3 files changed, 21 insertions, 1 deletions
diff --git a/core/string/ustring.cpp b/core/string/ustring.cpp
index 9e468f7075..b34d9f3271 100644
--- a/core/string/ustring.cpp
+++ b/core/string/ustring.cpp
@@ -4342,6 +4342,9 @@ bool String::is_valid_html_color() const {
 	return Color::html_is_valid(*this);
 }
 
+// Changes made to the set of invalid filename characters must also be reflected in the String documentation for is_valid_filename.
+static const char *invalid_filename_characters = ": / \\ ? * \" | % < >";
+
 bool String::is_valid_filename() const {
 	String stripped = strip_edges();
 	if (*this != stripped) {
@@ -4352,7 +4355,22 @@ bool String::is_valid_filename() const {
 		return false;
 	}
 
-	return !(find(":") != -1 || find("/") != -1 || find("\\") != -1 || find("?") != -1 || find("*") != -1 || find("\"") != -1 || find("|") != -1 || find("%") != -1 || find("<") != -1 || find(">") != -1);
+	Vector<String> chars = String(invalid_filename_characters).split(" ");
+	for (const String &ch : chars) {
+		if (contains(ch)) {
+			return false;
+		}
+	}
+	return true;
+}
+
+String String::validate_filename() const {
+	Vector<String> chars = String(invalid_filename_characters).split(" ");
+	String name = strip_edges();
+	for (int i = 0; i < chars.size(); i++) {
+		name = name.replace(chars[i], "_");
+	}
+	return name;
 }
 
 bool String::is_valid_ip_address() const {
diff --git a/core/string/ustring.h b/core/string/ustring.h
index 6338f1d3cd..1582504c57 100644
--- a/core/string/ustring.h
+++ b/core/string/ustring.h
@@ -433,6 +433,7 @@ public:
 	static const String invalid_node_name_characters;
 	String validate_node_name() const;
 	String validate_identifier() const;
+	String validate_filename() const;
 
 	bool is_valid_identifier() const;
 	bool is_valid_int() const;
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 9e8c6fccb3..9852ba9184 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -1695,6 +1695,7 @@ static void _register_variant_builtin_methods() {
 	bind_string_method(json_escape, sarray(), varray());
 
 	bind_string_method(validate_node_name, sarray(), varray());
+	bind_string_method(validate_filename, sarray(), varray());
 
 	bind_string_method(is_valid_identifier, sarray(), varray());
 	bind_string_method(is_valid_int, sarray(), varray());