QmlDesigner: Take advantage of stable references in std::map

References are stable for std::map for later insertions like
https://en.cppreference.com/w/cpp/container#Iterator_invalidation shows,
So there is no need to add an extra indirection.

The member has made to be mutable because the code is not const correct.

Change-Id: I9dd74aac80ddc2b9ae78000916d8a835cc9cb0cc
Reviewed-by: Vikas Pachdha <vikas.pachdha@qt.io>

src/plugins/qmldesigner/components/designsystemview/designsysteminterface.cpp

@@ -70,14 +70,12 @@ QStringList DesignSystemInterface::collections() const
 
 CollectionModel *DesignSystemInterface::createModel(const QString &typeName, DSThemeManager *collection)
 {
-    auto [iterator, inserted] = m_models.try_emplace(typeName,
+    auto [iterator, inserted] = m_models.try_emplace(typeName, collection, m_store);
-                                                     makeLazyUniquePtr<CollectionModel>(collection,
-                                                                                        m_store));
     if (inserted) {
         // Otherwise the model will be deleted by the QML engine.
-        QQmlEngine::setObjectOwnership(iterator->second.get(), QQmlEngine::CppOwnership);
+        QQmlEngine::setObjectOwnership(&iterator->second, QQmlEngine::CppOwnership);
     }
 
-    return iterator->second.get();
+    return &iterator->second;
 }
 } // namespace QmlDesigner

src/plugins/qmldesigner/components/designsystemview/designsysteminterface.h

@@ -42,7 +42,7 @@ private:
 
 private:
     class DSStore *m_store = nullptr;
-    std::map<QString, std::unique_ptr<CollectionModel>> m_models;
+    std::map<QString, CollectionModel> m_models;
 };
 
 } // namespace QmlDesigner

src/plugins/qmldesigner/libs/designsystem/dsstore.cpp

@@ -190,7 +190,7 @@ DSThemeManager *DSStore::addCollection(const QString &qmlTypeName)
 {
     const QString componentType = uniqueCollectionName(qmlTypeName);
 
-    auto [itr, success] = m_collections.try_emplace(componentType, DSThemeManager{});
+    auto [itr, success] = m_collections.try_emplace(componentType);
     if (success)
         return &itr->second;
 

src/plugins/qmldesigner/libs/designsystem/dsthememanager.cpp

@@ -116,7 +116,7 @@ void DSThemeManager::forAllGroups(std::function<void(GroupType, DSThemeGroup *)>
         return;
 
     for (auto &[gt, themeGroup] : m_groups)
-        callback(gt, themeGroup.get());
+        callback(gt, &themeGroup);
 }
 
 size_t DSThemeManager::themeCount() const
@@ -126,9 +126,8 @@ size_t DSThemeManager::themeCount() const
 
 size_t DSThemeManager::propertyCount() const
 {
-    using groupPair = std::pair<const GroupType, std::shared_ptr<DSThemeGroup>>;
+    return std::accumulate(m_groups.cbegin(), m_groups.cend(), 0ull, [](size_t c, const auto &g) {
-    return std::accumulate(m_groups.cbegin(), m_groups.cend(), 0ull, [](size_t c, const groupPair &g) {
+        return c + g.second.count();
-        return c + g.second->count();
     });
 }
 
@@ -138,7 +137,7 @@ void DSThemeManager::removeTheme(ThemeId id)
         return;
 
     for (auto &[gt, group] : m_groups)
-        group->removeTheme(id);
+        group.removeTheme(id);
 
     if (m_themes.erase(id))
         reviewActiveTheme();
@@ -147,13 +146,13 @@ void DSThemeManager::removeTheme(ThemeId id)
 void DSThemeManager::duplicateTheme(ThemeId from, ThemeId to)
 {
     for (auto &[gt, group] : m_groups)
-        group->duplicateValues(from, to);
+        group.duplicateValues(from, to);
 }
 
 std::optional<GroupType> DSThemeManager::groupType(const PropertyName &name) const
 {
     for (const auto &[gt, group] : m_groups) {
-        if (group->hasProperty(name))
+        if (group.hasProperty(name))
             return gt;
     }
     return {};
@@ -166,7 +165,7 @@ std::optional<ThemeProperty> DSThemeManager::property(ThemeId themeId,
     if (m_themes.contains(themeId)) {
         auto groupItr = m_groups.find(gType);
         if (groupItr != m_groups.end())
-            return groupItr->second->propertyValue(themeId, name);
+            return groupItr->second.propertyValue(themeId, name);
     }
 
     qCDebug(dsLog) << "Error fetching property: {" << themeId << GroupId(gType) << name << "}";
@@ -248,7 +247,7 @@ void DSThemeManager::decorate(ModelNode rootNode, const QByteArray &nodeType, bo
 
         // Add property groups
         for (auto &[gt, group] : m_groups)
-            group->decorate(themeId, themeNode, !isMCU);
+            group.decorate(themeId, themeNode, !isMCU);
     }
 }
 
@@ -258,21 +257,21 @@ void DSThemeManager::decorateThemeInterface(ModelNode rootNode) const
         return;
 
     for (auto &[gt, group] : m_groups)
-        group->decorateComponent(rootNode);
+        group.decorateComponent(rootNode);
 }
 
 DSThemeGroup *DSThemeManager::propertyGroup(GroupType type)
 {
-    auto itr = m_groups.try_emplace(type, makeLazySharedPtr<DSThemeGroup>(type)).first;
+    auto itr = m_groups.try_emplace(type, type).first;
 
-    return itr->second.get();
+    return &itr->second;
 }
 
 void DSThemeManager::addGroupAliases(ModelNode rootNode) const
 {
     std::set<PropertyName> groupNames;
     for (auto &[groupType, group] : m_groups) {
-        if (group->count())
+        if (group.count())
             groupNames.emplace(GroupId(groupType));
     }
 
@@ -396,7 +395,7 @@ PropertyName DSThemeManager::uniquePropertyName(const PropertyName &hint) const
 {
     auto isPropertyNameUsed = [this](const PropertyName &name) -> bool {
         return std::any_of(m_groups.begin(), m_groups.end(), [&name](const auto &p) {
-            return p.second->hasProperty(name);
+            return p.second.hasProperty(name);
         });
     };
 

src/plugins/qmldesigner/libs/designsystem/dsthememanager.h

@@ -79,7 +79,7 @@ private:
 
 private:
     std::map<ThemeId, ThemeName> m_themes;
-    std::map<GroupType, std::shared_ptr<DSThemeGroup>> m_groups;
+    mutable std::map<GroupType, DSThemeGroup> m_groups;
     ThemeId m_activeTheme = static_cast<ThemeId>(0);
 };