86 lines
2.2 KiB
Go
86 lines
2.2 KiB
Go
package fee
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import (
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"github.com/tendermint/basecoin"
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"github.com/tendermint/basecoin/errors"
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"github.com/tendermint/basecoin/stack"
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"github.com/tendermint/basecoin/types"
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)
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// NameFee - namespace for the fee module
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const NameFee = "fee"
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// AccountChecker - interface used by SimpleFeeHandler
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type AccountChecker interface {
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// Get amount checks the current amount
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GetAmount(store types.KVStore, addr basecoin.Actor) (types.Coins, error)
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// ChangeAmount modifies the balance by the given amount and returns the new balance
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// always returns an error if leading to negative balance
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ChangeAmount(store types.KVStore, addr basecoin.Actor, coins types.Coins) (types.Coins, error)
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}
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// SimpleFeeHandler - checker object for fee checking
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type SimpleFeeHandler struct {
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AccountChecker
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MinFee types.Coins
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stack.PassOption
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}
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// Name - return the namespace for the fee module
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func (SimpleFeeHandler) Name() string {
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return NameFee
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}
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var _ stack.Middleware = SimpleFeeHandler{}
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// Yes, I know refactor a bit... really too late already
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// CheckTx - check the transaction
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func (h SimpleFeeHandler) CheckTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Checker) (res basecoin.Result, err error) {
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feeTx, ok := tx.Unwrap().(*Fee)
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if !ok {
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return res, errors.ErrInvalidFormat(tx)
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}
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fees := types.Coins{feeTx.Fee}
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if !fees.IsGTE(h.MinFee) {
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return res, ErrInsufficientFees()
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}
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if !ctx.HasPermission(feeTx.Payer) {
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return res, errors.ErrUnauthorized()
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}
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_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
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if err != nil {
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return res, err
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}
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return basecoin.Result{Log: "Valid tx"}, nil
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}
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// DeliverTx - send the fee handler transaction
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func (h SimpleFeeHandler) DeliverTx(ctx basecoin.Context, store types.KVStore, tx basecoin.Tx, next basecoin.Deliver) (res basecoin.Result, err error) {
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feeTx, ok := tx.Unwrap().(*Fee)
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if !ok {
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return res, errors.ErrInvalidFormat(tx)
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}
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fees := types.Coins{feeTx.Fee}
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if !fees.IsGTE(h.MinFee) {
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return res, ErrInsufficientFees()
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}
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if !ctx.HasPermission(feeTx.Payer) {
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return res, errors.ErrUnauthorized()
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}
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_, err = h.ChangeAmount(store, feeTx.Payer, fees.Negative())
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if err != nil {
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return res, err
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}
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return next.DeliverTx(ctx, store, feeTx.Next())
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}
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