Add logging categories for Tumbler and TumblerView

Both types are complex, so it helps having logging that can simply
be turned on or off to aid debugging.

Change-Id: Id90a8b48b949d17710e8e0882531a497e80aae8b
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

3 files changed, 54 insertions, 0 deletions

diff --git a/src/quickcontrols2/qquicktumblerview.cpp b/src/quickcontrols2/qquicktumblerview.cpp
index a510a1fe..5f5c065d 100644
--- a/src/quickcontrols2/qquicktumblerview.cpp
+++ b/src/quickcontrols2/qquicktumblerview.cpp
@@ -36,6 +36,7 @@
 
 #include "qquicktumblerview_p.h"
 
+#include <QtCore/qloggingcategory.h>
 #include <QtQuick/private/qquickitem_p.h>
 #include <QtQuick/private/qquicklistview_p.h>
 #include <QtQuick/private/qquickpathview_p.h>
@@ -45,6 +46,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(lcTumblerView, "qt.quick.controls.tumblerview")
+
 QQuickTumblerView::QQuickTumblerView(QQuickItem *parent) :
     QQuickItem(parent)
 {
@@ -59,6 +62,8 @@ QVariant QQuickTumblerView::model() const
 
 void QQuickTumblerView::setModel(const QVariant &model)
 {
+    qCDebug(lcTumblerView) << "setting model to:" << model << "on"
+        << (m_pathView ? static_cast<QObject*>(m_pathView) : static_cast<QObject*>(m_listView));
     if (model == m_model)
         return;
 
@@ -85,6 +90,8 @@ QQmlComponent *QQuickTumblerView::delegate() const
 
 void QQuickTumblerView::setDelegate(QQmlComponent *delegate)
 {
+    qCDebug(lcTumblerView) << "setting delegate to:" << delegate << "on"
+        << (m_pathView ? static_cast<QObject*>(m_pathView) : static_cast<QObject*>(m_listView));
     if (delegate == m_delegate)
         return;
 
@@ -135,6 +142,8 @@ void QQuickTumblerView::createView()
         }
 
         if (!m_pathView) {
+            qCDebug(lcTumblerView) << "creating PathView";
+
             m_pathView = new QQuickPathView;
             QQmlEngine::setContextForObject(m_pathView, qmlContext(this));
             QQml_setParent_noEvent(m_pathView, this);
@@ -150,6 +159,8 @@ void QQuickTumblerView::createView()
             updateView();
             // Set the model.
             updateModel();
+
+            qCDebug(lcTumblerView) << "finished creating PathView";
         }
     } else {
         if (m_pathView) {
@@ -162,6 +173,8 @@ void QQuickTumblerView::createView()
         }
 
         if (!m_listView) {
+            qCDebug(lcTumblerView) << "creating ListView";
+
             m_listView = new QQuickListView;
             QQmlEngine::setContextForObject(m_listView, qmlContext(this));
             QQml_setParent_noEvent(m_listView, this);
@@ -181,6 +194,8 @@ void QQuickTumblerView::createView()
             // which we don't want when the contentItem has just been created.
             m_listView->setDelegate(m_delegate);
             m_listView->setHighlightMoveDuration(1000);
+
+            qCDebug(lcTumblerView) << "finished creating ListView";
         }
     }
 }
diff --git a/src/quicktemplates2/qquicktumbler.cpp b/src/quicktemplates2/qquicktumbler.cpp
index 25710231..8b702c60 100644
--- a/src/quicktemplates2/qquicktumbler.cpp
+++ b/src/quicktemplates2/qquicktumbler.cpp
@@ -36,6 +36,7 @@
 
 #include "qquicktumbler_p.h"
 
+#include <QtCore/qloggingcategory.h>
 #include <QtGui/qpa/qplatformtheme.h>
 #include <QtQml/qqmlinfo.h>
 #include <QtQuick/private/qquickflickable_p.h>
@@ -44,6 +45,8 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_LOGGING_CATEGORY(lcTumbler, "qt.quick.controls.tumbler")
+
 /*!
     \qmltype Tumbler
     \inherits Control
@@ -190,11 +193,22 @@ void QQuickTumblerPrivate::_q_onViewCurrentIndexChanged()
         // If the user set currentIndex in the onModelChanged handler,
         // we have to respect that currentIndex by ignoring changes in the view
         // until the model has finished being set.
+        qCDebug(lcTumbler).nospace() << "view currentIndex changed to "
+            << (view ? view->property("currentIndex").toString() : QStringLiteral("unknown index (no view)"))
+            << ", but we're ignoring it because one or more of the following conditions are true:"
+            << "\n- !view: " << !view
+            << "\n- ignoreCurrentIndexChanges: " << ignoreCurrentIndexChanges
+            << "\n- currentIndexSetDuringModelChange: " << currentIndexSetDuringModelChange;
         return;
     }
 
     const int oldCurrentIndex = currentIndex;
     currentIndex = view->property("currentIndex").toInt();
+
+    qCDebug(lcTumbler).nospace() << "view currentIndex changed to "
+        << (view ? view->property("currentIndex").toString() : QStringLiteral("unknown index (no view)"))
+        << ", our old currentIndex was " << oldCurrentIndex;
+
     if (oldCurrentIndex != currentIndex)
         emit q->currentIndexChanged();
 }
@@ -202,6 +216,7 @@ void QQuickTumblerPrivate::_q_onViewCurrentIndexChanged()
 void QQuickTumblerPrivate::_q_onViewCountChanged()
 {
     Q_Q(QQuickTumbler);
+    qCDebug(lcTumbler) << "view count changed - ignoring signals?" << ignoreSignals;
     if (ignoreSignals)
         return;
 
@@ -513,10 +528,12 @@ void QQuickTumbler::geometryChanged(const QRectF &newGeometry, const QRectF &old
 void QQuickTumbler::componentComplete()
 {
     Q_D(QQuickTumbler);
+    qCDebug(lcTumbler) << "componentComplete()";
     QQuickControl::componentComplete();
 
     if (!d->view) {
         // Force the view to be created.
+        qCDebug(lcTumbler) << "emitting wrapChanged() to force view to be created";
         emit wrapChanged();
         // Determine the type of view for attached properties, etc.
         d->setupViewData(d->contentItem);
@@ -532,6 +549,8 @@ void QQuickTumbler::componentComplete()
     d->_q_updateItemHeights();
     d->_q_updateItemWidths();
     d->_q_onViewCountChanged();
+
+    qCDebug(lcTumbler) << "componentComplete() is done";
 }
 
 void QQuickTumbler::contentItemChange(QQuickItem *newItem, QQuickItem *oldItem)
@@ -659,18 +678,29 @@ void QQuickTumblerPrivate::syncCurrentIndex()
 
 void QQuickTumblerPrivate::setPendingCurrentIndex(int index)
 {
+    qCDebug(lcTumbler) << "setting pendingCurrentIndex to" << index;
     pendingCurrentIndex = index;
 }
 
+QString QQuickTumblerPrivate::propertyChangeReasonToString(
+    QQuickTumblerPrivate::PropertyChangeReason changeReason)
+{
+    return changeReason == UserChange ? QStringLiteral("UserChange") : QStringLiteral("InternalChange");
+}
+
 void QQuickTumblerPrivate::setCurrentIndex(int newCurrentIndex,
     QQuickTumblerPrivate::PropertyChangeReason changeReason)
 {
     Q_Q(QQuickTumbler);
+    qCDebug(lcTumbler).nospace() << "setting currentIndex to " << newCurrentIndex
+        << ", old currentIndex was " << currentIndex
+        << ", changeReason is " << propertyChangeReasonToString(changeReason);
     if (newCurrentIndex == currentIndex || newCurrentIndex < -1)
         return;
 
     if (!q->isComponentComplete()) {
         // Views can't set currentIndex until they're ready.
+        qCDebug(lcTumbler) << "we're not complete; setting pendingCurrentIndex instead";
         setPendingCurrentIndex(newCurrentIndex);
         return;
     }
@@ -680,6 +710,7 @@ void QQuickTumblerPrivate::setCurrentIndex(int newCurrentIndex,
         // the model is in the process of being set and the user has set
         // the currentIndex in onModelChanged. We have to queue the currentIndex
         // change until we're ready.
+        qCDebug(lcTumbler) << "a model is being set; setting pendingCurrentIndex instead";
         setPendingCurrentIndex(newCurrentIndex);
         return;
     }
@@ -717,11 +748,16 @@ void QQuickTumblerPrivate::setCurrentIndex(int newCurrentIndex,
             currentIndex = newCurrentIndex;
             emit q->currentIndexChanged();
         }
+
+        qCDebug(lcTumbler) << "view's currentIndex is now" << view->property("currentIndex").toInt()
+            << "and ours is" << currentIndex;
     }
 }
 
 void QQuickTumblerPrivate::setCount(int newCount)
 {
+    qCDebug(lcTumbler).nospace() << "setting count to " << newCount
+        << ", old count was " << count;
     if (newCount == count)
         return;
 
@@ -743,6 +779,7 @@ void QQuickTumblerPrivate::setWrapBasedOnCount()
 
 void QQuickTumblerPrivate::setWrap(bool shouldWrap, bool isExplicit)
 {
+    qCDebug(lcTumbler) << "setting wrap to" << shouldWrap << "- exlicit?" << isExplicit;
     if (isExplicit)
         explicitWrap = true;
 
diff --git a/src/quicktemplates2/qquicktumbler_p_p.h b/src/quicktemplates2/qquicktumbler_p_p.h
index 75c6cd1b..049ab8a1 100644
--- a/src/quicktemplates2/qquicktumbler_p_p.h
+++ b/src/quicktemplates2/qquicktumbler_p_p.h
@@ -111,6 +111,8 @@ public:
         InternalChange
     };
 
+    static QString propertyChangeReasonToString(PropertyChangeReason changeReason);
+
     void setCurrentIndex(int newCurrentIndex, PropertyChangeReason changeReason = InternalChange);
     void setCount(int newCount);
     void setWrapBasedOnCount();