Files
dioxus/packages/generational-box
Evan AlmloffandJonathan Kelley 58c41f8561 Stores: Externally tracked state and reactive collections (#4483)
* map signals mutably

* boxed signals

* remove mutable borrow type from boxed writable

* improve map mut example

* restore boxed_mut helper

* make boxed readable/writable types copy

* Move away from the ReadOnlySignal alias in examples

* automatically convert Write

* Fix some tests

* ReadSignal and WriteSignal

* move read only signal alias

* make maps copy

* store prototype

* implement derive macro

* Handle generics in the derive macro

* Make Selector boxable

* derive boxed conversion

* Get rid of store type

* Remove hardcoded type from derive macro

* selector -> store

* Refactor store implementation

* more vec methods

* todo mvc store example

* Implement Storable for HashMap

* fix write

* restore sorting logic in todomvc

* derive readable and writable

* improve todomvc store example

* Result store

* Option store

* collect dead subscribers

* fix clippy and formatting

* recognize some common foreign types automatically

* fix foreign stores in props

* slice and array selectors

* clean up store example

* writable is child owned

* box selector

* read and write to builtins

* re-use the proc macro in the derive macro

* Switch to a extension trait based approach

* switch to extension traits in the derive macro

* transposed method

* derive enums

* Expose Store::new

* remove stores from the prelude

* More consistent naming scheme for SelectorScope methods

* document hashmap methods

* document index extension

* document option ext

* document result ext

* document slice extension

* document the vec extension

* make more methods borrow the store mutably

* Move to impls to have higher priority over the builtin write extension traits

* fix deadlock

* finish stores documentation

* Document the store macro

* cleanup docs and organization

* finish derive docs

* fix typo

* fix clippy

* fix doc tests

* fix derive macro with generics

* fix clippy

* test and fix empty structs

* clean up todomvc store example

* default to a boxed store writer to make it easier to type when providing to the context api

* fix cargo doc

* fix clippy in store example

* relax generational box lifetime bounds

* relax bounds

* relax signal bounds

* fix compilation

* read store

* relax bounds on default store impls

* fix enum derive

* Convert to readsignal and writesignal automatically

* simplify type matching logic

* add write store

* unsized stores

* shrink the path vec type

* use more concrete types

* remove opaque types

* remove copy bounds

* use lens as generic name everywhere

* more consistent borrow semantics

* use a concrete type for the signal metadata and mention references in the map docs

* improve todomvc store docs

* document store derive macro internals

* refactor macro

* improve selector node documentation

* fix clippy

* add btreemap

* fix doc tests

* more option methods

* fix doc

* fix clippy

* add a bunch more result methods

* add a bunch of bounds to the iterators

* fix clippy

* remove option from subscribers

* add store macro to generate extension traits

* fix store example

* fix deadlock

* fix docs

* fix doc tests

* fix clippy

* add stores to public api

* add store macro, and then update todomvc_store example

---------

Co-authored-by: Jonathan Kelley <jkelleyrtp@gmail.com>
2025-08-05 11:30:21 -07:00
..

Generational Box

Generational Box is a runtime for Rust that allows any static type to implement Copy. It can be combined with a global runtime to create an ergonomic state solution like dioxus-signals. This crate doesn't have any unsafe code.

Three main types manage state in Generational Box:

  • Store: Handles recycling generational boxes that have been dropped. Your application should have one store or one store per thread.
  • Owner: Handles dropping generational boxes. The owner acts like a runtime lifetime guard. Any states that you create with an owner will be dropped when that owner is dropped.
  • GenerationalBox: The core Copy state type. The generational box will be dropped when the owner is dropped.

Example:

use generational_box::{UnsyncStorage, AnyStorage};

// Create an owner for some state for a scope
let owner = UnsyncStorage::owner();

// Create some non-copy data, move it into a owner, and work with copy data
let data: String = "hello world".to_string();
let key = owner.insert(data);

// The generational box can be read from and written to like a RefCell
let value = key.read();
assert_eq!(*value, "hello world");

How it works

Internally, generational-box creates an arena of generational RefCells that are recycled when the owner is dropped. You can think of the cells as something like &'static RefCell<Box<dyn Any>> with a generational check to make recycling a cell easier to debug. Then GenerationalBoxes are Copy because the &'static pointer is Copy.