Struct ListVector 

pub struct ListVector;

Operations on LIST vectors.

A LIST vector stores a duckdb_list_entry { offset: u64, length: u64 } per row in the parent vector, and all element values in a flat child vector.

Write workflow

1. reserve — ensure child vector has capacity.
2. Write element values into the child via get_child + VectorWriter.
3. set_size — tell DuckDB how many elements were written.
4. set_entry — write the offset/length for each parent row.

Implementations

impl ListVector

pub unsafe fn get_child(vector: duckdb_vector) -> duckdb_vector

Returns the child vector containing all list elements (flat, across all rows).

Safety

• vector must be a valid DuckDB LIST vector.
• The returned handle is borrowed from vector.

pub unsafe fn get_size(vector: duckdb_vector) -> usize

Returns the total number of elements currently in the child vector.

Safety

vector must be a valid DuckDB LIST vector.

pub unsafe fn set_size(vector: duckdb_vector, size: usize)

Sets the number of elements in the child vector.

Call after writing all element values. DuckDB uses this to know how many child elements are valid.

Safety

• vector must be a valid DuckDB LIST vector.
• size must equal the number of elements written into the child vector.

pub unsafe fn reserve(vector: duckdb_vector, capacity: usize)

Reserves capacity in the child vector for at least capacity elements.

Call before writing elements to ensure the child vector has enough space.

Safety

vector must be a valid DuckDB LIST vector.

pub unsafe fn set_entry( vector: duckdb_vector, row_idx: usize, offset: u64, length: u64, )

Writes the offset/length metadata entry for a parent row.

This tells DuckDB where in the flat child vector this row’s elements start and how many elements it has.

Safety

• vector must be a valid DuckDB LIST vector.
• row_idx must be a valid row index in the parent vector.
• offset + length must not exceed the size of the child vector.

pub unsafe fn get_entry( vector: duckdb_vector, row_idx: usize, ) -> duckdb_list_entry

Returns the duckdb_list_entry for a given row (for reading).

Safety

• vector must be a valid DuckDB LIST vector.
• row_idx must be a valid row index.

pub unsafe fn child_writer(vector: duckdb_vector) -> VectorWriter

Creates a VectorWriter for the child vector (elements).

Safety

• vector must be a valid DuckDB LIST vector.
• The child must have been reserved with at least capacity elements.

pub unsafe fn child_reader( vector: duckdb_vector, element_count: usize, ) -> VectorReader

Creates a VectorReader for the child vector (reading list elements).

Safety

• vector must be a valid DuckDB LIST vector.
• element_count must equal the total number of elements in the child.