From 65f17fd76e90210e17091558ee5bfb6d50a3daf6 Mon Sep 17 00:00:00 2001
From: Amir Bandeali <abandeali1@gmail.com>
Date: Wed, 10 Jul 2019 21:47:40 -0700
Subject: [PATCH] Make LibEIP712 a library

---
 .../contracts/src/LibEIP712ExchangeDomain.sol        |  9 ++++-----
 contracts/utils/contracts/src/LibEIP712.sol          | 12 ++++++------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/contracts/exchange-libs/contracts/src/LibEIP712ExchangeDomain.sol b/contracts/exchange-libs/contracts/src/LibEIP712ExchangeDomain.sol
index 57ba23fef7..6f685f2d80 100644
--- a/contracts/exchange-libs/contracts/src/LibEIP712ExchangeDomain.sol
+++ b/contracts/exchange-libs/contracts/src/LibEIP712ExchangeDomain.sol
@@ -21,9 +21,8 @@ pragma solidity ^0.5.9;
 import "@0x/contracts-utils/contracts/src/LibEIP712.sol";
 
 
-contract LibEIP712ExchangeDomain is
-    LibEIP712
-{
+contract LibEIP712ExchangeDomain {
+
     // EIP712 Exchange Domain Name value
     string constant public EIP712_EXCHANGE_DOMAIN_NAME = "0x Protocol";
 
@@ -43,7 +42,7 @@ contract LibEIP712ExchangeDomain is
         public
     {
         address verifyingContractAddress = verifyingContractAddressIfExists == address(0) ? address(this) : verifyingContractAddressIfExists;
-        EIP712_EXCHANGE_DOMAIN_HASH = _hashEIP712Domain(
+        EIP712_EXCHANGE_DOMAIN_HASH = LibEIP712.hashEIP712Domain(
             EIP712_EXCHANGE_DOMAIN_NAME,
             EIP712_EXCHANGE_DOMAIN_VERSION,
             chainId,
@@ -60,6 +59,6 @@ contract LibEIP712ExchangeDomain is
         view
         returns (bytes32 result)
     {
-        return _hashEIP712Message(EIP712_EXCHANGE_DOMAIN_HASH, hashStruct);
+        return LibEIP712.hashEIP712Message(EIP712_EXCHANGE_DOMAIN_HASH, hashStruct);
     }
 }
diff --git a/contracts/utils/contracts/src/LibEIP712.sol b/contracts/utils/contracts/src/LibEIP712.sol
index 9563e1aea2..06e2a7daa6 100644
--- a/contracts/utils/contracts/src/LibEIP712.sol
+++ b/contracts/utils/contracts/src/LibEIP712.sol
@@ -19,7 +19,7 @@
 pragma solidity ^0.5.9;
 
 
-contract LibEIP712 {
+library LibEIP712 {
 
     // Hash of the EIP712 Domain Separator Schema
     // keccak256(abi.encodePacked(
@@ -30,14 +30,14 @@ contract LibEIP712 {
     //     "address verifyingContractAddress",
     //     ")"
     // ))
-    bytes32 constant public EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = 0xb1b295f2c1ed6b459ddeb95701466e4e0b385527a6cfa3873ae72a63c08466b6;
+    bytes32 constant internal _EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = 0xb1b295f2c1ed6b459ddeb95701466e4e0b385527a6cfa3873ae72a63c08466b6;
     
     /// @dev Calculates a EIP712 domain separator.
     /// @param name The EIP712 domain name.
     /// @param version The EIP712 domain version.
     /// @param verifyingContractAddress The EIP712 verifying contract.
     /// @return EIP712 domain separator.
-    function _hashEIP712Domain(
+    function hashEIP712Domain(
         string memory name,
         string memory version,
         uint256 chainId,
@@ -47,11 +47,11 @@ contract LibEIP712 {
         pure
         returns (bytes32 result)
     {
-        bytes32 schemaHash = EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH;
+        bytes32 schemaHash = _EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH;
 
         // Assembly for more efficient computing:
         // keccak256(abi.encodePacked(
-        //     EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
+        //     _EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
         //     keccak256(bytes(name)),
         //     keccak256(bytes(version)),
         //     chainId,
@@ -84,7 +84,7 @@ contract LibEIP712 {
     ///                         with getDomainHash().
     /// @param hashStruct The EIP712 hash struct.
     /// @return EIP712 hash applied to the given EIP712 Domain.
-    function _hashEIP712Message(bytes32 eip712DomainHash, bytes32 hashStruct)
+    function hashEIP712Message(bytes32 eip712DomainHash, bytes32 hashStruct)
         internal
         pure
         returns (bytes32 result)