Trait Query 

pub trait Query:
    Debug
    + Default
    + Sized
    + for<'d> QueryDb<'d> {
    type Key: Clone + Debug + Hash + Eq;
    type Value: Clone + Debug;
    type Storage;

    const QUERY_INDEX: u16;
    const QUERY_NAME: &'static str;

    // Required methods
    fn query_storage<'a>(
        group_storage: &'a <Self as QueryDb<'_>>::GroupStorage,
    ) -> &'a Arc<Self::Storage>;
    fn query_storage_mut<'a>(
        group_storage: &'a <Self as QueryDb<'_>>::GroupStorage,
    ) -> &'a Arc<Self::Storage>;
}

Trait implements by all of the “special types” associated with each of your queries.

Required Associated Constants

const QUERY_INDEX: u16

A unique index identifying this query within the group.

const QUERY_NAME: &'static str

Name of the query method (e.g., foo)

Required Associated Types

type Key: Clone + Debug + Hash + Eq

Type that you you give as a parameter – for queries with zero or more than one input, this will be a tuple.

type Value: Clone + Debug

What value does the query return?

type Storage

Internal struct storing the values for the query.

Required Methods

fn query_storage<'a>( group_storage: &'a <Self as QueryDb<'_>>::GroupStorage, ) -> &'a Arc<Self::Storage>

Extact storage for this query from the storage for its group.

fn query_storage_mut<'a>( group_storage: &'a <Self as QueryDb<'_>>::GroupStorage, ) -> &'a Arc<Self::Storage>

Extact storage for this query from the storage for its group.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors