review followup

server/market/balancer.go

@@ -21,8 +21,11 @@ type PendingAccounter interface {
 // MatchNegotiator can view match-reserved funds for an account-based asset's
 // address. MatchNegotiator is satisfied by *Swapper.
 type MatchNegotiator interface {
-	// AccountStats returns the qty, swap count, and redeem count pending in
-	// active matches.
+	// AccountStats collects stats about pending matches for account's address
+	// on an account-based asset. qty is the total pending outgoing quantity,
+	// swaps is the number matches with oustanding swaps funded by the account,
+	// and redeem is the number of matches with outstanding redemptions that pay
+	// to the account.
 	AccountStats(acctAddr string, assetID uint32) (qty, swaps uint64, redeems int)
 }
 
@@ -95,6 +98,9 @@ func (b *DEXBalancer) CheckBalance(acctAddr string, assetID uint32, qty, lots ui
 	redeems += newRedeems
 
 	assetInfo := backedAsset.assetInfo
+	// The fee rate assigned to redemptions is at the discretion of the user.
+	// MaxFeeRate is used as a conservatively high estimate. This is then a
+	// server policy that clients must satisfy.
 	redeemCosts := uint64(redeems) * assetInfo.RedeemSize * assetInfo.MaxFeeRate
 	reqFunds := calc.RequiredOrderFunds(qty, 0, lots, assetInfo) + redeemCosts
 

server/market/market.go

@@ -74,7 +74,12 @@ type FeeFetcher interface {
 	MaxFeeRate() uint64
 }
 
+// Balancer provides a method to check that an account on an account-based
+// asset has sufficient balance.
 type Balancer interface {
+	// CheckBalance checks that the address's account has sufficient balance to
+	// trade the outgoing number of lots (totaling qty) and incoming number of
+	// redeems.
 	CheckBalance(acctAddr string, assetID uint32, qty, lots uint64, redeems int) bool
 }
 

server/swap/swap.go

@@ -183,8 +183,7 @@ type SwapperAsset struct {
 type Swapper struct {
 	// coins is a map to all the Asset information, including the asset backends,
 	// used by this Swapper.
-	coins     map[uint32]*SwapperAsset
-	acctBased map[uint32]bool
+	coins map[uint32]*SwapperAsset
 	// storage is a Database backend.
 	storage Storage
 	// authMgr is an AuthManager for client messaging and authentication.
@@ -252,19 +251,16 @@ func NewSwapper(cfg *Config) (*Swapper, error) {
 		}
 	}
 
-	acctBased := make(map[uint32]bool, len(cfg.Assets))
 	acctMatches := make(map[uint32]map[string]map[order.MatchID]*matchTracker)
 	for _, a := range cfg.Assets {
 		if _, ok := a.Backend.(asset.AccountBalancer); ok {
-			acctBased[a.ID] = true
 			acctMatches[a.ID] = make(map[string]map[order.MatchID]*matchTracker)
 		}
 	}
 
 	authMgr := cfg.AuthManager
 	swapper := &Swapper{
 		coins:         cfg.Assets,
-		acctBased:     acctBased,
 		storage:       cfg.Storage,
 		authMgr:       authMgr,
 		swapDone:      cfg.SwapDone,
@@ -327,12 +323,12 @@ func (s *Swapper) addMatch(mt *matchTracker) {
 		acctMatches[mt.ID()] = mt
 	}
 
-	if s.acctBased[mt.Maker.Base()] {
+	if s.acctMatches[mt.Maker.Base()] != nil {
 		acctMatches := s.acctMatches[mt.Maker.Base()]
 		addAcctMatch(acctMatches, mt.Maker.BaseAccount(), mt)
 		addAcctMatch(acctMatches, mt.Taker.Trade().BaseAccount(), mt)
 	}
-	if s.acctBased[mt.Maker.Quote()] {
+	if s.acctMatches[mt.Maker.Quote()] != nil {
 		acctMatches := s.acctMatches[mt.Maker.Quote()]
 		addAcctMatch(acctMatches, mt.Maker.QuoteAccount(), mt)
 		addAcctMatch(acctMatches, mt.Taker.Trade().QuoteAccount(), mt)
@@ -373,12 +369,12 @@ func (s *Swapper) deleteMatch(mt *matchTracker) {
 		}
 	}
 
-	if s.acctBased[mt.Maker.Base()] {
+	if s.acctMatches[mt.Maker.Base()] != nil {
 		acctMatches := s.acctMatches[mt.Maker.Base()]
 		deleteAcctMatch(acctMatches, mt.Maker.BaseAccount(), mt)
 		deleteAcctMatch(acctMatches, mt.Taker.Trade().BaseAccount(), mt)
 	}
-	if s.acctBased[mt.Maker.Quote()] {
+	if s.acctMatches[mt.Maker.Quote()] != nil {
 		acctMatches := s.acctMatches[mt.Maker.Quote()]
 		deleteAcctMatch(acctMatches, mt.Maker.QuoteAccount(), mt)
 		deleteAcctMatch(acctMatches, mt.Taker.Trade().QuoteAccount(), mt)