Struct scylla_cql::types::serialize::writers::CellWriter

pub struct CellWriter<'buf> { /* private fields */ }

Represents a handle to a CQL value that needs to be written into.

The writer can either be transformed into a ready value right away (via set_null, set_unset or set_value or transformed into the CellValueBuilder in order to gradually initialize the value when the contents are not available straight away.

After the value is fully initialized, the handle is consumed and a WrittenCellProof object is returned in its stead. This is a type-level proof that the value was fully initialized and is used in SerializeValue::serialize in order to enforce the implementer to fully initialize the provided handle to CQL value.

Dropping this type without calling any of its methods will result in nothing being written.

Implementations

impl<'buf> CellWriter<'buf>

pub fn new(buf: &'buf mut Vec<u8>) -> Self

Creates a new cell writer based on an existing Vec.

The newly created row writer will append data to the end of the vec.

pub fn set_null(self) -> WrittenCellProof<'buf>

Sets this value to be null, consuming this object.

pub fn set_unset(self) -> WrittenCellProof<'buf>

Sets this value to represent an unset value, consuming this object.

pub fn set_value( self, contents: &[u8], ) -> Result<WrittenCellProof<'buf>, CellOverflowError>

Sets this value to a non-zero, non-unset value with given contents.

Prefer this to into_value_builder if you have all of the contents of the value ready up front (e.g. for fixed size types).

Fails if the contents size overflows the maximum allowed CQL cell size (which is i32::MAX).

pub fn into_value_builder(self) -> CellValueBuilder<'buf>

Turns this writter into a CellValueBuilder which can be used to gradually initialize the CQL value.

This method should be used if you don’t have all of the data up front, e.g. when serializing compound types such as collections or UDTs.