Struct 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 unsafe fn project_unchecked(self, cols: &ColList) -> AlgebraicValue

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

If cols contains zero or 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.

Safety

• cols must not specify any column which is out-of-bounds for the row `self´.

pub fn project( 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 zero or 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

Return the layout of the row.

All rows within the same table will have the same layout.

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

Returns the page the row is in and the offset of the row within that page.

pub fn row_hash(&self) -> RowHash

Returns the row hash for ptr.

pub fn static_layout(&self) -> Option<&StaticLayout>

Returns the static layout for this row reference, if any.

pub fn read_via_bsatn<T>( &self, scratch: &mut Vec<u8>, ) -> Result<T, ReadViaBsatnError>

where T: DeserializeOwned,

Encode the row referred to by self into a Vec<u8> using BSATN and then deserialize it.

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 Hash for RowRef<'_>

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq<ProductValue> for RowRef<'_>

fn eq(&self, rhs: &ProductValue) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialEq for RowRef<'_>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

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 ToBsatn for RowRef<'_>

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 StaticLayout if one is available, and may therefore be faster than calling bsatn::to_vec.

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 StaticLayout if one is available, and may therefore be faster than calling bsatn::to_writer.

fn static_bsatn_size(&self) -> Option<u16>

Returns the static size of the type of this object.

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

impl Eq for RowRef<'_>