1 files changed, 45 insertions, 0 deletions
diff --git a/contracts/utils/contracts/src/ReentrancyGuard.sol b/contracts/utils/contracts/src/ReentrancyGuard.sol
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+++ b/contracts/utils/contracts/src/ReentrancyGuard.sol
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+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+
+contract ReentrancyGuard {
+
+    // Locked state of mutex
+    bool private locked = false;
+
+    /// @dev Functions with this modifer cannot be reentered. The mutex will be locked
+    ///      before function execution and unlocked after.
+    modifier nonReentrant() {
+        // Ensure mutex is unlocked
+        require(
+            !locked,
+            "REENTRANCY_ILLEGAL"
+        );
+
+        // Lock mutex before function call
+        locked = true;
+
+        // Perform function call
+        _;
+
+        // Unlock mutex after function call
+        locked = false;
+    }
+}