Delay widget creation of options pages till their category is shown

Also add the alternative way: IOptionsPageProvider, which states
a category, and is asked for a list of options pages for that
category when it is shown.

Task-number: QTCREATORBUG-3131

2 files changed, 13 insertions, 2 deletions

diff --git a/src/plugins/cpptools/completionsettingspage.cpp b/src/plugins/cpptools/completionsettingspage.cpp
index 2db7dc3087..995ee2d7d8 100644
--- a/src/plugins/cpptools/completionsettingspage.cpp
+++ b/src/plugins/cpptools/completionsettingspage.cpp
@@ -40,7 +40,7 @@
 using namespace CppTools::Internal;
 
 CompletionSettingsPage::CompletionSettingsPage()
-    : m_page(new Ui_CompletionSettingsPage)
+    : m_page(0)
 {
 }
 
@@ -62,6 +62,7 @@ QString CompletionSettingsPage::displayName() const
 QWidget *CompletionSettingsPage::createPage(QWidget *parent)
 {
     QWidget *w = new QWidget(parent);
+    m_page = new Ui_CompletionSettingsPage;
     m_page->setupUi(w);
 
     const TextEditor::CompletionSettings &settings =
@@ -113,6 +114,8 @@ QWidget *CompletionSettingsPage::createPage(QWidget *parent)
 
 void CompletionSettingsPage::apply()
 {
+    if (!m_page) // page was never shown
+        return;
     TextEditor::CompletionSettings settings;
     settings.m_caseSensitivity = caseSensitivity();
     settings.m_completionTrigger = completionTrigger();
@@ -151,3 +154,11 @@ TextEditor::CompletionTrigger CompletionSettingsPage::completionTrigger() const
         return TextEditor::AutomaticCompletion;
     }
 }
+
+void CompletionSettingsPage::finish()
+{
+    if (!m_page) // page was never shown
+        return;
+    delete m_page;
+    m_page = 0;
+}
diff --git a/src/plugins/cpptools/completionsettingspage.h b/src/plugins/cpptools/completionsettingspage.h
index c2b0c56dc3..25ceac1258 100644
--- a/src/plugins/cpptools/completionsettingspage.h
+++ b/src/plugins/cpptools/completionsettingspage.h
@@ -55,7 +55,7 @@ public:
 
     QWidget *createPage(QWidget *parent);
     void apply();
-    void finish() { }
+    void finish();
     virtual bool matches(const QString &) const;
 
 private: