wip: example binary to build swift package (#2382)

Cargo.toml

@@ -11,6 +11,7 @@ members = [
   "weedle2",
 
   "examples/app/uniffi-bindgen-cli",
+  "examples/app/uniffi-bindgen-swift-package-cli",
   "examples/arithmetic",
   "examples/arithmetic-procmacro",
   "examples/async-api-client",

examples/app/uniffi-bindgen-swift-package-cli/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "uniffi-bindgen-swift-package-cli"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[[bin]]
+name = "uniffi-bindgen-swift-package"
+path = "uniffi-bindgen-swift-package.rs"
+
+[dependencies]
+uniffi = { workspace = true, features = ["cli"] }
+
+[features]
+ffi-trace = ["uniffi/ffi-trace"]

examples/app/uniffi-bindgen-swift-package-cli/README.md

@@ -0,0 +1,67 @@
+# uniffi-bindgen-swift-package-cli
+
+An example binary for building Swift packages based on Uniffi bindgen.
+
+The `--build` and its related options are provided as convenience to build all required targets.
+
+The resulting Swift package can be used as a local path dependnecy directly. Currently code
+signing and notorization is out of scope for this application.
+
+```
+Usage: uniffi-bindgen-swift-package [OPTIONS] --package-name <SPEC> --out-dir <OUT_DIR>
+
+Options:
+  -p, --package-name <SPEC>
+          Rust package to use for building the Swift package
+
+          Cargo metadata will be searched to determine the library name.
+
+      --library-type <LIB_TYPE>
+          Type of library to package, defaults to staticlib
+
+          Possible values:
+          - staticlib: Build an embedded XCFramework with static libraries
+          - dylib:     Build an embedded XCFrameowrk with embedded dynamic Framework libraries
+
+  -o, --out-dir <OUT_DIR>
+          Directory in which to generate the Swift package, i.e., Package.swift parent dir
+
+      --swift-package-name <NAME>
+          Swift package name
+
+          Defaults to the package library name.
+
+      --manifest-path <MANIFEST_PATH>
+          Path to manifest for Rust workspace/package
+
+          Defaults to search from current working path
+
+  -c, --consolidate
+          Consolidate crate bindings into single Swift target.
+
+          Otherwise separate targets will be generated to help avoid name conflicts.
+
+  -b, --build
+          Builds package for specified targets.
+
+          Otherwise assumes all targets have been built in the default target dir.
+
+  -r, --release
+          Build artifacts in release mode, with optimization
+
+          Requires build flag to be set
+
+  -F, --features <FEATURES>
+          Space or comma separated list of features to activate
+
+          Requires build flag to be set
+
+      --target <TARGET>
+          Target for target triple to include
+
+  -h, --help
+          Print help (see a summary with '-h')
+
+  -V, --version
+          Print version
+```

examples/app/uniffi-bindgen-swift-package-cli/uniffi-bindgen-swift-package.rs

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

uniffi/src/cli/mod.rs

@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 mod swift;
+mod swift_package;
 mod uniffi_bindgen;
 
 pub fn uniffi_bindgen_main() {
@@ -18,3 +19,10 @@ pub fn uniffi_bindgen_swift() {
         std::process::exit(1);
     }
 }
+
+pub fn uniffi_bindgen_swift_package() {
+    if let Err(e) = swift_package::run_main() {
+        eprintln!("{e:?}");
+        std::process::exit(1);
+    }
+}

uniffi/src/cli/swift_package.rs

@@ -0,0 +1,94 @@
+use anyhow::{bail, Result};
+use camino::Utf8PathBuf;
+use clap::{command, Parser};
+
+// TODO: Add all-features and no-default-features options
+// TODO: Add univeral library override option(s)
+
+#[derive(Debug, Parser)]
+#[command(version, about, long_about = None)]
+struct Cli {
+    /// Rust package to use for building the Swift package
+    ///
+    /// Cargo metadata will be searched to determine the library name.
+    #[arg(short = 'p', long, value_name = "SPEC")]
+    package_name: String,
+
+    /// Type of library to package, defaults to staticlib.
+    #[arg(long, value_name = "LIB_TYPE")]
+    library_type: Option<LibraryType>,
+
+    /// Directory in which to generate the Swift package, i.e., Package.swift parent dir
+    #[arg(short = 'o', long)]
+    out_dir: Utf8PathBuf,
+
+    /// Swift package name
+    ///
+    /// Defaults to the package library name.
+    #[arg(long, value_name = "NAME")]
+    swift_package_name: Option<String>,
+
+    /// Path to manifest for Rust workspace/package
+    ///
+    /// Defaults to search from current working path
+    #[arg(long, value_name = "MANIFEST_PATH")]
+    manifest_path: Option<Utf8PathBuf>,
+
+    /// Consolidate crate bindings into single Swift target.
+    ///
+    /// Otherwise separate Swift targets will be generated
+    #[arg(short = 'c', long)]
+    consolidate: bool,
+
+    /// Builds package for specified targets.
+    ///
+    /// Otherwise assumes all targets have been built in the default target dir.
+    #[arg(short = 'b', long)]
+    build: bool,
+
+    /// Build artifacts in release mode, with optimization
+    ///
+    /// Requires build flag to be set
+    #[arg(short = 'r', long)]
+    release: bool,
+
+    /// Space or comma separated list of features to activate
+    ///
+    /// Requires build flag to be set
+    #[arg(short = 'F', long)]
+    features: Vec<String>,
+
+    /// Target for target triple to include
+    #[arg(long)]
+    target: Vec<String>,
+}
+
+#[derive(Clone, Debug, clap::ValueEnum)]
+enum LibraryType {
+    /// Build an embedded XCFramework with static libraries
+    Staticlib,
+    /// Build an embedded XCFrameowrk with embedded dynamic Framework libraries
+    Dylib,
+}
+
+pub fn run_main() -> Result<()> {
+    let _ = Cli::parse();
+
+    // TODO: Specify targets from command line with default.
+    let _targets = [
+        "x86_64-apple-ios",
+        "aarch64-apple-ios-sim",
+        "aarch64-apple-ios",
+        "x86_64-apple-darwin",
+        "aarch64-apple-darwin",
+    ];
+
+    // TODO: Override xcframework libraries from command line.
+    let _library_targets = [
+        vec!["x86_64-apple-ios", "aarch64-apple-ios-sim"], // iOS simulator
+        vec!["aarch64-apple-ios"],                         // iOS
+        vec!["x86_64-apple-darwin", "aarch64-apple-darwin"], // macOS
+    ];
+
+    bail!("Building a Swift Package is unimplemented!");
+}