From f4097144294b65d162a06c9f74ec0817d489abea Mon Sep 17 00:00:00 2001
From: Max Hora <maxhora.ua@gmail.com>
Date: Fri, 21 Apr 2023 17:42:40 +0300
Subject: [PATCH 1/2] Mutex lock initialization call

---
 .../crypto/pedersen_hash/pedersen_lookup.cpp          | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp b/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
index f455c684be..cb3aff1f4b 100644
--- a/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
+++ b/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
@@ -1,5 +1,7 @@
 #include "./pedersen_lookup.hpp"
 
+#include <mutex>
+
 #include "barretenberg/ecc/curves/grumpkin/grumpkin.hpp"
 
 namespace crypto {
@@ -10,6 +12,10 @@ std::array<std::vector<grumpkin::g1::affine_element>, NUM_PEDERSEN_TABLES> peder
 std::vector<grumpkin::g1::affine_element> pedersen_iv_table;
 std::array<grumpkin::g1::affine_element, NUM_PEDERSEN_TABLES> generators;
 
+#if !defined(__wasm__)
+std::mutex init_mutex;
+#endif
+
 static bool inited = false;
 
 void init_single_lookup_table(const size_t index)
@@ -66,6 +72,11 @@ void init()
 {
     ASSERT(BITS_PER_TABLE < BITS_OF_BETA);
     ASSERT(BITS_PER_TABLE + BITS_OF_BETA < BITS_ON_CURVE);
+
+#if !defined(__wasm__)
+    const std::lock_guard<std::mutex> lock(init_mutex);
+#endif
+
     if (inited) {
         return;
     }

From 6036f528817f7cd701455acd7ca457d8c4b0ecb9 Mon Sep 17 00:00:00 2001
From: kevaundray <kevtheappdev@gmail.com>
Date: Fri, 21 Apr 2023 16:47:14 +0100
Subject: [PATCH 2/2] add comment on mutex

---
 cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp b/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
index cb3aff1f4b..980b41a225 100644
--- a/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
+++ b/cpp/src/barretenberg/crypto/pedersen_hash/pedersen_lookup.cpp
@@ -12,6 +12,8 @@ std::array<std::vector<grumpkin::g1::affine_element>, NUM_PEDERSEN_TABLES> peder
 std::vector<grumpkin::g1::affine_element> pedersen_iv_table;
 std::array<grumpkin::g1::affine_element, NUM_PEDERSEN_TABLES> generators;
 
+// Mutex is not available in the WASM context.
+// WASM runs in a single-thread so this is acceptable.
 #if !defined(__wasm__)
 std::mutex init_mutex;
 #endif