Swift Package for Mozilla's Rust Components

This repository is a Swift Package for distributing releases of Mozilla's various Rust-based application components. It provides the Swift source code packaged in a format understood by the Swift package manager, and depends on a pre-compiled binary release of the underlying Rust code published from mozilla/application-services.

For more information, please consult:

• application-services ADR-0003, which describes the overall plan for distributing Rust-based components as Swift packages.
• The Swift Package Manager docs and GitHub repo, which explain the details of how Swift Packages work (and hence why this repo is set up the way it is).
• The ios-rust crate which is currently responsible for publishing the pre-built MozillaRustComponents.xcframework.zip and FocusRustComponents.xcframework.zip bundles on which this repository depends.

Overview

Here's a diagram of how this repository relates to the application-services repository and its release artifacts:

Key points:

• The application-services repo publishes two binary artifacts MozillaRustComponents.xcframework.zip and FocusRustComponents.xcframework.zip containing the Rust code and FFI definitions for all components, compiled together into a single library.
• The Package.swift file refrences the xcframeworks as Swift binary targets.
• The Package.swift file defines a library per target (one for all the components used by firefox-ios and one for focus-ios)
  • Each library references its Swift source code directly as files in the repo. All components used by a target are copied into the same directory. For example, all the firefox-ios files are in the swift-source/all directory.
  • Each library depends on wrapper which wraps the binary to provide the pre-compiled Rust code. For example, FocusRustComponentWrapper wraps the Focus xcframework.

Cutting a new release

Whenever a new release of the underlying components is availble, we need to tag a new release in this repo to make them available to Swift components. To do so:

• Edit Package.swift to update the URL and checksum of MozillaRustComponents.xcframework.zip.
• Run ./make_tag.sh --as-version {APP_SERVICES_VERSION} X.Y.Z to create the new tag.
• Run git push origin X.Y.Z to publish it to GitHub.

Adding a new component

Check out the instructions in the docs in application-services for adding a new component and publishing it for iOS. The docs are also published for convenience in https://mozilla.github.io/application-services/book/index.html.

Testing

For testing instructions, you can checkout the docs in the application-services which are published for convenience in https://mozilla.github.io/application-services/book/index.html