, createdItem will be emitted.
     }
 
     fitViewport();
@@ -307,6 +307,14 @@ void QDeclarativeGeoMapItemView::removeItemFromMap(int index)
 {
     if (index >= 0 && index < m_instantiatedItems.size()) {
         QDeclarativeGeoMapItemBase *item = m_instantiatedItems.takeAt(index);
+        if (!item) {
+            if (m_incubatingItems.contains(index)) {
+                // cancel request
+                m_delegateModel->cancel(index);
+                m_incubatingItems.remove(index);
+            }
+            return;
+        }
         if (m_exit && m_map) {
             if (!item->m_transitionManager) {
                 QScopedPointer<QDeclarativeGeoMapItemTransitionManager>manager(new QDeclarativeGeoMapItemTransitionManager(item));
@@ -317,9 +325,12 @@ void QDeclarativeGeoMapItemView::removeItemFromMap(int index)
                     this, &QDeclarativeGeoMapItemView::exitTransitionFinished);
             item->m_transitionManager->transitionExit();
         } else {
+            disconnect(item, 0, this, 0);
             if (m_map)
                 m_map->removeMapItem(item);
-            m_delegateModel->release(item);
+            QQmlInstanceModel::ReleaseFlags releaseStatus = m_delegateModel->release(item);
+            if (releaseStatus == QQmlInstanceModel::Referenced)
+                qWarning() << "item "<< index << " still referenced";
         }
     }
 }
@@ -330,16 +341,24 @@ void QDeclarativeGeoMapItemView::exitTransitionFinished()
     disconnect(item, 0, this, 0);
     if (m_map)
         m_map->removeMapItem(item);
-    m_delegateModel->release(item);
+    QQmlInstanceModel::ReleaseFlags releaseStatus = m_delegateModel->release(item);
+    if (releaseStatus == QQmlInstanceModel::Referenced)
+        qWarning() << "item "<<item<<" still referenced";
 }
 
 void QDeclarativeGeoMapItemView::addItemToMap(QDeclarativeGeoMapItemBase *item, int index)
 {
-    if (!item || (m_map && item->quickMap() == m_map))
+    if (m_map && item && item->quickMap() == m_map) // belonging to another map??
         return;
 
     if (m_map) {
-        m_instantiatedItems.insert(index, item);
+        if (!item) {
+            m_incubatingItems.insert(index);
+            m_instantiatedItems.insert(index, nullptr);
+            return;
+        }
+
+        insertInstantiatedItem(index, item);
         m_map->addMapItem(item);
         if (m_enter) {
             if (!item->m_transitionManager) {
@@ -352,6 +371,16 @@ void QDeclarativeGeoMapItemView::addItemToMap(QDeclarativeGeoMapItemBase *item,
     }
 }
 
+void QDeclarativeGeoMapItemView::insertInstantiatedItem(int index, QDeclarativeGeoMapItemBase *o)
+{
+    if (m_incubatingItems.contains(index)) {
+        m_incubatingItems.remove(index);
+        m_instantiatedItems.replace(index, o);
+    } else {
+        m_instantiatedItems.insert(index, o);
+    }
+}
+
 QT_END_NAMESPACE
 
 
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