Add ERC1155URIStorage (OpenZeppelin#3210)

* Add ERC721URIStorage-like extension for ERC1155

* Add tests for ERC1155URIStorage extension

* add changelog entry for ERC721URIStorage

* Fix linting errors

* Emit URI event in ERC1155URIStorage

* Remove exists check and ERC1155Supply dependency

* Fix lint error

* Overwrite ERC1155 uri method

* Update ERC1155URIStorage specs

* Fix ERC1155URIStorageMock

* Rename _setTokenURI => _setURI in ERC1155URIStorage

* Add baseURI to ERC1155URIStorage

* Move super.uri call in ERC1155URIStorage

* Clearify ERC1155URIStorage description in change log

* reorder changelog & add documentation

* improve documentation

* fix typo

Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com>

Author: takahser

CHANGELOG.md

@@ -5,18 +5,19 @@
  * `AccessControl`: add a virtual `_checkRole(bytes32)` function that can be overridden to alter the `onlyRole` modifier behavior. ([#3137](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3137))
  * `EnumerableMap`: add new `AddressToUintMap` map type. ([#3150](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3150))
  * `EnumerableMap`: add new `Bytes32ToBytes32Map` map type. ([#3192](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3192))
+ * `ERC20FlashMint`: support infinite allowance when paying back a flash loan. ([#3226](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3226))
+ * `ERC20Wrapper`: the `decimals()` function now tries to fetch the value from the underlying token instance. If that calls revert, then the default value is used. ([#3259](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3259))
+ * `draft-ERC20Permit`: replace `immutable` with `constant` for `_PERMIT_TYPEHASH` since the `keccak256` of string literals is treated specially and the hash is evaluated at compile time. ([#3196](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3196))
  * `ERC1155`: Add a `_afterTokenTransfer` hook for improved extensibility. ([#3166](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3166))
+ * `ERC1155URIStorage`: add a new extension that implements a `_setURI` behavior similar to ERC721's `_setTokenURI`. ([#3210](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3210))
  * `DoubleEndedQueue`: a new data structure that supports efficient push and pop to both front and back, useful for FIFO and LIFO queues. ([#3153](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3153))
  * `Governor`: improved security of `onlyGovernance` modifier when using an external executor contract (e.g. a timelock) that can operate without necessarily going through the governance protocol. ([#3147](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3147))
  * `Governor`: Add a way to parameterize votes. This can be used to implement voting systems such as fractionalized voting, ERC721 based voting, or any number of other systems. The `params` argument added to `_countVote` method, and included in the newly added `_getVotes` method, can be used by counting and voting modules respectively for such purposes. ([#3043](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3043))
  * `Governor`: rewording of revert reason for consistency. ([#3275](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3275))
  * `Governor`: fix an inconsistency in data locations that could lead to invalid bytecode being produced. ([#3295](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3295))
- * `ERC20FlashMint`: support infinite allowance when paying back a flash loan. ([#3226](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3226))
- * `TimelockController`: Add a separate canceller role for the ability to cancel. ([#3165](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3165))
- * `draft-ERC20Permit`: replace `immutable` with `constant` for `_PERMIT_TYPEHASH` since the `keccak256` of string literals is treated specially and the hash is evaluated at compile time. ([#3196](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3196))
- * `ERC20Wrapper`: the `decimals()` function now tries to fetch the value from the underlying token instance. If that calls revert, then the default value is used. ([#3259](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3259))
  * `Governor`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by governors. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
  * `TimelockController`: Implement `IERC721Receiver` and `IERC1155Receiver` to improve token custody by timelocks. ([#3230](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3230))
+ * `TimelockController`: Add a separate canceller role for the ability to cancel. ([#3165](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3165))
  * `Initializable`: add a reinitializer modifier that enables the initialization of new modules, added to already initialized contracts through upgradeability. ([#3232](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3232))
  * `Initializable`: add an Initialized event that tracks initialized version numbers. ([#3294](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/3294))
 

contracts/mocks/ERC1155URIStorageMock.sol

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "./ERC1155Mock.sol";
+import "../token/ERC1155/extensions/ERC1155URIStorage.sol";
+
+contract ERC1155URIStorageMock is ERC1155Mock, ERC1155URIStorage {
+    constructor(string memory _uri) ERC1155Mock(_uri) {}
+
+    function uri(uint256 tokenId) public view virtual override(ERC1155, ERC1155URIStorage) returns (string memory) {
+        return ERC1155URIStorage.uri(tokenId);
+    }
+
+    function setURI(uint256 tokenId, string memory _tokenURI) public {
+        _setURI(tokenId, _tokenURI);
+    }
+
+    function setBaseURI(string memory baseURI) public {
+        _setBaseURI(baseURI);
+    }
+}

contracts/token/ERC1155/README.adoc

@@ -36,6 +36,8 @@ NOTE: This core set of contracts is designed to be unopinionated, allowing devel
 
 {{ERC1155Supply}}
 
+{{ERC1155URIStorage}}
+
 == Presets
 
 These contracts are preconfigured combinations of the above features. They can be used through inheritance or as models to copy and paste their source code.

contracts/token/ERC1155/extensions/ERC1155URIStorage.sol

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+import "../../../utils/Strings.sol";
+import "../ERC1155.sol";
+
+/**
+ * @dev ERC1155 token with storage based token URI management.
+ * Inspired by the ERC721URIStorage extension
+ *
+ * _Available since v4.6._
+ */
+abstract contract ERC1155URIStorage is ERC1155 {
+    using Strings for uint256;
+
+    // Optional base URI
+    string private _baseURI = "";
+
+    // Optional mapping for token URIs
+    mapping(uint256 => string) private _tokenURIs;
+
+    /**
+     * @dev See {IERC1155MetadataURI-uri}.
+     *
+     * This implementation returns the concatenation of the `_baseURI`
+     * and the token-specific uri if the latter is set
+     *
+     * This enables the following behaviors:
+     *
+     * - if `_tokenURIs[tokenId]` is set, then the result is the concatenation
+     *   of `_baseURI` and `_tokenURIs[tokenId]` (keep in mind that `_baseURI`
+     *   is empty per default);
+     *
+     * - if `_tokenURIs[tokenId]` is NOT set then we fallback to `super.uri()`
+     *   which in most cases will contain `ERC1155._uri`;
+     *
+     * - if `_tokenURIs[tokenId]` is NOT set, and if the parents do not have a
+     *   uri value set, then the result is empty.
+     */
+    function uri(uint256 tokenId) public view virtual override returns (string memory) {
+        string memory tokenURI = _tokenURIs[tokenId];
+
+        // If token URI is set, concatenate base URI and tokenURI (via abi.encodePacked).
+        return bytes(tokenURI).length > 0 ? string(abi.encodePacked(_baseURI, tokenURI)) : super.uri(tokenId);
+    }
+
+    /**
+     * @dev Sets `tokenURI` as the tokenURI of `tokenId`.
+     */
+    function _setURI(uint256 tokenId, string memory tokenURI) internal virtual {
+        _tokenURIs[tokenId] = tokenURI;
+        emit URI(uri(tokenId), tokenId);
+    }
+
+    /**
+     * @dev Sets `baseURI` as the `_baseURI` for all tokens
+     */
+    function _setBaseURI(string memory baseURI) internal virtual {
+        _baseURI = baseURI;
+    }
+}

test/token/ERC1155/extensions/ERC1155URIStorage.test.js

@@ -0,0 +1,66 @@
+const { BN, expectEvent } = require('@openzeppelin/test-helpers');
+
+const { expect } = require('chai');
+const { artifacts } = require('hardhat');
+
+const ERC1155URIStorageMock = artifacts.require('ERC1155URIStorageMock');
+
+contract(['ERC1155URIStorage'], function (accounts) {
+  const [ holder ] = accounts;
+
+  const erc1155Uri = 'https://token.com/nfts/';
+  const baseUri = 'https://token.com/';
+
+  const tokenId = new BN('1');
+  const amount = new BN('3000');
+
+  describe('with base uri set', function () {
+    beforeEach(async function () {
+      this.token = await ERC1155URIStorageMock.new(erc1155Uri);
+      this.token.setBaseURI(baseUri);
+
+      await this.token.mint(holder, tokenId, amount, '0x');
+    });
+
+    it('can request the token uri, returning the erc1155 uri if no token uri was set', async function () {
+      const receivedTokenUri = await this.token.uri(tokenId);
+
+      expect(receivedTokenUri).to.be.equal(erc1155Uri);
+    });
+
+    it('can request the token uri, returning the concatenated uri if a token uri was set', async function () {
+      const tokenUri = '1234/';
+      const receipt = await this.token.setURI(tokenId, tokenUri);
+
+      const receivedTokenUri = await this.token.uri(tokenId);
+
+      const expectedUri = `${baseUri}${tokenUri}`;
+      expect(receivedTokenUri).to.be.equal(expectedUri);
+      expectEvent(receipt, 'URI', { value: expectedUri, id: tokenId });
+    });
+  });
+
+  describe('with base uri set to the empty string', function () {
+    beforeEach(async function () {
+      this.token = await ERC1155URIStorageMock.new('');
+
+      await this.token.mint(holder, tokenId, amount, '0x');
+    });
+
+    it('can request the token uri, returning an empty string if no token uri was set', async function () {
+      const receivedTokenUri = await this.token.uri(tokenId);
+
+      expect(receivedTokenUri).to.be.equal('');
+    });
+
+    it('can request the token uri, returning the token uri if a token uri was set', async function () {
+      const tokenUri = 'ipfs://1234/';
+      const receipt = await this.token.setURI(tokenId, tokenUri);
+
+      const receivedTokenUri = await this.token.uri(tokenId);
+
+      expect(receivedTokenUri).to.be.equal(tokenUri);
+      expectEvent(receipt, 'URI', { value: tokenUri, id: tokenId });
+    });
+  });
+});