Add update_maker_order RPC

[shamardy]

fixes #814

[artemii235]

Please check the comments 🙂

[artemii235]

I have a few more change proposals 🙂

[artemii235]

Great 🔥

@tonymorony Could you please arrange a test of the following case:

1. Setup a maker order on the node.
2. Ensure that it's displayed on other nodes' order books.
3. Call update_maker_order.
4. Check that order books are updated.

It's not required for all nodes to use the mm2.1-update-maker-order. Only the order creator node should be on this branch.

[SirSevenG]

Following requested case: #926 (review)

No issues found, order is updated on all nodes.

[artemii235]

I've noticed 1 tricky situation, cc @tonymorony @cipig I would like to know your opinion on this, please check the comment below 🙂

[shamardy]

After discussion with @artemii235 Request now should be:

{
  "method":"update_maker_order",
  "params":{
    "uuid": "123e4567-e89b-12d3-a456-426614174000",
    "new_price": "1", (optional, can be supplied as decimal/fraction/rational)
    "volume_delta": "-1", (optional, can be supplied as decimal/fraction/rational, can be positive/negative number to increase/decrease the volume, ignored if max = true)
    "max": true, (optional, whether to use max available volume)
    "base_confs": 1, (optional)
    "base_nota": false, (optional)
    "rel_confs": 1, (optional)
    "rel_nota": false (optional)
  }
}

"new_volume" is now "volume_delta" which will be more beneficial for the GUI as well.

[artemii235]

The last of the last review iteration 😄

[artemii235]

Hopefully, this is really the last review iteration.

[artemii235]

This results in invalid volume being set for order:

1. Let's say the current max_base_vol = 5, reserved = 3 so available = 2.
2. We set volume_delta = 2 in the request. The new_volume = original_volume + volume_delta = 7.
3. Then we deduct new_volume - reserved_amount so max_base_vol = 7 - 3 = 4, which is even lower than initial one.

You also have let reserved_amount = order.reserved_amount(); in a couple of lines above, you can reuse it to avoid calculation duplication overhead.

[shamardy]

yeah I had it after order.apply_updated(&update_msg) but must have messed it up later. Will fix it.

[shamardy]

I can also use reserved_amount from here https://github.com/KomodoPlatform/atomicDEX-API/blob/db9c095995cc586c65573a68eada05752189f95c/mm2src/lp_ordermatch.rs#L3370
avoiding calculation in let reserved_amount = order.reserved_amount(); too, since we made sure It won't change through the update call.

[artemii235]

We did it, great! 😄