sqlx/sqlx-core/src/arguments.rs
Austin Bonander 7c32928ebc
feat(macros): implement query_scalar!() and variants
Signed-off-by: Austin Bonander <austin@launchbadge.com>
2021-01-20 22:23:04 -08:00

53 lines
1.7 KiB
Rust

//! Types and traits for passing arguments to SQL queries.
use crate::database::{Database, HasArguments};
use crate::encode::Encode;
use crate::types::Type;
/// A tuple of arguments to be sent to the database.
pub trait Arguments<'q>: Send + Sized + Default {
type Database: Database;
/// Reserves the capacity for at least `additional` more values (of `size` total bytes) to
/// be added to the arguments without a reallocation.
fn reserve(&mut self, additional: usize, size: usize);
/// Add the value to the end of the arguments.
fn add<T>(&mut self, value: T)
where
T: 'q + Send + Encode<'q, Self::Database> + Type<Self::Database>;
}
pub trait IntoArguments<'q, DB: HasArguments<'q>>: Sized + Send {
fn into_arguments(self) -> <DB as HasArguments<'q>>::Arguments;
}
// NOTE: required due to lack of lazy normalization
#[allow(unused_macros)]
macro_rules! impl_into_arguments_for_arguments {
($Arguments:path) => {
impl<'q>
crate::arguments::IntoArguments<
'q,
<$Arguments as crate::arguments::Arguments<'q>>::Database,
> for $Arguments
{
fn into_arguments(self) -> $Arguments {
self
}
}
};
}
/// used by the query macros to prevent supernumerary `.bind()` calls
pub struct ImmutableArguments<'q, DB: HasArguments<'q>>(pub <DB as HasArguments<'q>>::Arguments);
impl<'q, DB: HasArguments<'q>> IntoArguments<'q, DB> for ImmutableArguments<'q, DB> {
fn into_arguments(self) -> <DB as HasArguments<'q>>::Arguments {
self.0
}
}
// TODO: Impl `IntoArguments` for &[&dyn Encode]
// TODO: Impl `IntoArguments` for (impl Encode, ...) x16