Fix location bar being wrongly aligned on first startup

When starting Dolphin the very first time, the spacing in front of the
location bar is wrong. This commit fixes this by completely updating
all cached geometry every time adjustSpacing() is called. Because this
happens once on a timer 100 ms after every url change, it will happen
once shortly after the window is shown. At that point all geometry is
where it should be and spacing calculation works as expected.

The ViewContainer geometry retrieval is refactored into a small nested
helper class in DolphinNavigatorsWidgetAction by the name
ViewGeometriesHelper.

Previously the logic of that class was divided between DolphinTabPage
and DolphinNavigatorsWidgetAction.

BUG: 429447
FIXED-IN: 21.04.0

4 files changed, 191 insertions, 142 deletions

diff --git a/src/dolphinnavigatorswidgetaction.cpp b/src/dolphinnavigatorswidgetaction.cpp
index 6b76aad08..ace004f0f 100644
--- a/src/dolphinnavigatorswidgetaction.cpp
+++ b/src/dolphinnavigatorswidgetaction.cpp
@@ -26,11 +26,7 @@ DolphinNavigatorsWidgetAction::DolphinNavigatorsWidgetAction(QWidget *parent) :
     QWidgetAction{parent},
     m_splitter{new QSplitter(Qt::Horizontal)},
     m_adjustSpacingTimer{new QTimer(this)},
-    m_globalXOfSplitter{INT_MIN},
-    m_globalXOfPrimary{INT_MIN},
-    m_widthOfPrimary{INT_MIN},
-    m_globalXOfSecondary{INT_MIN},
-    m_widthOfSecondary{INT_MIN}
+    m_viewGeometriesHelper{m_splitter.get(), this}
 {
     updateText();
     setIcon(QIcon::fromTheme(QStringLiteral("dialog-scripts")));
@@ -45,6 +41,63 @@ DolphinNavigatorsWidgetAction::DolphinNavigatorsWidgetAction(QWidget *parent) :
             this, &DolphinNavigatorsWidgetAction::adjustSpacing);
 }
 
+void DolphinNavigatorsWidgetAction::adjustSpacing()
+{
+    auto viewGeometries = m_viewGeometriesHelper.viewGeometries();
+    const int widthOfSplitterPrimary = viewGeometries.globalXOfPrimary + viewGeometries.widthOfPrimary - viewGeometries.globalXOfNavigatorsWidget;
+    const QList<int> splitterSizes = {widthOfSplitterPrimary,
+                                      m_splitter->width() - widthOfSplitterPrimary};
+    m_splitter->setSizes(splitterSizes);
+
+    // primary side of m_splitter
+    int leadingSpacing = viewGeometries.globalXOfPrimary - viewGeometries.globalXOfNavigatorsWidget;
+    if (leadingSpacing < 0) {
+        leadingSpacing = 0;
+    }
+    int trailingSpacing = (viewGeometries.globalXOfNavigatorsWidget + m_splitter->width())
+                          - (viewGeometries.globalXOfPrimary + viewGeometries.widthOfPrimary);
+    if (trailingSpacing < 0 || emptyTrashButton(Primary)->isVisible()) {
+        trailingSpacing = 0;
+    }
+    const int widthLeftForUrlNavigator = m_splitter->widget(0)->width() - leadingSpacing - trailingSpacing;
+    const int widthNeededForUrlNavigator = primaryUrlNavigator()->sizeHint().width() - widthLeftForUrlNavigator;
+    if (widthNeededForUrlNavigator > 0) {
+        trailingSpacing -= widthNeededForUrlNavigator;
+        if (trailingSpacing < 0) {
+            leadingSpacing += trailingSpacing;
+            trailingSpacing = 0;
+        }
+        if (leadingSpacing < 0) {
+            leadingSpacing = 0;
+        }
+    }
+    spacing(Primary, Leading)->setMinimumWidth(leadingSpacing);
+    spacing(Primary, Trailing)->setFixedWidth(trailingSpacing);
+
+    // secondary side of m_splitter
+    if (viewGeometries.globalXOfSecondary == INT_MIN) {
+        Q_ASSERT(viewGeometries.widthOfSecondary == INT_MIN);
+        return;
+    }
+    spacing(Primary, Trailing)->setFixedWidth(0);
+
+    trailingSpacing = (viewGeometries.globalXOfNavigatorsWidget + m_splitter->width())
+                      - (viewGeometries.globalXOfSecondary + viewGeometries.widthOfSecondary);
+    if (trailingSpacing < 0 || emptyTrashButton(Secondary)->isVisible()) {
+        trailingSpacing = 0;
+    } else {
+        const int widthLeftForUrlNavigator2 = m_splitter->widget(1)->width() - trailingSpacing;
+        const int widthNeededForUrlNavigator2 = secondaryUrlNavigator()->sizeHint().width() - widthLeftForUrlNavigator2;
+        if (widthNeededForUrlNavigator2 > 0) {
+            trailingSpacing -= widthNeededForUrlNavigator2;
+            if (trailingSpacing < 0) {
+                trailingSpacing = 0;
+            }
+        }
+    }
+    spacing(Secondary, Trailing)->setMinimumWidth(trailingSpacing);
+}
+
 void DolphinNavigatorsWidgetAction::createSecondaryUrlNavigator()
 {
     Q_ASSERT(m_splitter->count() == 1);
@@ -53,31 +106,10 @@ void DolphinNavigatorsWidgetAction::createSecondaryUrlNavigator()
     updateText();
 }
 
-void DolphinNavigatorsWidgetAction::followViewContainerGeometry(
-                                    int globalXOfPrimary,   int widthOfPrimary)
-{
-    followViewContainersGeometry(globalXOfPrimary, widthOfPrimary, INT_MIN, INT_MIN);
-}
-
-void DolphinNavigatorsWidgetAction::followViewContainersGeometry(
-                                    int globalXOfPrimary,   int widthOfPrimary,
-                                    int globalXOfSecondary, int widthOfSecondary)
+void DolphinNavigatorsWidgetAction::followViewContainersGeometry(QWidget *primaryViewContainer,
+                                                                 QWidget *secondaryViewContainer)
 {
-    if (QApplication::layoutDirection() == Qt::LeftToRight) {
-        m_globalXOfSplitter = m_splitter->mapToGlobal(QPoint(0,0)).x();
-        m_globalXOfPrimary = globalXOfPrimary;
-        m_globalXOfSecondary = globalXOfSecondary;
-    } else {
-        // When the direction is reversed, globalX does not change.
-        // For the adjustSpacing() code to work we need globalX to measure from right to left
-        // and to measure up to the rightmost point of a widget instead of the leftmost.
-        m_globalXOfSplitter = (-1) * (m_splitter->mapToGlobal(QPoint(0,0)).x() + m_splitter->width());
-        m_globalXOfPrimary = (-1) * (globalXOfPrimary + widthOfPrimary);
-        m_globalXOfSecondary = (globalXOfSecondary == INT_MIN) ? INT_MIN :
-                               (-1) * (globalXOfSecondary + widthOfSecondary);
-    }
-    m_widthOfPrimary = widthOfPrimary;
-    m_widthOfSecondary = widthOfSecondary;
+    m_viewGeometriesHelper.setViewContainers(primaryViewContainer, secondaryViewContainer);
     adjustSpacing();
 }
 
@@ -137,65 +169,6 @@ void DolphinNavigatorsWidgetAction::deleteWidget(QWidget *widget)
     m_splitter->setParent(nullptr);
 }
 
-void DolphinNavigatorsWidgetAction::adjustSpacing()
-{
-    Q_ASSERT(m_globalXOfSplitter != INT_MIN);
-    Q_ASSERT(m_globalXOfPrimary  != INT_MIN);
-    Q_ASSERT(m_widthOfPrimary    != INT_MIN);
-    const int widthOfSplitterPrimary = m_globalXOfPrimary + m_widthOfPrimary - m_globalXOfSplitter;
-    const QList<int> splitterSizes = {widthOfSplitterPrimary,
-                                      m_splitter->width() - widthOfSplitterPrimary};
-    m_splitter->setSizes(splitterSizes);
-
-    // primary side of m_splitter
-    int leadingSpacing = m_globalXOfPrimary - m_globalXOfSplitter;
-    if (leadingSpacing < 0) {
-        leadingSpacing = 0;
-    }
-    int trailingSpacing = (m_globalXOfSplitter + m_splitter->width())
-                          - (m_globalXOfPrimary + m_widthOfPrimary);
-    if (trailingSpacing < 0 || emptyTrashButton(Primary)->isVisible()) {
-        trailingSpacing = 0;
-    }
-    const int widthLeftForUrlNavigator = m_splitter->widget(0)->width() - leadingSpacing - trailingSpacing;
-    const int widthNeededForUrlNavigator = primaryUrlNavigator()->sizeHint().width() - widthLeftForUrlNavigator;
-    if (widthNeededForUrlNavigator > 0) {
-        trailingSpacing -= widthNeededForUrlNavigator;
-        if (trailingSpacing < 0) {
-            leadingSpacing += trailingSpacing;
-            trailingSpacing = 0;
-        }
-        if (leadingSpacing < 0) {
-            leadingSpacing = 0;
-        }
-    }
-    spacing(Primary, Leading)->setMinimumWidth(leadingSpacing);
-    spacing(Primary, Trailing)->setFixedWidth(trailingSpacing);
-
-    // secondary side of m_splitter
-    if (m_globalXOfSecondary == INT_MIN) {
-        Q_ASSERT(m_widthOfSecondary == INT_MIN);
-        return;
-    }
-    spacing(Primary, Trailing)->setFixedWidth(0);
-
-    trailingSpacing = (m_globalXOfSplitter + m_splitter->width())
-                      - (m_globalXOfSecondary + m_widthOfSecondary);
-    if (trailingSpacing < 0 || emptyTrashButton(Secondary)->isVisible()) {
-        trailingSpacing = 0;
-    } else {
-        const int widthLeftForUrlNavigator2 = m_splitter->widget(1)->width() - trailingSpacing;
-        const int widthNeededForUrlNavigator2 = secondaryUrlNavigator()->sizeHint().width() - widthLeftForUrlNavigator2;
-        if (widthNeededForUrlNavigator2 > 0) {
-            trailingSpacing -= widthNeededForUrlNavigator2;
-            if (trailingSpacing < 0) {
-                trailingSpacing = 0;
-            }
-        }
-    }
-    spacing(Secondary, Trailing)->setMinimumWidth(trailingSpacing);
-}
-
 QWidget *DolphinNavigatorsWidgetAction::createNavigatorWidget(Side side) const
 {
     auto navigatorWidget = new QWidget(m_splitter.get());
@@ -281,3 +254,70 @@ void DolphinNavigatorsWidgetAction::updateText()
                                     2 : 1;
     setText(i18ncp("@action:inmenu", "Location Bar", "Location Bars", urlNavigatorsAmount));
 }
+
+DolphinNavigatorsWidgetAction::ViewGeometriesHelper::ViewGeometriesHelper
+    (QWidget *navigatorsWidget, DolphinNavigatorsWidgetAction *navigatorsWidgetAction) :
+    m_navigatorsWidget{navigatorsWidget},
+    m_navigatorsWidgetAction{navigatorsWidgetAction}
+{
+    Q_CHECK_PTR(navigatorsWidget);
+    Q_CHECK_PTR(navigatorsWidgetAction);
+}
+
+bool DolphinNavigatorsWidgetAction::ViewGeometriesHelper::eventFilter(QObject *watched, QEvent *event)
+{
+    if (event->type() == QEvent::Resize) {
+        m_navigatorsWidgetAction->adjustSpacing();
+        return false;
+    }
+    return QObject::eventFilter(watched, event);
+}
+
+void DolphinNavigatorsWidgetAction::ViewGeometriesHelper::setViewContainers(QWidget *primaryViewContainer,
+                                                                            QWidget *secondaryViewContainer)
+{
+    Q_CHECK_PTR(primaryViewContainer);
+    if (m_primaryViewContainer) {
+        m_primaryViewContainer->removeEventFilter(this);
+    }
+    primaryViewContainer->installEventFilter(this);
+    m_primaryViewContainer = primaryViewContainer;
+
+    // It is not possible to resize the secondaryViewContainer without simultaneously
+    // resizing the primaryViewContainer so we don't have to installEventFilter() here.
+    m_secondaryViewContainer = secondaryViewContainer;
+}
+
+DolphinNavigatorsWidgetAction::ViewGeometriesHelper::Geometries
+        DolphinNavigatorsWidgetAction::ViewGeometriesHelper::viewGeometries()
+{
+    Q_ASSERT(m_primaryViewContainer);
+    Geometries geometries;
+
+    // width
+    geometries.widthOfPrimary = m_primaryViewContainer->width();
+    if (m_secondaryViewContainer) {
+        geometries.widthOfSecondary = m_secondaryViewContainer->width();
+    } else {
+        geometries.widthOfSecondary = INT_MIN;
+    }
+
+    // globalX
+    if (QApplication::layoutDirection() == Qt::LeftToRight) {
+        geometries.globalXOfNavigatorsWidget = m_navigatorsWidget->mapToGlobal(QPoint(0,0)).x();
+        geometries.globalXOfPrimary = m_primaryViewContainer->mapToGlobal(QPoint(0,0)).x();
+        geometries.globalXOfSecondary = !m_secondaryViewContainer ? INT_MIN :
+                m_secondaryViewContainer->mapToGlobal(QPoint(0,0)).x();
+    } else {
+        // When the direction is reversed, globalX does not change.
+        // For the adjustSpacing() code to work we need globalX to measure from right to left
+        // and to measure up to the rightmost point of a widget instead of the leftmost.
+        geometries.globalXOfNavigatorsWidget =
+                (-1) * (m_navigatorsWidget->mapToGlobal(QPoint(0,0)).x() + m_navigatorsWidget->width());
+        geometries.globalXOfPrimary =
+                (-1) * (m_primaryViewContainer->mapToGlobal(QPoint(0,0)).x() + geometries.widthOfPrimary);
+        geometries.globalXOfSecondary = !m_secondaryViewContainer ? INT_MIN :
+                (-1) * (m_secondaryViewContainer->mapToGlobal(QPoint(0,0)).x() + geometries.widthOfSecondary);
+    }
+    return geometries;
+}
diff --git a/src/dolphinnavigatorswidgetaction.h b/src/dolphinnavigatorswidgetaction.h
index f15ea144d..804996532 100644
--- a/src/dolphinnavigatorswidgetaction.h
+++ b/src/dolphinnavigatorswidgetaction.h
@@ -10,6 +10,7 @@
 
 #include "dolphinurlnavigator.h"
 
+#include <QPointer>
 #include <QSplitter>
 #include <QTimer>
 #include <QWidgetAction>
@@ -42,6 +43,13 @@ public:
     DolphinNavigatorsWidgetAction(QWidget *parent = nullptr);
 
     /**
+     * Adjusts the width of the spacings used to align the UrlNavigators with ViewContainers.
+     * This can only work nicely if up-to-date geometry of ViewContainers is cached so
+     * followViewContainersGeometry() has to have been called at least once before.
+     */
+    void adjustSpacing();
+
+    /**
      * The secondary UrlNavigator is only created on-demand. Such an action is not necessary
      * for the primary UrlNavigator which is created preemptively.
      *
@@ -53,16 +61,11 @@ public:
     void createSecondaryUrlNavigator();
 
     /**
-     * Notify the primary UrlNavigator of changes in geometry of the ViewContainer it tries to be
-     * aligned with. Only call this method if there is no secondary UrlNavigator.
-     */
-    void followViewContainerGeometry(int globalXOfPrimary,   int widthOfPrimary);
-    /**
      * Notify this widget of changes in geometry of the ViewContainers it tries to be
      * aligned with.
      */
-    void followViewContainersGeometry(int globalXOfPrimary,   int widthOfPrimary,
-                                      int globalXOfSecondary, int widthOfSecondary);
+    void followViewContainersGeometry(QWidget *primaryViewContainer,
+                                      QWidget *secondaryViewContainer = nullptr);
 
     bool isInToolbar() const;
 
@@ -98,13 +101,6 @@ protected:
 
 private:
     /**
-     * Adjusts the width of the spacings used to align the UrlNavigators with ViewContainers.
-     * This can only work nicely if up-to-date geometry of ViewContainers is cached so
-     * followViewContainersGeometry() has to have been called at least once before.
-     */
-    void adjustSpacing();
-
-    /**
      * In Left-to-right languages the Primary side will be the left one.
      */
     enum Side {
@@ -157,12 +153,54 @@ private:
      */
     std::unique_ptr<QTimer> m_adjustSpacingTimer;
 
-    // cached values
-    int m_globalXOfSplitter;
-    int m_globalXOfPrimary;
-    int m_widthOfPrimary;
-    int m_globalXOfSecondary;
-    int m_widthOfSecondary;
+    /**
+     * Extracts the geometry information needed by adjustSpacing() from
+     * ViewContainers. They are also monitored for size changes which
+     * will lead to adjustSpacing() calls.
+     */
+    class ViewGeometriesHelper : public QObject
+    {
+    public:
+        /**
+         * @param navigatorsWidget       The QWidget of the navigatorsWidgetAction.
+         * @param navigatorsWidgetAction is only used to call adjustSpacing() whenever that is
+         *                               deemed necessary.
+         */
+        ViewGeometriesHelper(QWidget *navigatorsWidget, DolphinNavigatorsWidgetAction *navigatorsWidgetAction);
+
+        /**
+         * Calls m_navigatorsWidgetAction::adjustSpacing() when a watched object is resized.
+         */
+        bool eventFilter(QObject *watched, QEvent *event) override;
+
+        /**
+         * Sets the ViewContainers whose geometry is obtained when viewGeometries() is called.
+         */
+        void setViewContainers(QWidget *primaryViewContainer,
+                               QWidget *secondaryViewContainer = nullptr);
+
+        struct Geometries {
+            int globalXOfNavigatorsWidget;
+            int globalXOfPrimary;
+            int widthOfPrimary;
+            int globalXOfSecondary;
+            int widthOfSecondary;
+        };
+        /**
+         * @return a Geometries struct that contains values adjustSpacing() requires.
+         */
+        Geometries viewGeometries();
+
+    private:
+        QWidget *m_navigatorsWidget;
+        /** Is only used to call adjustSpacing() whenever that is deemed necessary. */
+        DolphinNavigatorsWidgetAction *m_navigatorsWidgetAction;
+
+        QPointer<QWidget> m_primaryViewContainer;
+        QPointer<QWidget> m_secondaryViewContainer;
+    };
+
+    ViewGeometriesHelper m_viewGeometriesHelper;
 };
 
 #endif // DOLPHINNAVIGATORSWIDGETACTION_H
diff --git a/src/dolphintabpage.cpp b/src/dolphintabpage.cpp
index a90e8e7f0..36049fa97 100644
--- a/src/dolphintabpage.cpp
+++ b/src/dolphintabpage.cpp
@@ -43,7 +43,6 @@ DolphinTabPage::DolphinTabPage(const QUrl &primaryUrl, const QUrl &secondaryUrl,
             this, &DolphinTabPage::slotViewUrlRedirection);
 
     m_splitter->addWidget(m_primaryViewContainer);
-    m_primaryViewContainer->installEventFilter(this);
     m_primaryViewContainer->show();
 
     if (secondaryUrl.isValid() || GeneralSettings::splitView()) {
@@ -53,7 +52,6 @@ DolphinTabPage::DolphinTabPage(const QUrl &primaryUrl, const QUrl &secondaryUrl,
         const QUrl& url = secondaryUrl.isValid() ? secondaryUrl : primaryUrl;
         m_secondaryViewContainer = createViewContainer(url);
         m_splitter->addWidget(m_secondaryViewContainer);
-        m_secondaryViewContainer->installEventFilter(this);
         m_secondaryViewContainer->show();
     }
 
@@ -98,9 +96,10 @@ void DolphinTabPage::setSplitViewEnabled(bool enabled, Animated animated, const
             }
             m_secondaryViewContainer->connectUrlNavigator(secondaryNavigator);
             m_navigatorsWidget->setSecondaryNavigatorVisible(true);
+            m_navigatorsWidget->followViewContainersGeometry(m_primaryViewContainer,
+                                                             m_secondaryViewContainer);
 
             m_splitter->addWidget(m_secondaryViewContainer);
-            m_secondaryViewContainer->installEventFilter(this);
             m_secondaryViewContainer->setActive(true);
 
             if (animated == WithAnimation) {
@@ -141,6 +140,7 @@ void DolphinTabPage::setSplitViewEnabled(bool enabled, Animated animated, const
                 }
             }
             m_primaryViewContainer->setActive(true);
+            m_navigatorsWidget->followViewContainersGeometry(m_primaryViewContainer, nullptr);
 
             if (animated == WithoutAnimation) {
                 view->close();
@@ -201,7 +201,8 @@ void DolphinTabPage::connectNavigators(DolphinNavigatorsWidgetAction *navigators
         auto secondaryNavigator = navigatorsWidget->secondaryUrlNavigator();
         m_secondaryViewContainer->connectUrlNavigator(secondaryNavigator);
     }
-    resizeNavigators();
+    m_navigatorsWidget->followViewContainersGeometry(m_primaryViewContainer,
+                                                     m_secondaryViewContainer);
 }
 
 void DolphinTabPage::disconnectNavigators()
@@ -213,15 +214,6 @@ void DolphinTabPage::disconnectNavigators()
     }
 }
 
-bool DolphinTabPage::eventFilter(QObject *watched, QEvent *event)
-{
-    if (event->type() == QEvent::Resize && m_navigatorsWidget) {
-        resizeNavigators();
-        return false;
-    }
-    return QWidget::eventFilter(watched, event);
-}
-
 void DolphinTabPage::insertNavigatorsWidget(DolphinNavigatorsWidgetAction* navigatorsWidget)
 {
     QGridLayout *gridLayout = static_cast<QGridLayout *>(layout());
@@ -235,22 +227,6 @@ void DolphinTabPage::insertNavigatorsWidget(DolphinNavigatorsWidgetAction* navig
     }
 }
 
-
-void DolphinTabPage::resizeNavigators() const
-{
-    if (!m_secondaryViewContainer) {
-        m_navigatorsWidget->followViewContainerGeometry(
-                m_primaryViewContainer->mapToGlobal(QPoint(0,0)).x(),
-                m_primaryViewContainer->width());
-    } else {
-        m_navigatorsWidget->followViewContainersGeometry(
-                m_primaryViewContainer->mapToGlobal(QPoint(0,0)).x(),
-                m_primaryViewContainer->width(),
-                m_secondaryViewContainer->mapToGlobal(QPoint(0,0)).x(),
-                m_secondaryViewContainer->width());
-    }
-}
-
 void DolphinTabPage::markUrlsAsSelected(const QList<QUrl>& urls)
 {
     m_primaryViewContainer->view()->markUrlsAsSelected(urls);
diff --git a/src/dolphintabpage.h b/src/dolphintabpage.h
index e90bf99bf..a3659aa18 100644
--- a/src/dolphintabpage.h
+++ b/src/dolphintabpage.h
@@ -93,11 +93,6 @@ public:
      */
     void disconnectNavigators();
 
-    /**
-     * Calls resizeNavigators() when a watched object is resized.
-     */
-    bool eventFilter(QObject *watched, QEvent *event) override;
-
     void insertNavigatorsWidget(DolphinNavigatorsWidgetAction *navigatorsWidget);
 
     /**