Trait DataAccessor 

pub trait DataAccessor<S: Scalar>: MetadataAccessor {
    // Required method
    fn get_column(
        &self,
        table_ref: &TableRef,
        column_id: &Ident,
    ) -> Column<'_, S>;

    // Provided method
    fn get_table(
        &self,
        table_ref: &TableRef,
        column_ids: &IndexSet<Ident, BuildHasherDefault<AHasher>>,
    ) -> Table<'_, S> { ... }
}

Access database columns of an in-memory table span.

Prover uses this information to process a query.

In pseudo-code, here is a sketch of how DataAccessor fits in with the prove workflow:

prove(query, database) {
      if(!validate_query(query, database)) {
          // if the query references columns that don't exist
          // we should error here before going any further
          invalid-query()
      }
      update-cached-columns(database, query)
           // if the database represents an in-memory cache of an externally persisted
           // database we should update the cache so that any column referenced in the query
           // will be available
      database.reader_lock()
          // we can't be updating the database while proving
      accessor <- make-data-accessor(database)
      proof <- prove-valid-query(query, accessor)
      database.reader_unlock()
      return proof
}

Note: we assume that the query has already been validated so that we will only be accessing information about columns that exist in the database.

Required Methods

fn get_column(&self, table_ref: &TableRef, column_id: &Ident) -> Column<'_, S>

Return the data span in the table (not the full-table data)

Provided Methods

fn get_table( &self, table_ref: &TableRef, column_ids: &IndexSet<Ident, BuildHasherDefault<AHasher>>, ) -> Table<'_, S>

Creates a new Table from a TableRef and Idents.

Columns are retrieved from the DataAccessor using the provided TableRef and Idents. The only reason why [table_ref] is needed is because [column_ids] can be empty.

Panics

Column length mismatches can occur in theory. In practice, this should not happen.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<'a, CP: CommitmentEvaluationProof> DataAccessor<<CP as CommitmentEvaluationProof>::Scalar> for TableTestAccessor<'a, CP>

Panics

Will panic if the table_ref is not found in self.tables, or if the column_id is not found in the inner table for that reference, indicating that an invalid column reference was provided.

impl<CP: CommitmentEvaluationProof> DataAccessor<<CP as CommitmentEvaluationProof>::Scalar> for OwnedTableTestAccessor<'_, CP>

Panics

Will panic if the table_ref is not found in self.tables, or if the column_id is not found in the inner table for that reference, indicating that an invalid column reference was provided.

impl<S: Scalar> DataAccessor<S> for DataAccessorImpl<'_, S>