QmlDesigner: Cleanup QmlTimelineKeyframeGroup

Many checks are not anymore need so we can just remove the code and make
it clean what we want. Use the filtered algorithm to remove some loops.
We add Utils::filteredCast to algorithm.h to return a different result
container and let it be cast in std::copy_if.

Change-Id: I114c17cd2d5a69c9ebbfbd804805c4d2fa0599e1
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/libs/utils/algorithm.h

@@ -890,6 +890,17 @@ C filtered(const C &container, R (S::*predicate)() const)
     return out;
 }
 
+//////////////////
+// filteredCast
+/////////////////
+template<typename R, typename C, typename F>
+Q_REQUIRED_RESULT R filteredCast(const C &container, F predicate)
+{
+    R out;
+    std::copy_if(std::begin(container), std::end(container), inserter(out), predicate);
+    return out;
+}
+
 //////////////////
 // partition
 /////////////////

src/plugins/qmldesigner/designercore/include/qmltimelinekeyframegroup.h

@@ -65,6 +65,7 @@ public:
 
     QmlTimeline timeline() const;
 
+    static bool isDangling(const ModelNode &node);
     bool isDangling() const;
 };
 

src/plugins/qmldesigner/designercore/model/qmltimelinekeyframegroup.cpp

@@ -12,6 +12,7 @@
 #include <nodelistproperty.h>
 #include <variantproperty.h>
 
+#include <utils/algorithm.h>
 #include <utils/qtcassert.h>
 
 #include <cmath>
@@ -42,10 +43,7 @@ void QmlTimelineKeyframeGroup::destroy()
 
 ModelNode QmlTimelineKeyframeGroup::target() const
 {
-    if (modelNode().property("target").isBindingProperty())
-        return modelNode().bindingProperty("target").resolveToModelNode();
-
-    return {};
+    return modelNode().bindingProperty("target").resolveToModelNode();
 }
 
 void QmlTimelineKeyframeGroup::setTarget(const ModelNode &target)
@@ -123,17 +121,17 @@ QmlTimeline QmlTimelineKeyframeGroup::timeline() const
 {
     QTC_CHECK(isValid());
 
-    if (modelNode().hasParentProperty())
-        return modelNode().parentProperty().parentModelNode();
+    return modelNode().parentProperty().parentModelNode();
+}
 
-    return {};
+bool QmlTimelineKeyframeGroup::isDangling(const ModelNode &node)
+{
+    QmlTimelineKeyframeGroup group{node};
+    return group.isDangling();
 }
 
 bool QmlTimelineKeyframeGroup::isDangling() const
 {
-    if (!isValid())
-        return false;
-
     return !target().isValid() || keyframes().isEmpty();
 }
 
@@ -247,14 +245,9 @@ QList<ModelNode> QmlTimelineKeyframeGroup::keyframes() const
 
 QList<ModelNode> QmlTimelineKeyframeGroup::keyframePositions() const
 {
-    QList<ModelNode> returnValues;
-    for (const ModelNode &childNode : modelNode().defaultNodeListProperty().toModelNodeList()) {
-        QVariant value = childNode.variantProperty("frame").value();
-        if (value.isValid())
-            returnValues.append(childNode);
-    }
-
-    return returnValues;
+    return Utils::filtered(modelNode().defaultNodeListProperty().toModelNodeList(), [](auto &&node) {
+        return node.variantProperty("frame").value().isValid();
+    });
 }
 
 bool QmlTimelineKeyframeGroup::isValidKeyframe(const ModelNode &node)
@@ -278,21 +271,21 @@ QmlTimelineKeyframeGroup QmlTimelineKeyframeGroup::keyframeGroupForKeyframe(cons
     return QmlTimelineKeyframeGroup();
 }
 
-QList<QmlTimelineKeyframeGroup> QmlTimelineKeyframeGroup::allInvalidTimelineKeyframeGroups(AbstractView *view)
+QList<QmlTimelineKeyframeGroup> QmlTimelineKeyframeGroup::allInvalidTimelineKeyframeGroups(
+    AbstractView *view)
 {
-    QList<QmlTimelineKeyframeGroup> ret;
+    QTC_CHECK(view);
+    QTC_CHECK(view->model());
 
-    QTC_ASSERT(view, return ret);
-    QTC_ASSERT(view->model(), return ret);
-    QTC_ASSERT(view->rootModelNode().isValid(), return ret);
+    if (!view || !view->model())
+        return {};
 
     const auto groups = view->rootModelNode().subModelNodesOfType(
         view->model()->qtQuickTimelineKeyframeGroupMetaInfo());
-    for (const QmlTimelineKeyframeGroup group : groups) {
-        if (group.isDangling())
-            ret.append(group);
-    }
-    return ret;
+
+    return Utils::filteredCast<QList<QmlTimelineKeyframeGroup>>(groups, [](auto &&group) {
+        return isDangling(group);
+    });
 }
 
 void QmlTimelineKeyframeGroup::moveAllKeyframes(qreal offset)