Trait relm4::component::AsyncComponent

source · 
pub trait AsyncComponent: Sized + 'static {
    type CommandOutput: Debug + Send + 'static;
    type Input: Debug + 'static;
    type Output: Debug + 'static;
    type Init;
    type Root: Debug + Clone;
    type Widgets: 'static;

    fn init_root() -> Self::Root;
    fn init<'async_trait>(
        init: Self::Init,
        root: Self::Root,
        sender: AsyncComponentSender<Self>
    ) -> Pin<Box<dyn Future<Output = AsyncComponentParts<Self>> + 'async_trait>>
    where
        Self: 'async_trait;

    fn builder() -> AsyncComponentBuilder<Self> { ... }
    fn init_loading_widgets(_root: &mut Self::Root) -> Option<LoadingWidgets> { ... }
    fn update<'life0, 'life1, 'async_trait>(
        &'life0 mut self,
        message: Self::Input,
        sender: AsyncComponentSender<Self>,
        root: &'life1 Self::Root
    ) -> Pin<Box<dyn Future<Output = ()> + 'async_trait>>
    where
        Self: 'async_trait,
        'life0: 'async_trait,
        'life1: 'async_trait,
    { ... }
    fn update_cmd<'life0, 'life1, 'async_trait>(
        &'life0 mut self,
        message: Self::CommandOutput,
        sender: AsyncComponentSender<Self>,
        root: &'life1 Self::Root
    ) -> Pin<Box<dyn Future<Output = ()> + 'async_trait>>
    where
        Self: 'async_trait,
        'life0: 'async_trait,
        'life1: 'async_trait,
    { ... }
    fn update_cmd_with_view<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 mut self,
        widgets: &'life1 mut Self::Widgets,
        message: Self::CommandOutput,
        sender: AsyncComponentSender<Self>,
        root: &'life2 Self::Root
    ) -> Pin<Box<dyn Future<Output = ()> + 'async_trait>>
    where
        Self: 'async_trait,
        'life0: 'async_trait,
        'life1: 'async_trait,
        'life2: 'async_trait,
    { ... }
    fn update_view(
        &self,
        widgets: &mut Self::Widgets,
        sender: AsyncComponentSender<Self>
    ) { ... }
    fn update_with_view<'life0, 'life1, 'life2, 'async_trait>(
        &'life0 mut self,
        widgets: &'life1 mut Self::Widgets,
        message: Self::Input,
        sender: AsyncComponentSender<Self>,
        root: &'life2 Self::Root
    ) -> Pin<Box<dyn Future<Output = ()> + 'async_trait>>
    where
        Self: 'async_trait,
        'life0: 'async_trait,
        'life1: 'async_trait,
        'life2: 'async_trait,
    { ... }
    fn shutdown(
        &mut self,
        widgets: &mut Self::Widgets,
        output: Sender<Self::Output>
    ) { ... }
    fn id(&self) -> String { ... }
}
Expand description

Asynchronous variant of Component.

AsyncComponent is powerful and flexible, but for many use-cases the SimpleAsyncComponent convenience trait will suffice.

Required Associated Types§

Messages which are received from commands executing in the background.

The message type that the component accepts as inputs.

The message type that the component provides as outputs.

The parameter used to initialize the component.

The widget that was constructed by the component.

The type that’s used for storing widgets created for this component.

Required Methods§

Initializes the root widget

Creates the initial model and view, docking it into the component.

Provided Methods§

Create a builder for this component.

Allows you to initialize the root widget with a temporary value as a placeholder until the init() future completes.

This method does nothing by default.

Examples found in repository?
src/component/async/builder.rs (line 154)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> AsyncConnector<C> {
        let Self {
            mut root, priority, ..
        } = self;
        let temp_widgets = C::init_loading_widgets(&mut root);

        let RuntimeSenders {
            output_sender,
            output_receiver,
            cmd_sender,
            cmd_receiver,
            shutdown_notifier,
            shutdown_recipient,
            shutdown_on_drop: destroy_on_drop,
            mut shutdown_event,
        } = RuntimeSenders::<C::Output, C::CommandOutput>::new();

        // Encapsulates the senders used by component methods.
        let component_sender = AsyncComponentSender::new(
            input_sender.clone(),
            output_sender.clone(),
            cmd_sender,
            shutdown_recipient,
        );

        let (source_id_sender, source_id_receiver) = oneshot::channel::<gtk::glib::SourceId>();

        let rt_root = root.clone();

        // Spawns the component's service. It will receive both `Self::Input` and
        // `Self::CommandOutput` messages. It will spawn commands as requested by
        // updates, and send `Self::Output` messages externally.
        let id = crate::spawn_local_with_priority(priority, async move {
            let id = source_id_receiver.await.unwrap();
            let mut state = C::init(payload, rt_root.clone(), component_sender.clone()).await;
            drop(temp_widgets);

            let mut cmd = GuardedReceiver::new(cmd_receiver);
            let mut input = GuardedReceiver::new(input_receiver);

            loop {
                futures::select!(
                    // Performs the model update, checking if the update requested a command.
                    // Runs that command asynchronously in the background using tokio.
                    message = input => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_with_view",
                            input=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_cmd_with_view",
                            cmd_output=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_cmd_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        model.shutdown(widgets, output_sender);

                        shutdown_notifier.shutdown();

                        id.remove();

                        return;
                    }
                );
            }
        });

        source_id_sender.send(id).unwrap();

        // Give back a type for controlling the component service.
        AsyncConnector {
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop: destroy_on_drop,
        }
    }

Processes inputs received by the component.

Examples found in repository?
src/component/async/traits.rs (line 131)
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    async fn update_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::Input,
        sender: AsyncComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update(message, sender.clone(), root).await;
        self.update_view(widgets, sender);
    }

Defines how the component should respond to command updates.

Examples found in repository?
src/component/async/traits.rs (line 103)
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    async fn update_cmd_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::CommandOutput,
        sender: AsyncComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update_cmd(message, sender.clone(), root).await;
        self.update_view(widgets, sender);
    }

Updates the model and view upon completion of a command.

Overriding this method is helpful if you need access to the widgets while processing a command output.

The default implementation of this method calls update_cmd followed by update_view. If you override this method while using the component macro, you must remember to call update_view in your implementation. Otherwise, the view will not reflect the updated model.

Examples found in repository?
src/component/async/builder.rs (line 226)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> AsyncConnector<C> {
        let Self {
            mut root, priority, ..
        } = self;
        let temp_widgets = C::init_loading_widgets(&mut root);

        let RuntimeSenders {
            output_sender,
            output_receiver,
            cmd_sender,
            cmd_receiver,
            shutdown_notifier,
            shutdown_recipient,
            shutdown_on_drop: destroy_on_drop,
            mut shutdown_event,
        } = RuntimeSenders::<C::Output, C::CommandOutput>::new();

        // Encapsulates the senders used by component methods.
        let component_sender = AsyncComponentSender::new(
            input_sender.clone(),
            output_sender.clone(),
            cmd_sender,
            shutdown_recipient,
        );

        let (source_id_sender, source_id_receiver) = oneshot::channel::<gtk::glib::SourceId>();

        let rt_root = root.clone();

        // Spawns the component's service. It will receive both `Self::Input` and
        // `Self::CommandOutput` messages. It will spawn commands as requested by
        // updates, and send `Self::Output` messages externally.
        let id = crate::spawn_local_with_priority(priority, async move {
            let id = source_id_receiver.await.unwrap();
            let mut state = C::init(payload, rt_root.clone(), component_sender.clone()).await;
            drop(temp_widgets);

            let mut cmd = GuardedReceiver::new(cmd_receiver);
            let mut input = GuardedReceiver::new(input_receiver);

            loop {
                futures::select!(
                    // Performs the model update, checking if the update requested a command.
                    // Runs that command asynchronously in the background using tokio.
                    message = input => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_with_view",
                            input=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_cmd_with_view",
                            cmd_output=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_cmd_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        model.shutdown(widgets, output_sender);

                        shutdown_notifier.shutdown();

                        id.remove();

                        return;
                    }
                );
            }
        });

        source_id_sender.send(id).unwrap();

        // Give back a type for controlling the component service.
        AsyncConnector {
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop: destroy_on_drop,
        }
    }

Updates the view after the model has been updated.

Examples found in repository?
src/component/async/traits.rs (line 104)
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    async fn update_cmd_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::CommandOutput,
        sender: AsyncComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update_cmd(message, sender.clone(), root).await;
        self.update_view(widgets, sender);
    }

    /// Updates the view after the model has been updated.
    #[allow(unused)]
    fn update_view(&self, widgets: &mut Self::Widgets, sender: AsyncComponentSender<Self>) {}

    /// Updates the model and view when a new input is received.
    ///
    /// Overriding this method is helpful if you need access to the widgets while processing an
    /// input.
    ///
    /// The default implementation of this method calls [`update`] followed by [`update_view`]. If
    /// you override this method while using the [`component`] macro, you must remember to
    /// call [`update_view`] in your implementation. Otherwise, the view will not reflect the
    /// updated model.
    ///
    /// [`update`]: Self::update
    /// [`update_view`]: Self::update_view
    /// [`component`]: relm4_macros::component
    async fn update_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::Input,
        sender: AsyncComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update(message, sender.clone(), root).await;
        self.update_view(widgets, sender);
    }

Updates the model and view when a new input is received.

Overriding this method is helpful if you need access to the widgets while processing an input.

The default implementation of this method calls update followed by update_view. If you override this method while using the component macro, you must remember to call update_view in your implementation. Otherwise, the view will not reflect the updated model.

Examples found in repository?
src/component/async/builder.rs (line 208)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> AsyncConnector<C> {
        let Self {
            mut root, priority, ..
        } = self;
        let temp_widgets = C::init_loading_widgets(&mut root);

        let RuntimeSenders {
            output_sender,
            output_receiver,
            cmd_sender,
            cmd_receiver,
            shutdown_notifier,
            shutdown_recipient,
            shutdown_on_drop: destroy_on_drop,
            mut shutdown_event,
        } = RuntimeSenders::<C::Output, C::CommandOutput>::new();

        // Encapsulates the senders used by component methods.
        let component_sender = AsyncComponentSender::new(
            input_sender.clone(),
            output_sender.clone(),
            cmd_sender,
            shutdown_recipient,
        );

        let (source_id_sender, source_id_receiver) = oneshot::channel::<gtk::glib::SourceId>();

        let rt_root = root.clone();

        // Spawns the component's service. It will receive both `Self::Input` and
        // `Self::CommandOutput` messages. It will spawn commands as requested by
        // updates, and send `Self::Output` messages externally.
        let id = crate::spawn_local_with_priority(priority, async move {
            let id = source_id_receiver.await.unwrap();
            let mut state = C::init(payload, rt_root.clone(), component_sender.clone()).await;
            drop(temp_widgets);

            let mut cmd = GuardedReceiver::new(cmd_receiver);
            let mut input = GuardedReceiver::new(input_receiver);

            loop {
                futures::select!(
                    // Performs the model update, checking if the update requested a command.
                    // Runs that command asynchronously in the background using tokio.
                    message = input => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_with_view",
                            input=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_cmd_with_view",
                            cmd_output=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_cmd_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        model.shutdown(widgets, output_sender);

                        shutdown_notifier.shutdown();

                        id.remove();

                        return;
                    }
                );
            }
        });

        source_id_sender.send(id).unwrap();

        // Give back a type for controlling the component service.
        AsyncConnector {
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop: destroy_on_drop,
        }
    }

Last method called before a component is shut down.

Examples found in repository?
src/component/async/builder.rs (line 236)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> AsyncConnector<C> {
        let Self {
            mut root, priority, ..
        } = self;
        let temp_widgets = C::init_loading_widgets(&mut root);

        let RuntimeSenders {
            output_sender,
            output_receiver,
            cmd_sender,
            cmd_receiver,
            shutdown_notifier,
            shutdown_recipient,
            shutdown_on_drop: destroy_on_drop,
            mut shutdown_event,
        } = RuntimeSenders::<C::Output, C::CommandOutput>::new();

        // Encapsulates the senders used by component methods.
        let component_sender = AsyncComponentSender::new(
            input_sender.clone(),
            output_sender.clone(),
            cmd_sender,
            shutdown_recipient,
        );

        let (source_id_sender, source_id_receiver) = oneshot::channel::<gtk::glib::SourceId>();

        let rt_root = root.clone();

        // Spawns the component's service. It will receive both `Self::Input` and
        // `Self::CommandOutput` messages. It will spawn commands as requested by
        // updates, and send `Self::Output` messages externally.
        let id = crate::spawn_local_with_priority(priority, async move {
            let id = source_id_receiver.await.unwrap();
            let mut state = C::init(payload, rt_root.clone(), component_sender.clone()).await;
            drop(temp_widgets);

            let mut cmd = GuardedReceiver::new(cmd_receiver);
            let mut input = GuardedReceiver::new(input_receiver);

            loop {
                futures::select!(
                    // Performs the model update, checking if the update requested a command.
                    // Runs that command asynchronously in the background using tokio.
                    message = input => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_with_view",
                            input=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_cmd_with_view",
                            cmd_output=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_cmd_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        model.shutdown(widgets, output_sender);

                        shutdown_notifier.shutdown();

                        id.remove();

                        return;
                    }
                );
            }
        });

        source_id_sender.send(id).unwrap();

        // Give back a type for controlling the component service.
        AsyncConnector {
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop: destroy_on_drop,
        }
    }

An identifier for the component used for debug logging.

The default implementation of this method uses the address of the component, but implementations are free to provide more meaningful identifiers.

Examples found in repository?
src/component/async/builder.rs (line 204)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> AsyncConnector<C> {
        let Self {
            mut root, priority, ..
        } = self;
        let temp_widgets = C::init_loading_widgets(&mut root);

        let RuntimeSenders {
            output_sender,
            output_receiver,
            cmd_sender,
            cmd_receiver,
            shutdown_notifier,
            shutdown_recipient,
            shutdown_on_drop: destroy_on_drop,
            mut shutdown_event,
        } = RuntimeSenders::<C::Output, C::CommandOutput>::new();

        // Encapsulates the senders used by component methods.
        let component_sender = AsyncComponentSender::new(
            input_sender.clone(),
            output_sender.clone(),
            cmd_sender,
            shutdown_recipient,
        );

        let (source_id_sender, source_id_receiver) = oneshot::channel::<gtk::glib::SourceId>();

        let rt_root = root.clone();

        // Spawns the component's service. It will receive both `Self::Input` and
        // `Self::CommandOutput` messages. It will spawn commands as requested by
        // updates, and send `Self::Output` messages externally.
        let id = crate::spawn_local_with_priority(priority, async move {
            let id = source_id_receiver.await.unwrap();
            let mut state = C::init(payload, rt_root.clone(), component_sender.clone()).await;
            drop(temp_widgets);

            let mut cmd = GuardedReceiver::new(cmd_receiver);
            let mut input = GuardedReceiver::new(input_receiver);

            loop {
                futures::select!(
                    // Performs the model update, checking if the update requested a command.
                    // Runs that command asynchronously in the background using tokio.
                    message = input => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_with_view",
                            input=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        let span = info_span!(
                            "update_cmd_with_view",
                            cmd_output=?message,
                            component=any::type_name::<C>(),
                            id=model.id(),
                        );
                        let _enter = span.enter();

                        model.update_cmd_with_view(widgets, message, component_sender.clone(), &rt_root).await;
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let AsyncComponentParts {
                            model,
                            widgets,
                        } = &mut state;

                        model.shutdown(widgets, output_sender);

                        shutdown_notifier.shutdown();

                        id.remove();

                        return;
                    }
                );
            }
        });

        source_id_sender.send(id).unwrap();

        // Give back a type for controlling the component service.
        AsyncConnector {
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop: destroy_on_drop,
        }
    }

Implementors§