Struct spacetimedb_vm::expr::SourceSet

pub struct SourceSet<T, const N: usize>(/* private fields */);

A SourceProvider backed by an ArrayVec.

Internally, the SourceSet stores an Option<T> for each planned SourceId which are Option::taken out of the set.

Implementations

impl<T, const N: usize> SourceSet<T, N>

pub fn empty() -> Self

Returns an empty source set.

pub fn add(&mut self, table: T) -> SourceId

Insert an entry into this SourceSet so it can be used in a query plan, and return a SourceId which can be embedded in that plan.

pub fn take(&mut self, id: SourceId) -> Option<T>

Extract the entry referred to by id from this SourceSet, leaving a “gap” in its place.

Subsequent calls to take on the same id will return None.

pub fn len(&self) -> usize

Returns the number of slots for MemTables in this set.

Calling self.take_mem_table(...) or self.take_table(...) won’t affect this number.

pub fn is_empty(&self) -> bool

Returns whether this set has any slots for MemTables.

Calling self.take_mem_table(...) or self.take_table(...) won’t affect whether the set is empty.

impl<const N: usize> SourceSet<Vec<ProductValue>, N>

pub fn add_mem_table(&mut self, table: MemTable) -> SourceExpr

Insert a MemTable into this SourceSet so it can be used in a query plan, and return a SourceExpr which can be embedded in that plan.

pub fn take_table(&mut self, source: &SourceExpr) -> Option<Table>

Resolve source to a Table for use in query execution.

If the source is a SourceExpr::DbTable, this simply clones the DbTable and returns it. (DbTable::clone is inexpensive.) In this case, self is not modified.

If the source is a [SourceExpr::MemTable], this behaves like [Self::take_mem_table]. Subsequent calls to take_table or take_mem_table with the same source will fail.

Trait Implementations

impl<T: Clone, const N: usize> Clone for SourceSet<T, N>

fn clone(&self) -> SourceSet<T, N>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug, const N: usize> Debug for SourceSet<T, N>

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

Formats the value using the given formatter.

impl<T, const N: usize> From<[T; N]> for SourceSet<T, N>

fn from(sources: [T; N]) -> Self

Converts to this type from the input type.

impl<T, const N: usize> Index<SourceId> for SourceSet<T, N>

type Output = Option<T>

The returned type after indexing.

fn index(&self, idx: SourceId) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<T, const N: usize> IndexMut<SourceId> for SourceSet<T, N>

fn index_mut(&mut self, idx: SourceId) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation.

impl<T: PartialEq, const N: usize> PartialEq for SourceSet<T, N>

fn eq(&self, other: &SourceSet<T, N>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<'a, T: 'a + IntoIterator<Item = RelValue<'a>>, const N: usize> SourceProvider<'a> for SourceSet<T, N>

type Source = T

The type of in-memory tables that this provider uses.

fn take_source(&mut self, id: SourceId) -> Option<T>

Retrieve the Self::Source associated with id, if any.

impl<T: Eq, const N: usize> Eq for SourceSet<T, N>

impl<T, const N: usize> StructuralPartialEq for SourceSet<T, N>