slint_build

Shared plumbing for the repo's native-assets hooks: every hook/build.dart drives cargo through this package instead of shelling out itself.

API

• runCargoBuild(...) — build one crate for the hook's target and copy the artifact into the hook output directory. Parameters cover the crate name and manifest, the artifact kind (cdylib default, staticlib for the AOT link-hook path), extra env (e.g. RUSTFLAGS=--print=native-static-libs), and source dirs registered as hook dependencies. Returns the bundled artifact URI plus cargo's combined output — the AOT build hook parses rustc's native-static-libs: note out of it.
• buildCargoCrate(...) — the one-call convenience for FFI packages (slint_interpreter, slint_skia): runCargoBuild plus emitting the cdylib as a DynamicLoadingBundled code asset.
• Target-triple mapping (rustTriple) and cross-compile env for Android NDK / iOS / macOS. Cargo gets CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER (uppercased); the cc crate gets CC_aarch64_linux_android / AR_aarch64_linux_android (same underscores, original case).

The staged Cargo workspace

The Rust crates inherit their dependencies from a Cargo workspace (workspace = true) and reach each other by relative path (../../slint/rust). From pub.dev, though, a package sits in the pub cache as slint-0.0.1/, with no workspace above it and no sibling called slint. So every build goes through a workspace this package stages next to the package config, in .dart_tool/slint_cargo/:

• a link packages/<name> to each slint_dart package root the config lists;
• a generated Cargo.toml (marked GENERATED) listing their crates, with the pinned Slint version and the shared lint levels;
• the checkout's Cargo.lock as a seed, when there is one; a pub consumer resolves afresh.

runCargoBuild builds a package's rust/ crate there by default, and the slint-introspect tool and the generated AOT crate go through it too, so target/ and Cargo.lock never land in the pub cache. stageCargoWorkspace(packageConfig) and stagedCargoManifest(packageConfig, package) expose it.

The package also carries slint-dart-interpreter (interpreter/), the crate that wraps slint-interpreter for the interpreter, testing and Skia FFI crates. It lives here because slint_build is the one package all three depend on, and a crate can only reach crates of packages its Dart package depends on.

The worker

Cargo runs inside a bazel_worker persistent worker (bin/cargo_worker.dart), so repeated hook invocations reuse one process. The request names the crate, manifest, triple, cargo profile, artifact kind, and env; the response carries the artifact path and the full cargo output.

The cargo profile defaults to release (debug Slint rendering is unusably slow) and is switched per package via pubspec user-defines — see the root README's "Native assets build" section.