IOracle.sol

//SPDX-License-Identifier: MIT
pragma solidity >=0.5.0 <0.9.0;

import "./IUpdateable.sol";
import "./ILiquidityOracle.sol";
import "./IPriceOracle.sol";

/**
 * @title IOracle
 * @notice An interface that defines a price and liquidity oracle.
 */
abstract contract IOracle is IUpdateable, IPriceOracle, ILiquidityOracle {
    /**
     * @notice Gets the price of a token in terms of the quote token along with the liquidity levels of the token
     *  andquote token in the underlying pool.
     * @param token The token to get the price of.
     * @return price The quote token denominated price for a whole token.
     * @return tokenLiquidity The amount of the token that is liquid in the underlying pool, in wei.
     * @return quoteTokenLiquidity The amount of the quote token that is liquid in the underlying pool, in wei.
     */
    function consult(
        address token
    ) public view virtual returns (uint112 price, uint112 tokenLiquidity, uint112 quoteTokenLiquidity);

    /**
     * @notice Gets the price of a token in terms of the quote token along with the liquidity levels of the token and
     *  quote token in the underlying pool, reverting if the quotation is older than the maximum allowable age.
     * @dev Using maxAge of 0 can be gas costly and the returned data is easier to manipulate.
     * @param token The token to get the price of.
     * @param maxAge The maximum age of the quotation, in seconds. If 0, the function gets the instant rates as of the
     *   latest block, straight from the source. WARNING: Using a maxAge of 0 is expensive and is generally insecure.
     * @return price The quote token denominated price for a whole token.
     * @return tokenLiquidity The amount of the token that is liquid in the underlying pool, in wei.
     * @return quoteTokenLiquidity The amount of the quote token that is liquid in the underlying pool, in wei.
     */
    function consult(
        address token,
        uint256 maxAge
    ) public view virtual returns (uint112 price, uint112 tokenLiquidity, uint112 quoteTokenLiquidity);

    function liquidityDecimals() public view virtual returns (uint8);
}