Function find_change_sequence

atomic-repository/src/history/operations.rs:193–210

Find the sequence number for a change by its hash. # Arguments `txn` - Read transaction `view` - View to search `hash` - Hash of the change to find # Returns The sequence number if found, or None if the change is not in the view.

(
    txn: &T,
    view: &ViewState,
    hash: &Hash,
)

///
/// The sequence number if found, or None if the change is not in the view.
pub fn find_change_sequence<T: ViewTxnT>(
    txn: &T,
    view: &ViewState,
    hash: &Hash,
) -> HistoryResult<Option<u64>> {
    // First get the internal ID
    let node_id = match txn.get_internal(hash) {
        Ok(Some(id)) => id,
        Ok(None) => return Ok(None),
        Err(e) => return Err(HistoryError::Database(e.to_string())),
    };

    // Then look up the sequence
    match txn.get_change_seq(view, node_id) {
        Ok(seq) => Ok(seq),
        Err(e) => Err(HistoryError::Database(e.to_string())),
    }
}

/// Get the state immediately before a change was applied.
///