interface IChainStorageContainer {
    /********************
     * Public Functions *
     ********************/

    /**
     * Sets the container's global metadata field. We're using `bytes27` here because we use five
     * bytes to maintain the length of the underlying data structure, meaning we have an extra
     * 27 bytes to store arbitrary data.
     * @param _globalMetadata New global metadata to set.
     */
    function setGlobalMetadata(bytes27 _globalMetadata) external;

    /**
     * Retrieves the container's global metadata field.
     * @return Container global metadata field.
     */
    function getGlobalMetadata() external view returns (bytes27);

    /**
     * Retrieves the number of objects stored in the container.
     * @return Number of objects in the container.
     */
    function length() external view returns (uint256);

    /**
     * Pushes an object into the container.
     * @param _object A 32 byte value to insert into the container.
     */
    function push(bytes32 _object) external;

    /**
     * Pushes an object into the container. Function allows setting the global metadata since
     * we'll need to touch the "length" storage slot anyway, which also contains the global
     * metadata (it's an optimization).
     * @param _object A 32 byte value to insert into the container.
     * @param _globalMetadata New global metadata for the container.
     */
    function push(bytes32 _object, bytes27 _globalMetadata) external;

    /**
     * Set an object into the container. Function allows setting the global metadata since
     * we'll need to touch the "length" storage slot anyway, which also contains the global
     * metadata (it's an optimization).
     * @param _index position.
     * @param _object A 32 byte value to insert into the container.
     */  
    function setByChainId(
        uint256 _chainId,
        uint256 _index,
        bytes32 _object
    )
        external;
        
    /**
     * Retrieves an object from the container.
     * @param _index Index of the particular object to access.
     * @return 32 byte object value.
     */
    function get(uint256 _index) external view returns (bytes32);

    /**
     * Removes all objects after and including a given index.
     * @param _index Object index to delete from.
     */
    function deleteElementsAfterInclusive(uint256 _index) external;

    /**
     * Removes all objects after and including a given index. Also allows setting the global
     * metadata field.
     * @param _index Object index to delete from.
     * @param _globalMetadata New global metadata for the container.
     */
    function deleteElementsAfterInclusive(uint256 _index, bytes27 _globalMetadata) external;

    /**
     * Sets the container's global metadata field. We're using `bytes27` here because we use five
     * bytes to maintain the length of the underlying data structure, meaning we have an extra
     * 27 bytes to store arbitrary data.
     * @param _chainId identity for the l2 chain.
     * @param _globalMetadata New global metadata to set.
     */
    function setGlobalMetadataByChainId(
        uint256 _chainId,
        bytes27 _globalMetadata
    )
        external;

    /**
     * Retrieves the container's global metadata field.
     * @param _chainId identity for the l2 chain.
     * @return Container global metadata field.
     */
    function getGlobalMetadataByChainId(
        uint256 _chainId
        )
        external
        view
        returns (
            bytes27
        );

    /**
     * Retrieves the number of objects stored in the container.
     * @param _chainId identity for the l2 chain.
     * @return Number of objects in the container.
     */
    function lengthByChainId(
        uint256 _chainId
        )
        external
        view
        returns (
            uint256
        );

    /**
     * Pushes an object into the container.
     * @param _chainId identity for the l2 chain.
     * @param _object A 32 byte value to insert into the container.
     */
    function pushByChainId(
        uint256 _chainId,
        bytes32 _object
    )
        external;

    /**
     * Pushes an object into the container. Function allows setting the global metadata since
     * we'll need to touch the "length" storage slot anyway, which also contains the global
     * metadata (it's an optimization).
     * @param _chainId identity for the l2 chain.
     * @param _object A 32 byte value to insert into the container.
     * @param _globalMetadata New global metadata for the container.
     */
    function pushByChainId(
        uint256 _chainId,
        bytes32 _object,
        bytes27 _globalMetadata
    )
        external;

    /**
     * Retrieves an object from the container.
     * @param _chainId identity for the l2 chain.
     * @param _index Index of the particular object to access.
     * @return 32 byte object value.
     */
    function getByChainId(
        uint256 _chainId,
        uint256 _index
    )
        external
        view
        returns (
            bytes32
        );

    /**
     * Removes all objects after and including a given index.
     * @param _chainId identity for the l2 chain.
     * @param _index Object index to delete from.
     */
    function deleteElementsAfterInclusiveByChainId(
        uint256 _chainId,
        uint256 _index
    )
        external;
        
    /**
     * Removes all objects after and including a given index. Also allows setting the global
     * metadata field.
     * @param _chainId identity for the l2 chain.
     * @param _index Object index to delete from.
     * @param _globalMetadata New global metadata for the container.
     */
    function deleteElementsAfterInclusiveByChainId(
        uint256 _chainId,
        uint256 _index,
        bytes27 _globalMetadata
    )
        external;
        
}
/**
 * @title IChainStorageContainer
 */
function lengthByChainId(
    uint256 _chainId
    )
    external
    view
    returns (
        uint256
    );

/**
 * Retrieves the number of objects stored in the container.
 * @param _chainId identity for the l2 chain.
 * @return Number of objects in the container.
 */