Add LuaMan::FileExists, since FileOpen now spits out an error if the file doesn't exist so can't be cleanly used as a check (and shouldn't anyway)

Author: garethyr

CHANGELOG.md

@@ -637,6 +637,8 @@ This can be accessed via the new Lua (R/W) `SettingsMan` property `AIUpdateInter
 
 - Added `Activity` Lua function `GetPlayerController`, which gets you the `Controller` used for GUI stuff and when there's no `Actor` selected in an `Activity`. Be aware, it's very likely possible to cause problems by doing dumb things with this.
 
+- Added `LuaMan` Lua function `FileExists`, which lets you check whether a specified file exists. Like with `FileOpen`, the file must be inside a folder ending in `.rte`.
+
 </details>
 
 <details><summary><b>Changed</b></summary>

Managers/LuaMan.cpp

@@ -59,6 +59,7 @@ namespace RTE {
 				.def_readonly("TempEntities", &LuaMan::m_TempEntityVector, luabind::return_stl_iterator)
 				.def("GetDirectoryList", &LuaMan::DirectoryList, luabind::return_stl_iterator)
 				.def("GetFileList", &LuaMan::FileList, luabind::return_stl_iterator)
+				.def("FileExists", &LuaMan::FileExists)
 				.def("FileOpen", &LuaMan::FileOpen)
 				.def("FileClose", &LuaMan::FileClose)
 				.def("FileReadLine", &LuaMan::FileReadLine)
@@ -522,6 +523,17 @@ namespace RTE {
 		return m_FileOrDirectoryPaths;
 	}
 
+/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+	bool LuaMan::FileExists(const std::string &fileName) {
+		std::string fullPath = System::GetWorkingDirectory() + g_PresetMan.GetFullModulePath(fileName);
+		if ((fullPath.find("..") == std::string::npos) && (fullPath.find(System::GetModulePackageExtension()) != std::string::npos)) {
+			return std::filesystem::exists(fullPath);
+		}
+
+		return false;
+	}
+
 /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 	int LuaMan::FileOpen(const std::string &fileName, const std::string &accessMode) {

Managers/LuaMan.h

@@ -194,6 +194,13 @@ namespace RTE {
 		/// <returns>A vector of the files in relativeDirectory.</returns>
 		const std::vector<std::string> & FileList(const std::string &relativeDirectory);
 
+		/// <summary>
+		/// Returns whether or not the specified file exists. You can only check for files inside .rte folders in the working directory.
+		/// </summary>
+		/// <param name="fileName">Path to the file. All paths are made absolute by adding current working directory to the specified path.</param>
+		/// <returns>Whether or not the specified file exists.</returns>
+		bool FileExists(const std::string &fileName);
+
 		/// <summary>
 		/// Opens a file or creates one if it does not exist, depending on access mode. You can open files only inside .rte folders in the working directly. You can't open more that c_MaxOpenFiles file simultaneously.
 		/// On Linux will attempt to open a file case insensitively.