# ffi-support

**Repository Path**: mirrors_mozilla/ffi-support

## Basic Information

- **Project Name**: ffi-support
- **Description**: A crate to help expose Rust functions over the FFI.
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-22
- **Last Updated**: 2026-03-07

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# FFI Support

[![Docs](https://docs.rs/ffi-support/badge.svg)](https://docs.rs/ffi-support)

This crate is deprecated and has been archived.

This crate implements a low-level support library to simplify implementing certain FFI patterns.
It was originally created for patterns in the [mozilla/application-services](https://github.com/mozilla/application-services)
repository, but that repo is working on replacing all uses of this crate with
the [mozilla/uniffi-rs](https://github.com/mozilla/uniffi-rs) project.

In other words, we consider this crate HARD-deprecated and replaced by [UniFFI](https://github.com/mozilla/uniffi-rs).

If this crate proves useful to others, it should be forked. It can assist with the following areas:

1. Avoiding throwing panics over the FFI (which is undefined behavior)
2. Translating rust errors (and panics) into errors that the caller on the other side of the FFI is able to handle.
3. Converting strings to/from rust str.
4. Passing non-string data (in a few ways, including exposing an opaque pointeer, marshalling data to JSON strings with serde, as well as arbitrary custom handling) back and forth between Rust and whatever the caller on the other side of the FFI is.

Additionally, it's documentation describes a number of the problems we've hit doing this to expose libraries to consumers on mobile platforms.

## Usage

Add the following to your Cargo.toml

```toml
ffi-support = "0.4.4"
```

For further examples, the examples in the docs is the best starting point, followed by the usage code in the [mozilla/application-services](https://github.com/mozilla/application-services) repo (for example [here](https://github.com/mozilla/application-services/blob/main/components/places/ffi/src/lib.rs) or [here](https://github.com/mozilla/application-services/blob/main/components/places/src/ffi.rs)).

## License

Dual licensed under the Apache License, Version 2.0 <LICENSE-APACHE> or
<http://www.apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT> or
<http://opensource.org/licenses/MIT>, at your option. All files in the project
carrying such notice may not be copied, modified, or distributed except
according to those terms.