Trait relm4::component::Component

source · 
pub trait Component: 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(
        init: Self::Init,
        root: &Self::Root,
        sender: ComponentSender<Self>
    ) -> ComponentParts<Self>;

    fn builder() -> ComponentBuilder<Self> { ... }
    fn update(
        &mut self,
        message: Self::Input,
        sender: ComponentSender<Self>,
        root: &Self::Root
    ) { ... }
    fn update_cmd(
        &mut self,
        message: Self::CommandOutput,
        sender: ComponentSender<Self>,
        root: &Self::Root
    ) { ... }
    fn update_cmd_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::CommandOutput,
        sender: ComponentSender<Self>,
        root: &Self::Root
    ) { ... }
    fn update_view(
        &self,
        widgets: &mut Self::Widgets,
        sender: ComponentSender<Self>
    ) { ... }
    fn update_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::Input,
        sender: ComponentSender<Self>,
        root: &Self::Root
    ) { ... }
    fn shutdown(
        &mut self,
        widgets: &mut Self::Widgets,
        output: Sender<Self::Output>
    ) { ... }
    fn id(&self) -> String { ... }
}
Expand description

The fundamental building block of a Relm4 application.

A Component is an element of an application that defines initialization, state, behavior and communication as a modular unit.

Component is powerful and flexible, but for many use-cases the SimpleComponent convenience trait will suffice. SimpleComponent enforces separation between model and view updates, and provides no-op implementations for advanced features that are not relevant for most use-cases.

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.

Processes inputs received by the component.

Examples found in repository?
src/component/sync/traits.rs (line 115)
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    fn update_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::Input,
        sender: ComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update(message, sender.clone(), root);
        self.update_view(widgets, sender);
    }

Defines how the component should respond to command updates.

Examples found in repository?
src/component/sync/traits.rs (line 87)
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    fn update_cmd_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::CommandOutput,
        sender: ComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update_cmd(message, sender.clone(), root);
        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/worker.rs (line 141)
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    pub fn detach_worker(self, payload: C::Init) -> WorkerHandle<C> {
        let Self { root, .. } = self;

        // Used for all events to be processed by this component's internal service.
        let (input_sender, input_receiver) = crate::channel::<C::Input>();

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

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

        let mut state = C::init(payload, &root, component_sender.clone());

        thread::spawn(move || {
            let context =
                glib::MainContext::thread_default().unwrap_or_else(glib::MainContext::new);

            // 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.
            context.block_on(async move {
                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 ComponentParts {
                                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(), &root);
                        }

                        // Handles responses from a command.
                        message = cmd => {
                            let ComponentParts {
                                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(), &root);
                        },

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

                            model.shutdown(widgets, output_sender);

                            shutdown_notifier.shutdown();

                            return;
                        }
                    );
                }
            });
        });

        // Give back a type for controlling the component service.
        WorkerHandle {
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop,
        }
    }
More examples
Hide additional examples
src/component/sync/builder.rs (line 251)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> Connector<C> {
        let Self { root, priority, .. } = self;

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

        // Gets notifications when a component's model and view is updated externally.
        let (notifier, notifier_receiver) = crate::channel();

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

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

        // Constructs the initial model and view with the initial payload.
        let state = Rc::new(RefCell::new(C::init(
            payload,
            &root,
            component_sender.clone(),
        )));
        let watcher = StateWatcher {
            state,
            notifier,
            shutdown_on_drop,
        };

        let rt_state = watcher.state.clone();
        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 notifier = GuardedReceiver::new(notifier_receiver);
            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 ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Triggered when the model and view have been updated externally.
                    _ = notifier => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        model.update_view(widgets, component_sender.clone());
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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.
        Connector {
            state: watcher,
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
        }
    }

Updates the view after the model has been updated.

Examples found in repository?
src/component/sync/traits.rs (line 88)
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    fn update_cmd_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::CommandOutput,
        sender: ComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update_cmd(message, sender.clone(), root);
        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: ComponentSender<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
    fn update_with_view(
        &mut self,
        widgets: &mut Self::Widgets,
        message: Self::Input,
        sender: ComponentSender<Self>,
        root: &Self::Root,
    ) {
        self.update(message, sender.clone(), root);
        self.update_view(widgets, sender);
    }
More examples
Hide additional examples
src/component/sync/builder.rs (line 261)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> Connector<C> {
        let Self { root, priority, .. } = self;

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

        // Gets notifications when a component's model and view is updated externally.
        let (notifier, notifier_receiver) = crate::channel();

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

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

        // Constructs the initial model and view with the initial payload.
        let state = Rc::new(RefCell::new(C::init(
            payload,
            &root,
            component_sender.clone(),
        )));
        let watcher = StateWatcher {
            state,
            notifier,
            shutdown_on_drop,
        };

        let rt_state = watcher.state.clone();
        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 notifier = GuardedReceiver::new(notifier_receiver);
            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 ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Triggered when the model and view have been updated externally.
                    _ = notifier => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        model.update_view(widgets, component_sender.clone());
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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.
        Connector {
            state: watcher,
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
        }
    }

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/worker.rs (line 123)
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    pub fn detach_worker(self, payload: C::Init) -> WorkerHandle<C> {
        let Self { root, .. } = self;

        // Used for all events to be processed by this component's internal service.
        let (input_sender, input_receiver) = crate::channel::<C::Input>();

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

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

        let mut state = C::init(payload, &root, component_sender.clone());

        thread::spawn(move || {
            let context =
                glib::MainContext::thread_default().unwrap_or_else(glib::MainContext::new);

            // 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.
            context.block_on(async move {
                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 ComponentParts {
                                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(), &root);
                        }

                        // Handles responses from a command.
                        message = cmd => {
                            let ComponentParts {
                                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(), &root);
                        },

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

                            model.shutdown(widgets, output_sender);

                            shutdown_notifier.shutdown();

                            return;
                        }
                    );
                }
            });
        });

        // Give back a type for controlling the component service.
        WorkerHandle {
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop,
        }
    }
More examples
Hide additional examples
src/component/sync/builder.rs (line 233)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> Connector<C> {
        let Self { root, priority, .. } = self;

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

        // Gets notifications when a component's model and view is updated externally.
        let (notifier, notifier_receiver) = crate::channel();

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

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

        // Constructs the initial model and view with the initial payload.
        let state = Rc::new(RefCell::new(C::init(
            payload,
            &root,
            component_sender.clone(),
        )));
        let watcher = StateWatcher {
            state,
            notifier,
            shutdown_on_drop,
        };

        let rt_state = watcher.state.clone();
        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 notifier = GuardedReceiver::new(notifier_receiver);
            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 ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Triggered when the model and view have been updated externally.
                    _ = notifier => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        model.update_view(widgets, component_sender.clone());
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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.
        Connector {
            state: watcher,
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
        }
    }

Last method called before a component is shut down.

Examples found in repository?
src/component/worker.rs (line 151)
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    pub fn detach_worker(self, payload: C::Init) -> WorkerHandle<C> {
        let Self { root, .. } = self;

        // Used for all events to be processed by this component's internal service.
        let (input_sender, input_receiver) = crate::channel::<C::Input>();

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

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

        let mut state = C::init(payload, &root, component_sender.clone());

        thread::spawn(move || {
            let context =
                glib::MainContext::thread_default().unwrap_or_else(glib::MainContext::new);

            // 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.
            context.block_on(async move {
                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 ComponentParts {
                                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(), &root);
                        }

                        // Handles responses from a command.
                        message = cmd => {
                            let ComponentParts {
                                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(), &root);
                        },

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

                            model.shutdown(widgets, output_sender);

                            shutdown_notifier.shutdown();

                            return;
                        }
                    );
                }
            });
        });

        // Give back a type for controlling the component service.
        WorkerHandle {
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop,
        }
    }
More examples
Hide additional examples
src/component/sync/builder.rs (line 271)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> Connector<C> {
        let Self { root, priority, .. } = self;

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

        // Gets notifications when a component's model and view is updated externally.
        let (notifier, notifier_receiver) = crate::channel();

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

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

        // Constructs the initial model and view with the initial payload.
        let state = Rc::new(RefCell::new(C::init(
            payload,
            &root,
            component_sender.clone(),
        )));
        let watcher = StateWatcher {
            state,
            notifier,
            shutdown_on_drop,
        };

        let rt_state = watcher.state.clone();
        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 notifier = GuardedReceiver::new(notifier_receiver);
            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 ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Triggered when the model and view have been updated externally.
                    _ = notifier => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        model.update_view(widgets, component_sender.clone());
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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.
        Connector {
            state: watcher,
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
        }
    }

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/worker.rs (line 119)
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    pub fn detach_worker(self, payload: C::Init) -> WorkerHandle<C> {
        let Self { root, .. } = self;

        // Used for all events to be processed by this component's internal service.
        let (input_sender, input_receiver) = crate::channel::<C::Input>();

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

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

        let mut state = C::init(payload, &root, component_sender.clone());

        thread::spawn(move || {
            let context =
                glib::MainContext::thread_default().unwrap_or_else(glib::MainContext::new);

            // 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.
            context.block_on(async move {
                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 ComponentParts {
                                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(), &root);
                        }

                        // Handles responses from a command.
                        message = cmd => {
                            let ComponentParts {
                                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(), &root);
                        },

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

                            model.shutdown(widgets, output_sender);

                            shutdown_notifier.shutdown();

                            return;
                        }
                    );
                }
            });
        });

        // Give back a type for controlling the component service.
        WorkerHandle {
            sender: input_sender,
            receiver: output_receiver,
            shutdown_on_drop,
        }
    }
More examples
Hide additional examples
src/component/sync/builder.rs (line 229)
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    fn launch_with_input_channel(
        self,
        payload: C::Init,
        input_sender: Sender<C::Input>,
        input_receiver: Receiver<C::Input>,
    ) -> Connector<C> {
        let Self { root, priority, .. } = self;

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

        // Gets notifications when a component's model and view is updated externally.
        let (notifier, notifier_receiver) = crate::channel();

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

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

        // Constructs the initial model and view with the initial payload.
        let state = Rc::new(RefCell::new(C::init(
            payload,
            &root,
            component_sender.clone(),
        )));
        let watcher = StateWatcher {
            state,
            notifier,
            shutdown_on_drop,
        };

        let rt_state = watcher.state.clone();
        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 notifier = GuardedReceiver::new(notifier_receiver);
            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 ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Handles responses from a command.
                    message = cmd => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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);
                    }

                    // Triggered when the model and view have been updated externally.
                    _ = notifier => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        model.update_view(widgets, component_sender.clone());
                    }

                    // Triggered when the component is destroyed
                    _ = shutdown_event => {
                        let ComponentParts {
                            model,
                            widgets,
                        } = &mut *rt_state.borrow_mut();

                        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.
        Connector {
            state: watcher,
            widget: root,
            sender: input_sender,
            receiver: output_receiver,
        }
    }

Implementors§