Fallible allocation functions for Vec

Fallible allocation functions for the Rust standard library's alloc::vec::Vec type.

These functions are designed to be usable with #![no_std] and #[cfg(no_global_oom_handling)](see rust-lang/rust#84266) enabled.

Usage

The recommended way to add these functions to Vec is by adding a use declaration for the entire module: use fallible_vec::*:

use fallible_vec::*;
let mut vec = try_vec![1, 2]?;
vec.try_push(3)?;
assert_eq!(vec, [1, 2, 3]);

Panic Safety

These methods are "panic safe", meaning that if a call to external code (e.g., an iterator's next() method or an implementation of Clone::clone()) panics, then these methods will leave the Vec in a consistent state:

len() will be less than or equal to capacity().
Items in 0..len() will only be items originally in the Vec or items being added to the Vec. It will never include uninitialized memory, duplicated items or dropped items.
Items originally (but no longer) in the Vec or being added to (but not yet in) the Vec may be leaked - any method that may leak items like this will have a note to specify its behavior.

The exact behavior of each method is specified in its documentations.

Code origin

Most of this code is forked form Rust's Standard Library. While we will attempt to keep the code and docs in sync, if you notice any issues please check if they have been fixed in the Standard Library first.

This API is incomplete

There are many more infallible functions on Vec which have not been ported yet. If there's a particular API that you're missing feel free to open a PR or file an Issue to get it added.

Why are these not already in the Standard Library

There is a PR to add these and more to the Standard Library, followed by an RFC to discuss if it's a good idea or not to do so.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

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This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Trademarks

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calebcartwright/rust_fallible_vec