Replace cargo-swift with equivalent script (#15)

Building the framework with a shell script will (hopefully) make it clearer what's actually going on.

Going forward it will also give us more control over the exact procedure like for instance whether to build universal binaries or support arm64 only. For example it's only necessary to build a single target on the CI when running unit tests (for now we build for all platforms on the CI).

Last but not least it will allow us to remove a dependency that we don't actually need.

.github/workflows/build+test.yml

@@ -21,14 +21,13 @@ jobs:
     - name: Setup Rust
       run: |
         rustup default "${{env.rust_version}}"
-        rustup target install aarch64-apple-darwin x86_64-apple-darwin
-        cargo install cargo-swift
+        rustup target install aarch64-apple-darwin aarch64-apple-ios aarch64-apple-ios-sim x86_64-apple-darwin x86_64-apple-ios
     - name: Check out sources
       uses: actions/checkout@v4
       with:
         submodules: recursive
-    - name: Build rust bindings (macOS only)
-      run: cargo swift package --name=ConcordiumWalletCrypto --platforms=macos --release
+    - name: Build rust bindings
+      run: ./build.sh
       working-directory: ./lib/crypto
     - name: Check formatting
       run: swift package plugin --allow-writing-to-package-directory swiftformat --lint

README.md

@@ -46,18 +46,17 @@ This SDK includes a thin wrapper for providing bindings to the Rust library
 [`wallet_library`](https://github.com/Concordium/concordium-base/tree/main/rust-src/wallet_library)
 which exposes functions specifically relevant for wallets.
 
-These bindings are located in `./lib/crypto` and built using [`cargo-swift`](https://github.com/antoniusnaumann/cargo-swift/)
-into a [XCFramework](https://developer.apple.com/documentation/xcode/distributing-binary-frameworks-as-swift-packages).
+These bindings are located in `./lib/crypto` and compiled into an
+[XCFramework](https://developer.apple.com/documentation/xcode/distributing-binary-frameworks-as-swift-packages).
 The SDK pulls in this framework from a local path, so the bindings have to built manually before the SDK can be used.
 
-Building is only a matter of installing `cargo-swift` and invoking a Make target:
+Building is only a matter of invoking the Make target
 
 ```shell
-cargo install cargo-swift
 make build-crypto
 ```
 
-This will place the target framework at `./lib/crypto/ConcordiumWalletCrypto`.
+This will place the target framework in `./lib/crypto/ConcordiumWalletCrypto`.
 
 ### Build and test SDK
 

lib/crypto/.gitignore

@@ -1,3 +1,2 @@
 /target
 /generated
-/ConcordiumWalletCrypto

lib/crypto/Cargo.toml

@@ -8,9 +8,13 @@ crate-type = ["staticlib", "lib"]
 name = "crypto"
 
 [dependencies]
-thiserror = "1.0.56"
-uniffi = "0.25"
+thiserror = "1"
+uniffi = { version = "0.25", features = ["cli"] }
 wallet_library = { path = "./concordium-base/rust-src/wallet_library" }
 
 [build-dependencies]
 uniffi = { version = "0.25", features = ["build"] }
+
+[[bin]]
+name = "uniffi-bindgen"
+path = "uniffi-bindgen.rs"

lib/crypto/ConcordiumWalletCrypto/.gitignore

@@ -0,0 +1,3 @@
+*
+!*ignore
+!/Package.swift

lib/crypto/ConcordiumWalletCrypto/Package.swift

@@ -0,0 +1,29 @@
+// swift-tools-version:5.6
+
+import PackageDescription
+
+let package = Package(
+    name: "ConcordiumWalletCrypto",
+    platforms: [
+        .iOS(.v13),
+        .macOS(.v10_15),
+    ],
+    products: [
+        .library(
+            name: "ConcordiumWalletCrypto",
+            targets: ["ConcordiumWalletCrypto"]
+        ),
+    ],
+    targets: [
+        .binaryTarget(
+            name: "RustFramework",
+            path: "./RustFramework.xcframework"
+        ),
+        .target(
+            name: "ConcordiumWalletCrypto",
+            dependencies: [
+                .target(name: "RustFramework"),
+            ]
+        ),
+    ]
+)

lib/crypto/build.sh

@@ -2,5 +2,40 @@
 
 set -eux
 
-rm -rf ./ConcordiumWalletCrypto/
-cargo swift package --name=ConcordiumWalletCrypto --platforms=ios --platforms=macos --release
+# Generate bindings/bridge code.
+mkdir -p ./ConcordiumWalletCrypto/Sources/ConcordiumWalletCrypto
+cargo run --bin uniffi-bindgen generate src/lib.udl --language=swift --out-dir=./generated
+mv ./generated/crypto.swift ./ConcordiumWalletCrypto/Sources/ConcordiumWalletCrypto/crypto.swift
+mv ./generated/cryptoFFI.modulemap ./generated/module.modulemap
+
+# Compile for Darwin (macOS) as universal binary.
+cargo build --target=x86_64-apple-darwin --release
+cargo build --target=aarch64-apple-darwin --release
+mkdir -p ./target/universal/darwin/release
+lipo \
+  ./target/x86_64-apple-darwin/release/libcrypto.a \
+  ./target/aarch64-apple-darwin/release/libcrypto.a \
+  -create -output ./target/universal/darwin/release/libcrypto.a
+
+# Compile for iOS.
+cargo build --target=aarch64-apple-ios --release
+
+# Compile for iOS Simulator as universal binary.
+cargo build --target=x86_64-apple-ios --release
+cargo build --target=aarch64-apple-ios-sim --release
+mkdir -p ./target/universal/ios/release
+lipo \
+  ./target/x86_64-apple-ios/release/libcrypto.a \
+  ./target/aarch64-apple-ios-sim/release/libcrypto.a \
+  -create -output ./target/universal/ios/release/libcrypto.a
+
+# Build binary framework.
+rm -rf ./ConcordiumWalletCrypto/RustFramework.xcframework
+xcodebuild -create-xcframework \
+  -library ./target/universal/darwin/release/libcrypto.a -headers ./generated \
+  -library ./target/aarch64-apple-ios/release/libcrypto.a -headers ./generated \
+  -library ./target/universal/ios/release/libcrypto.a -headers ./generated \
+  -output ./ConcordiumWalletCrypto/RustFramework.xcframework
+
+# Clean up.
+rm -rf ./generated

lib/crypto/uniffi-bindgen.rs

@@ -0,0 +1,3 @@
+fn main() {
+    uniffi::uniffi_bindgen_main()
+}