Alternative fix for #3236 that avoids causing #3503 (#3505)

* Revert "recreate EventLoopDispatcher in NetworkTransport on hot reload in RN (#3340)" This reverts commit 4c4e497. * Alternative fix for #3236 that avoids causing #3503 The problem with the fix in #3340 was that it was causing the EventLoopDispatcher to be constructed on the sync thread rather than on the JS thread, which is required. This alternative fix initializes it on the JS thread, but ensures it is re-initialized when RN apps are reloaded. Co-authored-by: Kenneth Geisshirt <[email protected]>
realm · Jan 15, 2021 · d10f75b · d10f75b
1 parent 83185e1
commit d10f75b
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Showing 3 changed files with 22 additions and 18 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,6 +5,7 @@
 
 ### Fixed
 * Fixed a bug where elements in the `User#identities` array would have a `userId` which was actually an `id` of the identity. ([#3481](https://github.com/realm/realm-js/pull/3481), since v10.0.0-beta.13)
+* Fixed a crash after getting a 401 error inside sync. ([#3503](https://github.com/realm/realm-js/issues/3206), since v10.0.0)
 * Fixed a bug which could lead to a `BadChangeset Error` (`ProtocolErrorCode=212`).
 
 ### Compatibility

diff --git a/src/js_app.hpp b/src/js_app.hpp
@@ -115,6 +115,7 @@ class AppClass : public ClassDefinition<T, SharedApp> {
 template<typename T>
 inline typename T::Function AppClass<T>::create_constructor(ContextType ctx) {
     FunctionType app_constructor = ObjectWrap<T, AppClass<T>>::create_constructor(ctx);
+    NetworkTransport::init(ctx);
     return app_constructor;
 }
 

diff --git a/src/js_network_transport.hpp b/src/js_network_transport.hpp
@@ -169,10 +169,7 @@ struct JavaScriptNetworkTransport : public app::GenericNetworkTransport {
     using NetworkTransportFactory = std::function<std::unique_ptr<app::GenericNetworkTransport>(ContextType)>;
     using SendRequestHandler = void(ContextType m_ctx, const app::Request request, std::function<void(const app::Response)> completion_callback);
 
-	JavaScriptNetworkTransport(ContextType ctx) : m_ctx(ctx),
-		m_dispatcher {JavaScriptNetworkTransport::send_request_to_server_impl}
-	{
-	};
+    JavaScriptNetworkTransport(ContextType ctx) : m_ctx(ctx) {};
 
     static ObjectType makeRequest(ContextType ctx, const app::Request& request) {
         ObjectType headers_object = Object::create_empty(ctx);
@@ -191,26 +188,31 @@ struct JavaScriptNetworkTransport : public app::GenericNetworkTransport {
         return request_object;
     }
 
-    void send_request_to_server(const app::Request request, std::function<void(const app::Response)> completion_callback) override {
-        m_dispatcher(m_ctx, request, completion_callback);
-    }
+    static void init(ContextType ctx) {
+        // This initializes the EventLoopDispatcher on the main JS thread.
+        s_dispatcher.reset(new realm::util::EventLoopDispatcher([]
+            (ContextType m_ctx, const app::Request request, std::function<void(const app::Response)> completion_callback) {
+                HANDLESCOPE(m_ctx);
 
-private:
-    ContextType m_ctx;
-    realm::util::EventLoopDispatcher<SendRequestHandler> m_dispatcher;
+                ObjectType realm_constructor = Value::validated_to_object(m_ctx, Object::get_global(m_ctx, "Realm"));
+                ValueType network_transport = Object::get_property(m_ctx, realm_constructor, "_networkTransport");
 
-    static void send_request_to_server_impl(ContextType m_ctx, const app::Request request, std::function<void(const app::Response)> completion_callback) {
-        HANDLESCOPE(m_ctx);
+                Object::call_method(m_ctx, Value::to_object(m_ctx, network_transport), "fetchWithCallbacks", {
+                    makeRequest(m_ctx, request),
+                    ResponseHandlerClass<T>::create_instance(m_ctx, std::move(completion_callback)),
+                });
+            }));
 
-        ObjectType realm_constructor = Value::validated_to_object(m_ctx, Object::get_global(m_ctx, "Realm"));
-        ValueType network_transport = Object::get_property(m_ctx, realm_constructor, "_networkTransport");
+    }
 
-        Object::call_method(m_ctx, Value::to_object(m_ctx, network_transport), "fetchWithCallbacks", {
-            makeRequest(m_ctx, request),
-            ResponseHandlerClass<T>::create_instance(m_ctx, std::move(completion_callback)),
-        });
+    void send_request_to_server(const app::Request request, std::function<void(const app::Response)> completion_callback) override {
+        (*s_dispatcher)(m_ctx, request, completion_callback);
     }
 
+private:
+    ContextType m_ctx;
+    inline static std::unique_ptr<realm::util::EventLoopDispatcher<SendRequestHandler>> s_dispatcher;
+
     std::string static fromHttpMethod(app::HttpMethod method) {
         switch (method) {
             case app::HttpMethod::get:   return "GET";