uniffi-bindgen-cs - UniFFI C# bindings generator

Generate UniFFI bindings for C#. uniffi-bindgen-cs lives as a separate project from uniffi-rs, as per uniffi-rs #1355.

How to install

Minimum Rust version required to install uniffi-bindgen-cs is 1.72. Newer Rust versions should also work fine.

cargo install uniffi-bindgen-cs --git https://github.com/NordSecurity/uniffi-bindgen-cs --tag v0.8.0+v0.25.0

How to generate bindings

uniffi-bindgen-cs path/to/definitions.udl

Generates bindings file path/to/definitions.cs

How to integrate bindings

To integrate the bindings into your projects, simply add the generated bindings file to your project. There are a few requirements depending on your target framework version.

• .NET core 6.0 or higher

  <PropertyGroup>
      <TargetFramework>net6.0</TargetFramework>
      <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
  </PropertyGroup>

• .NET framework 4.8

  <PropertyGroup>
      <TargetFramework>net48</TargetFramework>
      <LangVersion>10.0</LangVersion>
      <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
      <PackageReference Include="IsExternalInit" Version="1.0.3"/>
      <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
  </PropertyGroup>

Unsupported features

The following uniffi features are unsupported.

• External types #40

• Async functions #41

Known Limitations

The following valid Rust type definitions fail to be converted properly, but a simple work-around is given:

• Enum variants having the same name as their member type #60

Configuration options

It's possible to configure some settings by passing --config argument to the generator.

uniffi-bindgen-cs path/to/definitions.udl --config path/to/uniffi.toml

Versioning

uniffi-bindgen-cs is versioned separately from uniffi-rs. UniFFI follows the SemVer rules from the Cargo Book which states "Versions are considered compatible if their left-most non-zero major/minor/patch component is the same". A breaking change is any modification to the C# bindings that demands the consumer of the bindings to make corresponding changes to their code to ensure that the bindings continue to function properly. uniffi-bindgen-cs is young, and it's unclear how stable the generated bindings are going to be between versions. For this reason, major version is currently 0, and most changes are probably going to bump minor version.

To ensure consistent feature set across external binding generators, uniffi-bindgen-cs targets a specific uniffi-rs version. A consumer using Go bindings (in uniffi-bindgen-go) and C# bindings (in uniffi-bindgen-cs) expects the same features to be available across multiple bindings generators. This means that the consumer should choose external binding generator versions such that each generator targets the same uniffi-rs version.

To simplify this choice uniffi-bindgen-cs and uniffi-bindgen-go use tag naming convention as follows: vX.Y.Z+vA.B.C, where X.Y.Z is the version of the generator itself, and A.B.C is the version of uniffi-rs it is based on.

The table shows uniffi-rs version history for tags that were published before tag naming convention described above was introduced.

uniffi-bindgen-cs version	uniffi-rs version
v0.6.0	v0.25.0
v0.5.0	v0.24.0
v0.3.0 (DONT USE, UNFINISHED)	3142151e v0.24.0?
v0.2.0	v0.23.0
v0.1.0	v0.20.0

Documentation

More documentation is available in docs directory.

Contributing

For contribution guidelines, read CONTRIBUTING.md.