[ERC4987] トークンをコントラクトに預けた時にアドレスと残高を紐付ける仕組みを理解しよう！

/**
 * @notice the ERC20 holder standard provides a common interface to query
 * token balance information
 */
interface IERC20Holder is IERC165 {
  /**
   * @notice emitted when the token is transferred to the contract
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenAmount held token amount
   */
  event Hold(
    address indexed owner,
    address indexed tokenAddress,
    uint256 tokenAmount
  );

  /**
   * @notice emitted when the token is released back to the user
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenAmount held token amount
   */
  event Release(
    address indexed owner,
    address indexed tokenAddress,
    uint256 tokenAmount
  );

  /**
   * @notice get the held balance of the token owner
   * @dev should throw for invalid queries and return zero for no balance
   * @param tokenAddress held token address
   * @param owner functional token owner
   * @return held token balance
   */
  function heldBalanceOf(address tokenAddress, address owner)
    external
    view
    returns (uint256);
}

/**
 * @notice the ERC721 holder standard provides a common interface to query
 * token ownership and balance information
 */
interface IERC721Holder is IERC165 {
  /**
   * @notice emitted when the token is transferred to the contract
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenId held token ID
   */
  event Hold(
    address indexed owner,
    address indexed tokenAddress,
    uint256 indexed tokenId
  );

  /**
   * @notice emitted when the token is released back to the user
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenId held token ID
   */
  event Release(
    address indexed owner,
    address indexed tokenAddress,
    uint256 indexed tokenId
  );

  /**
   * @notice get the functional owner of a held token
   * @dev should throw for invalid queries and return zero for a token ID that is not held
   * @param tokenAddress held token address
   * @param tokenId held token ID
   * @return functional token owner
   */
  function heldOwnerOf(address tokenAddress, uint256 tokenId)
    external
    view
    returns (address);

  /**
   * @notice get the held balance of the token owner
   * @dev should throw for invalid queries and return zero for no balance
   * @param tokenAddress held token address
   * @param owner functional token owner
   * @return held token balance
   */
  function heldBalanceOf(address tokenAddress, address owner)
    external
    view
    returns (uint256);
}

/**
 * @notice the ERC1155 holder standard provides a common interface to query
 * token balance information
 */
interface IERC1155Holder is IERC165 {
  /**
   * @notice emitted when the token is transferred to the contract
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenId held token ID
   * @param tokenAmount held token amount
   */
  event Hold(
    address indexed owner,
    address indexed tokenAddress,
    uint256 indexed tokenId,
    uint256 tokenAmount
  );

  /**
   * @notice emitted when the token is released back to the user
   * @param owner functional token owner
   * @param tokenAddress held token address
   * @param tokenId held token ID
   * @param tokenAmount held token amount
   */
  event Release(
    address indexed owner,
    address indexed tokenAddress,
    uint256 indexed tokenId,
    uint256 tokenAmount
  );

  /**
   * @notice get the held balance of the token owner
   * @dev should throw for invalid queries and return zero for no balance
   * @param tokenAddress held token address
   * @param owner functional token owner
   * @param tokenId held token ID
   * @return held token balance
   */
  function heldBalanceOf(
    address tokenAddress,
    address owner,
    uint256 tokenId
  ) external view returns (uint256);
}