feat(enumerablemap): add EnumerableBytes32ToBytes32Map

contracts/mocks/EnumerableMapMock.sol

@@ -4,7 +4,7 @@ pragma solidity ^0.8.0;
 
 import "../utils/structs/EnumerableMap.sol";
 
-contract EnumerableMapMock {
+contract EnumerableUintToAddressMapMock {
     using EnumerableMap for EnumerableMap.UintToAddressMap;
 
     event OperationResult(bool result);
@@ -45,3 +45,45 @@ contract EnumerableMapMock {
         return _map.get(key, errorMessage);
     }
 }
+
+contract EnumerableBytes32ToBytes32MapMock {
+    using EnumerableMap for EnumerableMap.Bytes32ToBytes32Map;
+
+    event OperationResult(bool result);
+
+    EnumerableMap.Bytes32ToBytes32Map private _map;
+
+    function contains(bytes32 key) public view returns (bool) {
+        return _map.contains(key);
+    }
+
+    function set(bytes32 key, bytes32 value) public {
+        bool result = _map.set(key, value);
+        emit OperationResult(result);
+    }
+
+    function remove(bytes32 key) public {
+        bool result = _map.remove(key);
+        emit OperationResult(result);
+    }
+
+    function length() public view returns (uint256) {
+        return _map.length();
+    }
+
+    function at(uint256 index) public view returns (bytes32 key, bytes32 value) {
+        return _map.at(index);
+    }
+
+    function tryGet(bytes32 key) public view returns (bool, bytes32) {
+        return _map.tryGet(key);
+    }
+
+    function get(bytes32 key) public view returns (bytes32) {
+        return _map.get(key);
+    }
+
+    function getWithMessage(bytes32 key, string calldata errorMessage) public view returns (bytes32) {
+        return _map.get(key, errorMessage);
+    }
+}

contracts/utils/structs/EnumerableMap.sol

@@ -237,4 +237,96 @@ library EnumerableMap {
     ) internal view returns (address) {
         return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));
     }
+
+    // Bytes32ToBytes32Map
+
+    struct Bytes32ToBytes32Map {
+        Map _inner;
+    }
+
+    /**
+     * @dev Adds a key-value pair to a map, or updates the value for an existing
+     * key. O(1).
+     *
+     * Returns true if the key was added to the map, that is if it was not
+     * already present.
+     */
+    function set(
+        Bytes32ToBytes32Map storage map,
+        bytes32 key,
+        bytes32 value
+    ) internal returns (bool) {
+        return _set(map._inner, key, value);
+    }
+
+    /**
+     * @dev Removes a value from a set. O(1).
+     *
+     * Returns true if the key was removed from the map, that is if it was present.
+     */
+    function remove(Bytes32ToBytes32Map storage map, bytes32 key) internal returns (bool) {
+        return _remove(map._inner, key);
+    }
+
+    /**
+     * @dev Returns true if the key is in the map. O(1).
+     */
+    function contains(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool) {
+        return _contains(map._inner, key);
+    }
+
+    /**
+     * @dev Returns the number of elements in the map. O(1).
+     */
+    function length(Bytes32ToBytes32Map storage map) internal view returns (uint256) {
+        return _length(map._inner);
+    }
+
+    /**
+     * @dev Returns the element stored at position `index` in the set. O(1).
+     * Note that there are no guarantees on the ordering of values inside the
+     * array, and it may change when more values are added or removed.
+     *
+     * Requirements:
+     *
+     * - `index` must be strictly less than {length}.
+     */
+    function at(Bytes32ToBytes32Map storage map, uint256 index) internal view returns (bytes32, bytes32) {
+        return _at(map._inner, index);
+    }
+
+    /**
+     * @dev Tries to returns the value associated with `key`.  O(1).
+     * Does not revert if `key` is not in the map.
+     *
+     * _Available since v3.4._
+     */
+    function tryGet(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bool, bytes32) {
+        return _tryGet(map._inner, key);
+    }
+
+    /**
+     * @dev Returns the value associated with `key`.  O(1).
+     *
+     * Requirements:
+     *
+     * - `key` must be in the map.
+     */
+    function get(Bytes32ToBytes32Map storage map, bytes32 key) internal view returns (bytes32) {
+        return _get(map._inner, key);
+    }
+
+    /**
+     * @dev Same as {get}, with a custom error message when `key` is not in the map.
+     *
+     * CAUTION: This function is deprecated because it requires allocating memory for the error
+     * message unnecessarily. For custom revert reasons use {tryGet}.
+     */
+    function get(
+        Bytes32ToBytes32Map storage map,
+        bytes32 key,
+        string memory errorMessage
+    ) internal view returns (bytes32) {
+        return _get(map._inner, key, errorMessage);
+    }
 }

test/utils/structs/EnumerableMap.behavior.js

@@ -0,0 +1,176 @@
+const { expectEvent, expectRevert } = require('@openzeppelin/test-helpers');
+const { expect } = require('chai');
+
+const zip = require('lodash.zip');
+
+function shouldBehaveLikeMap (keys, values, zeroValue) {
+  const [keyA, keyB, keyC] = keys;
+  const [valueA, valueB, valueC] = values;
+
+  async function expectMembersMatch (map, keys, values) {
+    expect(keys.length).to.equal(values.length);
+
+    await Promise.all(keys.map(async key =>
+      expect(await map.contains(key)).to.equal(true),
+    ));
+
+    expect(await map.length()).to.bignumber.equal(keys.length.toString());
+
+    expect(await Promise.all(keys.map(key =>
+      map.get(key),
+    ))).to.have.same.members(values);
+
+    // To compare key-value pairs, we zip keys and values, and convert BNs to
+    // strings to workaround Chai limitations when dealing with nested arrays
+    expect(await Promise.all([...Array(keys.length).keys()].map(async (index) => {
+      const entry = await map.at(index);
+      return [entry.key.toString(), entry.value];
+    }))).to.have.same.deep.members(
+      zip(keys.map(k => k.toString()), values),
+    );
+  }
+
+  it('starts empty', async function () {
+    expect(await this.map.contains(keyA)).to.equal(false);
+
+    await expectMembersMatch(this.map, [], []);
+  });
+
+  describe('set', function () {
+    it('adds a key', async function () {
+      const receipt = await this.map.set(keyA, valueA);
+      expectEvent(receipt, 'OperationResult', { result: true });
+
+      await expectMembersMatch(this.map, [keyA], [valueA]);
+    });
+
+    it('adds several keys', async function () {
+      await this.map.set(keyA, valueA);
+      await this.map.set(keyB, valueB);
+
+      await expectMembersMatch(this.map, [keyA, keyB], [valueA, valueB]);
+      expect(await this.map.contains(keyC)).to.equal(false);
+    });
+
+    it('returns false when adding keys already in the set', async function () {
+      await this.map.set(keyA, valueA);
+
+      const receipt = (await this.map.set(keyA, valueA));
+      expectEvent(receipt, 'OperationResult', { result: false });
+
+      await expectMembersMatch(this.map, [keyA], [valueA]);
+    });
+
+    it('updates values for keys already in the set', async function () {
+      await this.map.set(keyA, valueA);
+
+      await this.map.set(keyA, valueB);
+
+      await expectMembersMatch(this.map, [keyA], [valueB]);
+    });
+  });
+
+  describe('remove', function () {
+    it('removes added keys', async function () {
+      await this.map.set(keyA, valueA);
+
+      const receipt = await this.map.remove(keyA);
+      expectEvent(receipt, 'OperationResult', { result: true });
+
+      expect(await this.map.contains(keyA)).to.equal(false);
+      await expectMembersMatch(this.map, [], []);
+    });
+
+    it('returns false when removing keys not in the set', async function () {
+      const receipt = await this.map.remove(keyA);
+      expectEvent(receipt, 'OperationResult', { result: false });
+
+      expect(await this.map.contains(keyA)).to.equal(false);
+    });
+
+    it('adds and removes multiple keys', async function () {
+      // []
+
+      await this.map.set(keyA, valueA);
+      await this.map.set(keyC, valueC);
+
+      // [A, C]
+
+      await this.map.remove(keyA);
+      await this.map.remove(keyB);
+
+      // [C]
+
+      await this.map.set(keyB, valueB);
+
+      // [C, B]
+
+      await this.map.set(keyA, valueA);
+      await this.map.remove(keyC);
+
+      // [A, B]
+
+      await this.map.set(keyA, valueA);
+      await this.map.set(keyB, valueB);
+
+      // [A, B]
+
+      await this.map.set(keyC, valueC);
+      await this.map.remove(keyA);
+
+      // [B, C]
+
+      await this.map.set(keyA, valueA);
+      await this.map.remove(keyB);
+
+      // [A, C]
+
+      await expectMembersMatch(this.map, [keyA, keyC], [valueA, valueC]);
+
+      expect(await this.map.contains(keyB)).to.equal(false);
+    });
+  });
+
+  describe('read', function () {
+    beforeEach(async function () {
+      await this.map.set(keyA, valueA);
+    });
+
+    describe('get', function () {
+      it('existing value', async function () {
+        expect(await this.map.get(keyA)).to.be.equal(valueA);
+      });
+      it('missing value', async function () {
+        await expectRevert(this.map.get(keyB), 'EnumerableMap: nonexistent key');
+      });
+    });
+
+    describe('get with message', function () {
+      it('existing value', async function () {
+        expect(await this.map.getWithMessage(keyA, 'custom error string')).to.be.equal(valueA);
+      });
+      it('missing value', async function () {
+        await expectRevert(this.map.getWithMessage(keyB, 'custom error string'), 'custom error string');
+      });
+    });
+
+    describe('tryGet', function () {
+      it('existing value', async function () {
+        expect(await this.map.tryGet(keyA)).to.be.deep.equal({
+          0: true,
+          1: valueA,
+        });
+      });
+      it('missing value', async function () {
+        expect(await this.map.tryGet(keyB)).to.be.deep.equal({
+          0: false,
+          1: zeroValue,
+        });
+      });
+    });
+  });
+}
+
+module.exports = {
+  shouldBehaveLikeMap,
+};