EIP: XXX
Title: ERCXXX Eternal Storage
Author: Augusto Lemble <me@augustolemble.com>
Type: Contract Standard
Category: ERC
Status: Draft
Created: 2018-03-14
This contract provides the necessary logic to store any type of data outside a smart contract, allowing the developer to migrate the storage much more easily to another contract if needed.
The ES (Eternal Storage) contract is owned by an address that have write permissions. The storage is public, which means everyone has read permissions. It store the data on mappings, using one mapping per type of variable.
// Using contract storage
string myName = "Vitalik";
// Using Eternal Storage
s._strings[keccak256("myName")] = "Vitalik";
There is some implementations of Eternal Storage contracts already done and being used but there is not some consensus over it. Storage is one of the most important parts of smart contracts development and using this contract will allow developers to use a standardized version of ES and therefore have safer contracts and also use this standard to design new ones for upgradeable tokens for example.
Note The nomenclature used for the functions and variables was tried to be as short as possible, since we don't want to have to use +30 more characters per line to assign an uint.
- s == storage
- h == hash
- v == value
The storage of the contract is stored in a internal variable, it is also an struct with a set of mappings, one per each variable type.
struct Storage {
mapping(bytes32 => bool) _bool;
mapping(bytes32 => int) _int;
mapping(bytes32 => uint) _uint;
mapping(bytes32 => string) _string;
mapping(bytes32 => address) _address;
mapping(bytes32 => bytes) _bytes;
}
Storage internal s;
Returns the owner address of the ES.
function owner() constant returns (address owner)
Execute a write operation over the storage, it can only be called by the ES
owner. It will write the value v over the boolean value identified with the
hash h.
The function SHOULD revert if the msg.sender is not the owner.
function setBoolean(bytes32 h, bool v) public onlyOwner {
s._bool[h] = v;
}
function setInt(bytes32 h, int v) public onlyOwner {
s._int[h] = v;
}
function setUint(bytes32 h, uint256 v) public onlyOwner {
s._uint[h] = v;
}
function setAddress(bytes32 h, address v) public onlyOwner {
s._address[h] = v;
}
function setString(bytes32 h, string v) public onlyOwner {
s._string[h] = v;
}
function setBytes(bytes32 h, bytes v) public onlyOwner {
s._bytes[h] = v;
}
Execute a read operation over the storage. It receives the hash identifier h of the variable stored and it returns the value of it.
function getBoolean(bytes32 h) public view returns (bool){
return s._bool[h];
}
function getInt(bytes32 h) public view returns (int){
return s._int[h];
}
function getUint(bytes32 h) public view returns (uint256){
return s._uint[h];
}
function getAddress(bytes32 h) public view returns (address){
return s._address[h];
}
function getString(bytes32 h) public view returns (string){
return s._string[h];
}
function getBytes(bytes32 h) public view returns (bytes){
return s._bytes[h];
}
Triggered when the ownership of the contract change.
event OwnershipTransfered(address indexed previousOwner, address indexed newOwner);
- 2018/03/14: Initial Draft
Copyright and related rights waived via CC0