Add lua monkeypatch for Unicode support on Windows

automation/include/unicode-monkeypatch.lua

@@ -0,0 +1,128 @@
+local fii = require("ffi")
+
+if ffi.os ~= "Windows" then
+	return
+end
+
+-- Safety first!
+do
+	if pcall(string.dump, io.open) then
+		error("io.open is already patched!")
+	end
+
+	local function index(t, k)
+		return t[k]
+	end
+
+	if pcall(index, ffi.C, "GetACP") == false then
+		ffi.cdef[[
+		uint32_t __stdcall GetACP();
+		]]
+	end
+end
+
+local CP_UTF8 = 65001
+local MB_ERR_INVALID_CHARS = 8
+
+if ffi.C.GetACP() == CP_UTF8 then
+	-- "Use Unicode UTF-8 for worldwide language support" is ticked.
+	-- Don't bother patching it.
+	return
+end
+
+ffi.cdef[[
+int32_t __stdcall MultiByteToWideChar(
+	uint32_t CodePage,
+	uint32_t dwFlags,
+	const char *lpMultiByteStr,
+	int32_t cbMultiByte,
+	wchar_t *lpWideCharStr,
+	int32_t cchWideChar
+);
+void *_wfreopen(wchar_t *path, wchar_t *mode, void *file);
+int32_t _wrename(wchar_t *oldname, wchar_t *newname);
+int32_t _wremove(wchar_t *path);
+int32_t _wsystem(wchar_t *command);
+char *strerror(int errnum);
+]]
+
+local function widen(ch)
+	local size = ffi.C.MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, ch, #ch, nil, 0)
+	if size == 0 then
+		error(fname .. ": invalid character sequence")
+	end
+
+	local buf = ffi.new("wchar_t[?]", size + 1)
+	if ffi.C.MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, ch, #ch, buf, size) == 0 then
+		error(fname .. ": char conversion error")
+	end
+
+	return buf
+end
+
+local function fileresult(stat, fname)
+	if stat == 0 then
+		return true
+	end
+
+	local errno = ffi.errno
+	local msg = ffi.C.strerror(errno)
+
+	if fname then
+		return nil, fname .. ": " .. msg, errno
+	end
+	return nil, msg, errno
+end
+
+local function execresult(stat)
+	if stat == -1 then
+		return fileresult(0, nil)
+
+	if stat == 0 then
+		return true, "exit", stat
+	end
+	return nil, "exit", stat
+end
+
+local orig_open = io.open
+local orig_rename = os.rename
+local orig_remove = os.remove
+local orig_execute = os.execute
+
+function io.open(fname, mode)
+	local wfname = widen(path)
+	local wmode = widen(mode)
+
+	local file = assert(open("nul", "rb"))
+	if ffi.C._wfreopen(wfname, wmode, file) == nil then
+		local msg, errno = select(2, file:close())
+		return nil, fname .. ": " .. msg, errno
+	end
+
+	return file
+end
+
+function os.rename(oldname, newname)
+	local woldname = widen(oldname)
+	local wnewname = widen(newname)
+
+	local stat = ffi.C._wrename(woldname, wnewname)
+	return fileresult(stat, oldname)
+end
+
+function os.remove(fname)
+	local wfname = widen(path)
+
+	local stat = ffi.C._wremove(wfname)
+	return fileresult(stat, fname)
+end
+
+function os.execute(command)
+	local wcommand = command
+	if command then
+		wcommand = widen(command)
+		return execresult(wcommand)
+	end
+
+	return true
+end