added readme + rename denom_resolver

app/app.go

@@ -323,7 +323,7 @@ func New(
 	app.ModuleManager.RegisterInvariants(app.CrisisKeeper)
 
 	// to support multiple denom as fee token
-	app.FeeMarketKeeper.SetDenomResolver(xfeemarketkeeper.NewTestDenomResolver(app.XFeeMarketKeeper))
+	app.FeeMarketKeeper.SetDenomResolver(xfeemarketkeeper.NewXFeeMarketDenomResolver(app.XFeeMarketKeeper))
 
 	// create the simulation manager and define the order of the modules for deterministic simulations
 	overrideModules := map[string]module.AppModuleSimulation{

x/xfeemarket/README.md

@@ -0,0 +1,72 @@
+# `x/xfeemarket`
+
+## Abstract
+
+This document specifies the `xfeemarket` module of mantrachain.
+
+The `xfeemarket` module is to supplement the `feemarket` module by skip-mev.
+
+It provides an implementation for the `DenomResolver` interface, which is 
+required to support multiple different fee tokens. It also has a `PostHandler`
+that Replaces the default feemarket `PostHandler`  to eliminate tips and burn 
+all fees paid by users.
+
+## Contents
+
+* [DenomResolver](#denomresolver)
+* [PostHandler](#posthandler)
+* [State](#state)
+* [Messages](#messages)
+
+## DenomResolver
+
+The current `DenomResolver` implementation allows an authority account to update a 
+map of denom => multiplier. This enables the module to calculate gas fees for 
+different fee tokens based on a multiplier applied to the base denom's gas fee.
+
+Future versions may leverage the skip-mev `connect` module to dynamically fetch 
+oracle prices for the base fee token and the supplied token, enabling more 
+accurate gas fee calculations.
+
+## PostHandler
+
+The custom `PostHandler` eliminates tips and burns all fees paid by users.
+
+## State
+
+The `x/xfeemarket` module keeps state of the following primary objects:
+
+1. Denomination Multipliers
+
+In addition, the `x/xfeemarket` module keeps the following indexes to manage the
+aforementioned state:
+
+* Denomination Multipliers: `0x1 | byte(denom) -> sdk.DecProto(multiplier)`
+
+## Messages
+
+### MsgUpsertFeeDenom
+
+Upsert a multiplier for denom.
+
+```protobuf reference
+https://github.com/MANTRA-Chain/mantrachain/proto/mantrachain/xfeemarket/v1/tx.proto#L41-L46
+```
+
+The message handling can fail if:
+
+* signer is not the gov module account address.
+* denom Metadata does not exists.
+
+### MsgRemoveFeeDenom
+
+Remove a multiplier for denom.
+
+```protobuf reference
+https://github.com/MANTRA-Chain/mantrachain/proto/mantrachain/xfeemarket/v1/tx.proto#L50-L54
+```
+
+The message handling can fail if:
+
+* signer is not the gov module account address.
+* denom is not stored in the current Denomination Multipliers

x/xfeemarket/keeper/resolver.go

@@ -5,18 +5,18 @@ import (
 	feemarkettypes "github.com/skip-mev/feemarket/x/feemarket/types"
 )
 
-var _ feemarkettypes.DenomResolver = &DenomResolver{}
+var _ feemarkettypes.DenomResolver = &XFeeMarketDenomResolver{}
 
-type DenomResolver struct {
+type XFeeMarketDenomResolver struct {
 	k Keeper
 }
 
-func NewTestDenomResolver(k Keeper) *DenomResolver {
-	return &DenomResolver{k: k}
+func NewXFeeMarketDenomResolver(k Keeper) *XFeeMarketDenomResolver {
+	return &XFeeMarketDenomResolver{k: k}
 }
 
 // ConvertToDenom returns "coin.Amount denom" for all coins that are not the denom.
-func (r *DenomResolver) ConvertToDenom(ctx sdk.Context, coin sdk.DecCoin, denom string) (sdk.DecCoin, error) {
+func (r *XFeeMarketDenomResolver) ConvertToDenom(ctx sdk.Context, coin sdk.DecCoin, denom string) (sdk.DecCoin, error) {
 	if coin.Denom == denom {
 		return coin, nil
 	}
@@ -30,7 +30,7 @@ func (r *DenomResolver) ConvertToDenom(ctx sdk.Context, coin sdk.DecCoin, denom
 	return sdk.NewDecCoinFromDec(denom, amount), nil
 }
 
-func (r *DenomResolver) ExtraDenoms(ctx sdk.Context) ([]string, error) {
+func (r *XFeeMarketDenomResolver) ExtraDenoms(ctx sdk.Context) ([]string, error) {
 	iter, err := r.k.DenomMultipliers.Iterate(ctx, nil)
 	if err != nil {
 		return nil, err