fix data race (#25)

TheLartians · web-flow · commit c8a7c3e1bcc7 · 2020-04-24T15:07:10.000+02:00
diff --git a/include/observe/event.h b/include/observe/event.h
@@ -120,9 +120,9 @@ namespace observe {
      */
     void emit(Args... args) const {
       std::vector<std::weak_ptr<Handler>> handlers;
-      handlers.resize(data->observers.size());
       {
         std::lock_guard<std::mutex> lock(data->observerMutex);
+        handlers.resize(data->observers.size());
         std::transform(data->observers.begin(), data->observers.end(), handlers.begin(),
                        [](auto &h) { return h.callback; });
       }

Original file line number	Diff line number	Diff line change
`@@ -120,9 +120,9 @@ namespace observe {`
`120`	`120`	`*/`
`121`	`121`	`void emit(Args... args) const {`
`122`	`122`	`std::vector<std::weak_ptr<Handler>> handlers;`
`123`		`- handlers.resize(data->observers.size());`
`124`	`123`	`{`
`125`	`124`	`std::lock_guard<std::mutex> lock(data->observerMutex);`
	`125`	`+ handlers.resize(data->observers.size());`
`126`	`126`	`std::transform(data->observers.begin(), data->observers.end(), handlers.begin(),`
`127`	`127`	`[](auto &h) { return h.callback; });`
`128`	`128`	`}`