refactor!: reorganize DI containers

BREAKING CHANGE: DIContainer, AsyncDIContainer & the binding structs have been relocated

4 files changed, 788 insertions, 0 deletions

diff --git a/src/di_container/asynchronous/binding/builder.rs b/src/di_container/asynchronous/binding/builder.rs
new file mode 100644
index 0000000..6daba30
--- /dev/null
+++ b/src/di_container/asynchronous/binding/builder.rs
@@ -0,0 +1,653 @@
+//! Binding builder for types inside of a [`AsyncDIContainer`].
+use std::any::type_name;
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+use crate::di_container::asynchronous::binding::scope_configurator::AsyncBindingScopeConfigurator;
+#[cfg(feature = "factory")]
+use crate::di_container::asynchronous::binding::when_configurator::AsyncBindingWhenConfigurator;
+use crate::errors::async_di_container::AsyncBindingBuilderError;
+use crate::interfaces::async_injectable::AsyncInjectable;
+use crate::AsyncDIContainer;
+
+/// Alias for a threadsafe boxed function.
+#[cfg(feature = "factory")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "factory")))]
+pub type BoxFn<Args, Return> = Box<(dyn Fn<Args, Output = Return> + Send + Sync)>;
+
+/// Binding builder for type `Interface` inside a [`AsyncDIContainer`].
+pub struct AsyncBindingBuilder<Interface>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+{
+    di_container: Arc<AsyncDIContainer>,
+    interface_phantom: PhantomData<Interface>,
+}
+
+impl<Interface> AsyncBindingBuilder<Interface>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+{
+    pub(crate) fn new(di_container: Arc<AsyncDIContainer>) -> Self
+    {
+        Self {
+            di_container,
+            interface_phantom: PhantomData,
+        }
+    }
+
+    /// Creates a binding of type `Interface` to type `Implementation` inside of the
+    /// associated [`AsyncDIContainer`].
+    ///
+    /// The scope of the binding is transient. But that can be changed by using the
+    /// returned [`AsyncBindingScopeConfigurator`]
+    ///
+    /// # Errors
+    /// Will return Err if the associated [`AsyncDIContainer`] already have a binding for
+    /// the interface.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::error::Error;
+    /// #
+    /// # use syrette::{AsyncDIContainer, injectable};
+    /// #
+    /// # trait Foo: Send + Sync {}
+    /// #
+    /// # struct Bar {}
+    /// #
+    /// # #[injectable(Foo, async = true)]
+    /// # impl Bar {
+    /// #   fn new() -> Self
+    /// #   {
+    /// #       Self {}
+    /// #   }
+    /// # }
+    /// #
+    /// # impl Foo for Bar {}
+    /// #
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn Error>>
+    /// # {
+    /// # let mut di_container = AsyncDIContainer::new();
+    /// #
+    /// di_container.bind::<dyn Foo>().to::<Bar>().await?;
+    /// #
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub async fn to<Implementation>(
+        &self,
+    ) -> Result<
+        AsyncBindingScopeConfigurator<Interface, Implementation>,
+        AsyncBindingBuilderError,
+    >
+    where
+        Implementation: AsyncInjectable,
+    {
+        {
+            let bindings_lock = self.di_container.bindings.lock().await;
+
+            if bindings_lock.has::<Interface>(None) {
+                return Err(AsyncBindingBuilderError::BindingAlreadyExists(type_name::<
+                    Interface,
+                >(
+                )));
+            }
+        }
+
+        let binding_scope_configurator =
+            AsyncBindingScopeConfigurator::new(self.di_container.clone());
+
+        binding_scope_configurator.in_transient_scope().await;
+
+        Ok(binding_scope_configurator)
+    }
+
+    /// Creates a binding of factory type `Interface` to a factory inside of the
+    /// associated [`AsyncDIContainer`].
+    ///
+    /// # Errors
+    /// Will return Err if the associated [`AsyncDIContainer`] already have a binding
+    /// for the interface.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::error::Error;
+    /// #
+    /// # use syrette::{AsyncDIContainer, factory};
+    /// # use syrette::ptr::TransientPtr;
+    /// #
+    /// # trait Foo: Send + Sync {}
+    /// #
+    /// # struct Bar
+    /// # {
+    /// #   num: i32,
+    /// #   some_str: String
+    /// # }
+    /// #
+    /// # impl Foo for Bar {}
+    /// #
+    /// # #[factory(threadsafe = true)]
+    /// # type FooFactory = dyn Fn(i32, String) -> dyn Foo;
+    /// #
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn Error>>
+    /// # {
+    /// # let mut di_container = AsyncDIContainer::new();
+    /// #
+    /// di_container
+    ///     .bind::<FooFactory>()
+    ///     .to_factory(&|_| {
+    ///         Box::new(|num, some_str| {
+    ///             let bar = TransientPtr::new(Bar { num, some_str });
+    ///
+    ///             bar as TransientPtr<dyn Foo>
+    ///         })
+    ///     })
+    ///     .await?;
+    /// #
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "factory")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "factory")))]
+    pub async fn to_factory<Args, Return, FactoryFunc>(
+        &self,
+        factory_func: &'static FactoryFunc,
+    ) -> Result<AsyncBindingWhenConfigurator<Interface>, AsyncBindingBuilderError>
+    where
+        Args: 'static,
+        Return: 'static + ?Sized,
+        Interface: Fn<Args, Output = Return> + Send + Sync,
+        FactoryFunc:
+            Fn<(Arc<AsyncDIContainer>,), Output = BoxFn<Args, Return>> + Send + Sync,
+    {
+        use crate::castable_factory::threadsafe::ThreadsafeCastableFactory;
+        use crate::provider::r#async::AsyncFactoryVariant;
+
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        if bindings_lock.has::<Interface>(None) {
+            return Err(AsyncBindingBuilderError::BindingAlreadyExists(type_name::<
+                Interface,
+            >(
+            )));
+        }
+
+        let factory_impl = ThreadsafeCastableFactory::new(factory_func);
+
+        bindings_lock.set::<Interface>(
+            None,
+            Box::new(crate::provider::r#async::AsyncFactoryProvider::new(
+                crate::ptr::ThreadsafeFactoryPtr::new(factory_impl),
+                AsyncFactoryVariant::Normal,
+            )),
+        );
+
+        Ok(AsyncBindingWhenConfigurator::new(self.di_container.clone()))
+    }
+
+    /// Creates a binding of factory type `Interface` to a async factory inside of the
+    /// associated [`AsyncDIContainer`].
+    ///
+    /// # Errors
+    /// Will return Err if the associated [`AsyncDIContainer`] already have a binding
+    /// for the interface.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::error::Error;
+    /// # use std::time::Duration;
+    /// #
+    /// # use syrette::{AsyncDIContainer, factory, async_closure};
+    /// # use syrette::ptr::TransientPtr;
+    /// #
+    /// # trait Foo: Send + Sync {}
+    /// #
+    /// # struct Bar
+    /// # {
+    /// #   num: i32,
+    /// #   some_str: String
+    /// # }
+    /// #
+    /// # impl Foo for Bar {}
+    /// #
+    /// # #[factory(async = true)]
+    /// # type FooFactory = dyn Fn(i32, String) -> dyn Foo;
+    /// #
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn Error>>
+    /// # {
+    /// # let mut di_container = AsyncDIContainer::new();
+    /// #
+    /// di_container
+    ///     .bind::<FooFactory>()
+    ///     .to_async_factory(&|_| {
+    ///         async_closure!(|num, some_str| {
+    ///             let bar = TransientPtr::new(Bar { num, some_str });
+    ///
+    ///             tokio::time::sleep(Duration::from_secs(2)).await;
+    ///
+    ///             bar as TransientPtr<dyn Foo>
+    ///         })
+    ///     })
+    ///     .await?;
+    /// #
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "factory")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "factory")))]
+    pub async fn to_async_factory<Args, Return, FactoryFunc>(
+        &self,
+        factory_func: &'static FactoryFunc,
+    ) -> Result<AsyncBindingWhenConfigurator<Interface>, AsyncBindingBuilderError>
+    where
+        Args: 'static,
+        Return: 'static + ?Sized,
+        Interface:
+            Fn<Args, Output = crate::future::BoxFuture<'static, Return>> + Send + Sync,
+        FactoryFunc: Fn<
+                (Arc<AsyncDIContainer>,),
+                Output = BoxFn<Args, crate::future::BoxFuture<'static, Return>>,
+            > + Send
+            + Sync,
+    {
+        use crate::castable_factory::threadsafe::ThreadsafeCastableFactory;
+        use crate::provider::r#async::AsyncFactoryVariant;
+
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        if bindings_lock.has::<Interface>(None) {
+            return Err(AsyncBindingBuilderError::BindingAlreadyExists(type_name::<
+                Interface,
+            >(
+            )));
+        }
+
+        let factory_impl = ThreadsafeCastableFactory::new(factory_func);
+
+        bindings_lock.set::<Interface>(
+            None,
+            Box::new(crate::provider::r#async::AsyncFactoryProvider::new(
+                crate::ptr::ThreadsafeFactoryPtr::new(factory_impl),
+                AsyncFactoryVariant::Normal,
+            )),
+        );
+
+        Ok(AsyncBindingWhenConfigurator::new(self.di_container.clone()))
+    }
+
+    /// Creates a binding of type `Interface` to a factory that takes no arguments
+    /// inside of the associated [`AsyncDIContainer`].
+    ///
+    /// # Errors
+    /// Will return Err if the associated [`AsyncDIContainer`] already have a binding
+    /// for the interface.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::error::Error;
+    /// #
+    /// # use syrette::AsyncDIContainer;
+    /// # use syrette::ptr::TransientPtr;
+    /// #
+    /// # trait Foo: Send + Sync {}
+    /// #
+    /// # struct Bar
+    /// # {
+    /// #   num: i32,
+    /// #   some_str: String
+    /// # }
+    /// #
+    /// # impl Foo for Bar {}
+    /// #
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn Error>>
+    /// # {
+    /// # let mut di_container = AsyncDIContainer::new();
+    /// #
+    /// di_container
+    ///     .bind::<dyn Foo>()
+    ///     .to_default_factory(&|_| {
+    ///         Box::new(|| {
+    ///             let bar = TransientPtr::new(Bar {
+    ///                 num: 42,
+    ///                 some_str: "hello".to_string(),
+    ///             });
+    ///
+    ///             bar as TransientPtr<dyn Foo>
+    ///         })
+    ///     })
+    ///     .await?;
+    /// #
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "factory")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "factory")))]
+    pub async fn to_default_factory<Return, FactoryFunc>(
+        &self,
+        factory_func: &'static FactoryFunc,
+    ) -> Result<AsyncBindingWhenConfigurator<Interface>, AsyncBindingBuilderError>
+    where
+        Return: 'static + ?Sized,
+        FactoryFunc: Fn<
+                (Arc<AsyncDIContainer>,),
+                Output = BoxFn<(), crate::ptr::TransientPtr<Return>>,
+            > + Send
+            + Sync,
+    {
+        use crate::castable_factory::threadsafe::ThreadsafeCastableFactory;
+        use crate::provider::r#async::AsyncFactoryVariant;
+
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        if bindings_lock.has::<Interface>(None) {
+            return Err(AsyncBindingBuilderError::BindingAlreadyExists(type_name::<
+                Interface,
+            >(
+            )));
+        }
+
+        let factory_impl = ThreadsafeCastableFactory::new(factory_func);
+
+        bindings_lock.set::<Interface>(
+            None,
+            Box::new(crate::provider::r#async::AsyncFactoryProvider::new(
+                crate::ptr::ThreadsafeFactoryPtr::new(factory_impl),
+                AsyncFactoryVariant::Default,
+            )),
+        );
+
+        Ok(AsyncBindingWhenConfigurator::new(self.di_container.clone()))
+    }
+
+    /// Creates a binding of factory type `Interface` to a async factory inside of the
+    /// associated [`AsyncDIContainer`].
+    ///
+    /// # Errors
+    /// Will return Err if the associated [`AsyncDIContainer`] already have a binding
+    /// for the interface.
+    ///
+    /// # Examples
+    /// ```
+    /// # use std::error::Error;
+    /// # use std::time::Duration;
+    /// #
+    /// # use syrette::{AsyncDIContainer, async_closure};
+    /// # use syrette::ptr::TransientPtr;
+    /// #
+    /// # trait Foo: Send + Sync {}
+    /// #
+    /// # struct Bar
+    /// # {
+    /// #   num: i32,
+    /// #   some_str: String
+    /// # }
+    /// #
+    /// # impl Foo for Bar {}
+    /// #
+    /// # #[tokio::main]
+    /// # async fn main() -> Result<(), Box<dyn Error>>
+    /// # {
+    /// # let mut di_container = AsyncDIContainer::new();
+    /// #
+    /// di_container
+    ///     .bind::<dyn Foo>()
+    ///     .to_async_default_factory(&|_| {
+    ///         async_closure!(|| {
+    ///             let bar = TransientPtr::new(Bar {
+    ///                 num: 42,
+    ///                 some_str: "hello".to_string(),
+    ///             });
+    ///
+    ///             tokio::time::sleep(Duration::from_secs(1)).await;
+    ///
+    ///             bar as TransientPtr<dyn Foo>
+    ///         })
+    ///     })
+    ///     .await?;
+    /// #
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "factory")]
+    #[cfg_attr(doc_cfg, doc(cfg(feature = "factory")))]
+    pub async fn to_async_default_factory<Return, FactoryFunc>(
+        &self,
+        factory_func: &'static FactoryFunc,
+    ) -> Result<AsyncBindingWhenConfigurator<Interface>, AsyncBindingBuilderError>
+    where
+        Return: 'static + ?Sized,
+        FactoryFunc: Fn<
+                (Arc<AsyncDIContainer>,),
+                Output = BoxFn<(), crate::future::BoxFuture<'static, Return>>,
+            > + Send
+            + Sync,
+    {
+        use crate::castable_factory::threadsafe::ThreadsafeCastableFactory;
+        use crate::provider::r#async::AsyncFactoryVariant;
+
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        if bindings_lock.has::<Interface>(None) {
+            return Err(AsyncBindingBuilderError::BindingAlreadyExists(type_name::<
+                Interface,
+            >(
+            )));
+        }
+
+        let factory_impl = ThreadsafeCastableFactory::new(factory_func);
+
+        bindings_lock.set::<Interface>(
+            None,
+            Box::new(crate::provider::r#async::AsyncFactoryProvider::new(
+                crate::ptr::ThreadsafeFactoryPtr::new(factory_impl),
+                AsyncFactoryVariant::AsyncDefault,
+            )),
+        );
+
+        Ok(AsyncBindingWhenConfigurator::new(self.di_container.clone()))
+    }
+}
+
+#[cfg(test)]
+mod tests
+{
+    use std::error::Error;
+
+    use super::*;
+    use crate::ptr::TransientPtr;
+    use crate::test_utils::subjects_async;
+
+    #[tokio::test]
+    async fn can_bind_to() -> Result<(), Box<dyn Error>>
+    {
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<dyn subjects_async::IUserManager>()
+            .to::<subjects_async::UserManager>()
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn can_bind_to_transient() -> Result<(), Box<dyn Error>>
+    {
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<dyn subjects_async::IUserManager>()
+            .to::<subjects_async::UserManager>()
+            .await?
+            .in_transient_scope()
+            .await;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn can_bind_to_transient_when_named() -> Result<(), Box<dyn Error>>
+    {
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<dyn subjects_async::IUserManager>()
+            .to::<subjects_async::UserManager>()
+            .await?
+            .in_transient_scope()
+            .await
+            .when_named("regular")
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn can_bind_to_singleton() -> Result<(), Box<dyn Error>>
+    {
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<dyn subjects_async::IUserManager>()
+            .to::<subjects_async::UserManager>()
+            .await?
+            .in_singleton_scope()
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn can_bind_to_singleton_when_named() -> Result<(), Box<dyn Error>>
+    {
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<dyn subjects_async::IUserManager>()
+            .to::<subjects_async::UserManager>()
+            .await?
+            .in_singleton_scope()
+            .await?
+            .when_named("cool")
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    #[cfg(feature = "factory")]
+    async fn can_bind_to_factory() -> Result<(), Box<dyn Error>>
+    {
+        use crate as syrette;
+        use crate::factory;
+
+        #[factory(threadsafe = true)]
+        type IUserManagerFactory = dyn Fn() -> dyn subjects_async::IUserManager;
+
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<IUserManagerFactory>()
+            .to_factory(&|_| {
+                Box::new(|| {
+                    let user_manager: TransientPtr<dyn subjects_async::IUserManager> =
+                        TransientPtr::new(subjects_async::UserManager::new());
+
+                    user_manager
+                })
+            })
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+
+    #[tokio::test]
+    #[cfg(feature = "factory")]
+    async fn can_bind_to_factory_when_named() -> Result<(), Box<dyn Error>>
+    {
+        use crate as syrette;
+        use crate::factory;
+
+        #[factory(threadsafe = true)]
+        type IUserManagerFactory = dyn Fn() -> dyn subjects_async::IUserManager;
+
+        let mut di_container = AsyncDIContainer::new();
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 0);
+        }
+
+        di_container
+            .bind::<IUserManagerFactory>()
+            .to_factory(&|_| {
+                Box::new(|| {
+                    let user_manager: TransientPtr<dyn subjects_async::IUserManager> =
+                        TransientPtr::new(subjects_async::UserManager::new());
+
+                    user_manager
+                })
+            })
+            .await?
+            .when_named("awesome")
+            .await?;
+
+        {
+            assert_eq!(di_container.bindings.lock().await.count(), 1);
+        }
+
+        Ok(())
+    }
+}
diff --git a/src/di_container/asynchronous/binding/mod.rs b/src/di_container/asynchronous/binding/mod.rs
new file mode 100644
index 0000000..6a09bff
--- /dev/null
+++ b/src/di_container/asynchronous/binding/mod.rs
@@ -0,0 +1,5 @@
+//! Types for building & configurating DI container bindings.
+
+pub mod builder;
+pub mod scope_configurator;
+pub mod when_configurator;
diff --git a/src/di_container/asynchronous/binding/scope_configurator.rs b/src/di_container/asynchronous/binding/scope_configurator.rs
new file mode 100644
index 0000000..2b0f0b3
--- /dev/null
+++ b/src/di_container/asynchronous/binding/scope_configurator.rs
@@ -0,0 +1,76 @@
+//! Scope configurator for a binding for types inside of a [`AsyncDIContainer`].
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+use crate::di_container::asynchronous::binding::when_configurator::AsyncBindingWhenConfigurator;
+use crate::errors::async_di_container::AsyncBindingScopeConfiguratorError;
+use crate::interfaces::async_injectable::AsyncInjectable;
+use crate::provider::r#async::{AsyncSingletonProvider, AsyncTransientTypeProvider};
+use crate::ptr::ThreadsafeSingletonPtr;
+use crate::AsyncDIContainer;
+
+/// Scope configurator for a binding for type 'Interface' inside a [`AsyncDIContainer`].
+pub struct AsyncBindingScopeConfigurator<Interface, Implementation>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+    Implementation: AsyncInjectable,
+{
+    di_container: Arc<AsyncDIContainer>,
+    interface_phantom: PhantomData<Interface>,
+    implementation_phantom: PhantomData<Implementation>,
+}
+
+impl<Interface, Implementation> AsyncBindingScopeConfigurator<Interface, Implementation>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+    Implementation: AsyncInjectable,
+{
+    pub(crate) fn new(di_container: Arc<AsyncDIContainer>) -> Self
+    {
+        Self {
+            di_container,
+            interface_phantom: PhantomData,
+            implementation_phantom: PhantomData,
+        }
+    }
+
+    /// Configures the binding to be in a transient scope.
+    ///
+    /// This is the default.
+    pub async fn in_transient_scope(&self) -> AsyncBindingWhenConfigurator<Interface>
+    {
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        bindings_lock.set::<Interface>(
+            None,
+            Box::new(AsyncTransientTypeProvider::<Implementation>::new()),
+        );
+
+        AsyncBindingWhenConfigurator::new(self.di_container.clone())
+    }
+
+    /// Configures the binding to be in a singleton scope.
+    ///
+    /// # Errors
+    /// Will return Err if resolving the implementation fails.
+    pub async fn in_singleton_scope(
+        &self,
+    ) -> Result<AsyncBindingWhenConfigurator<Interface>, AsyncBindingScopeConfiguratorError>
+    {
+        let singleton: ThreadsafeSingletonPtr<Implementation> =
+            ThreadsafeSingletonPtr::from(
+                Implementation::resolve(&self.di_container, Vec::new())
+                    .await
+                    .map_err(
+                        AsyncBindingScopeConfiguratorError::SingletonResolveFailed,
+                    )?,
+            );
+
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        bindings_lock
+            .set::<Interface>(None, Box::new(AsyncSingletonProvider::new(singleton)));
+
+        Ok(AsyncBindingWhenConfigurator::new(self.di_container.clone()))
+    }
+}
diff --git a/src/di_container/asynchronous/binding/when_configurator.rs b/src/di_container/asynchronous/binding/when_configurator.rs
new file mode 100644
index 0000000..b245ad8
--- /dev/null
+++ b/src/di_container/asynchronous/binding/when_configurator.rs
@@ -0,0 +1,54 @@
+//! When configurator for a binding for types inside of a [`AsyncDIContainer`].
+use std::any::type_name;
+use std::marker::PhantomData;
+use std::sync::Arc;
+
+use crate::errors::async_di_container::AsyncBindingWhenConfiguratorError;
+use crate::AsyncDIContainer;
+
+/// When configurator for a binding for type 'Interface' inside a [`AsyncDIContainer`].
+pub struct AsyncBindingWhenConfigurator<Interface>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+{
+    di_container: Arc<AsyncDIContainer>,
+    interface_phantom: PhantomData<Interface>,
+}
+
+impl<Interface> AsyncBindingWhenConfigurator<Interface>
+where
+    Interface: 'static + ?Sized + Send + Sync,
+{
+    pub(crate) fn new(di_container: Arc<AsyncDIContainer>) -> Self
+    {
+        Self {
+            di_container,
+            interface_phantom: PhantomData,
+        }
+    }
+
+    /// Configures the binding to have a name.
+    ///
+    /// # Errors
+    /// Will return Err if no binding for the interface already exists.
+    pub async fn when_named(
+        &self,
+        name: &'static str,
+    ) -> Result<(), AsyncBindingWhenConfiguratorError>
+    {
+        let mut bindings_lock = self.di_container.bindings.lock().await;
+
+        let binding = bindings_lock.remove::<Interface>(None).map_or_else(
+            || {
+                Err(AsyncBindingWhenConfiguratorError::BindingNotFound(
+                    type_name::<Interface>(),
+                ))
+            },
+            Ok,
+        )?;
+
+        bindings_lock.set::<Interface>(Some(name), binding);
+
+        Ok(())
+    }
+}