Fee middleware using IPC

modules/fee/errors.go

@@ -2,14 +2,14 @@
 package fee
 
 import (
-	rawerr "errors"
+	"fmt"
 
 	abci "github.com/tendermint/abci/types"
 	"github.com/tendermint/basecoin/errors"
 )
 
 var (
-	errInsufficientFees = rawerr.New("Insufficient Fees")
+	errInsufficientFees = fmt.Errorf("Insufficient Fees")
 )
 
 func ErrInsufficientFees() errors.TMError {

modules/fee/handler.go

@@ -11,76 +11,62 @@ import (
 // NameFee - namespace for the fee module
 const NameFee = "fee"
 
-// AccountChecker - interface used by SimpleFeeHandler
+// SimpleFeeMiddleware - middleware for fee checking, constant amount
-type AccountChecker interface {
+// It used modules.coin to move the money
-	// Get amount checks the current amount
+type SimpleFeeMiddleware struct {
-	GetAmount(store state.KVStore, addr basecoin.Actor) (coin.Coins, error)
+	MinFee    coin.Coin //
-
+	Collector basecoin.Actor
-	// ChangeAmount modifies the balance by the given amount and returns the new balance
-	// always returns an error if leading to negative balance
-	ChangeAmount(store state.KVStore, addr basecoin.Actor, coins coin.Coins) (coin.Coins, error)
-}
-
-// SimpleFeeHandler - checker object for fee checking
-type SimpleFeeHandler struct {
-	AccountChecker
-	MinFee coin.Coins
 	stack.PassOption
 }
 
+var _ stack.Middleware = SimpleFeeMiddleware{}
+
+// NewSimpleFeeMiddleware returns a fee handler with a fixed minimum fee.
+//
+// If minFee is 0, then the FeeTx is optional
+func NewSimpleFeeMiddleware(minFee coin.Coin) SimpleFeeMiddleware {
+	return SimpleFeeMiddleware{
+		MinFee: minFee,
+	}
+}
+
 // Name - return the namespace for the fee module
-func (SimpleFeeHandler) Name() string {
+func (SimpleFeeMiddleware) Name() string {
 	return NameFee
 }
 
-var _ stack.Middleware = SimpleFeeHandler{}
-
-// Yes, I know refactor a bit... really too late already
-
 // CheckTx - check the transaction
-func (h SimpleFeeHandler) CheckTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx, next basecoin.Checker) (res basecoin.Result, err error) {
+func (h SimpleFeeMiddleware) CheckTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx, next basecoin.Checker) (res basecoin.Result, err error) {
-	feeTx, ok := tx.Unwrap().(*Fee)
+	return h.doTx(ctx, store, tx, next.CheckTx)
-	if !ok {
-		return res, errors.ErrInvalidFormat(tx)
-	}
-
-	fees := coin.Coins{feeTx.Fee}
-	if !fees.IsGTE(h.MinFee) {
-		return res, ErrInsufficientFees()
-	}
-
-	if !ctx.HasPermission(feeTx.Payer) {
-		return res, errors.ErrUnauthorized()
-	}
-
-	_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
-	if err != nil {
-		return res, err
-	}
-
-	return basecoin.Result{Log: "Valid tx"}, nil
 }
 
 // DeliverTx - send the fee handler transaction
-func (h SimpleFeeHandler) DeliverTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx, next basecoin.Deliver) (res basecoin.Result, err error) {
+func (h SimpleFeeMiddleware) DeliverTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx, next basecoin.Deliver) (res basecoin.Result, err error) {
-	feeTx, ok := tx.Unwrap().(*Fee)
+	return h.doTx(ctx, store, tx, next.DeliverTx)
-	if !ok {
-		return res, errors.ErrInvalidFormat(tx)
 }
 
-	fees := coin.Coins{feeTx.Fee}
+func (h SimpleFeeMiddleware) doTx(ctx basecoin.Context, store state.KVStore, tx basecoin.Tx, next basecoin.CheckerFunc) (res basecoin.Result, err error) {
-	if !fees.IsGTE(h.MinFee) {
+	feeTx, ok := tx.Unwrap().(Fee)
+	if !ok {
+		// the fee wrapper is not required if there is no minimum
+		if h.MinFee.IsZero() {
+			return next(ctx, store, tx)
+		}
+		return res, errors.ErrInvalidFormat(TypeFees, tx)
+	}
+
+	// see if it is big enough...
+	fee := feeTx.Fee
+	if !fee.IsGTE(h.MinFee) {
 		return res, ErrInsufficientFees()
 	}
 
-	if !ctx.HasPermission(feeTx.Payer) {
+	// now, try to make a IPC call to coins...
-		return res, errors.ErrUnauthorized()
+	send := coin.NewSendOneTx(feeTx.Payer, h.Collector, coin.Coins{fee})
-	}
+	_, err = next(ctx, store, send)
-
-	_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
 	if err != nil {
 		return res, err
 	}
 
-	return next.DeliverTx(ctx, store, feeTx.Next())
+	return next(ctx, store, feeTx.Tx)
 }

modules/fee/tx.go

@@ -7,38 +7,38 @@ import (
 
 // nolint
 const (
-	ByteFees = 0x20
+	ByteFees = 0x21
-	TypeFees = "fee"
+	TypeFees = NameFee + "/tx"
 )
 
 func init() {
 	basecoin.TxMapper.
-		RegisterImplementation(&Fee{}, TypeFees, ByteFees)
+		RegisterImplementation(Fee{}, TypeFees, ByteFees)
 }
 
 /**** Fee ****/
 
-var _ basecoin.TxLayer = &Fee{}
-
 // Fee attaches a fee payment to the embedded tx
 type Fee struct {
-	Tx    basecoin.Tx    `json:"tx"`
+	// Gas coin.Coin `json:"gas"`  // ?????
 	Fee   coin.Coin      `json:"fee"`
 	Payer basecoin.Actor `json:"payer"` // the address who pays the fee
-	// Gas coin.Coin `json:"gas"`  // ?????
+	Tx    basecoin.Tx    `json:"tx"`
+}
+
+// NewFee wraps a tx with a promised fee from this actor
+func NewFee(tx basecoin.Tx, fee coin.Coin, payer basecoin.Actor) basecoin.Tx {
+	return Fee{Tx: tx, Fee: fee, Payer: payer}.Wrap()
 }
 
 // nolint - TxInner Functions
-func NewFee(tx basecoin.Tx, fee coin.Coin, payer basecoin.Actor) basecoin.Tx {
+func (f Fee) ValidateBasic() error {
-	return (&Fee{Tx: tx, Fee: fee, Payer: payer}).Wrap()
-}
-func (f *Fee) ValidateBasic() error {
 	// TODO: more checks
 	return f.Tx.ValidateBasic()
 }
-func (f *Fee) Wrap() basecoin.Tx {
+func (f Fee) Wrap() basecoin.Tx {
 	return basecoin.Tx{f}
 }
-func (f *Fee) Next() basecoin.Tx {
+func (f Fee) Next() basecoin.Tx {
 	return f.Tx
 }

modules/roles/handler.go

@@ -56,7 +56,7 @@ func checkTx(ctx basecoin.Context, tx basecoin.Tx) (create CreateRoleTx, err err
 	// check if the tx is proper type and valid
 	create, ok := tx.Unwrap().(CreateRoleTx)
 	if !ok {
-		return create, errors.ErrInvalidFormat(tx)
+		return create, errors.ErrInvalidFormat(TypeCreateRoleTx, tx)
 	}
 	err = create.ValidateBasic()
 	return create, err