Function get_missing_changes

atomic-repository/src/apply/queries.rs:59–81

Get changes that are in the source view but not in the target view. # Arguments `txn` - Read transaction `from_view` - Source view `to_view` - Target view # Returns Vector of hashes that need to be inserted, in dependency order.

(
    txn: &T,
    from_view: &ViewState,
    to_view: &ViewState,
)

///
/// Vector of hashes that need to be inserted, in dependency order.
pub fn get_missing_changes<T: ViewTxnT>(
    txn: &T,
    from_view: &ViewState,
    to_view: &ViewState,
) -> InsertResult<Vec<Hash>> {
    // Get all changes in source
    let source_changes = get_view_changes(txn, from_view)?;

    // Build set of changes in target
    let target_set: HashSet<Hash> = get_view_changes(txn, to_view)?
        .into_iter()
        .map(|(_, hash)| hash)
        .collect();

    // Filter to changes not in target, preserving order
    let missing: Vec<Hash> = source_changes
        .into_iter()
        .filter(|(_, hash)| !target_set.contains(hash))
        .map(|(_, hash)| hash)
        .collect();

    Ok(missing)
}

/// Get changes up to a specific sequence number.
///