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use crate::{ channel::lifeline::{receiver::LifelineReceiver, sender::LifelineSender}, error::{AlreadyLinkedError, TakeChannelError, TakeResourceError}, Channel, Storage, }; use std::fmt::{Debug, Display}; /// Attaches a channel to the [Bus](./trait.Bus.html), carrying `Self` as a message. /// /// The Channel associated type should be the Sender of the channel which will carry this message. /// /// Once implemented, the [bus.rx::\<Self\>()](trait.Bus.html#tymethod.rx), [bus.tx::\<Self\>()](trait.Bus.html#tymethod.tx), and [bus.capacity::\<Self\>()](trait.Bus.html#tymethod.capacity) methods can be called. /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use tokio::sync::mpsc; /// /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Debug)] /// pub struct ExampleMessage; /// /// impl Message<ExampleBus> for ExampleMessage { /// type Channel = mpsc::Sender<Self>; /// } /// /// fn main() -> anyhow::Result<()> { /// let bus = ExampleBus::default(); /// let mut tx = bus.tx::<ExampleMessage>()?; /// Ok(()) /// } /// ``` pub trait Message<Bus>: Debug { type Channel: Channel; } /// Attaches a resource to the [Bus](./trait.Bus.html). This resource can accessed from the bus using [bus.resource::\<Self\>()](trait.Bus.html#tymethod.resource). /// /// The resource must implement [Storage](./trait.Storage.html), which describes whether the resource is taken or cloned. /// /// Lifeline provides helper macros: [impl_storage_take!(MyResource)](./macro.impl_storage_take.html) and [impl_storage_clone!(MyResource)](./macro.impl_storage_clone.html). /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use lifeline::impl_storage_clone; /// use tokio::sync::mpsc; /// /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Clone, Debug)] /// pub struct MyResource; /// impl_storage_clone!(MyResource); /// /// impl Resource<ExampleBus> for MyResource {} /// ``` pub trait Resource<Bus>: Storage + Debug + Send {} /// Stores and distributes channel endpoints ([Senders](./trait.Sender.html) and [Receivers](./trait.Receiver.html)), as well as [Resource](./trait.Resource.html) values. /// /// The bus allows you to write loosely-coupled applications, with adjacent lifeline [Services](./trait.Service.html) that do not depend on each other. /// /// Most Bus implementations are defined using the [lifeline_bus!](./macro.lifeline_bus.html) macro. /// /// ## Example: /// ``` /// use lifeline::lifeline_bus; /// /// lifeline_bus!(pub struct ExampleBus); /// ``` pub trait Bus: Default + Debug + Sized { /// Configures the channel capacity, if the linked channel implementation takes a capacity during initialization /// /// Returns an [AlreadyLinkedError](./error/struct.AlreadyLinkedError.html), if the channel has already been initalized from another call to `capacity`, `rx`, or `tx`. /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use tokio::sync::mpsc; /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Debug)] /// struct ExampleMessage {} /// impl Message<ExampleBus> for ExampleMessage { /// type Channel = mpsc::Sender<Self>; /// } /// /// fn main() { /// let bus = ExampleBus::default(); /// bus.capacity::<ExampleMessage>(1024); /// let rx = bus.rx::<ExampleMessage>(); /// } fn capacity<Msg>(&self, capacity: usize) -> Result<(), AlreadyLinkedError> where Msg: Message<Self> + 'static; /// Takes (or clones) the channel [Receiver](./trait.Receiver.html). The message type must implement [Message\<Bus\>](./trait.Message.html), which defines the channel type. /// /// Returns the [Receiver](./trait.Receiver.html), or a [TakeChannelError](./error/enum.TakeChannelError.html) if the channel endpoint is not clonable, and has already been taken. /// /// - For `mpsc` channels, the Receiver is taken. /// - For `broadcast` channels, the Receiver is cloned. /// - For `watch` channels, the Receiver is cloned. /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use tokio::sync::mpsc; /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Debug)] /// struct ExampleMessage {} /// impl Message<ExampleBus> for ExampleMessage { /// type Channel = mpsc::Sender<Self>; /// } /// /// fn main() { /// let bus = ExampleBus::default(); /// let rx = bus.rx::<ExampleMessage>(); /// } /// ``` fn rx<Msg>( &self, ) -> Result<LifelineReceiver<Msg, <Msg::Channel as Channel>::Rx>, TakeChannelError> where Msg: Message<Self> + 'static; /// Takes (or clones) the channel [Sender](./trait.Sender.html). The message type must implement [Message\<Bus\>](./trait.Message.html), which defines the channel type. /// /// Returns the sender, or a [TakeChannelError](./error/enum.TakeChannelError.html) if the channel endpoint is not clonable, and has already been taken. /// /// - For `mpsc` channels, the Sender is cloned. /// - For `broadcast` channels, the Sender is cloned. /// - For `watch` channels, the Sender is taken. /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use tokio::sync::mpsc; /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Debug)] /// struct ExampleMessage {} /// impl Message<ExampleBus> for ExampleMessage { /// type Channel = mpsc::Sender<Self>; /// } /// /// fn main() { /// let bus = ExampleBus::default(); /// let tx = bus.tx::<ExampleMessage>(); /// } /// ``` fn tx<Msg>( &self, ) -> Result<LifelineSender<Msg, <Msg::Channel as Channel>::Tx>, TakeChannelError> where Msg: Message<Self> + 'static; /// Takes (or clones) the [Resource](./trait.Resource.html). /// /// Returns the resource, or a [TakeResourceError](./error/enum.TakeResourceError.html) if the resource is not clonable, and has already been taken. /// /// ## Example: /// ``` /// use lifeline::prelude::*; /// use lifeline::impl_storage_clone; /// use tokio::sync::mpsc; /// lifeline_bus!(pub struct ExampleBus); /// /// #[derive(Debug, Clone)] /// struct ExampleResource {} /// impl_storage_clone!(ExampleResource); /// impl Resource<ExampleBus> for ExampleResource {} /// /// fn main() { /// let bus = ExampleBus::default(); /// let resource = bus.resource::<ExampleResource>(); /// } /// ``` fn resource<Res>(&self) -> Result<Res, TakeResourceError> where Res: Resource<Self>; } /// Represents the Sender, Receiver, or Both. Used in error types. #[derive(Debug)] pub enum Link { /// The Sender half of the channel Tx, /// The Receiver half of the channel Rx, /// Both the Sender and Receiver endpoints Both, } impl Display for Link { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { match self { Link::Tx => f.write_str("Tx"), Link::Rx => f.write_str("Rx"), Link::Both => f.write_str("Both"), } } }