Struct AggregateAdapter 

pub struct AggregateAdapter<F> { /* private fields */ }

Type-erased adapter that wraps a concrete AggregateFunction so the registry can store heterogeneous aggregates behind a single trait object.

The adapter implements AggregateFunction<State = Box<dyn Any + Send>>, boxing the concrete state on creation and downcasting on step/finalize.

Implementations

impl<F> AggregateAdapter<F>

pub const fn new(inner: F) -> Self

Wrap a concrete aggregate function for type-erased storage.

Trait Implementations

impl<F> AggregateFunction for AggregateAdapter<F>

where F: AggregateFunction, F::State: 'static,

type State = Box<dyn Any + Send>

The per-group accumulator type.

fn initial_state(&self) -> Self::State

Create a fresh accumulator (zero/identity state).

fn step(&self, state: &mut Self::State, args: &[SqliteValue]) -> Result<()>

Process one row, updating the accumulator.

fn finalize(&self, state: Self::State) -> Result<SqliteValue>

Consume the accumulator and produce the final result.

fn num_args(&self) -> i32

The number of arguments this function accepts (-1 = variadic).

fn min_args(&self) -> i32

Minimum accepted SQL argument count for variadic functions.

fn max_args(&self) -> Option<i32>

Maximum accepted SQL argument count, or None for unbounded variadic functions.

fn name(&self) -> &str

The function name, used in error messages and EXPLAIN output.

fn accepts_arg_count(&self, num_args: i32) -> bool

Return whether this function accepts num_args SQL arguments.