Struct CheckpointVisitor 

pub struct CheckpointVisitor { /* private fields */ }

Available on crate feature internal-api only.

Extracts the first checkpoint action found, leaving checkpoint as None if a batch has none. The action is an array of single-key tagged objects, each one of the metadata actions embedded in an adaptiveMetadata manifest commit.

Trait Implementations

impl Default for CheckpointVisitor

fn default() -> CheckpointVisitor

Returns the “default value” for a type.

impl RowVisitor for CheckpointVisitor

Available on crate feature adaptive-metadata-in-dev only.

fn selected_column_names_and_types( &self, ) -> (&'static [ColumnName], &'static [DataType])

The names and types of leaf fields this visitor accesses. The EngineData being visited validates these types when extracting column getters, and RowVisitor::visit will receive one getter for each selected field, in the requested order. The column names are used by RowVisitor::visit_rows_of to select fields from a “typical” EngineData; callers whose engine data has different column names can manually invoke EngineData::visit_rows.

fn visit<'a>( &mut self, row_count: usize, getters: &[&'a dyn GetData<'a>], ) -> DeltaResult<()>

Have the visitor visit the data. This will be called on a visitor passed to EngineData::visit_rows. For each leaf in the schema that was passed to extract a “getter” of type GetData will be present. This can be used to actually get at the data for each row. You can use the TypedGetData trait if you want to have a way to extract typed data that will fail if the “getter” is for an unexpected type. The data in getters does not outlive the call to this function (i.e. it should be copied if needed).

fn visit_rows_of(&mut self, data: &dyn EngineData) -> DeltaResult<()>

where Self: Sized,

Visit the rows of an EngineData, selecting the leaf column names given by RowVisitor::selected_column_names_and_types. This is a thin wrapper around EngineData::visit_rows which in turn will eventually invoke RowVisitor::visit.