Struct spacetimedb_table::table::RowRef

pub struct RowRef<'a> { /* private fields */ }

A reference to a single row within a table.

Safety

Having a r: RowRef is a proof that r.pointer() refers to a valid row. This makes constructing a RowRef, i.e., RowRef::new, an unsafe operation.

Implementations

impl<'a> RowRef<'a>

pub fn to_product_value(&self) -> ProductValue

Extract a ProductValue from the table.

This is a potentially expensive operation, as it must walk the table’s ProductTypeLayout and heap-allocate various substructures of the ProductValue.

pub fn read_col<T: ReadColumn>( self, col: impl Into<ColId> ) -> Result<T, TypeError>

Check that the idxth column of the row type stored by self is compatible with T, and read the value of that column from self.

pub fn project_not_empty( self, cols: &ColList ) -> Result<AlgebraicValue, InvalidFieldError>

Construct a projection of the row at self by extracting the cols.

Returns an error if cols specifies an index which is out-of-bounds for the row at self.

If cols contains more than one column, the values of the projected columns are wrapped in a ProductValue. If cols is a single column, the value of that column is returned without wrapping in a ProductValue.

pub fn pointer(&self) -> RowPointer

Returns the raw row pointer for this row reference.

pub fn row_layout(&self) -> &RowTypeLayout

pub fn page_and_offset(&self) -> (&Page, PageOffset)

pub fn bsatn_length(&self) -> Option<usize>

The length of this row when BSATN-encoded.

Only available for rows whose types have a static BSATN layout. Returns None for rows of other types, e.g. rows containing strings.

pub fn to_bsatn_vec(&self) -> Result<Vec<u8>, BsatnError>

BSATN-encode the row referred to by self into a freshly-allocated Vec<u8>.

This method will use a StaticBsatnLayout if one is available, and may therefore be faster than calling bsatn::to_vec.

pub fn to_bsatn_extend(&self, buf: &mut Vec<u8>) -> Result<(), BsatnError>

BSATN-encode the row referred to by self into buf, pushing self’s bytes onto the end of buf, similar to Vec::extend.

This method will use a StaticBsatnLayout if one is available, and may therefore be faster than calling bsatn::to_writer.

Trait Implementations

impl<'a> Clone for RowRef<'a>

fn clone(&self) -> RowRef<'a>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RowRef<'_>

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Serialize for RowRef<'_>

fn serialize<S: Serializer>(&self, ser: S) -> Result<S::Ok, S::Error>

Serialize self in the data format of S using the provided serializer.

impl<'a> Copy for RowRef<'a>