LibraryEncapsulation.sol

LibraryEncapsulation.sol

pragma solidity ^0.5.5;

// Libs

library FooLib {
    struct Foo {
        uint a;
        uint b;
        uint c;
    }
    
    function addToFoos(Foo storage foo, uint amount) public {
        foo.a += amount;
        foo.b += amount;
        foo.c += amount;
    }
    
    function sumFoos(Foo storage foo) public view returns (uint) {
        return foo.a + foo.b + foo.c;
    }
}

library BarLib {
    struct Bar {
        uint d;
        uint e;
    }
    
    function doSomeStateChange(Bar storage bar, uint amount) public {
        bar.d = bar.e + amount;
    }
}

// Wrappers

contract FooWrapper {
    using FooLib for FooLib.Foo;
    
    FooLib.Foo private foo;
    
    /**
     *  Public interface of Foo wrapper
     *  Outside of this contract, only these functions can change foo's state
     */
    function addToFoos(uint amount) public {
        foo.addToFoos(amount);
    }
    
    /**
     *  Foo getters
     */
    
    function getA() public view returns (uint) {
        return foo.a;
    }
    
    function getB() public view returns (uint) {
        return foo.b;
    }
    
    function getC() public view returns (uint) {
        return foo.c;
    }
}

contract BarWrapper {
    BarLib.Bar private bar;
    
    function getD() public view returns (uint) {
        return bar.d;
    }
    
    function getE() public view returns (uint) {
        return bar.e;
    }
}

// Main Contract
// The main contract has state that is one Foo struct and on Bar struct.
// All state changes to Foo state must happen through the FooWrapper interface
// All state changes to Bar state must happen through the BarWrapper interface

contract MainContract is FooWrapper, BarWrapper {
    
    function addDToAllFoos() public {
        // gets D from BarWrapper
        uint d = getD();
        // sets values in Foo through the Foo wrapper interface
        addToFoos(d);
    }
    
}