Feat: Add Interface (#243)

* Add interfaces

* Use interfaces in main contracts

* change structure similar to OZ

* move errors in interfaces class level

* run prettier

contracts/ERC721A.sol

@@ -3,28 +3,13 @@
 
 pragma solidity ^0.8.4;
 
-import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
+import './IERC721A.sol';
 import '@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol';
-import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol';
 import '@openzeppelin/contracts/utils/Address.sol';
 import '@openzeppelin/contracts/utils/Context.sol';
 import '@openzeppelin/contracts/utils/Strings.sol';
 import '@openzeppelin/contracts/utils/introspection/ERC165.sol';
 
-error ApprovalCallerNotOwnerNorApproved();
-error ApprovalQueryForNonexistentToken();
-error ApproveToCaller();
-error ApprovalToCurrentOwner();
-error BalanceQueryForZeroAddress();
-error MintToZeroAddress();
-error MintZeroQuantity();
-error OwnerQueryForNonexistentToken();
-error TransferCallerNotOwnerNorApproved();
-error TransferFromIncorrectOwner();
-error TransferToNonERC721ReceiverImplementer();
-error TransferToZeroAddress();
-error URIQueryForNonexistentToken();
-
 /**
  * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
  * the Metadata extension. Built to optimize for lower gas during batch mints.
@@ -35,34 +20,10 @@ error URIQueryForNonexistentToken();
  *
  * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
  */
-contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
+contract ERC721A is Context, ERC165, IERC721A {
     using Address for address;
     using Strings for uint256;
 
-    // Compiler will pack this into a single 256bit word.
-    struct TokenOwnership {
-        // The address of the owner.
-        address addr;
-        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
-        uint64 startTimestamp;
-        // Whether the token has been burned.
-        bool burned;
-    }
-
-    // Compiler will pack this into a single 256bit word.
-    struct AddressData {
-        // Realistically, 2**64-1 is more than enough.
-        uint64 balance;
-        // Keeps track of mint count with minimal overhead for tokenomics.
-        uint64 numberMinted;
-        // Keeps track of burn count with minimal overhead for tokenomics.
-        uint64 numberBurned;
-        // For miscellaneous variable(s) pertaining to the address
-        // (e.g. number of whitelist mint slots used).
-        // If there are multiple variables, please pack them into a uint64.
-        uint64 aux;
-    }
-
     // The tokenId of the next token to be minted.
     uint256 internal _currentIndex;
 
@@ -341,7 +302,7 @@ contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
      *
      * Requirements:
      *
-     * - If `to` refers to a smart contract, it must implement 
+     * - If `to` refers to a smart contract, it must implement
      *   {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
      * - `quantity` must be greater than 0.
      *

contracts/IERC721A.sol

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '@openzeppelin/contracts/token/ERC721/IERC721.sol';
+import '@openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol';
+
+/**
+ * @dev Interface of an ERC721A compliant contract.
+ */
+interface IERC721A is IERC721, IERC721Metadata {
+    error ApprovalCallerNotOwnerNorApproved();
+    error ApprovalQueryForNonexistentToken();
+    error ApproveToCaller();
+    error ApprovalToCurrentOwner();
+    error BalanceQueryForZeroAddress();
+    error MintToZeroAddress();
+    error MintZeroQuantity();
+    error OwnerQueryForNonexistentToken();
+    error TransferCallerNotOwnerNorApproved();
+    error TransferFromIncorrectOwner();
+    error TransferToNonERC721ReceiverImplementer();
+    error TransferToZeroAddress();
+    error URIQueryForNonexistentToken();
+
+    // Compiler will pack this into a single 256bit word.
+    struct TokenOwnership {
+        // The address of the owner.
+        address addr;
+        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
+        uint64 startTimestamp;
+        // Whether the token has been burned.
+        bool burned;
+    }
+
+    // Compiler will pack this into a single 256bit word.
+    struct AddressData {
+        // Realistically, 2**64-1 is more than enough.
+        uint64 balance;
+        // Keeps track of mint count with minimal overhead for tokenomics.
+        uint64 numberMinted;
+        // Keeps track of burn count with minimal overhead for tokenomics.
+        uint64 numberBurned;
+        // For miscellaneous variable(s) pertaining to the address
+        // (e.g. number of whitelist mint slots used).
+        // If there are multiple variables, please pack them into a uint64.
+        uint64 aux;
+    }
+
+    /**
+     * @dev Returns the total amount of tokens stored by the contract.
+     * @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
+     */
+    function totalSupply() external view returns (uint256);
+}

contracts/extensions/ERC721ABurnable.sol

@@ -3,13 +3,14 @@
 
 pragma solidity ^0.8.4;
 
+import './IERC721ABurnable.sol';
 import '../ERC721A.sol';
 
 /**
  * @title ERC721A Burnable Token
  * @dev ERC721A Token that can be irreversibly burned (destroyed).
  */
-abstract contract ERC721ABurnable is ERC721A {
+abstract contract ERC721ABurnable is ERC721A, IERC721ABurnable {
     /**
      * @dev Burns `tokenId`. See {ERC721A-_burn}.
      *

contracts/extensions/ERC721AQueryable.sol

@@ -3,15 +3,14 @@
 
 pragma solidity ^0.8.4;
 
+import './IERC721AQueryable.sol';
 import '../ERC721A.sol';
 
-error InvalidQueryRange();
-
 /**
  * @title ERC721A Queryable
  * @dev ERC721A subclass with convenience query functions.
  */
-abstract contract ERC721AQueryable is ERC721A {
+abstract contract ERC721AQueryable is ERC721A, IERC721AQueryable {
     /**
      * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
      *

contracts/extensions/IERC721ABurnable.sol

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '../IERC721A.sol';
+
+/**
+ * @dev Interface of an ERC721ABurnable compliant contract.
+ */
+interface IERC721ABurnable is IERC721A {
+    /**
+     * @dev Burns `tokenId`. See {ERC721A-_burn}.
+     *
+     * Requirements:
+     *
+     * - The caller must own `tokenId` or be an approved operator.
+     */
+    function burn(uint256 tokenId) external;
+}

contracts/extensions/IERC721AQueryable.sol

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '../IERC721A.sol';
+
+/**
+ * @dev Interface of an ERC721AQueryable compliant contract.
+ */
+interface IERC721AQueryable is IERC721A {
+    error InvalidQueryRange();
+
+    /**
+     * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
+     *
+     * If the `tokenId` is out of bounds:
+     *   - `addr` = `address(0)`
+     *   - `startTimestamp` = `0`
+     *   - `burned` = `false`
+     *
+     * If the `tokenId` is burned:
+     *   - `addr` = `<Address of owner before token was burned>`
+     *   - `startTimestamp` = `<Timestamp when token was burned>`
+     *   - `burned = `true`
+     *
+     * Otherwise:
+     *   - `addr` = `<Address of owner>`
+     *   - `startTimestamp` = `<Timestamp of start of ownership>`
+     *   - `burned = `false`
+     */
+    function explicitOwnershipOf(uint256 tokenId) external view returns (TokenOwnership memory);
+
+    /**
+     * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
+     * See {ERC721AQueryable-explicitOwnershipOf}
+     */
+    function explicitOwnershipsOf(uint256[] memory tokenIds) external view returns (TokenOwnership[] memory);
+
+    /**
+     * @dev Returns an array of token IDs owned by `owner`,
+     * in the range [`start`, `stop`)
+     * (i.e. `start <= tokenId < stop`).
+     *
+     * This function allows for tokens to be queried if the collection
+     * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
+     *
+     * Requirements:
+     *
+     * - `start` < `stop`
+     */
+    function tokensOfOwnerIn(
+        address owner,
+        uint256 start,
+        uint256 stop
+    ) external view returns (uint256[] memory);
+
+    /**
+     * @dev Returns an array of token IDs owned by `owner`.
+     *
+     * This function scans the ownership mapping and is O(totalSupply) in complexity.
+     * It is meant to be called off-chain.
+     *
+     * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
+     * multiple smaller scans if the collection is large enough to cause
+     * an out-of-gas error (10K pfp collections should be fine).
+     */
+    function tokensOfOwner(address owner) external view returns (uint256[] memory);
+}

contracts/interfaces/IERC721A.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '../IERC721A.sol';

contracts/interfaces/IERC721ABurnable.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '../extensions/IERC721ABurnable.sol';

contracts/interfaces/IERC721AQueryable.sol

@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: MIT
+// Creator: Chiru Labs
+
+pragma solidity ^0.8.4;
+
+import '../extensions/IERC721AQueryable.sol';

contracts/mocks/ERC721AMock.sol

@@ -36,7 +36,11 @@ contract ERC721AMock is ERC721A {
         _safeMint(to, quantity);
     }
 
-    function safeMint(address to, uint256 quantity, bytes memory _data) public {
+    function safeMint(
+        address to,
+        uint256 quantity,
+        bytes memory _data
+    ) public {
         _safeMint(to, quantity, _data);
     }