# Fruity
[<img alt="github" src="https://img.shields.io/badge/github-nvzqz/fruity-8da0cb?style=for-the-badge&labelColor=555555&logo=github" height="24">](https://github.com/nvzqz/fruity)
[<img alt="crates.io" src="https://img.shields.io/crates/v/fruity.svg?style=for-the-badge&color=fc8d62&logo=rust" height="24">](https://crates.io/crates/fruity)
[<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-fruity-66c2a5?style=for-the-badge&labelColor=555555&logoColor=white&logo=data:image/svg+xml;base64,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" height="24">](https://docs.rs/fruity)
Rusty bindings for Apple libraries, brought to you by
[@NikolaiVazquez](https://twitter.com/NikolaiVazquez).
## Index
1. [Donate](#donate)
2. [Usage](#usage)
1. [Feature Flags](#feature-flags)
3. [Goals](#goals)
1. [Idiomatic Rust](#idiomatic-rust)
2. [Zero Cost](#zero-cost)
4. [License](#license)
## Donate
If this project is useful to you, consider
[sponsoring me](https://github.com/sponsors/nvzqz) or
[donating directly](https://www.paypal.me/nvzqz)!
Doing so enables me to create high-quality open source software like this. ❤️
## Usage
This library is available [on crates.io][crate] and can be used in your project
by adding the following to your project's [`Cargo.toml`]:
```toml
[dependencies.fruity]
version = "0.3.0"
```
### Feature Flags
Each module for a library or framework has its own
[feature flag](https://doc.rust-lang.org/cargo/reference/features.html)
with the same name.
For example, this is how you enable the
[`foundation`](https://docs.rs/fruity/0.3.0/fruity/foundation/index.html)
module:
```toml
[dependencies.fruity]
version = "0.3.0"
features = ["foundation"]
```
This feature transitively enables the
[`objc`](https://docs.rs/fruity/0.3.0/fruity/objc/index.html)
feature/module.
## Goals
### Idiomatic Rust
Fruity makes interfacing with these C and Objective-C APIs feel natural in Rust.
- **Automatic Reference Counting.**
Fruity takes advantage of Rust's
[ownership model](https://doc.rust-lang.org/book/ch04-01-what-is-ownership.html)
to handle object reference counting for you.
[`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html)
is a smart pointer that calls
[`retain`](https://developer.apple.com/documentation/objectivec/1418956-nsobject/1571946-retain)
on [`Clone`](https://doc.rust-lang.org/std/clone/trait.Clone.html) and
[`release`](https://developer.apple.com/documentation/objectivec/1418956-nsobject/1571957-release)
on [`Drop`](https://doc.rust-lang.org/std/ops/trait.Drop.html). This is
exactly how Rust's
[`Arc<T>`](https://doc.rust-lang.org/std/sync/struct.Arc.html) works.
- **`Option<NSObject>`.**
In Objective-C, all objects are nullable unless marked with `_Nonnull`. This
often leads to either very defensive checks or careless ignoring of null
objects.
Fruity reverses that and instead makes all objects (such as
[`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html))
non-null by default. An object can be made nullable by wrapping it with
[`Option<T>`](https://doc.rust-lang.org/std/option/enum.Option.html).
To make FFI safe and easy, the following Objective-C and Rust types are
ABI-compatible:
- `NSObject * _Nonnull` and `NSObject`
- `NSObject * _Nullable` and `Option<NSObject>`
This is because
[`NSObject`](https://docs.rs/fruity/0.3.0/fruity/objc/struct.NSObject.html)
is a
[`#[repr(transparent)]`](https://doc.rust-lang.org/nomicon/other-reprs.html#reprtransparent)
wrapper around a
[`NonNull<T>`](https://doc.rust-lang.org/std/ptr/struct.NonNull.html)
pointer.
- **`Result<T, NSError>`.**
In Objective-C, methods take a pointer to where an
[`NSError`](https://developer.apple.com/documentation/foundation/nserror)
is placed upon failure. This makes it easy to avoid error handling and assume
the happy path, which can lead to bugs when errors occur.
Fruity instead returns a
[`Result`](https://doc.rust-lang.org/std/result/enum.Result.html), which
is the canonical way to handle errors in Rust. This ensures that errors must
be acknowledged in some way.
- **Natural inheritance.**
Most of these types are classes that inherit from each other. Because true
inheritance is not possible in Rust, Fruity uses
[`Deref`](https://doc.rust-lang.org/std/ops/trait.Deref.html)
to model Objective-C subclassing.
- **Builder Pattern.**
Types like
[`DispatchQueue`](https://docs.rs/fruity/0.3.0/fruity/dispatch/struct.DispatchQueue.html)
have many configurable inputs to create an instance. Many of these inputs have
standard default values, so it is cumbersome to specify them all each time.
Swift solves this by having default parameters in
[`init`](https://developer.apple.com/documentation/dispatch/dispatchqueue/2300059-init).
However, Rust does not have default function parameters.
Fruity instead solves this using the
[builder pattern](https://doc.rust-lang.org/1.0.0/style/ownership/builders.html).
See
[`DispatchQueueBuilder`](https://docs.rs/fruity/0.3.0/fruity/dispatch/struct.DispatchQueueBuilder.html)
as an example. This reduces and simplifies code for creating dispatch queues.
### Zero Cost
Using Fruity to interface with Objective-C libraries should have as little
runtime cost as writing the same code directly in Objective-C.
This is true for the following:
- **Calling object methods.**
Method dispatch is always direct and does not need the error checking overhead
of other wrappers that use the
[`objc::msg_send!`](https://docs.rs/objc/0.2.*/objc/macro.msg_send.html)
macro. This also reduces the size of your program by not emitting panics that
would otherwise never get called.
This library is carefully written to ensure that calls to
[`objc_msgSend`](https://developer.apple.com/documentation/objectivec/1456712-objc_msgsend)
are always done with the correct object type, method selector, and arguments.
- **Getting a static class.**
Getters like `NSString::class` retrieve the class directly through its symbol.
This is instantaneous, especially when compared to calling into the
Objective-C runtime via
[`objc_getClass`](https://developer.apple.com/documentation/objectivec/1418952-objc_getclass).
- **Creating an `NSString` from a Rust string literal.**
The [`nsstring!`](https://docs.rs/fruity/0.3.0/fruity/macro.nsstring.html)
macro creates an `NSString` literal (i.e. `@"string"`) at compile time. There
is no runtime dispatch/allocation/initialization cost.
Some parts of this library still aren't zero cost. Your help would be much
appreciated here!
These are:
- **The `selector!` macro.** See
[issue #2](https://github.com/nvzqz/fruity/issues/2)
for details.
## License
This project is released under either the
[MIT License](https://github.com/nvzqz/fruity/blob/main/LICENSE-MIT) or
[Apache License (Version 2.0)](https://github.com/nvzqz/fruity/blob/main/LICENSE-APACHE),
at your choosing.
[crate]: https://crates.io/crates/fruity
[`Cargo.toml`]: https://doc.rust-lang.org/cargo/reference/manifest.html