[0.62] Drop Views left in Shadow Node Registry during UIManager dtor (m…

…icrosoft#5871)

* Drop remaining ShadowNodes in UIManager dtor

* Change files

change/react-native-windows-2020-08-28-15-47-39-dropview62.json

@@ -0,0 +1,8 @@
+{
+  "type": "patch",
+  "comment": "Drop remaining ShadowNodes in UIManager dtor",
+  "packageName": "react-native-windows",
+  "email": "email not defined",
+  "dependentChangeType": "patch",
+  "date": "2020-08-28T22:47:39.486Z"
+}

vnext/ReactWindowsCore/Modules/UIManagerModule.cpp

@@ -28,7 +28,9 @@ UIManager::UIManager(std::vector<std::unique_ptr<IViewManager>> &&viewManagers,
 
 UIManager::~UIManager() {
   m_nodeRegistry.removeAllRootViews([this](int64_t rootViewTag) { removeRootView(rootViewTag); });
-
+  m_nodeRegistry.ForAllNodes([this](int64_t tag, shadow_ptr const &shadowNode) noexcept {
+    DropView(tag, false, true);
+  });
   m_nativeUIManager->setHost(nullptr);
   m_nativeUIManager->destroy();
 }

vnext/ReactWindowsCore/ShadowNodeRegistry.cpp

@@ -68,5 +68,11 @@ ShadowNode *ShadowNodeRegistry::getParentRootShadowNode(int64_t nodeTag) {
   return nullptr;
 }
 
+void ShadowNodeRegistry::ForAllNodes(const Mso::FunctorRef<void(int64_t, shadow_ptr const &) noexcept> &fnDo) noexcept {
+  for (auto &kvp : m_allNodes) {
+    fnDo(kvp.first, kvp.second);
+  }
+}
+
 } // namespace react
 } // namespace facebook

vnext/ReactWindowsCore/ShadowNodeRegistry.h

@@ -3,6 +3,7 @@
 
 #pragma once
 #include <ShadowNode.h>
+#include <functional/functorref.h>
 #include <map>
 
 namespace facebook {
@@ -32,6 +33,8 @@ struct ShadowNodeRegistry {
 
   ShadowNode *getParentRootShadowNode(int64_t nodeTag);
 
+  void ForAllNodes(const Mso::FunctorRef<void(int64_t, shadow_ptr const &) noexcept> &fnDo) noexcept;
+
  private:
   std::unordered_set<int64_t> m_roots;
   std::map<int64_t, std::unique_ptr<ShadowNode, ShadowNodeDeleter>> m_allNodes;