Function resolve_position

atomic-core/src/apply/position.rs:65–95

Convert an external position (with Hash) to an internal position (with NodeId). This is the bridge between the serialized change format (using hashes) and the internal graph format (using NodeIds). # Arguments `txn` - Transaction for looking up internal IDs `pos` - External position with optional hash `current_change` - NodeId of the change being applied (used for self-references) # Returns T

(
    txn: &T,
    pos: &Position<Option<Hash>>,
    current_change: NodeId,
)

/// Returns `LocalApplyError::DependencyMissing` if the referenced change
/// is not registered in the repository.
pub fn resolve_position<T: GraphTxnT>(
    txn: &T,
    pos: &Position<Option<Hash>>,
    current_change: NodeId,
) -> Result<Position<NodeId>, LocalApplyError> {
    let change_id = match pos.change {
        Some(hash) if hash.is_none() => {
            // Hash::NONE (all zeros) represents the ROOT position.
            // This is a virtual span that doesn't exist in the database
            // but serves as the parent for all top-level files.
            NodeId::ROOT
        }
        Some(hash) => {
            // External reference - look up the internal ID
            txn.get_internal(&hash)
                .map_err(|e| LocalApplyError::Internal {
                    message: format!("Failed to resolve position: {}", e),
                })?
                .ok_or(LocalApplyError::DependencyMissing { hash })?
        }
        None => {
            // Self-reference - use the current change ID
            current_change
        }
    };

    Ok(Position {
        change: change_id,
        pos: pos.pos,
    })
}

/// Convert an external span (with Hash) to an internal span (with NodeId).
///