Move UniFFI types to own, feature-gated module

While we need quite a bit of dependencies and custom impls for UniFFI support, there is
no reason to pull them in for Rust-only builds. Here we move the
UniFFI-specific types and trait impls to a dedicated module and hide it
behind a new `uniffi` feature.

Author: tnull

.github/workflows/build.yml

@@ -22,10 +22,16 @@ jobs:
           profile: minimal
       - name: Build on Rust ${{ matrix.toolchain }}
         run: cargo build --verbose --color always
+      - name: Build with UniFFI support on Rust ${{ matrix.toolchain }}
+        run: cargo build --features uniffi --verbose --color always
       - name: Check release build on Rust ${{ matrix.toolchain }}
         run: cargo check --release --verbose --color always
+      - name: Check release build with UniFFI support on Rust ${{ matrix.toolchain }}
+        run: cargo check --release --features uniffi --verbose --color always
+      - name: Test on Rust ${{ matrix.toolchain }}
+        run: cargo test
+      - name: Test with UniFFI support on Rust ${{ matrix.toolchain }}
+        run: cargo test --features uniffi
       - name: Check formatting on Rust ${{ matrix.toolchain }}
         if: matrix.check-fmt
         run: rustup component add rustfmt && cargo fmt --all -- --check
-      - name: Test on Rust ${{ matrix.toolchain }}
-        run: cargo test

Cargo.toml

@@ -27,7 +27,9 @@ opt-level = 'z'     # Optimize for size.
 lto = true          # Enable Link Time Optimization
 codegen-units = 1   # Reduce number of codegen units to increase optimizations.
 panic = 'abort'     # Abort on panic
-strip = true        # Strip symbols from binary*
+
+[features]
+default = []
 
 [dependencies]
 lightning = { version = "0.0.115", features = ["max_level_trace", "std"] }
@@ -67,7 +69,7 @@ serde_json = { version = "1.0" }
 tokio = { version = "1", default-features = false, features = [ "rt-multi-thread", "time", "sync" ] }
 esplora-client = { version = "0.4", default-features = false }
 libc = "0.2"
-uniffi = { version = "0.23.0", features = ["build"] }
+uniffi = { version = "0.23.0", features = ["build"], optional = true }
 
 [dev-dependencies]
 electrsd = { version = "0.22.0", features = ["legacy", "esplora_a33e97e1", "bitcoind_23_0"] }
@@ -76,8 +78,7 @@ proptest = "1.0.0"
 regex = "1.5.6"
 
 [build-dependencies]
-uniffi = { version = "0.23.0", features = ["build", "cli"] }
-
+uniffi = { version = "0.23.0", features = ["build", "cli"], optional = true }
 
 [profile.release]
 panic = "abort"

build.rs

@@ -1,3 +1,4 @@
 fn main() {
+	#[cfg(feature = "uniffi")]
 	uniffi::generate_scaffolding("bindings/ldk_node.udl").unwrap();
 }

scripts/uniffi_bindgen_generate_kotlin.sh

@@ -12,7 +12,7 @@ fi
 
 #rustup target add aarch64-apple-darwin
 #cargo build --target aarch64-apple-darwin || exit 1
-cargo build --release || exit 1
+cargo build --release --features uniffi || exit 1
 $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language kotlin -o "$TARGET_DIR" || exit 1
 
 mkdir -p "$BINDINGS_DIR"/"$PROJECT_DIR"/lib/src/main/kotlin/"$PACKAGE_DIR" || exit 1

scripts/uniffi_bindgen_generate_kotlin_android.sh

@@ -9,10 +9,9 @@ LLVM_ARCH_PATH="darwin-x86_64"
 PATH="$ANDROID_NDK_ROOT/toolchains/llvm/prebuilt/$LLVM_ARCH_PATH/bin:$PATH"
 
 rustup +nightly target add x86_64-linux-android aarch64-linux-android armv7-linux-androideabi
-#cargo build --release || exit 1
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER="x86_64-linux-android21-clang" CC="x86_64-linux-android21-clang" cargo +nightly build --profile release-smaller --target x86_64-linux-android || exit 1
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER="armv7a-linux-androideabi21-clang" CC="armv7a-linux-androideabi21-clang" cargo +nightly build --profile release-smaller --target armv7-linux-androideabi || exit 1
-CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo +nightly build --profile release-smaller --target aarch64-linux-android || exit 1
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_X86_64_LINUX_ANDROID_LINKER="x86_64-linux-android21-clang" CC="x86_64-linux-android21-clang" cargo +nightly build --profile release-smaller --features uniffi --target x86_64-linux-android || exit 1
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_ARMV7_LINUX_ANDROIDEABI_LINKER="armv7a-linux-androideabi21-clang" CC="armv7a-linux-androideabi21-clang" cargo +nightly build --profile release-smaller --features uniffi --target armv7-linux-androideabi || exit 1
+CFLAGS="-D__ANDROID_MIN_SDK_VERSION__=21" AR=llvm-ar CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo +nightly build --profile release-smaller --features uniffi --target aarch64-linux-android || exit 1
 $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language kotlin -o "$BINDINGS_DIR"/"$PROJECT_DIR"/lib/src/main/kotlin || exit 1
 
 JNI_LIB_DIR="$BINDINGS_DIR"/"$PROJECT_DIR"/lib/src/main/jniLibs/ 

scripts/uniffi_bindgen_generate_python.sh

@@ -2,6 +2,6 @@
 BINDINGS_DIR="./bindings/python"
 UNIFFI_BINDGEN_BIN="cargo +nightly run --features=uniffi/cli --bin uniffi-bindgen"
 
-cargo +nightly build --release || exit 1
+cargo +nightly build --release --features uniffi || exit 1
 $UNIFFI_BINDGEN_BIN generate bindings/ldk_node.udl --language python -o "$BINDINGS_DIR" || exit 1
 cp ./target/release/libldk_node.dylib "$BINDINGS_DIR"/libldk_node.dylib || exit 1

scripts/uniffi_bindgen_generate_swift.sh

@@ -15,12 +15,12 @@ rustup target add aarch64-apple-ios-sim --toolchain nightly
 rustup target add aarch64-apple-darwin x86_64-apple-darwin
 
 # Build rust target libs
-cargo build --profile release-smaller || exit 1
-cargo build --profile release-smaller --target x86_64-apple-darwin || exit 1
-cargo build --profile release-smaller --target aarch64-apple-darwin || exit 1
-cargo build --profile release-smaller --target x86_64-apple-ios || exit 1
-cargo build --profile release-smaller --target aarch64-apple-ios || exit 1
-cargo +nightly build --release --target aarch64-apple-ios-sim || exit 1
+cargo build --profile release-smaller --features uniffi || exit 1
+cargo build --profile release-smaller --features uniffi --target x86_64-apple-darwin || exit 1
+cargo build --profile release-smaller --features uniffi --target aarch64-apple-darwin || exit 1
+cargo build --profile release-smaller --features uniffi --target x86_64-apple-ios || exit 1
+cargo build --profile release-smaller --features uniffi --target aarch64-apple-ios || exit 1
+cargo +nightly build --release --features uniffi --target aarch64-apple-ios-sim || exit 1
 
 # Combine ios-sim and apple-darwin (macos) libs for x86_64 and aarch64 (m1)
 mkdir -p target/lipo-ios-sim/release-smaller || exit 1

src/hex_utils.rs

@@ -1,5 +1,6 @@
 use std::fmt::Write;
 
+#[cfg(feature = "uniffi")]
 pub fn to_vec(hex: &str) -> Option<Vec<u8>> {
 	let mut out = Vec::with_capacity(hex.len() / 2);
 

src/lib.rs

@@ -86,6 +86,8 @@ mod peer_store;
 #[cfg(test)]
 mod test;
 mod types;
+#[cfg(feature = "uniffi")]
+mod uniffi_types;
 mod wallet;
 
 pub use bip39;
@@ -100,6 +102,9 @@ use error::Error;
 pub use event::Event;
 pub use types::NetAddress;
 
+#[cfg(feature = "uniffi")]
+use {bitcoin::OutPoint, lightning::ln::PaymentSecret, uniffi_types::*};
+
 use event::{EventHandler, EventQueue};
 use gossip::GossipSource;
 use io::fs_store::FilesystemStore;
@@ -122,7 +127,7 @@ use lightning::ln::channelmanager::{
 	self, ChainParameters, ChannelManagerReadArgs, PaymentId, RecipientOnionFields, Retry,
 };
 use lightning::ln::peer_handler::{IgnoringMessageHandler, MessageHandler};
-use lightning::ln::{PaymentHash, PaymentPreimage, PaymentSecret};
+use lightning::ln::{PaymentHash, PaymentPreimage};
 use lightning::routing::scoring::{ProbabilisticScorer, ProbabilisticScoringParameters};
 
 use lightning::util::config::{ChannelHandshakeConfig, ChannelHandshakeLimits, UserConfig};
@@ -147,7 +152,7 @@ use bitcoin::Network;
 
 use bip39::Mnemonic;
 
-use bitcoin::{Address, BlockHash, OutPoint, Txid};
+use bitcoin::{Address, BlockHash, Txid};
 
 use rand::Rng;
 
@@ -159,6 +164,7 @@ use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex, RwLock};
 use std::time::{Duration, Instant, SystemTime};
 
+#[cfg(feature = "uniffi")]
 uniffi::include_scaffolding!("ldk_node");
 
 // Config defaults
@@ -703,10 +709,6 @@ impl Builder {
 	}
 }
 
-/// This type alias is required as Uniffi doesn't support generics, i.e., we can only expose the
-/// concretized types via this aliasing hack.
-type LDKNode = Node<FilesystemStore>;
-
 /// The main interface object of LDK Node, wrapping the necessary LDK and BDK functionalities.
 ///
 /// Needs to be initialized and instantiated through [`Builder::build`].