修复bug

module/Local_Server/Aircraft/aircraftlist_json.h

@@ -2,6 +2,9 @@
 
 #include "../Data_Source/Database.h"
 
+#include <iomanip>
+#include <sstream>
+
 // https://wiki.jetvision.de/wiki/Radarcape:Software_Features#Aircraft_List_JSON_Service
 struct Aircraft_List_JSON_Service_O {
     size_t times; //自定义添加出现的次数  用于显示的优先级
@@ -56,7 +59,7 @@ struct Aircraft_List_JSON_Service_O {
     RET<size_t> nocl; // Number of sensors providing data aircraft
     RET<std::string> tq;  // Time quality of this entry
 
-    static Psc::JSON view_model() {
+    static Psc::JSON build_view_model() {
         auto columns = Psc::JSON::array();
         const auto add_column = [&columns](const char* key, const char* label, const char* type,
                                            const char* default_sort_order = nullptr,
@@ -149,6 +152,35 @@ struct Aircraft_List_JSON_Service_O {
         return model;
     }
 
+    static constexpr std::uint32_t view_model_schema_version = 1;
+
+    static const std::string& view_model_schema_hash() {
+        static const std::string hash = [] {
+            auto model = build_view_model();
+            model.append({"schema_version", view_model_schema_version});
+            const auto serialized = model.to_json_string();
+            std::uint64_t value = 14695981039346656037ull;
+            for(const unsigned char byte : serialized) {
+                value ^= byte;
+                value *= 1099511628211ull;
+            }
+            std::ostringstream stream;
+            stream << std::hex << std::setfill('0') << std::setw(16) << value;
+            return stream.str();
+        }();
+        return hash;
+    }
+
+    static const Psc::JSON& view_model() {
+        static const Psc::JSON model = [] {
+            auto value = build_view_model();
+            value.append({"schema_version", view_model_schema_version});
+            value.append({"schema_hash", view_model_schema_hash()});
+            return value;
+        }();
+        return model;
+    }
+
     Psc::JSON toJson() {
         auto ret = Psc::JSON::object();
         ADD_Json(times);