ProcessJson: Cache parsed JSON to make accessing significantly faster

The cache is invalidated when the string is set

src/game_interpreter.cpp

@@ -5080,7 +5080,12 @@ bool Game_Interpreter::CommandEasyRpgProcessJson(lcf::rpg::EventCommand const& c
 	int target_var_id = ValueOrVariable(com.parameters[6], com.parameters[7]);
 
 	std::string json_path = ToString(CommandStringOrVariable(com, 8, 9));
-	std::string json_data = ToString(Main_Data::game_strings->Get(source_var_id));
+	auto* json_data = Main_Data::game_strings->ParseJson(source_var_id);
+
+	if (!json_data) {
+		Output::Warning("JSON Parse error for {}", Main_Data::game_strings->Get(source_var_id));
+		return true;
+	}
 
 	if (target_var_type == 2 && !Player::IsPatchManiac()) {
 		Output::Warning("CommandEasyRpgProcessJson: String operations require Maniac Patch support");
@@ -5090,7 +5095,7 @@ bool Game_Interpreter::CommandEasyRpgProcessJson(lcf::rpg::EventCommand const& c
 	std::optional<std::string> result;
 
 	if (operation == 0) { // Get operation: Extract a value from JSON data
-		result = Json_Helper::GetValue(json_data, json_path);
+		result = Json_Helper::GetValue(*json_data, json_path);
 
 		if (result) {
 			switch (target_var_type) {
@@ -5127,7 +5132,7 @@ bool Game_Interpreter::CommandEasyRpgProcessJson(lcf::rpg::EventCommand const& c
 			return true;
 		}
 
-		result = Json_Helper::SetValue(json_data, json_path, new_value);
+		result = Json_Helper::SetValue(*json_data, json_path, new_value);
 
 		if (result) {
 			Main_Data::game_strings->Asg({ source_var_id }, *result);

src/game_strings.cpp

@@ -28,11 +28,34 @@
 #include "player.h"
 #include "utils.h"
 
+#ifdef HAVE_NLOHMANN_JSON
+#include "json_helper.h"
+#endif
+
 void Game_Strings::WarnGet(int id) const {
 	Output::Debug("Invalid read strvar[{}]!", id);
 	--_warnings;
 }
 
+#ifdef HAVE_NLOHMANN_JSON
+nlohmann::json* Game_Strings::ParseJson(int id) {
+	auto it = _json_cache.find(id);
+	if (it != _json_cache.end()) {
+		return &(it->second);
+	}
+
+	auto str = ToString(Get(id));
+	auto res = Json_Helper::Parse(str);
+
+	if (!res) {
+		return nullptr;
+	} else {
+		_json_cache[id] = *res;
+		return &_json_cache[id];
+	}
+}
+#endif
+
 StringView Game_Strings::Asg(Str_Params params, StringView string) {
 	Set(params, string);
 	return Get(params.string_id);

src/game_strings.h

@@ -15,7 +15,8 @@
  * along with EasyRPG Player. If not, see <http://www.gnu.org/licenses/>.
  */
 
- // Headers
+// Headers
+#include "system.h"
 #include <cstdint>
 #include <string>
 #include <lcf/data.h>
@@ -27,6 +28,10 @@
 #include "player.h"
 #include "string_view.h"
 
+#ifdef HAVE_NLOHMANN_JSON
+#include <nlohmann/json.hpp>
+#endif
+
 /**
  * Game_Strings class.
  */
@@ -59,6 +64,10 @@ class Game_Strings {
 	StringView GetWithMode(StringView str_data, int mode, int arg, const Game_Variables& variables) const;
 	StringView GetWithModeAndPos(StringView str_data, int mode, int arg, int* pos, const Game_Variables& variables);
 
+#ifdef HAVE_NLOHMANN_JSON
+	nlohmann::json* ParseJson(int id);
+#endif
+
 	StringView Asg(Str_Params params, StringView string);
 	StringView Cat(Str_Params params, StringView string);
 	int ToNum(Str_Params params, int var_id, Game_Variables& variables);
@@ -85,8 +94,11 @@ class Game_Strings {
 
 	Strings_t _strings;
 	mutable int _warnings = max_warnings;
-};
 
+#ifdef HAVE_NLOHMANN_JSON
+	std::unordered_map<int, nlohmann::json> _json_cache;
+#endif
+};
 
 inline void Game_Strings::Set(Str_Params params, StringView string) {
 	if (params.string_id <= 0) {
@@ -108,10 +120,18 @@ inline void Game_Strings::Set(Str_Params params, StringView string) {
 	} else {
 		it->second = ins_string;
 	}
+
+#ifdef HAVE_NLOHMANN_JSON
+	_json_cache.erase(params.string_id);
+#endif
 }
 
 inline void Game_Strings::SetData(Strings_t s) {
 	_strings = std::move(s);
+
+#ifdef HAVE_NLOHMANN_JSON
+	_json_cache.clear();
+#endif
 }
 
 inline void Game_Strings::SetData(const std::vector<lcf::DBString>& s) {
@@ -122,6 +142,10 @@ inline void Game_Strings::SetData(const std::vector<lcf::DBString>& s) {
 		}
 		++i;
 	}
+
+#ifdef HAVE_NLOHMANN_JSON
+	_json_cache.clear();
+#endif
 }
 
 inline const Game_Strings::Strings_t& Game_Strings::GetData() const {

src/json_helper.cpp

@@ -61,36 +61,22 @@ namespace Json_Helper {
 		return json_obj;
 	}
 
-	std::optional<std::string> GetValue(std::string_view json_data, std::string_view json_path) {
-		auto json_obj = Parse(json_data);
-
-		if (!json_obj) {
-			Output::Warning("JSON: Parse error for {}", json_data);
-    		return {};
-		}
-
+	std::optional<std::string> GetValue(nlohmann::json& json_obj, std::string_view json_path) {
 		json::json_pointer ptr((std::string(json_path)));
 
 		if (ptr.empty()) {
 			Output::Warning("JSON: Bad json pointer {}", json_path);
 			return {};
 		}
 
-		if (!json_obj->contains(ptr)) {
+		if (!json_obj.contains(ptr)) {
 			return "";
 		}
 
-		return GetValueAsString((*json_obj)[ptr]);
+		return GetValueAsString(json_obj[ptr]);
 	}
 
-	std::string SetValue(std::string_view json_data, std::string_view json_path, std::string_view value) {
-		auto json_obj = Parse(json_data);
-
-		if (!json_obj) {
-			Output::Warning("JSON Parse error for {}", json_data);
-    		return std::string(json_data);
-		}
-
+	std::string SetValue(nlohmann::json& json_obj, std::string_view json_path, std::string_view value) {
 		json::json_pointer ptr((std::string(json_path)));
 
 		if (ptr.empty()) {
@@ -102,12 +88,12 @@ namespace Json_Helper {
 
 		if (obj_value.is_discarded()) {
 			// If parsing fails, treat it as a string value
-			(*json_obj)[ptr] = std::string(value);
+			json_obj[ptr] = std::string(value);
 		} else {
-			(*json_obj)[ptr] = obj_value;
+			json_obj[ptr] = obj_value;
 		}
 
-		return (*json_obj).dump();
+		return json_obj.dump();
 	}
 }
 

src/json_helper.h

@@ -28,8 +28,8 @@
 
 namespace Json_Helper {
 	std::optional<nlohmann::json> Parse(std::string_view json_data);
-	std::optional<std::string> GetValue(std::string_view json_data, std::string_view json_path);
-	std::string SetValue(std::string_view json_data, std::string_view json_path, std::string_view value);
+	std::optional<std::string> GetValue(nlohmann::json& json_obj, std::string_view json_path);
+	std::string SetValue(nlohmann::json& json_obj, std::string_view json_path, std::string_view value);
 }
 
 #endif // HAVE_NLOHMANN_JSON