WASM: add bindings for Witness

Author: andiflabs

ironfish-rust-wasm/src/lib.rs

@@ -22,6 +22,7 @@ pub mod merkle_note;
 pub mod note;
 pub mod primitives;
 pub mod transaction;
+pub mod witness;
 
 /// Creates a [`wasm_bindgen`] wrapper for an existing type.
 ///

ironfish-rust-wasm/src/witness.rs

@@ -0,0 +1,90 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::{merkle_note::MerkleNoteHash, primitives::Scalar, wasm_bindgen_wrapper};
+use ironfish::witness::WitnessTrait;
+use wasm_bindgen::prelude::*;
+
+wasm_bindgen_wrapper! {
+    #[derive(Clone, PartialEq, Eq, Debug)]
+    pub struct Witness(ironfish::witness::Witness);
+}
+
+#[wasm_bindgen]
+impl Witness {
+    #[wasm_bindgen(constructor)]
+    pub fn new(tree_size: usize, root_hash: Scalar, auth_path: Vec<WitnessNode>) -> Self {
+        Self(ironfish::witness::Witness {
+            tree_size,
+            root_hash: root_hash.into(),
+            auth_path: auth_path.into_iter().map(WitnessNode::into).collect(),
+        })
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn tree_size(&self) -> usize {
+        self.0.tree_size
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn root_hash(&self) -> Scalar {
+        self.0.root_hash.into()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn auth_path(&self) -> Vec<WitnessNode> {
+        self.0
+            .auth_path
+            .iter()
+            .cloned()
+            .map(WitnessNode::from)
+            .collect()
+    }
+
+    #[wasm_bindgen]
+    pub fn verify(&self, hash: &MerkleNoteHash) -> bool {
+        self.0.verify(hash.as_ref())
+    }
+}
+
+wasm_bindgen_wrapper! {
+    #[derive(Clone, PartialEq, Eq, Debug)]
+    pub struct WitnessNode(ironfish::witness::WitnessNode<blstrs::Scalar>);
+}
+
+#[wasm_bindgen]
+impl WitnessNode {
+    #[wasm_bindgen]
+    pub fn left(hash: Scalar) -> Self {
+        Self(ironfish::witness::WitnessNode::Left(hash.into()))
+    }
+
+    #[wasm_bindgen]
+    pub fn right(hash: Scalar) -> Self {
+        Self(ironfish::witness::WitnessNode::Right(hash.into()))
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn is_left(&self) -> bool {
+        match self.0 {
+            ironfish::witness::WitnessNode::Left(_) => true,
+            ironfish::witness::WitnessNode::Right(_) => false,
+        }
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn is_right(&self) -> bool {
+        !self.is_left()
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn hash(&self) -> Scalar {
+        match self.0 {
+            ironfish::witness::WitnessNode::Left(ref hash) => hash,
+            ironfish::witness::WitnessNode::Right(ref hash) => hash,
+        }
+        .to_owned()
+        .into()
+    }
+}

ironfish-rust/src/witness.rs

@@ -35,21 +35,13 @@ pub trait WitnessTrait {
 
 /// A Rust implementation of a WitnessTrait, used for testing Witness-related
 /// code within Rust.
+#[derive(Clone, PartialEq, Eq)]
 pub struct Witness {
     pub tree_size: usize,
     pub root_hash: Scalar,
     pub auth_path: Vec<WitnessNode<Scalar>>,
 }
 
-/// Implement partial equality, ignoring the Sapling Arc
-impl PartialEq for Witness {
-    fn eq(&self, other: &Witness) -> bool {
-        self.tree_size == other.tree_size
-            && self.root_hash == other.root_hash
-            && self.auth_path == other.auth_path
-    }
-}
-
 impl WitnessTrait for Witness {
     fn verify(&self, my_hash: &MerkleNoteHash) -> bool {
         let mut cur_hash = my_hash.0;