chore(waku): Add script and command for building `RLN`

.gitignore

@@ -14,3 +14,18 @@ nimble.paths
 # Nix & Direnv
 .direnv
 result
+
+# Executables shall be put in an ignored build/ directory
+/build
+
+# Ignore dynamic, static libs and libtool archive files
+*.so
+*.dylib
+*.a
+*.la
+*.exe
+*.dll
+
+# RLN / keystore
+rlnKeystore.json
+*.tar.gz

Makefile

@@ -0,0 +1,28 @@
+##################
+##     RLN      ##
+##################
+.PHONY: librln
+
+LIBRLN_BUILDDIR := $(CURDIR)/vendor/zerokit
+LIBRLN_VERSION := v0.3.4
+
+ifeq ($(OS),Windows_NT)
+LIBRLN_FILE := rln.lib
+else
+LIBRLN_FILE := librln_$(LIBRLN_VERSION).a
+endif
+
+$(LIBRLN_FILE):
+	echo -e $(BUILD_MSG) "$@" && \
+		./scripts/build_rln.sh $(LIBRLN_BUILDDIR) $(LIBRLN_VERSION) $(LIBRLN_FILE)
+
+
+librln: | $(LIBRLN_FILE)
+	$(eval NIM_PARAMS += --passL:$(LIBRLN_FILE) --passL:-lm)
+
+clean-librln:
+	cargo clean --manifest-path vendor/zerokit/rln/Cargo.toml
+	rm -f $(LIBRLN_FILE)
+
+# Extend clean target
+clean: | clean-librln

scripts/build_rln.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env bash
+
+# This script is used to build the rln library for the current platform, or download it from the
+# release page if it is available.
+
+set -e
+
+# first argument is the build directory
+build_dir=$1
+rln_version=$2
+output_filename=$3
+
+[[ -z "${build_dir}" ]]       && { echo "No build directory specified"; exit 1; }
+[[ -z "${rln_version}" ]]     && { echo "No rln version specified";     exit 1; }
+[[ -z "${output_filename}" ]] && { echo "No output filename specified"; exit 1; }
+
+# Get the host triplet
+host_triplet=$(rustc --version --verbose | awk '/host:/{print $2}')
+
+# Download the prebuilt rln library if it is available
+if curl --silent --fail-with-body -L \
+  "https://github.com/vacp2p/zerokit/releases/download/$rln_version/${host_triplet}-rln.tar.gz" \
+  -o "${host_triplet}-rln.tar.gz";
+then
+    echo "Downloaded ${host_triplet}-rln.tar.gz"
+    tar -xzf "${host_triplet}-rln.tar.gz"
+    mv "release/librln.a" "${output_filename}"
+    rm -rf "${host_triplet}-rln.tar.gz" release
+else
+    echo "Failed to download ${host_triplet}-rln.tar.gz"
+    # Build rln instead
+    # first, check if submodule version = version in Makefile
+    cargo metadata --format-version=1 --no-deps --manifest-path "${build_dir}/rln/Cargo.toml"
+    submodule_version=$(
+      cargo metadata --format-version=1 --no-deps --manifest-path "${build_dir}/rln/Cargo.toml" \
+        | jq -r '.packages[] | select(.name == "rln") | .version'
+    )
+    if [[ "v${submodule_version}" != "${rln_version}" ]]; then
+        echo "Submodule version (v${submodule_version}) does not match version in Makefile (${rln_version})"
+        echo "Please update the submodule to ${rln_version}"
+        exit 1
+    fi
+    # if submodule version = version in Makefile, build rln
+    cargo build --release -p rln --manifest-path "${build_dir}/rln/Cargo.toml"
+    cp "${build_dir}/target/release/librln.a" "${output_filename}"
+fi