Thoughts on adding deadline wrapper?

[Art3miX]

interested to hear thoughts about this wrapper to live in cw-utils.

#[cw_serde]
#[serde(untagged)]
pub enum Deadline {
    Expiration(Expiration),
    Duration(Duration),
}

impl Default for Deadline {
    fn default() -> Self {
        Deadline::Expiration(Expiration::default())
    }
}

impl Deadline {
  pub fn into_expiration(self, block: &BlockInfo) -> Expiration {
    match self {
      Deadline::Expiration(expiration) => expiration,
      Deadline::Duration(duration) => duration.after(block)
    }
  }
}

The main idea here is to export a wrapper that can accept either Expiration or a Duration, and turns it into an Expiration.

The main benefit is that it removes all custom logic that a contract need to handle both cases if a contract wants to accept either one of the options.

Example:

Looking at cw721 ExecuteMsg::Approve:

Approve {
    spender: String,
    token_id: String,
    expires: Option<Expiration>,
},

can be turned into:

Approve {
    spender: String,
    token_id: String,
    expires: Deadline, // or  Option<Deadline>,
},

In contract, we can easily turn deadline into expiration:

let expiration = expires.into_expiration(&env.block)

Or using an optional Deadline

let expiration = expires.unwrap_or_default().into_expiration(&env.block)

Now the user can specify either a specific block/time or some random duration

NOTE:

The #[serde(untagged)] here is to provide a nicer UI, should work nicely given untagged should be supported now and Expiration and Duration enums doesn't have an overlapping values.