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36 lines
1.6 KiB
Markdown
36 lines
1.6 KiB
Markdown
# Generational Box
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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 contains no `unsafe` code.
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Three main types manage state in Generational Box:
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- Store: Handles recycling generational boxes that have been dropped. Your application should have one store or one store per thread.
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- 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.
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- GenerationalBox: The core Copy state type. The generational box will be dropped when the owner is dropped.
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Example:
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```rust
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use generational_box::Store;
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// Create a store for this thread
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let store = Store::default();
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{
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// Create an owner for some state for a scope
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let owner = store.owner();
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// Create some non-copy data, move it into a owner, and work with copy data
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let data: String = "hello world".to_string();
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let key = owner.insert(data);
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// The generational box can be read from and written to like a RefCell
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let value = key.read();
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assert_eq!(*value, "hello world");
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}
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// Reading value at this point will cause a panic
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```
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## How it works
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Internally, `generational-box` creates an arena of generational RefCell's that are recyled 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 recyling a cell easier to debug. Then GenerationalBox's are `Copy` because the `&'static` pointer is `Copy`
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