Function: _matchIncomingOrder(PerpBook ds, Order matchedOrder, Order incomingOrder, bool amountIsBase)

This internal function handles a single match between an incoming taker order and a matched maker order during the _matchIncomingBid or _matchIncomingAsk functions' execution. This function executes the maker fill logic and performs cleanup or updates to the matched maker order. This function prevents self-trade by removing an order if the maker is the same user.

Additionally, this function

• calculates the matched baseDelta and quoteDelta,

• executes maker-side fill logic,

• updates or removes the maker order in the order book, and

• returns the MatchData, which contains matchedAmount, baseDelta, quoteDelta, and takerFee.

Branches and code coverage

Intended branches

• The order book contains only the opposite order of the same account. The order was removed, and matchedAmount, baseDelta, quoteDelta, and takerFee are zero.

  Test coverage

• matchedOrder is reduceOnly.

  Test coverage

• amountIsBase is true for the incomingOrder. The baseDelta, quoteDelta, and matchedAmount are calculated correctly.

  Test coverage

• amountIsBase is false for the incomingOrder. The baseDelta, quoteDelta and matchedAmount are calculated correctly.

  Test coverage

• When baseDelta > 0, the makerFee, maker’s position, and margin are updated correctly.

  Test coverage

• Fully matches matchedOrder, and it is removed from the order book.

  Test coverage

• Partially matches matchedOrder, and the amount is updated.

  Test coverage