34 lines
868 B
Rust
34 lines
868 B
Rust
//! Field guards
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use crate::{Context, FieldResult};
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/// Field guard
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///
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/// Guard is a precondition for a field that is resolved if `Ok(()` is returned, otherwise an error is returned.
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#[async_trait::async_trait]
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pub trait Guard {
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#[allow(missing_docs)]
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async fn check(&self, ctx: &Context<'_>) -> FieldResult<()>;
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}
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/// An extension trait for `Guard`
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pub trait GuardExt: Guard + Sized {
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/// Merge the two guards.
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fn and<R: Guard>(self, other: R) -> And<Self, R> {
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And(self, other)
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}
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}
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impl<T: Guard> GuardExt for T {}
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/// Guard for `GuardExt::and`
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pub struct And<A: Guard, B: Guard>(A, B);
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#[async_trait::async_trait]
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impl<A: Guard + Send + Sync, B: Guard + Send + Sync> Guard for And<A, B> {
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async fn check(&self, ctx: &Context<'_>) -> FieldResult<()> {
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self.0.check(ctx).await?;
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self.1.check(ctx).await
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}
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}
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