| //! Serde helpers. |
| |
| use serde_yaml::mapping::Mapping; |
| use serde_yaml::Value; |
| |
| /// Merge two serde structures. |
| /// |
| /// This will take all values from `replacement` and use `base` whenever a value isn't present in |
| /// `replacement`. |
| pub fn merge(base: Value, replacement: Value) -> Value { |
| match (base, replacement) { |
| (Value::Sequence(mut base), Value::Sequence(mut replacement)) => { |
| base.append(&mut replacement); |
| Value::Sequence(base) |
| }, |
| (Value::Mapping(base), Value::Mapping(replacement)) => { |
| Value::Mapping(merge_mapping(base, replacement)) |
| }, |
| (value, Value::Null) => value, |
| (_, value) => value, |
| } |
| } |
| |
| /// Merge two key/value mappings. |
| fn merge_mapping(mut base: Mapping, replacement: Mapping) -> Mapping { |
| for (key, value) in replacement { |
| let value = match base.remove(&key) { |
| Some(base_value) => merge(base_value, value), |
| None => value, |
| }; |
| base.insert(key, value); |
| } |
| |
| base |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| |
| #[test] |
| fn merge_primitive() { |
| let base = Value::Null; |
| let replacement = Value::Bool(true); |
| assert_eq!(merge(base, replacement.clone()), replacement); |
| |
| let base = Value::Bool(false); |
| let replacement = Value::Bool(true); |
| assert_eq!(merge(base, replacement.clone()), replacement); |
| |
| let base = Value::Number(0.into()); |
| let replacement = Value::Number(1.into()); |
| assert_eq!(merge(base, replacement.clone()), replacement); |
| |
| let base = Value::String(String::new()); |
| let replacement = Value::String(String::from("test")); |
| assert_eq!(merge(base, replacement.clone()), replacement); |
| |
| let base = Value::Mapping(Mapping::new()); |
| let replacement = Value::Null; |
| assert_eq!(merge(base.clone(), replacement), base); |
| } |
| |
| #[test] |
| fn merge_sequence() { |
| let base = Value::Sequence(vec![Value::Null]); |
| let replacement = Value::Sequence(vec![Value::Bool(true)]); |
| let expected = Value::Sequence(vec![Value::Null, Value::Bool(true)]); |
| assert_eq!(merge(base, replacement), expected); |
| } |
| |
| #[test] |
| fn merge_mapping() { |
| let mut base_mapping = Mapping::new(); |
| base_mapping.insert(Value::String(String::from("a")), Value::Bool(true)); |
| base_mapping.insert(Value::String(String::from("b")), Value::Bool(false)); |
| let base = Value::Mapping(base_mapping); |
| |
| let mut replacement_mapping = Mapping::new(); |
| replacement_mapping.insert(Value::String(String::from("a")), Value::Bool(true)); |
| replacement_mapping.insert(Value::String(String::from("c")), Value::Bool(false)); |
| let replacement = Value::Mapping(replacement_mapping); |
| |
| let merged = merge(base, replacement); |
| |
| let mut expected_mapping = Mapping::new(); |
| expected_mapping.insert(Value::String(String::from("b")), Value::Bool(false)); |
| expected_mapping.insert(Value::String(String::from("a")), Value::Bool(true)); |
| expected_mapping.insert(Value::String(String::from("c")), Value::Bool(false)); |
| let expected = Value::Mapping(expected_mapping); |
| |
| assert_eq!(merged, expected); |
| } |
| } |