From e7d6501553db39fcaef26be4bb78aa8c5179f2bd Mon Sep 17 00:00:00 2001
From: hjk <hjk@qt.io>
Date: Tue, 18 Apr 2023 15:58:03 +0200
Subject: [PATCH] ProjectExplorer: Postpone ToolChainConfigWidget creation

... until they are actually used, i.e. when the respective
tool chain is selected in the Toolchain tab. Some of them
(QNX) can be expensive to set up.

Previously all of were created when the Kits settings page
was opened.

Change-Id: I80e4238269b9f08788c330e2052c525dcf41d1ba
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
---
 .../projectexplorer/toolchainoptionspage.cpp  | 45 +++++++++++--------
 1 file changed, 27 insertions(+), 18 deletions(-)

diff --git a/src/plugins/projectexplorer/toolchainoptionspage.cpp b/src/plugins/projectexplorer/toolchainoptionspage.cpp
index b8df603850f..e0717ab7804 100644
--- a/src/plugins/projectexplorer/toolchainoptionspage.cpp
+++ b/src/plugins/projectexplorer/toolchainoptionspage.cpp
@@ -48,20 +48,8 @@ class ToolChainTreeItem : public TreeItem
 {
 public:
     ToolChainTreeItem(QStackedWidget *parentWidget, ToolChain *tc, bool c) :
-        toolChain(tc), changed(c)
-    {
-        widget = tc->createConfigurationWidget().release();
-        if (widget) {
-            parentWidget->addWidget(widget);
-            if (tc->isAutoDetected())
-                widget->makeReadOnly();
-            QObject::connect(widget, &ToolChainConfigWidget::dirty,
-                             [this] {
-                changed = true;
-                update();
-            });
-        }
-    }
+        toolChain(tc), changed(c), m_parentWidget(parentWidget)
+    {}
 
     QVariant data(int column, int role) const override
     {
@@ -93,9 +81,30 @@ public:
         return QVariant();
     }
 
+    ToolChainConfigWidget *widget()
+    {
+        if (!m_widget) {
+           m_widget = toolChain->createConfigurationWidget().release();
+           if (m_widget) {
+                m_parentWidget->addWidget(m_widget);
+                if (toolChain->isAutoDetected())
+                    m_widget->makeReadOnly();
+                QObject::connect(m_widget, &ToolChainConfigWidget::dirty,
+                                 [this] {
+                    changed = true;
+                    update();
+                });
+            }
+        }
+        return m_widget;
+    }
+
     ToolChain *toolChain;
-    ToolChainConfigWidget *widget;
     bool changed;
+
+private:
+    ToolChainConfigWidget *m_widget = nullptr;
+    QStackedWidget *m_parentWidget = nullptr;
 };
 
 class DetectionSettingsDialog : public QDialog
@@ -423,7 +432,7 @@ void ToolChainOptionsWidget::toolChainSelectionChanged()
 {
     ToolChainTreeItem *item = currentTreeItem();
 
-    QWidget *currentTcWidget = item ? item->widget : nullptr;
+    QWidget *currentTcWidget = item ? item->widget() : nullptr;
     if (currentTcWidget)
         m_widgetStack->setCurrentWidget(currentTcWidget);
     m_container->setVisible(currentTcWidget);
@@ -447,8 +456,8 @@ void ToolChainOptionsWidget::apply()
             for (TreeItem *item : *parent) {
                 auto tcItem = static_cast<ToolChainTreeItem *>(item);
                 Q_ASSERT(tcItem->toolChain);
-                if (!tcItem->toolChain->isAutoDetected() && tcItem->widget && tcItem->changed)
-                    tcItem->widget->apply();
+                if (!tcItem->toolChain->isAutoDetected() && tcItem->widget() && tcItem->changed)
+                    tcItem->widget()->apply();
                 tcItem->changed = false;
                 tcItem->update();
             }