send.go

package keeper

import (
	"github.com/cosmos/cosmos-sdk/codec"
	"github.com/cosmos/cosmos-sdk/store/prefix"
	"github.com/cosmos/cosmos-sdk/telemetry"
	sdk "github.com/cosmos/cosmos-sdk/types"
	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
	"github.com/cosmos/cosmos-sdk/x/bank/types"
	paramtypes "github.com/cosmos/cosmos-sdk/x/params/types"
)

// SendKeeper defines a module interface that facilitates the transfer of coins
// between accounts without the possibility of creating coins.
type SendKeeper interface {
	ViewKeeper

	InputOutputCoins(ctx sdk.Context, inputs []types.Input, outputs []types.Output) error
	SendCoins(ctx sdk.Context, fromAddr sdk.AccAddress, toAddr sdk.AccAddress, amt sdk.Coins) error

	SubtractCoins(ctx sdk.Context, addr sdk.AccAddress, amt sdk.Coins) error
	AddCoins(ctx sdk.Context, addr sdk.AccAddress, amt sdk.Coins) error

	SetBalance(ctx sdk.Context, addr sdk.AccAddress, balance sdk.Coin) error
	SetBalances(ctx sdk.Context, addr sdk.AccAddress, balances sdk.Coins) error

	GetParams(ctx sdk.Context) types.Params
	SetParams(ctx sdk.Context, params types.Params)

	SendEnabledCoin(ctx sdk.Context, coin sdk.Coin) bool
	SendEnabledCoins(ctx sdk.Context, coins ...sdk.Coin) error

	BlockedAddr(addr sdk.AccAddress) bool
}

var _ SendKeeper = (*BaseSendKeeper)(nil)

// BaseSendKeeper only allows transfers between accounts without the possibility of
// creating coins. It implements the SendKeeper interface.
type BaseSendKeeper struct {
	BaseViewKeeper

	cdc        codec.BinaryMarshaler
	ak         types.AccountKeeper
	storeKey   sdk.StoreKey
	paramSpace paramtypes.Subspace

	// list of addresses that are restricted from receiving transactions
	blockedAddrs map[string]bool
}

func NewBaseSendKeeper(
	cdc codec.BinaryMarshaler, storeKey sdk.StoreKey, ak types.AccountKeeper, paramSpace paramtypes.Subspace, blockedAddrs map[string]bool,
) BaseSendKeeper {

	return BaseSendKeeper{
		BaseViewKeeper: NewBaseViewKeeper(cdc, storeKey, ak),
		cdc:            cdc,
		ak:             ak,
		storeKey:       storeKey,
		paramSpace:     paramSpace,
		blockedAddrs:   blockedAddrs,
	}
}

// GetParams returns the total set of bank parameters.
func (k BaseSendKeeper) GetParams(ctx sdk.Context) (params types.Params) {
	k.paramSpace.GetParamSet(ctx, &params)
	return params
}

// SetParams sets the total set of bank parameters.
func (k BaseSendKeeper) SetParams(ctx sdk.Context, params types.Params) {
	k.paramSpace.SetParamSet(ctx, &params)
}

// InputOutputCoins performs multi-send functionality. It accepts a series of
// inputs that correspond to a series of outputs. It returns an error if the
// inputs and outputs don't lineup or if any single transfer of tokens fails.
func (k BaseSendKeeper) InputOutputCoins(ctx sdk.Context, inputs []types.Input, outputs []types.Output) error {
	// Safety check ensuring that when sending coins the keeper must maintain the
	// Check supply invariant and validity of Coins.
	if err := types.ValidateInputsOutputs(inputs, outputs); err != nil {
		return err
	}

	for _, in := range inputs {
		inAddress, err := sdk.AccAddressFromBech32(in.Address)
		if err != nil {
			return err
		}

		err = k.SubtractCoins(ctx, inAddress, in.Coins)
		if err != nil {
			return err
		}

		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				sdk.EventTypeMessage,
				sdk.NewAttribute(types.AttributeKeySender, in.Address),
			),
		)
	}

	for _, out := range outputs {
		outAddress, err := sdk.AccAddressFromBech32(out.Address)
		if err != nil {
			return err
		}
		err = k.AddCoins(ctx, outAddress, out.Coins)
		if err != nil {
			return err
		}

		ctx.EventManager().EmitEvent(
			sdk.NewEvent(
				types.EventTypeTransfer,
				sdk.NewAttribute(types.AttributeKeyRecipient, out.Address),
				sdk.NewAttribute(sdk.AttributeKeyAmount, out.Coins.String()),
			),
		)

		// Create account if recipient does not exist.
		//
		// NOTE: This should ultimately be removed in favor a more flexible approach
		// such as delegated fee messages.
		acc := k.ak.GetAccount(ctx, outAddress)
		if acc == nil {
			defer telemetry.IncrCounter(1, "new", "account")
			k.ak.SetAccount(ctx, k.ak.NewAccountWithAddress(ctx, outAddress))
		}
	}

	return nil
}

// SendCoins transfers amt coins from a sending account to a receiving account.
// An error is returned upon failure.
func (k BaseSendKeeper) SendCoins(ctx sdk.Context, fromAddr sdk.AccAddress, toAddr sdk.AccAddress, amt sdk.Coins) error {
	ctx.EventManager().EmitEvents(sdk.Events{
		sdk.NewEvent(
			types.EventTypeTransfer,
			sdk.NewAttribute(types.AttributeKeyRecipient, toAddr.String()),
			sdk.NewAttribute(types.AttributeKeySender, fromAddr.String()),
			sdk.NewAttribute(sdk.AttributeKeyAmount, amt.String()),
		),
		sdk.NewEvent(
			sdk.EventTypeMessage,
			sdk.NewAttribute(types.AttributeKeySender, fromAddr.String()),
		),
	})

	err := k.SubtractCoins(ctx, fromAddr, amt)
	if err != nil {
		return err
	}

	err = k.AddCoins(ctx, toAddr, amt)
	if err != nil {
		return err
	}

	// Create account if recipient does not exist.
	//
	// NOTE: This should ultimately be removed in favor a more flexible approach
	// such as delegated fee messages.
	acc := k.ak.GetAccount(ctx, toAddr)
	if acc == nil {
		defer telemetry.IncrCounter(1, "new", "account")
		k.ak.SetAccount(ctx, k.ak.NewAccountWithAddress(ctx, toAddr))
	}

	return nil
}

// SubtractCoins removes amt coins the account by the given address. An error is
// returned if the resulting balance is negative or the initial amount is invalid.
func (k BaseSendKeeper) SubtractCoins(ctx sdk.Context, addr sdk.AccAddress, amt sdk.Coins) error {
	if !amt.IsValid() {
		return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, amt.String())
	}

	lockedCoins := k.LockedCoins(ctx, addr)

	for _, coin := range amt {
		balance := k.GetBalance(ctx, addr, coin.Denom)
		locked := sdk.NewCoin(coin.Denom, lockedCoins.AmountOf(coin.Denom))
		spendable := balance.Sub(locked)

		_, hasNeg := sdk.Coins{spendable}.SafeSub(sdk.Coins{coin})
		if hasNeg {
			return sdkerrors.Wrapf(sdkerrors.ErrInsufficientFunds, "%s is smaller than %s", spendable, coin)
		}

		newBalance := balance.Sub(coin)

		err := k.SetBalance(ctx, addr, newBalance)
		if err != nil {
			return err
		}
	}

	return nil
}

// AddCoins adds amt to the account balance given by the provided address. An
// error is returned if the initial amount is invalid or if any resulting new
// balance is negative.
func (k BaseSendKeeper) AddCoins(ctx sdk.Context, addr sdk.AccAddress, amt sdk.Coins) error {
	if !amt.IsValid() {
		return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, amt.String())
	}

	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
		}
	}

	return nil
}

// ClearBalances removes all balances for a given account by address.
func (k BaseSendKeeper) ClearBalances(ctx sdk.Context, addr sdk.AccAddress) {
	keys := [][]byte{}
	k.IterateAccountBalances(ctx, addr, func(balance sdk.Coin) bool {
		keys = append(keys, []byte(balance.Denom))
		return false
	})

	store := ctx.KVStore(k.storeKey)
	balancesStore := prefix.NewStore(store, types.BalancesPrefix)
	accountStore := prefix.NewStore(balancesStore, addr.Bytes())

	for _, key := range keys {
		accountStore.Delete(key)
	}
}

// SetBalances sets the balance (multiple coins) for an account by address. It will
// clear out all balances prior to setting the new coins as to set existing balances
// to zero if they don't exist in amt. An error is returned upon failure.
func (k BaseSendKeeper) SetBalances(ctx sdk.Context, addr sdk.AccAddress, balances sdk.Coins) error {
	k.ClearBalances(ctx, addr)

	for _, balance := range balances {
		err := k.SetBalance(ctx, addr, balance)
		if err != nil {
			return err
		}
	}

	return nil
}

// SetBalance sets the coin balance for an account by address.
func (k BaseSendKeeper) SetBalance(ctx sdk.Context, addr sdk.AccAddress, balance sdk.Coin) error {
	if !balance.IsValid() {
		return sdkerrors.Wrap(sdkerrors.ErrInvalidCoins, balance.String())
	}

	store := ctx.KVStore(k.storeKey)
	balancesStore := prefix.NewStore(store, types.BalancesPrefix)
	accountStore := prefix.NewStore(balancesStore, addr.Bytes())

	bz := k.cdc.MustMarshalBinaryBare(&balance)
	accountStore.Set([]byte(balance.Denom), bz)

	return nil
}

// SendEnabledCoins checks the coins provide and returns an ErrSendDisabled if
// any of the coins are not configured for sending.  Returns nil if sending is enabled
// for all provided coin
func (k BaseSendKeeper) SendEnabledCoins(ctx sdk.Context, coins ...sdk.Coin) error {
	for _, coin := range coins {
		if !k.SendEnabledCoin(ctx, coin) {
			return sdkerrors.Wrapf(types.ErrSendDisabled, "%s transfers are currently disabled", coin.Denom)
		}
	}
	return nil
}

// SendEnabledCoin returns the current SendEnabled status of the provided coin's denom
func (k BaseSendKeeper) SendEnabledCoin(ctx sdk.Context, coin sdk.Coin) bool {
	return k.GetParams(ctx).SendEnabledDenom(coin.Denom)
}

// BlockedAddr checks if a given address is restricted from
// receiving funds.
func (k BaseSendKeeper) BlockedAddr(addr sdk.AccAddress) bool {
	return k.blockedAddrs[addr.String()]
}