Repository: launchbadge/sqlx
File: sqlx-core/src/postgres/types/ltree.rs (Rust)

Code before:
impl PgLTree {
    pub fn push(&mut self, label: String) -> Result<(), Error> {
        if label.chars().all(|c| c.is_ascii_alphabetic() || c.is_ascii_digit() || c == '_') {
            self.labels.push(label);
            Ok(())
        } else {
            Err(Error::InvalidLtreeLabel)
        }
    }
}

impl FromStr for PgLTree {
    type Err = Error;

    fn from_str(s: &str) -> Result<Self, Error> {
        Ok(
            Self {
                labels: s.split('.').map(|s| s.to_owned()).collect()
            }
        )
    }
}

impl Display for PgLTree {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        write!(f, "{}", self.labels.join("."))
    }
}

impl Type<Postgres> for PgLTree {
    fn type_info() -> PgTypeInfo {
        PgTypeInfo::LTREE
    }
}

impl Encode<'_, Postgres> for PgLTree {
    fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> IsNull {
        buf.extend(1i8.to_le_bytes());
        buf.extend(self.to_string().as_bytes());

        IsNull::No
    }
}

impl<'r> Decode<'r, Postgres> for PgLTree {
    fn decode(value: PgValueRef<'r>) -> Result<Self, BoxDynError> {
        match value.format() {
            PgValueFormat::Binary => {
                let bytes = value.as_bytes()?;
                let version = i8::from_le_bytes([bytes[0]; 1]);
                if version != 1 {

Review comment (performance):
This seems inefficient to me, as it allocates just to write to `f`. I'd go with a manual implementation

Code after:
#[derive(Debug, thiserror::Error)]
#[non_exhaustive]
pub enum PgLTreeParseError {
    /// LTree labels can only contain [A-Za-z0-9_]
    #[error("ltree label cotains invalid characters")]
    InvalidLtreeLabel,

    /// LTree version not supported
    #[error("ltree version not supported")]
    InvalidLtreeVersion,
}

/// Container for a Label Tree (`ltree`) in Postgres.
///
/// See https://www.postgresql.org/docs/current/ltree.html
///
/// ### Note: Requires Postgres 13+
///
/// This integration requires that the `ltree` type support the binary format in the Postgres
/// wire protocol, which only became available in Postgres 13.
/// ([Postgres 13.0 Release Notes, Additional Modules][https://www.postgresql.org/docs/13/release-13.html#id-1.11.6.11.5.14])
///
/// Ideally, SQLx's Postgres driver should support falling back to text format for types
/// which don't have `typsend` and `typrecv` entries in `pg_type`, but that work still needs
/// to be done.
///
/// ### Note: Extension Required
/// The `ltree` extension is not enabled by default in Postgres. You will need to do so explicitly:
///
/// ```ignore
/// CREATE EXTENSION IF NOT EXISTS "ltree";
/// ```
#[derive(Clone, Debug, Default, PartialEq)]
pub struct PgLTree {
    labels: Vec<String>,
}

impl PgLTree {
    /// creates default/empty ltree
    pub fn new() -> Self {
        Self::default()
    }

    /// creates ltree from a [Vec<String>] without checking labels
    pub fn new_unchecked(labels: Vec<String>) -> Self {
        Self { labels }
    }

    /// creates ltree from an iterator with checking labels
    pub fn from_iter<I, S>(labels: I) -> Result<Self, PgLTreeParseError>
    where