1 files changed, 45 insertions, 0 deletions
diff --git a/ui/util.go b/ui/util.go
new file mode 100644
index 00000000..b17f106c
--- /dev/null
+++ b/ui/util.go
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package ui
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/lxn/walk"
+)
+
+func writeFileWithOverwriteHandling(owner walk.Form, filePath string, write func(file *os.File) error) bool {
+	showError := func(err error) bool {
+		if err == nil {
+			return false
+		}
+
+		walk.MsgBox(owner, "Writing file failed", err.Error(), walk.MsgBoxIconError)
+
+		return true
+	}
+
+	file, err := os.OpenFile(filePath, os.O_CREATE|os.O_WRONLY|os.O_EXCL, 0600)
+	if err != nil {
+		if os.IsExist(err) {
+			if walk.DlgCmdNo == walk.MsgBox(owner, "Writing file failed", fmt.Sprintf(`File "%s" already exists.
+
+Do you want to overwrite it?`, filePath), walk.MsgBoxYesNo|walk.MsgBoxDefButton2|walk.MsgBoxIconWarning) {
+				return false
+			}
+
+			if file, err = os.Create(filePath); err != nil {
+				return !showError(err)
+			}
+		} else {
+			return !showError(err)
+		}
+	}
+	defer file.Close()
+
+	return !showError(write(file))
+}