chore: split transfer AppModule/IBCModule

CHANGELOG.md

@@ -45,6 +45,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 * (core) [\#227](https://github.com/cosmos/ibc-go/pull/227) Remove sdk.Result from application callbacks
 * (transfer) [\#350](https://github.com/cosmos/ibc-go/pull/350) Change FungibleTokenPacketData to use a string for the Amount field. This enables token transfers with amounts previously restricted by uint64. Up to the maximum uint256 value is supported. 
+* (transfer) [\#517](https://github.com/cosmos/ibc-go/pull/517) Separates the ICS 26 callback functions from `AppModule` into a new type `IBCModule` for ICS 20 transfer.
 
 ### State Machine Breaking
 

modules/apps/transfer/ibc_module.go

@@ -0,0 +1,297 @@
+package transfer
+
+import (
+	"fmt"
+	"math"
+
+	sdk "github.com/cosmos/cosmos-sdk/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	capabilitytypes "github.com/cosmos/cosmos-sdk/x/capability/types"
+
+	"github.com/cosmos/ibc-go/v2/modules/apps/transfer/keeper"
+	"github.com/cosmos/ibc-go/v2/modules/apps/transfer/types"
+	channeltypes "github.com/cosmos/ibc-go/v2/modules/core/04-channel/types"
+	porttypes "github.com/cosmos/ibc-go/v2/modules/core/05-port/types"
+	host "github.com/cosmos/ibc-go/v2/modules/core/24-host"
+	ibcexported "github.com/cosmos/ibc-go/v2/modules/core/exported"
+)
+
+// IBCModule implements the ICS26 interface for transfer given the transfer keeper.
+type IBCModule struct {
+	keeper keeper.Keeper
+}
+
+// NewIBCModule creates a new IBCModule given the keeper
+func NewIBCModule(k keeper.Keeper) IBCModule {
+	return IBCModule{
+		keeper: k,
+	}
+}
+
+// ValidateTransferChannelParams does validation of a newly created transfer channel. A transfer
+// channel must be UNORDERED, use the correct port (by default 'transfer'), and use the current
+// supported version. Only 2^32 channels are allowed to be created.
+func ValidateTransferChannelParams(
+	ctx sdk.Context,
+	keeper keeper.Keeper,
+	order channeltypes.Order,
+	portID string,
+	channelID string,
+	version string,
+) error {
+	// NOTE: for escrow address security only 2^32 channels are allowed to be created
+	// Issue: https://github.com/cosmos/cosmos-sdk/issues/7737
+	channelSequence, err := channeltypes.ParseChannelSequence(channelID)
+	if err != nil {
+		return err
+	}
+	if channelSequence > uint64(math.MaxUint32) {
+		return sdkerrors.Wrapf(types.ErrMaxTransferChannels, "channel sequence %d is greater than max allowed transfer channels %d", channelSequence, uint64(math.MaxUint32))
+	}
+	if order != channeltypes.UNORDERED {
+		return sdkerrors.Wrapf(channeltypes.ErrInvalidChannelOrdering, "expected %s channel, got %s ", channeltypes.UNORDERED, order)
+	}
+
+	// Require portID is the portID transfer module is bound to
+	boundPort := keeper.GetPort(ctx)
+	if boundPort != portID {
+		return sdkerrors.Wrapf(porttypes.ErrInvalidPort, "invalid port: %s, expected %s", portID, boundPort)
+	}
+
+	if version != types.Version {
+		return sdkerrors.Wrapf(types.ErrInvalidVersion, "got %s, expected %s", version, types.Version)
+	}
+	return nil
+}
+
+// OnChanOpenInit implements the IBCModule interface
+func (im IBCModule) OnChanOpenInit(
+	ctx sdk.Context,
+	order channeltypes.Order,
+	connectionHops []string,
+	portID string,
+	channelID string,
+	chanCap *capabilitytypes.Capability,
+	counterparty channeltypes.Counterparty,
+	version string,
+) error {
+	if err := ValidateTransferChannelParams(ctx, im.keeper, order, portID, channelID, version); err != nil {
+		return err
+	}
+
+	// Claim channel capability passed back by IBC module
+	if err := im.keeper.ClaimCapability(ctx, chanCap, host.ChannelCapabilityPath(portID, channelID)); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// OnChanOpenTry implements the IBCModule interface
+func (im IBCModule) OnChanOpenTry(
+	ctx sdk.Context,
+	order channeltypes.Order,
+	connectionHops []string,
+	portID,
+	channelID string,
+	chanCap *capabilitytypes.Capability,
+	counterparty channeltypes.Counterparty,
+	version,
+	counterpartyVersion string,
+) error {
+	if err := ValidateTransferChannelParams(ctx, im.keeper, order, portID, channelID, version); err != nil {
+		return err
+	}
+
+	if counterpartyVersion != types.Version {
+		return sdkerrors.Wrapf(types.ErrInvalidVersion, "invalid counterparty version: got: %s, expected %s", counterpartyVersion, types.Version)
+	}
+
+	// Module may have already claimed capability in OnChanOpenInit in the case of crossing hellos
+	// (ie chainA and chainB both call ChanOpenInit before one of them calls ChanOpenTry)
+	// If module can already authenticate the capability then module already owns it so we don't need to claim
+	// Otherwise, module does not have channel capability and we must claim it from IBC
+	if !im.keeper.AuthenticateCapability(ctx, chanCap, host.ChannelCapabilityPath(portID, channelID)) {
+		// Only claim channel capability passed back by IBC module if we do not already own it
+		if err := im.keeper.ClaimCapability(ctx, chanCap, host.ChannelCapabilityPath(portID, channelID)); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// OnChanOpenAck implements the IBCModule interface
+func (im IBCModule) OnChanOpenAck(
+	ctx sdk.Context,
+	portID,
+	channelID string,
+	counterpartyVersion string,
+) error {
+	if counterpartyVersion != types.Version {
+		return sdkerrors.Wrapf(types.ErrInvalidVersion, "invalid counterparty version: %s, expected %s", counterpartyVersion, types.Version)
+	}
+	return nil
+}
+
+// OnChanOpenConfirm implements the IBCModule interface
+func (im IBCModule) OnChanOpenConfirm(
+	ctx sdk.Context,
+	portID,
+	channelID string,
+) error {
+	return nil
+}
+
+// OnChanCloseInit implements the IBCModule interface
+func (im IBCModule) OnChanCloseInit(
+	ctx sdk.Context,
+	portID,
+	channelID string,
+) error {
+	// Disallow user-initiated channel closing for transfer channels
+	return sdkerrors.Wrap(sdkerrors.ErrInvalidRequest, "user cannot close channel")
+}
+
+// OnChanCloseConfirm implements the IBCModule interface
+func (im IBCModule) OnChanCloseConfirm(
+	ctx sdk.Context,
+	portID,
+	channelID string,
+) error {
+	return nil
+}
+
+// OnRecvPacket implements the IBCModule interface. A successful acknowledgement
+// is returned if the packet data is succesfully decoded and the receive application
+// logic returns without error.
+func (im IBCModule) OnRecvPacket(
+	ctx sdk.Context,
+	packet channeltypes.Packet,
+	relayer sdk.AccAddress,
+) ibcexported.Acknowledgement {
+	ack := channeltypes.NewResultAcknowledgement([]byte{byte(1)})
+
+	var data types.FungibleTokenPacketData
+	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
+		ack = channeltypes.NewErrorAcknowledgement("cannot unmarshal ICS-20 transfer packet data")
+	}
+
+	// only attempt the application logic if the packet data
+	// was successfully decoded
+	if ack.Success() {
+		err := im.keeper.OnRecvPacket(ctx, packet, data)
+		if err != nil {
+			ack = channeltypes.NewErrorAcknowledgement(err.Error())
+		}
+	}
+
+	ctx.EventManager().EmitEvent(
+		sdk.NewEvent(
+			types.EventTypePacket,
+			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
+			sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
+			sdk.NewAttribute(types.AttributeKeyDenom, data.Denom),
+			sdk.NewAttribute(types.AttributeKeyAmount, data.Amount),
+			sdk.NewAttribute(types.AttributeKeyAckSuccess, fmt.Sprintf("%t", ack.Success())),
+		),
+	)
+
+	// NOTE: acknowledgement will be written synchronously during IBC handler execution.
+	return ack
+}
+
+// OnAcknowledgementPacket implements the IBCModule interface
+func (im IBCModule) OnAcknowledgementPacket(
+	ctx sdk.Context,
+	packet channeltypes.Packet,
+	acknowledgement []byte,
+	relayer sdk.AccAddress,
+) error {
+	var ack channeltypes.Acknowledgement
+	if err := types.ModuleCdc.UnmarshalJSON(acknowledgement, &ack); err != nil {
+		return sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet acknowledgement: %v", err)
+	}
+	var data types.FungibleTokenPacketData
+	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
+		return sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet data: %s", err.Error())
+	}
+
+	if err := im.keeper.OnAcknowledgementPacket(ctx, packet, data, ack); err != nil {
+		return err
+	}
+
+	ctx.EventManager().EmitEvent(
+		sdk.NewEvent(
+			types.EventTypePacket,
+			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
+			sdk.NewAttribute(types.AttributeKeyReceiver, data.Receiver),
+			sdk.NewAttribute(types.AttributeKeyDenom, data.Denom),
+			sdk.NewAttribute(types.AttributeKeyAmount, data.Amount),
+			sdk.NewAttribute(types.AttributeKeyAck, ack.String()),
+		),
+	)
+
+	switch resp := ack.Response.(type) {
+	case *channeltypes.Acknowledgement_Result:
+		ctx.EventManager().EmitEvent(
+			sdk.NewEvent(
+				types.EventTypePacket,
+				sdk.NewAttribute(types.AttributeKeyAckSuccess, string(resp.Result)),
+			),
+		)
+	case *channeltypes.Acknowledgement_Error:
+		ctx.EventManager().EmitEvent(
+			sdk.NewEvent(
+				types.EventTypePacket,
+				sdk.NewAttribute(types.AttributeKeyAckError, resp.Error),
+			),
+		)
+	}
+
+	return nil
+}
+
+// OnTimeoutPacket implements the IBCModule interface
+func (im IBCModule) OnTimeoutPacket(
+	ctx sdk.Context,
+	packet channeltypes.Packet,
+	relayer sdk.AccAddress,
+) error {
+	var data types.FungibleTokenPacketData
+	if err := types.ModuleCdc.UnmarshalJSON(packet.GetData(), &data); err != nil {
+		return sdkerrors.Wrapf(sdkerrors.ErrUnknownRequest, "cannot unmarshal ICS-20 transfer packet data: %s", err.Error())
+	}
+	// refund tokens
+	if err := im.keeper.OnTimeoutPacket(ctx, packet, data); err != nil {
+		return err
+	}
+
+	ctx.EventManager().EmitEvent(
+		sdk.NewEvent(
+			types.EventTypeTimeout,
+			sdk.NewAttribute(sdk.AttributeKeyModule, types.ModuleName),
+			sdk.NewAttribute(types.AttributeKeyRefundReceiver, data.Sender),
+			sdk.NewAttribute(types.AttributeKeyRefundDenom, data.Denom),
+			sdk.NewAttribute(types.AttributeKeyRefundAmount, data.Amount),
+		),
+	)
+
+	return nil
+}
+
+// NegotiateAppVersion implements the IBCModule interface
+func (im IBCModule) NegotiateAppVersion(
+	ctx sdk.Context,
+	order channeltypes.Order,
+	connectionID string,
+	portID string,
+	counterparty channeltypes.Counterparty,
+	proposedVersion string,
+) (string, error) {
+	if proposedVersion != types.Version {
+		return "", sdkerrors.Wrapf(types.ErrInvalidVersion, "failed to negotiate app version: expected %s, got %s", types.Version, proposedVersion)
+	}
+
+	return types.Version, nil
+}