Mark autosave files with the current date and time

This makes it so that autosave files are (almost) never overwritten, so
that opening an old version of the file won't result in the autosaves
from a newer version being replaced.

Clean up old autosave files on startup to limit the total to 100
files/100 MB. Maybe make this configurable in the future?

Closes #1155.

aegisub/src/ass_file.cpp

@@ -164,10 +164,9 @@ wxString AssFile::AutoSave() {
 		wxMkdir(path);
 
 	wxString name = origfile.GetName();
-	if (name.empty())
-		dstpath.SetFullName("Untitled.AUTOSAVE.ass");
-	else
-		dstpath.SetFullName(name + ".AUTOSAVE.ass");
+	if (!name)
+		name = "Untitled";
+	dstpath.SetFullName(wxString::Format("%s.%s.AUTOSAVE.ass", name, wxDateTime::Now().Format("%Y-%m-%d-%H-%M-%S")));
 
 	Save(dstpath.GetFullPath(), false, false);
 

aegisub/src/main.cpp

@@ -282,15 +282,14 @@ bool AegisubApp::OnInit() {
 	}
 #endif
 
+	StartupLog("Clean old autosave files");
+	wxString autosave_path = lagi_wxString(OPT_GET("Path/Auto/Save")->GetString());
+	CleanCache(autosave_path, "*.AUTOSAVE.ass", 100, 1000);
+
 	StartupLog("Initialization complete");
 	return true;
 }
 
-
-
-/// @brief Exit
-/// @return
-///
 int AegisubApp::OnExit() {
 	if (frame)
 		delete frame;