open-standards/wai/wai-sink-swift/Package.swift

// swift-tools-version:5.9
// The native sink for the platforms whose native player is reached from Swift
// (wai/extensions/native-sink.md): the C interface of libwai (feature `native_sink`), wrapped,
// and integrated with the platform's player through a loopback relay.
import Foundation
import PackageDescription

// `WaiFFI`, the C interface, is a binary target: a release's WaiFFI.xcframework, named by URL and
// checksum. scripts/package-release.sh writes the two into the copy of this package a release
// attaches (wai-sink-swift-<version>.zip), and SwiftPM refuses an archive whose checksum is not
// the one named. While scripts/build-xcframework.sh has built the framework here
// (build/WaiFFI.xcframework), the target is that build instead: the repository's own tests run
// against the libwai of their checkout.
let release: (url: String, checksum: String)? = nil
let localBuild = Context.packageDirectory + "/build/WaiFFI.xcframework"
let ffi: Target
if let release, !FileManager.default.fileExists(atPath: localBuild) {
    ffi = .binaryTarget(name: "WaiFFI", url: release.url, checksum: release.checksum)
} else {
    ffi = .binaryTarget(name: "WaiFFI", path: "build/WaiFFI.xcframework")
}

let package = Package(
    name: "WaiSink",
    platforms: [.iOS(.v16), .tvOS(.v16), .macOS(.v13)],
    products: [
        .library(name: "WaiSink", targets: ["WaiSink"]),
    ],
    targets: [
        ffi,
        // libwai's integer decode drives the device's GPU through Metal (native-sink §13); on the
        // desktop its measured choice reads the GPU's energy rail through the system's IOReport
        // library (native-sink §13.2).
        .target(name: "WaiSink", dependencies: ["WaiFFI"], path: "Sources/WaiSink",
                linkerSettings: [.linkedFramework("Metal"), .linkedFramework("QuartzCore"), .linkedFramework("CoreGraphics"), .linkedFramework("Foundation"),
                                 .linkedLibrary("IOReport", .when(platforms: [.macOS]))]),
        // Resources/ holds the native sink corpus, staged by scripts/build-xcframework.sh, so the
        // tests read it on a device as on the desktop.
        .testTarget(name: "WaiSinkTests", dependencies: ["WaiSink"], path: "Tests/WaiSinkTests", resources: [.copy("Resources")]),
    ]
)