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uniffi-bindgen-swift

Swift bindings can be generated like other languages using uniffi-bindgen -l swift. However, you can also use the uniffi-bindgen-swift binary which gives greater control over Swift-specific features:

  • Select which kind of files to generate: headers, modulemaps, and/or Swift sources.
  • Generate a single modulemap for a library.
  • Generate XCFramework-compatible modulemaps.
  • Customize the modulemap module name.
  • Customize the modulemap filename.

uniffi-bindgen-swift can be added to your project using the same general steps as uniffi-bindgen. See https://mozilla.github.io/uniffi-rs/latest/tutorial/foreign_language_bindings.html#creating-the-bindgen-binary. The Rust source for the binary should be:

fn main() {
    uniffi::uniffi_bindgen_swift()
}

uniffi-bindgen-swift always inputs a library path and runs in "library mode". This means proc-macro-based bindings generation is always supported.

Examples:

Generate .swift source files for a library 

cargo run -p uniffi-bindgen-swift -- target/release/mylibrary.a build/swift --swift-sources

Generate .h files for a library 

cargo run -p uniffi-bindgen-swift -- target/release/mylibrary.a build/swift/Headers --headers

Generate a modulemap 

cargo run -p uniffi-bindgen-swift -- target/release/mylibrary.a build/swift/Modules --modulemap --modulemap-filename mymodule.modulemap

Generate a Xcframework-compatible modulemap 

cargo run -p uniffi-bindgen-swift -- target/release/mylibrary.a build/swift/Modules --xcframework --modulemap --modulemap-filename mymodule.modulemap