feat(bank/v2): Send function

x/bank/v2/keeper/keeper.go

@@ -1,12 +1,20 @@
 package keeper
 
 import (
+	"context"
+
 	"cosmossdk.io/collections"
+	"cosmossdk.io/collections/indexes"
 	"cosmossdk.io/core/address"
 	appmodulev2 "cosmossdk.io/core/appmodule/v2"
+	"cosmossdk.io/core/event"
+	errorsmod "cosmossdk.io/errors"
+	"cosmossdk.io/math"
 	"cosmossdk.io/x/bank/v2/types"
 
 	"github.com/cosmos/cosmos-sdk/codec"
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 )
 
 // Keeper defines the bank/v2 module keeper.
@@ -18,6 +26,8 @@ type Keeper struct {
 	addressCodec address.Codec
 	schema       collections.Schema
 	params       collections.Item[types.Params]
+	balances     *collections.IndexedMap[collections.Pair[[]byte, string], math.Int, BalancesIndexes]
+	supply       collections.Map[string, math.Int]
 }
 
 func NewKeeper(authority []byte, addressCodec address.Codec, env appmodulev2.Environment, cdc codec.BinaryCodec) *Keeper {
@@ -28,6 +38,8 @@ func NewKeeper(authority []byte, addressCodec address.Codec, env appmodulev2.Env
 		authority:    authority,
 		addressCodec: addressCodec, // TODO(@julienrbrt): Should we add address codec to the environment?
 		params:       collections.NewItem(sb, types.ParamsKey, "params", codec.CollValue[types.Params](cdc)),
+		balances:     collections.NewIndexedMap(sb, types.BalancesPrefix, "balances", collections.PairKeyCodec(collections.BytesKey, collections.StringKey), sdk.IntValue, newBalancesIndexes(sb)),
+		supply:       collections.NewMap(sb, types.SupplyKey, "supply", collections.StringKey, sdk.IntValue),
 	}
 
 	schema, err := sb.Build()
@@ -38,3 +50,205 @@ func NewKeeper(authority []byte, addressCodec address.Codec, env appmodulev2.Env
 
 	return k
 }
+
+// MintCoins creates new coins from thin air and adds it to the module account.
+// An error is returned if the module account does not exist or is unauthorized.
+func (k Keeper) MintCoins(ctx context.Context, addr []byte, amounts sdk.Coins) error {
+	// TODO: Mint restriction & permission
+
+	if !amounts.IsValid() {
+		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amounts.String())
+	}
+
+	err := k.addCoins(ctx, addr, amounts)
+	if err != nil {
+		return err
+	}
+
+	for _, amount := range amounts {
+		supply := k.GetSupply(ctx, amount.GetDenom())
+		supply = supply.Add(amount)
+		k.setSupply(ctx, supply)
+	}
+
+	addrStr, err := k.addressCodec.BytesToString(addr)
+	if err != nil {
+		return err
+	}
+
+	// emit mint event
+	return k.EventService.EventManager(ctx).EmitKV(
+		types.EventTypeCoinMint,
+		event.NewAttribute(types.AttributeKeyMinter, addrStr),
+		event.NewAttribute(sdk.AttributeKeyAmount, amounts.String()),
+	)
+}
+
+// SendCoins transfers amt coins from a sending account to a receiving account.
+// Function take sender & receipient as []byte.
+// They can be sdk address or module name.
+// An error is returned upon failure.
+func (k Keeper) SendCoins(ctx context.Context, from, to []byte, amt sdk.Coins) error {
+	if !amt.IsValid() {
+		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, amt.String())
+	}
+
+	var err error
+	// TODO: Send restriction
+
+	err = k.subUnlockedCoins(ctx, from, amt)
+	if err != nil {
+		return err
+	}
+
+	err = k.addCoins(ctx, to, amt)
+	if err != nil {
+		return err
+	}
+
+	fromAddrString, err := k.addressCodec.BytesToString(from)
+	if err != nil {
+		return err
+	}
+	toAddrString, err := k.addressCodec.BytesToString(to)
+	if err != nil {
+		return err
+	}
+
+	return k.EventService.EventManager(ctx).EmitKV(
+		types.EventTypeTransfer,
+		event.NewAttribute(types.AttributeKeyRecipient, toAddrString),
+		event.NewAttribute(types.AttributeKeySender, fromAddrString),
+		event.NewAttribute(sdk.AttributeKeyAmount, amt.String()),
+	)
+}
+
+// GetSupply retrieves the Supply from store
+func (k Keeper) GetSupply(ctx context.Context, denom string) sdk.Coin {
+	amt, err := k.supply.Get(ctx, denom)
+	if err != nil {
+		return sdk.NewCoin(denom, math.ZeroInt())
+	}
+	return sdk.NewCoin(denom, amt)
+}
+
+// GetBalance returns the balance of a specific denomination for a given account
+// by address.
+func (k Keeper) GetBalance(ctx context.Context, addr []byte, denom string) sdk.Coin {
+	amt, err := k.balances.Get(ctx, collections.Join(addr, denom))
+	if err != nil {
+		return sdk.NewCoin(denom, math.ZeroInt())
+	}
+	return sdk.NewCoin(denom, amt)
+}
+
+// subUnlockedCoins removes the unlocked amt coins of the given account.
+// An error is returned if the resulting balance is negative.
+//
+// CONTRACT: The provided amount (amt) must be valid, non-negative coins.
+//
+// A coin_spent event is emitted after the operation.
+func (k Keeper) subUnlockedCoins(ctx context.Context, addr []byte, amt sdk.Coins) error {
+	for _, coin := range amt {
+		balance := k.GetBalance(ctx, addr, coin.Denom)
+		spendable := sdk.Coins{balance}
+
+		_, hasNeg := spendable.SafeSub(coin)
+		if hasNeg {
+			if len(spendable) == 0 {
+				spendable = sdk.Coins{sdk.Coin{Denom: coin.Denom, Amount: math.ZeroInt()}}
+			}
+			return errorsmod.Wrapf(
+				sdkerrors.ErrInsufficientFunds,
+				"spendable balance %s is smaller than %s",
+				spendable, coin,
+			)
+		}
+
+		newBalance := balance.Sub(coin)
+
+		if err := k.setBalance(ctx, addr, newBalance); err != nil {
+			return err
+		}
+	}
+
+	addrStr, err := k.addressCodec.BytesToString(addr)
+	if err != nil {
+		return err
+	}
+
+	return k.EventService.EventManager(ctx).EmitKV(
+		types.EventTypeCoinSpent,
+		event.NewAttribute(types.AttributeKeySpender, addrStr),
+		event.NewAttribute(sdk.AttributeKeyAmount, amt.String()),
+	)
+}
+
+// addCoins increases the balance of the given address by the specified amount.
+//
+// CONTRACT: The provided amount (amt) must be valid, non-negative coins.
+//
+// It emits a coin_received event after the operation.
+func (k Keeper) addCoins(ctx context.Context, addr []byte, amt sdk.Coins) error {
+	for _, coin := range amt {
+		balance := k.GetBalance(ctx, addr, coin.Denom)
+		newBalance := balance.Add(coin)
+
+		err := k.setBalance(ctx, addr, newBalance)
+		if err != nil {
+			return err
+		}
+	}
+
+	addrStr, err := k.addressCodec.BytesToString(addr)
+	if err != nil {
+		return err
+	}
+
+	return k.EventService.EventManager(ctx).EmitKV(
+		types.EventTypeCoinReceived,
+		event.NewAttribute(types.AttributeKeyReceiver, addrStr),
+		event.NewAttribute(sdk.AttributeKeyAmount, amt.String()),
+	)
+}
+
+// setSupply sets the supply for the given coin
+func (k Keeper) setSupply(ctx context.Context, coin sdk.Coin) {
+	// Bank invariants and IBC requires to remove zero coins.
+	if coin.IsZero() {
+		_ = k.supply.Remove(ctx, coin.Denom)
+	} else {
+		_ = k.supply.Set(ctx, coin.Denom, coin.Amount)
+	}
+}
+
+// setBalance sets the coin balance for an account by address.
+func (k Keeper) setBalance(ctx context.Context, addr []byte, balance sdk.Coin) error {
+	if !balance.IsValid() {
+		return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, balance.String())
+	}
+
+	// x/bank invariants prohibit persistence of zero balances
+	if balance.IsZero() {
+		err := k.balances.Remove(ctx, collections.Join(addr, balance.Denom))
+		if err != nil {
+			return err
+		}
+		return nil
+	}
+	return k.balances.Set(ctx, collections.Join(addr, balance.Denom), balance.Amount)
+}
+
+func newBalancesIndexes(sb *collections.SchemaBuilder) BalancesIndexes {
+	return BalancesIndexes{
+		Denom: indexes.NewReversePair[math.Int](
+			sb, types.DenomAddressPrefix, "address_by_denom_index",
+			collections.PairKeyCodec(collections.BytesKey, collections.StringKey),
+			indexes.WithReversePairUncheckedValue(), // denom to address indexes were stored as Key: Join(denom, address) Value: []byte{0}, this will migrate the value to []byte{} in a lazy way.
+		),
+	}
+}
+
+type BalancesIndexes struct {
+	Denom *indexes.ReversePair[[]byte, string, math.Int]
+}