nix: added flake and derivation for the project

Signed-off-by: markoburcul <marko@status.im>

.gitignore

@@ -5,7 +5,11 @@ target/
 
 # Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
 # More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
+# Commented since for nix derivation we need the Cargo.lock file.
+# Cargo.lock
+
+# If built with Nix, the target with be within result directory.
+result
 
 # These are backup files generated by rustfmt
 **/*.rs.bk

Cargo.toml

@@ -18,7 +18,7 @@ crate-type = [
 
 [dependencies]
 
-ark-circom = { git = "https://github.com/codex-storage/circom-compat.git#71f1ceb11aef27256", features = ["circom-2", "ethereum"]}
+ark-circom = { git = "https://github.com/codex-storage/circom-compat.git", rev = "71f1ceb11aef27256", features = ["circom-2", "ethereum"]}
 
 ark-crypto-primitives = { version = "=0.4.0" }
 ark-ec = { version = "=0.4.1", default-features = false, features = ["parallel"] }

README.md

@@ -1,2 +1,8 @@
 # circom-compat-ffi
 circom-compat (ark-circom) ffi
+
+
+# Build with Nix
+```nix
+nix build
+```

default.nix

@@ -0,0 +1,21 @@
+{ pkgs }:
+
+pkgs.rustPlatform.buildRustPackage {
+  pname = "circom-compat-ffi";
+  version = "0.1.0";
+
+  src = ./.;
+
+  cargoLock = {
+    lockFile = ./Cargo.lock;
+    allowBuiltinFetchGit = true;
+  };
+
+  CARGO_HOME = "/tmp";
+  cargoBuildFlags = ["--release"];
+
+  meta = with pkgs.lib; {
+    description = "circom-compat (ark-circom) ffi";
+    license = licenses.mit;
+  };
+}

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1731386116,
+        "narHash": "sha256-lKA770aUmjPHdTaJWnP3yQ9OI1TigenUqVC3wweqZuI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "689fed12a013f56d4c4d3f612489634267d86529",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-24.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,24 @@
+{
+  description = "A flake for building circom-compat (ark-circom) ffi";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
+  };
+
+  outputs = { self, nixpkgs }: 
+    let
+      stableSystems = [
+        "x86_64-linux" "aarch64-linux"
+        "x86_64-darwin" "aarch64-darwin"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs stableSystems;
+      pkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
+    in
+    {
+      packages = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in {
+        default = pkgs.callPackage ./default.nix {};
+      });
+    };
+}