GPUI

Entity

Entity<T>'s are used when you need to store application state that must communicate between different parts of your application. They are owned by GPUI and can be managed with any type that implements the AppContext trait, App and Context<T> are two common types seen in GPUI which implement AppContext. All entities are owned inside of App and all other types that implement AppContext dereference to App to access the entities.

There are some other types that also implement AppContext that are used in more advanced cases relating to async GPUI.

If the T type of a Entity<T> implements the Render trait it is commonly referred to as a view.

Creating a Entity

This will create a Entity with the given state.

use gpui::{AppContext, Application};

pub struct SomeState {
    some_value: bool,
}

fn main() {
    Application::new().run(|app| {
        let entity = app.new(|_cx| SomeState { some_value: true });
    });
}

Reading a Entity

This will give you a reference to the state.

use gpui::{AppContext, Application};

pub struct SomeState {
    some_value: bool,
}

fn main() {
    Application::new().run(|app| {
        let entity = app.new(|_cx| SomeState { some_value: true });

        let some_state = entity.read(app);
    });
}

Updating a Entity

This will update the state.

use gpui::{AppContext, Application};

pub struct SomeState {
    some_value: bool,
}

fn main() {
    Application::new().run(|app| {
        let entity = app.new(|_cx| SomeState { some_value: true });

        entity.update(app, |some_state, _cx| {
            some_state.some_value = false;
        });
    });
}

Downgrading a Entity

This will turn a Entity into a WeakEntity which is a weak pointer.

use gpui::{AppContext, Application};

pub struct SomeState {
    some_value: bool,
}

fn main() {
    Application::new().run(|app| {
        let entity = app.new(|_cx| SomeState { some_value: true });

        let weak_entity = entity.downgrade();
    });
}