Remove unused `ShieldStateCode::SentInClear`
`VerificationState::to_shield_state_{strict,lax}` return a type `ShieldState`, whose inner
type `ShieldStateCode` currently includes a variant `SentInClear` for "unencrypted event".
This is very misleading, because those functions never actually set that variant.
Rather, there is a separate method in `matrix-sdk-ui`, `EventTimelineItem::get_shield`,
which uses the same type, but *does* set that variant where appropriate.
As a user of matrix-sdk-common, without the matrix-sdk-ui layer, this is dangerously
misleading: it gives the impression that we are checking for unencrypted events, when in
fact we are not.
The solution seems to be to use different types for the different levels of the stack.
While we're at it, we fix up some of the confusion of methods that return an `Option` of an
enum type which itself has a `None` variant.
Matrix Rust SDK
The Matrix Rust SDK is a collection of libraries that make it easier to build Matrix clients in Rust.
Development of the SDK is proudly sponsored and maintained by Element. Element uses the SDK in their next-generation mobile apps Element X on iOS and Android and has plans to introduce it to the web and desktop clients as well.
The SDK is also the basis for multiple Matrix projects and we welcome contributions from all.
Purpose
The SDK takes care of the low-level details like encryption, syncing, and room state, so you can focus on your app's logic and UI. Whether you're writing a small bot, a desktop client, or something in between, the SDK is designed to be flexible, async-friendly, and ready to use out of the box.
Project structure
The Matrix Rust SDK is made up of several crates that build on top of each other. The following crates are expected to be usable as direct dependencies:
- matrix-sdk-ui – A high-level client library that makes it easy to build full-featured UI clients with minimal setup. Check out our reference client, multiverse, for an example.
- matrix-sdk – A mid-level client library, ideal for building bots, custom clients, or higher-level abstractions. You can find example usage in the examples directory.
- matrix-sdk-crypto – A standalone encryption state machine with no network I/O, providing end-to-end encryption support for Matrix clients and libraries. See the crypto tutorial for a step-by-step introduction.
All other crates are effectively internal-only and only structured as crates for organizational purposes and to improve compilation times. Direct usage of them is discouraged.
Status
The library is considered production ready and backs multiple client implementations such as Element X [1] [2], Fractal and iamb. Client developers should feel confident to build upon it.
Bindings
The higher-level crates of the Matrix Rust SDK can be embedded in other environments such as Swift, Kotlin, JavaScript, and Node.js. Check out the bindings/ directory to learn more about how to integrate the SDK into your language of choice.