From eb2dd8ebd7a0831b07f8d187eb2686e5d9179ace Mon Sep 17 00:00:00 2001
From: Rubidium <rubidium@openttd.org>
Date: Tue, 30 Apr 2024 18:36:50 +0200
Subject: [PATCH] Codechange: make using a RAII managed FILE* less clunky

---
 src/dedicated.cpp | 2 +-
 src/fileio.cpp    | 4 ++--
 src/fileio_func.h | 5 ++++-
 src/highscore.cpp | 4 ++--
 4 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/src/dedicated.cpp b/src/dedicated.cpp
index df457f2559..1b8759db81 100644
--- a/src/dedicated.cpp
+++ b/src/dedicated.cpp
@@ -12,7 +12,7 @@
 #include "debug.h"
 
 std::string _log_file; ///< File to reroute output of a forked OpenTTD to
-std::unique_ptr<FILE, FileDeleter> _log_fd; ///< File to reroute output of a forked OpenTTD to
+AutoCloseFile _log_fd; ///< File to reroute output of a forked OpenTTD to
 
 #if defined(UNIX)
 
diff --git a/src/fileio.cpp b/src/fileio.cpp
index c99ec88bc1..1ef7ea3e3a 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -638,14 +638,14 @@ bool ExtractTar(const std::string &tar_filename, Subdirectory subdir)
 
 		/* First open the file in the .tar. */
 		size_t to_copy = 0;
-		std::unique_ptr<FILE, FileDeleter> in(FioFOpenFileTar(it2.second, &to_copy));
+		AutoCloseFile in(FioFOpenFileTar(it2.second, &to_copy));
 		if (!in) {
 			Debug(misc, 6, "Extracting {} failed; could not open {}", filename, tar_filename);
 			return false;
 		}
 
 		/* Now open the 'output' file. */
-		std::unique_ptr<FILE, FileDeleter> out(fopen(filename.c_str(), "wb"));
+		AutoCloseFile out(fopen(filename.c_str(), "wb"));
 		if (!out) {
 			Debug(misc, 6, "Extracting {} failed; could not open {}", filename, filename);
 			return false;
diff --git a/src/fileio_func.h b/src/fileio_func.h
index eaa6f76164..0aa24403c5 100644
--- a/src/fileio_func.h
+++ b/src/fileio_func.h
@@ -97,8 +97,11 @@ public:
 struct FileDeleter {
 	void operator()(FILE *f)
 	{
-		if (f) fclose(f);
+		if (f != nullptr) fclose(f);
 	}
 };
 
+/** Helper type for RAII management of a FILE that gets closed when it goes out of scope. */
+using AutoCloseFile = std::unique_ptr<FILE, FileDeleter>;
+
 #endif /* FILEIO_FUNC_H */
diff --git a/src/highscore.cpp b/src/highscore.cpp
index f6fd57978b..ee04b07f05 100644
--- a/src/highscore.cpp
+++ b/src/highscore.cpp
@@ -122,7 +122,7 @@ int8_t SaveHighScoreValueNetwork()
 /** Save HighScore table to file */
 void SaveToHighScore()
 {
-	std::unique_ptr<FILE, FileDeleter> fp(fopen(_highscore_file.c_str(), "wb"));
+	AutoCloseFile fp(fopen(_highscore_file.c_str(), "wb"));
 	if (fp == nullptr) return;
 
 	/* Does not iterate through the complete array!. */
@@ -146,7 +146,7 @@ void LoadFromHighScore()
 {
 	std::fill(_highscore_table.begin(), _highscore_table.end(), HighScores{});
 
-	std::unique_ptr<FILE, FileDeleter> fp(fopen(_highscore_file.c_str(), "rb"));
+	AutoCloseFile fp(fopen(_highscore_file.c_str(), "rb"));
 	if (fp == nullptr) return;
 
 	/* Does not iterate through the complete array!. */