Check for layer parent-child cycles.

src/lottie/lottieitem.cpp

@@ -69,6 +69,16 @@ static bool strokeProp(rlottie::Property prop)
     }
 }
 
+static bool isGoodParentLayer(LOTLayerItem *parent, LOTLayerItem *child) {
+    do {
+        if (parent == child) {
+            return false;
+        }
+        parent = parent->resolvedParentLayer();
+    } while (parent);
+    return true;
+}
+
 LOTCompItem::LOTCompItem(LOTModel *model)
     : mCurFrameNo(-1)
 {
@@ -520,7 +530,10 @@ LOTCompLayerItem::LOTCompLayerItem(LOTLayerData *layerModel)
             auto search =
                 std::find_if(mLayers.begin(), mLayers.end(),
                              [id](const auto &val) { return val->id() == id; });
-            if (search != mLayers.end()) layer->setParentLayer((*search).get());
+            if (search != mLayers.end() &&
+                isGoodParentLayer((*search).get(), layer.get())) {
+                layer->setParentLayer((*search).get());
+            }
         }
     }
 

src/lottie/lottieitem.h

@@ -107,6 +107,7 @@ public:
    int id() const {return mLayerData->id();}
    int parentId() const {return mLayerData->parentId();}
    void setParentLayer(LOTLayerItem *parent){mParentLayer = parent;}
+   LOTLayerItem *resolvedParentLayer() const {return mParentLayer;}
    void setComplexContent(bool value) { mComplexContent = value;}
    bool complexContent() const {return mComplexContent;}
    virtual void update(int frameNo, const VMatrix &parentMatrix, float parentAlpha);