Use file backup system for config files (#29)

librecomp/CMakeLists.txt

@@ -8,6 +8,7 @@ add_library(librecomp STATIC
     "${CMAKE_CURRENT_SOURCE_DIR}/src/dp.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/src/eep.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/src/euc-jp.cpp"
+    "${CMAKE_CURRENT_SOURCE_DIR}/src/files.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/src/flash.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/src/math_routines.cpp"
     "${CMAKE_CURRENT_SOURCE_DIR}/src/overlays.cpp"

librecomp/include/librecomp/recomp_files.h

@@ -0,0 +1,14 @@
+#ifndef __RECOMP_FILES_H__
+#define __RECOMP_FILES_H__
+
+#include <filesystem>
+#include <fstream>
+
+namespace recomp {
+    std::ifstream open_input_file_with_backup(const std::filesystem::path& filepath, std::ios_base::openmode mode = std::ios_base::in);
+    std::ifstream open_input_backup_file(const std::filesystem::path& filepath, std::ios_base::openmode mode = std::ios_base::in);
+    std::ofstream open_output_file_with_backup(const std::filesystem::path& filepath, std::ios_base::openmode mode = std::ios_base::out);
+    bool finalize_output_file_with_backup(const std::filesystem::path& filepath);
+};
+
+#endif

librecomp/src/files.cpp

@@ -0,0 +1,51 @@
+#include "recomp_files.h"
+
+constexpr std::u8string_view backup_suffix = u8".bak";
+constexpr std::u8string_view temp_suffix = u8".temp";
+
+std::ifstream recomp::open_input_backup_file(const std::filesystem::path& filepath, std::ios_base::openmode mode) {
+    std::filesystem::path backup_path{filepath};
+    backup_path += backup_suffix;
+    return std::ifstream{backup_path, mode};
+}
+
+std::ifstream recomp::open_input_file_with_backup(const std::filesystem::path& filepath, std::ios_base::openmode mode) {
+    std::ifstream ret{filepath, mode};
+
+    // Check if the file failed to open and open the corresponding backup file instead if so.
+    if (!ret.good()) {
+        return open_input_backup_file(filepath, mode);
+    }
+
+    return ret;
+}
+
+std::ofstream recomp::open_output_file_with_backup(const std::filesystem::path& filepath, std::ios_base::openmode mode) {
+    std::filesystem::path temp_path{filepath};
+    temp_path += temp_suffix;
+    std::ofstream temp_file_out{ temp_path, mode };
+
+    return temp_file_out;
+}
+
+bool recomp::finalize_output_file_with_backup(const std::filesystem::path& filepath) {
+    std::filesystem::path backup_path{filepath};
+    backup_path += backup_suffix;
+
+    std::filesystem::path temp_path{filepath};
+    temp_path += temp_suffix;
+
+    std::error_code ec;
+    if (std::filesystem::exists(filepath, ec)) {
+        std::filesystem::copy_file(filepath, backup_path, std::filesystem::copy_options::overwrite_existing, ec);
+        if (ec) {
+            return false;
+        }
+    }
+    std::filesystem::copy_file(temp_path, filepath, std::filesystem::copy_options::overwrite_existing, ec);
+    if (ec) {
+        return false;
+    }
+    std::filesystem::remove(temp_path, ec);
+    return true;
+}

librecomp/src/pi.cpp

@@ -6,6 +6,7 @@
 #include <mutex>
 #include "recomp.h"
 #include "recomp_game.h"
+#include "recomp_files.h"
 #include <ultramodern/ultra64.h>
 #include <ultramodern/ultramodern.hpp>
 
@@ -101,37 +102,24 @@ std::filesystem::path get_save_file_path() {
     return config_path / save_folder / (std::u8string{recomp::current_game_id()} + u8".bin");
 }
 
-std::filesystem::path get_save_file_path_temp() {
-    return config_path / save_folder / (recomp::current_game_id() + u8".bin.temp");
-}
-
-std::filesystem::path get_save_file_path_backup() {
-    return config_path / save_folder / (recomp::current_game_id() + u8".bin.bak");
-}
-
 void update_save_file() {
+    bool saving_failed = false;
     {
-        std::ofstream save_file{ get_save_file_path_temp(), std::ios_base::binary };
+        std::ofstream save_file = recomp::open_output_file_with_backup(get_save_file_path(), std::ios_base::binary);
 
         if (save_file.good()) {
             std::lock_guard lock{ save_context.save_buffer_mutex };
             save_file.write(save_context.save_buffer.data(), save_context.save_buffer.size());
         }
         else {
-            ultramodern::error_handling::message_box("Failed to write to the save file. Check your file permissions. If you have moved your appdata folder to Dropbox or similar, this can cause issues.");
+            saving_failed = false;
         }
     }
-
-    std::error_code ec;
-    if (std::filesystem::exists(get_save_file_path(), ec)) {
-        std::filesystem::copy_file(get_save_file_path(), get_save_file_path_backup(), std::filesystem::copy_options::overwrite_existing, ec);
-        if (ec) {
-            printf("[ERROR] Failed to copy save file backup\n");
+    if (!saving_failed) {
+        saving_failed = !recomp::finalize_output_file_with_backup(get_save_file_path());
     }
-    }
-    std::filesystem::copy_file(get_save_file_path_temp(), get_save_file_path(), std::filesystem::copy_options::overwrite_existing, ec);
-    if (ec) {
-        ultramodern::error_handling::message_box("Failed to write to the save file. Check your file permissions. If you have moved your appdata folder to Dropbox or similar, this can cause issues.");
+    if (saving_failed) {
+        ultramodern::error_handling::message_box("Failed to write to the save file. Check your file permissions and whether the save folder has been moved to Dropbox or similar, as this can cause issues.");
     }
 }
 
@@ -198,25 +186,19 @@ void save_clear(uint32_t start, uint32_t size, char value) {
 
 void ultramodern::init_saving(RDRAM_ARG1) {
     std::filesystem::path save_file_path = get_save_file_path();
-    std::filesystem::path save_file_path_backup = get_save_file_path_backup();
 
     // Ensure the save file directory exists.
     std::filesystem::create_directories(save_file_path.parent_path());
 
     // Read the save file if it exists.
-    std::ifstream save_file{ save_file_path, std::ios_base::binary };
+    std::ifstream save_file = recomp::open_input_file_with_backup(save_file_path, std::ios_base::binary);
     if (save_file.good()) {
         save_file.read(save_context.save_buffer.data(), save_context.save_buffer.size());
-    } else {
-        // Reading the save file faield, so try to read the backup save file.
-        std::ifstream save_file_backup{ save_file_path_backup, std::ios_base::binary };
-        if (save_file_backup.good()) {
-            save_file_backup.read(save_context.save_buffer.data(), save_context.save_buffer.size());
-        } else {
+    }
+    else {
         // Otherwise clear the save file to all zeroes.
         save_context.save_buffer.fill(0);
     }
-    }
 
     save_context.saving_thread = std::thread{saving_thread_func, PASS_RDRAM};
 }