63 lines
1.6 KiB
Rust
63 lines
1.6 KiB
Rust
//! Field guards
|
|
|
|
use crate::{Context, Result};
|
|
|
|
/// Field guard
|
|
///
|
|
/// Guard is a pre-condition for a field that is resolved if `Ok(())` is
|
|
/// returned, otherwise an error is returned.
|
|
#[async_trait::async_trait]
|
|
pub trait Guard {
|
|
/// Check whether the guard will allow access to the field.
|
|
async fn check(&self, ctx: &Context<'_>) -> Result<()>;
|
|
}
|
|
|
|
#[async_trait::async_trait]
|
|
impl<T> Guard for T
|
|
where
|
|
T: Fn(&Context<'_>) -> Result<()> + Send + Sync + 'static,
|
|
{
|
|
async fn check(&self, ctx: &Context<'_>) -> Result<()> {
|
|
self(ctx)
|
|
}
|
|
}
|
|
|
|
/// An extension trait for `Guard`.
|
|
pub trait GuardExt: Guard + Sized {
|
|
/// Perform `and` operator on two rules
|
|
fn and<R: Guard>(self, other: R) -> And<Self, R> {
|
|
And(self, other)
|
|
}
|
|
|
|
/// Perform `or` operator on two rules
|
|
fn or<R: Guard>(self, other: R) -> Or<Self, R> {
|
|
Or(self, other)
|
|
}
|
|
}
|
|
|
|
impl<T: Guard> GuardExt for T {}
|
|
|
|
/// Guard for [`GuardExt::and`](trait.GuardExt.html#method.and).
|
|
pub struct And<A: Guard, B: Guard>(A, B);
|
|
|
|
#[async_trait::async_trait]
|
|
impl<A: Guard + Send + Sync, B: Guard + Send + Sync> Guard for And<A, B> {
|
|
async fn check(&self, ctx: &Context<'_>) -> Result<()> {
|
|
self.0.check(ctx).await?;
|
|
self.1.check(ctx).await
|
|
}
|
|
}
|
|
|
|
/// Guard for [`GuardExt::or`](trait.GuardExt.html#method.or).
|
|
pub struct Or<A: Guard, B: Guard>(A, B);
|
|
|
|
#[async_trait::async_trait]
|
|
impl<A: Guard + Send + Sync, B: Guard + Send + Sync> Guard for Or<A, B> {
|
|
async fn check(&self, ctx: &Context<'_>) -> Result<()> {
|
|
if self.0.check(ctx).await.is_ok() {
|
|
return Ok(());
|
|
}
|
|
self.1.check(ctx).await
|
|
}
|
|
}
|