Dedup _withdrawableAmountOf

[PaulRBerg]

The _withdrawableAmountOf implementations in SablierV2LockupLinear and SablierV2LockupDynamic can be moved to the SablierV2Lockup abstract.

[andreivladbrg]

It would require to add _streamedAmountOf and getWithdrawnAmount as a virtual functions
https://github.com/sablierhq/v2-core/blob/2b71d0762706ad04cdad58e37d2c6db0b6274496/src/SablierV2LockupLinear.sol#L348

Wouldn't calling getWithdrawnAmount increase the gas?

[PaulRBerg]

We have the internal function _withdrawableAmountOf defined in SablierV2Lockup.

[andreivladbrg]

We have the internal function _withdrawableAmountOf defined in SablierV2Lockup.

Yes we do but we don't have the _streamedAmountOf and getWithdrawnAmount functions. If you really want to move it there, we could also move refundableAmountOf.

[PaulRBerg]

We can simply define it like this:

/// @inheritdoc ISablierV2Lockup
function withdrawableAmountOf(uint256 streamId)
    external
    view
    override
    isNotNull(streamId)
    returns (uint128 withdrawableAmount)
{
    withdrawableAmount = _withdrawableAmountOf(streamId);
}

You'll see when I make the PR.

[PaulRBerg]

If you really want to move it there, we could also move refundableAmountOf

We can't do that for reasons I will explain in my PR (related to my status enum updates).