initial refactor sketch

internal/x/paychan/README.md

@@ -4,12 +4,7 @@ Simplifications:
 
  - unidirectional paychans
  - no top ups or partial withdrawals (only opening and closing)
- - no protection against fund lock up from dissapearing receiver
 
 
  TODO
-  - fix issue with multisig accounts and sequence numbers
+ - chnge module name to "channel"?
-  - create a nicer paychan store key for querying (and implement query)
-  - expand client code
-  - tidy up - add return tags
-  - start removing simplifications, refactor

internal/x/paychan/client/cmd/cmd.go

@@ -33,6 +33,7 @@ import (
 // send paychan payment
 // get balance from receiver
 
+/*
 func CreatePaychanCmd(cdc *wire.Codec) *cobra.Command {
 	flagTo := "to"
 	flagAmount := "amount"
@@ -297,3 +298,4 @@ func EnsureSignBuild(ctx context.CoreContext, name string, msg sdk.Msg, cdc *wir
 	}
 	return txBytes, nil
 }
+*/

internal/x/paychan/client/rest/rest.go

@@ -7,6 +7,7 @@ import (
 	//"github.com/cosmos/cosmos-sdk/wire"
 )
 
+/*
 // RegisterRoutes registers paychan-related REST handlers to a router
 func RegisterRoutes(ctx context.CoreContext, r *mux.Router, cdc *wire.Codec, kb keys.Keybase) {
 	//r.HandleFunc("/accounts/{address}/send", SendRequestHandlerFn(cdc, kb, ctx)).Methods("POST")
@@ -20,3 +21,4 @@ func RegisterRoutes(ctx context.CoreContext, r *mux.Router, cdc *wire.Codec, kb
 // get balance from receiver
 // get balance from local storage
 // handle incoming payment
+*/

internal/x/paychan/endblocker.go

@@ -0,0 +1,13 @@
+package paychan
+
+import ()
+
+func EndBlocker(ctx sdk.Context k Keeper) sdk.Tags {
+
+	// Iterate through submittedUpdates and for each
+	//		if current block height >= executionDate
+	//			k.CloseChannel(...)
+
+	tags := sdk.NewTags()
+	return tags
+}

internal/x/paychan/handler.go

@@ -12,8 +12,8 @@ func NewHandler(k Keeper) sdk.Handler {
 		switch msg := msg.(type) {
 		case MsgCreate:
 			return handleMsgCreate(ctx, k, msg)
-		case MsgClose:
+		case MsgSubmitUpdate:
-			return handleMsgClose(ctx, k, msg)
+			return handleMsgSubmitUpdate(ctx, k, msg)
 		default:
 			errMsg := "Unrecognized paychan Msg type: " + reflect.TypeOf(msg).Name()
 			return sdk.ErrUnknownRequest(errMsg).Result()
@@ -21,11 +21,10 @@ func NewHandler(k Keeper) sdk.Handler {
 	}
 }
 
-// Handle CreateMsg.
+// Handle MsgCreate
 // Leaves validation to the keeper methods.
 func handleMsgCreate(ctx sdk.Context, k Keeper, msg MsgCreate) sdk.Result {
-	// TODO maybe remove tags for first version
+	tags, err := k.CreateChannel(ctx, msg.Participants[0], msg.Participants[len(msg.Participants)-1], msg.Coins)
-	tags, err := k.CreatePaychan(ctx, msg.Sender, msg.Receiver, msg.Amount)
 	if err != nil {
 		return err.Result()
 	}
@@ -35,15 +34,19 @@ func handleMsgCreate(ctx sdk.Context, k Keeper, msg MsgCreate) sdk.Result {
 	}
 }
 
-// Handle CloseMsg.
+// Handle MsgSubmitUpdate
 // Leaves validation to the keeper methods.
-func handleMsgClose(ctx sdk.Context, k Keeper, msg MsgClose) sdk.Result {
+func handleMsgSubmitUpdate(ctx sdk.Context, k Keeper, msg MsgSubmitUpdate) sdk.Result {
-	// TODO maybe remove tags for first version
+
-	tags, err := k.ClosePaychan(ctx, msg.Sender, msg.Receiver, msg.Id, msg.ReceiverAmount)
+	// if only sender sig then
+	tags, err := k.InitChannelCloseBySender()
+	// else (if there are both)
+	tags, err := k.ChannelCloseByReceiver()
+
 	if err != nil {
 		return err.Result()
 	}
-	// These tags can be used to subscribe to channel closures
+	// These tags can be used by clients to subscribe to channel close attempts
 	return sdk.Result{
 		Tags: tags,
 	}

internal/x/paychan/keeper.go

@@ -8,20 +8,19 @@ import (
 	"github.com/cosmos/cosmos-sdk/x/bank"
 )
 
-// keeper of the paychan store
+// Keeper of the paychan store
 // Handles validation internally. Does not rely on calling code to do validation.
-// Aim to keep public methids safe, private ones not necessaily.
+// Aim to keep public methods safe, private ones not necessaily.
 type Keeper struct {
 	storeKey   sdk.StoreKey
 	cdc        *wire.Codec // needed to serialize objects before putting them in the store
 	coinKeeper bank.Keeper
 
-	// codespace
+	// TODO investigate codespace
-	//codespace sdk.CodespaceType // ??
+	//codespace sdk.CodespaceType
 }
 
 // Called when creating new app.
-//func NewKeeper(cdc *wire.Codec, key sdk.StoreKey, ck bank.Keeper, codespace sdk.CodespaceType) Keeper {
 func NewKeeper(cdc *wire.Codec, key sdk.StoreKey, ck bank.Keeper) Keeper {
 	keeper := Keeper{
 		storeKey:   key,
@@ -33,7 +32,7 @@ func NewKeeper(cdc *wire.Codec, key sdk.StoreKey, ck bank.Keeper) Keeper {
 }
 
 // bunch of business logic ...
-
+/*
 // Reteive a payment channel struct from the blockchain store.
 // They are indexed by a concatenation of sender address, receiver address, and an integer.
 func (k Keeper) GetPaychan(ctx sdk.Context, sender sdk.Address, receiver sdk.Address, id int64) (Paychan, bool) {
@@ -60,60 +59,91 @@ func (k Keeper) setPaychan(ctx sdk.Context, pych Paychan) {
 	pychKey := paychanKey(pych.Sender, pych.Receiver, pych.Id)
 	store.Set(pychKey, bz) // panics if something goes wrong
 }
+*/
 
 // Create a new payment channel and lock up sender funds.
-func (k Keeper) CreatePaychan(ctx sdk.Context, sender sdk.Address, receiver sdk.Address, amount sdk.Coins) (sdk.Tags, sdk.Error) {
+func (k Keeper) CreatePaychan(ctx sdk.Context, sender sdk.Address, receiver sdk.Address, coins sdk.Coins) (sdk.Tags, sdk.Error) {
-	// TODO move validation somewhere nicer
+	// TODO do validation and maybe move somewhere nicer
-	// args present
+	/*
-	if len(sender) == 0 {
+		// args present
-		return nil, sdk.ErrInvalidAddress(sender.String())
+		if len(sender) == 0 {
-	}
+			return nil, sdk.ErrInvalidAddress(sender.String())
-	if len(receiver) == 0 {
+		}
-		return nil, sdk.ErrInvalidAddress(receiver.String())
+		if len(receiver) == 0 {
-	}
+			return nil, sdk.ErrInvalidAddress(receiver.String())
-	if len(amount) == 0 {
+		}
-		return nil, sdk.ErrInvalidCoins(amount.String())
+		if len(amount) == 0 {
-	}
+			return nil, sdk.ErrInvalidCoins(amount.String())
-	// Check if coins are sorted, non zero, positive
+		}
-	if !amount.IsValid() {
+		// Check if coins are sorted, non zero, positive
-		return nil, sdk.ErrInvalidCoins(amount.String())
+		if !amount.IsValid() {
-	}
+			return nil, sdk.ErrInvalidCoins(amount.String())
-	if !amount.IsPositive() {
+		}
-		return nil, sdk.ErrInvalidCoins(amount.String())
+		if !amount.IsPositive() {
-	}
+			return nil, sdk.ErrInvalidCoins(amount.String())
-	// sender should exist already as they had to sign.
+		}
-	// receiver address exists. am is the account mapper in the coin keeper.
+		// sender should exist already as they had to sign.
-	// TODO automatically create account if not present?
+		// receiver address exists. am is the account mapper in the coin keeper.
-	// TODO remove as account mapper not available to this pkg
+		// TODO automatically create account if not present?
-	//if k.coinKeeper.am.GetAccount(ctx, receiver) == nil {
+		// TODO remove as account mapper not available to this pkg
-	//	return nil, sdk.ErrUnknownAddress(receiver.String())
+		//if k.coinKeeper.am.GetAccount(ctx, receiver) == nil {
-	//}
+		//	return nil, sdk.ErrUnknownAddress(receiver.String())
+		//}
 
-	// sender has enough coins - done in Subtract method
+		// sender has enough coins - done in Subtract method
-	// TODO check if sender and receiver different?
+		// TODO check if sender and receiver different?
+	*/
 
-	// Calculate next id (just num of existing paychans - zero indexed)
+	// Calculate next id
-	id := int64(len(k.GetPaychans(sender, receiver)))
+	id := k.getNewChannelID(ctx)
 	// subtract coins from sender
-	_, tags, err := k.coinKeeper.SubtractCoins(ctx, sender, amount)
+	_, tags, err := k.coinKeeper.SubtractCoins(ctx, sender, coins)
 	if err != nil {
 		return nil, err
 	}
 	// create new Paychan struct
-	pych := Paychan{
+	channel := Channel{
-		Sender:   sender,
+		ID: id
-		Receiver: receiver,
+		Participants:	[2]sdk.AccAddress{sender, receiver},
-		Id:       id,
+		Coins:  coins,
-		Balance:  amount,
 	}
 	// save to db
-	k.setPaychan(ctx, pych)
+	k.setChannel(ctx, channel)
 
 	// TODO create tags
 	//tags := sdk.NewTags()
 	return tags, err
 }
 
+/* This is how gov manages creating unique IDs. Needs to be deterministic - can't use UUID
+func (keeper Keeper) getNewChannelID(ctx sdk.Context) (channelID int64, err sdk.Error) {
+	store := ctx.KVStore(keeper.storeKey)
+	bz := store.Get(KeyNextProposalID)
+	if bz == nil {
+		return -1, ErrInvalidGenesis(keeper.codespace, "InitialProposalID never set")
+	}
+	keeper.cdc.MustUnmarshalBinary(bz, &proposalID)
+	bz = keeper.cdc.MustMarshalBinary(proposalID + 1)
+	store.Set(KeyNextProposalID, bz)
+	return proposalID, nil
+*/
+
+func (k Keeper) ChannelCloseByReceiver() () {
+	// Validate inputs
+	// k.closeChannel
+}
+
+func (k Keeper) InitChannelCloseBySender() () {
+	// Validate inputs
+	// Create SubmittedUpdate from Update and add to queue
+}
+
+func (k Keeper) closeChannel() () {
+	// Remove corresponding SubmittedUpdate from queue (if it exist)
+	// Add coins to sender and receiver
+	// Delete Channel
+}
+/*
 // Close a payment channel and distribute funds to participants.
 func (k Keeper) ClosePaychan(ctx sdk.Context, sender sdk.Address, receiver sdk.Address, id int64, receiverAmount sdk.Coins) (sdk.Tags, sdk.Error) {
 	if len(sender) == 0 {
@@ -190,3 +220,4 @@ func (k Keeper) GetPaychans(sender sdk.Address, receiver sdk.Address) []Paychan
 }
 
 // maybe getAllPaychans(sender sdk.address) []Paychan
+*/

internal/x/paychan/types.go

@@ -5,81 +5,91 @@ import (
 	"strconv"
 )
 
-// Paychan Type
+/*  CHANNEL TYPES  */
-// Used to represent paychan in keeper module and to serialize.
+
-// probably want to convert this to a general purpose "state"
+// Used to represent a channel in the keeper module.
-type Paychan struct {
+// Participants is limited to two as currently these are unidirectional channels.
-	Sender   sdk.Address
+// Last participant is designated as receiver.
-	Receiver sdk.Address
+type Channel struct {
-	Id       int64
+	ID       int64
-	Balance  sdk.Coins
+	Participants [2]sdk.AccAddress
+	Coins  sdk.Coins
 }
 
-// Message Types
+// The data that is passed between participants as payments, and submitted to the blockchain to close a channel.
+type Update struct {
+	ChannelID int64
+	CoinsUpdate //TODO type
+	Sequence int64
+	sig // TODO type, only sender needs to sign
+}
 
-// Message implement the sdk.Msg interface:
+// An update that has been submitted to the blockchain, but not yet acted on.
+type SubmittedUpdate {
+	Update
+	executionDate int64 // BlockHeight
+}
 
-// type Msg interface {
+/*  MESSAGE TYPES  */
+/*
+Message implement the sdk.Msg interface:
+type Msg interface {
 
-// 	// Return the message type.
+	// Return the message type.
-// 	// Must be alphanumeric or empty.
+	// Must be alphanumeric or empty.
-// 	Type() string
+	Type() string
 
-// 	// Get the canonical byte representation of the Msg.
+	// Get the canonical byte representation of the Msg.
-// 	GetSignBytes() []byte
+	GetSignBytes() []byte
 
-// 	// ValidateBasic does a simple validation check that
+	// ValidateBasic does a simple validation check that
-// 	// doesn't require access to any other information.
+	// doesn't require access to any other information.
-// 	ValidateBasic() Error
+	ValidateBasic() Error
 
-// 	// Signers returns the addrs of signers that must sign.
+	// Signers returns the addrs of signers that must sign.
-// 	// CONTRACT: All signatures must be present to be valid.
+	// CONTRACT: All signatures must be present to be valid.
-// 	// CONTRACT: Returns addrs in some deterministic order.
+	// CONTRACT: Returns addrs in some deterministic order.
-// 	GetSigners() []Address
+	GetSigners() []Address
-// }
+}
+*/
 
 // A message to create a payment channel.
 type MsgCreate struct {
-	// maybe just wrap a paychan struct
+	Participants	[2]sdk.AccAddress
-	Sender   sdk.Address
+	Coins	sdk.Coins
-	Receiver sdk.Address
-	Amount   sdk.Coins
 }
 
-// Create a new message.
+//Create a new message.
-// Called in client code when constructing transaction from cli args to send to the network.
+/*
-// maybe just a placeholder for more advanced future functionality?
+Called in client code when constructing transaction from cli args to send to the network.
-// func (msg CreatMsg) NewMsgCreate(sender sdk.Address, receiver sdk.Address, amount sdk.Coins) MsgCreate {
+maybe just a placeholder for more advanced future functionality?
-// 	return MsgCreate{
+func (msg CreatMsg) NewMsgCreate(sender sdk.Address, receiver sdk.Address, amount sdk.Coins) MsgCreate {
-// 		sender
+	return MsgCreate{
-// 		receiver
+		sender
-// 		amount
+		receiver
-// 	}
+		amount
-// }
+	}
+}
+*/
 
 func (msg MsgCreate) Type() string { return "paychan" }
 
 func (msg MsgCreate) GetSignBytes() []byte {
 	// TODO create msgCdc in wire.go
-	b, err := msgCdc.MarshalJSON(struct {
+	bz, err := msgCdc.Marshal(msg)
-		SenderAddr   string    `json:"sender_addr"`
-		ReceiverAddr string    `json:"receiver_addr"`
-		Amount       sdk.Coins `json:"amount"`
-	}{
-		SenderAddr:   sdk.MustBech32ifyAcc(msg.Sender),
-		ReceiverAddr: sdk.MustBech32ifyAcc(msg.Receiver),
-		Amount:       msg.Amount,
-	})
 	if err != nil {
 		panic(err)
 	}
-	return b
+	return MustSortJSON(bz)
 }
 
 func (msg MsgCreate) ValidateBasic() sdk.Error {
 	// Validate msg as an optimisation to avoid all validation going to keeper. It's run before the sigs are checked by the auth module.
 	// Validate without external information (such as account balance)
 
+	//TODO implement
+
+	/*
 	// check if all fields present / not 0 valued
 	if len(msg.Sender) == 0 {
 		return sdk.ErrInvalidAddress(msg.Sender.String())
@@ -98,55 +108,42 @@ func (msg MsgCreate) ValidateBasic() sdk.Error {
 		return sdk.ErrInvalidCoins(msg.Amount.String())
 	}
 	// TODO check if Address valid?
+	*/
 	return nil
 }
 
 func (msg MsgCreate) GetSigners() []sdk.Address {
 	// Only sender must sign to create a paychan
-	return []sdk.Address{msg.Sender}
+	return []sdk.AccAddress{msg.Participants[0]} // select sender address
 }
 
 // A message to close a payment channel.
-type MsgClose struct {
+type MsgSubmitUpdate struct {
-	// have to include sender and receiver in msg explicitly (rather than just universal paychanID)
+	Update
-	//  this gives ability to verify signatures with no external information
+	// might need a "signer" to be able to say who is signing this as either can or not
-	Sender         sdk.Address
-	Receiver       sdk.Address
-	Id             int64     // TODO is another int type better?
-	ReceiverAmount sdk.Coins // amount the receiver should get - sender amount implicit with paychan balance
 }
 
-// func (msg MsgClose) NewMsgClose(sender sdk.Address, receiver sdk.Address, id integer, receiverAmount sdk.Coins) MsgClose {
+// func (msg MsgSubmitUpdate) NewMsgSubmitUpdate(update Update) MsgSubmitUpdate {
-// 	return MsgClose{
+// 	return MsgSubmitUpdate{
-// 		sender
+// 		update
-// 		receiver
-// 		id
-// 		receiverAmount
 // 	}
 // }
 
-func (msg MsgClose) Type() string { return "paychan" }
+func (msg MsgSubmitUpdate) Type() string { return "paychan" }
 
-func (msg MsgClose) GetSignBytes() []byte {
+func (msg MsgSubmitUpdate) GetSignBytes() []byte {
 	// TODO create msgCdc in wire.go
-	b, err := msgCdc.MarshalJSON(struct {
+	bz, err := msgCdc.Marshal(msg)
-		SenderAddr     string    `json:"sender_addr"`
-		ReceiverAddr   string    `json:"receiver_addr"`
-		Id             int64     `json:"id"`
-		ReceiverAmount sdk.Coins `json:"receiver_amount"`
-	}{
-		SenderAddr:     sdk.MustBech32ifyAcc(msg.Sender),
-		ReceiverAddr:   sdk.MustBech32ifyAcc(msg.Receiver),
-		Id:             msg.Id,
-		ReceiverAmount: msg.ReceiverAmount,
-	})
 	if err != nil {
 		panic(err)
 	}
-	return b
+	return MustSortJSON(bz)
 }
 
-func (msg MsgClose) ValidateBasic() sdk.Error {
+func (msg MsgSubmitUpdate) ValidateBasic() sdk.Error {
+
+	// TODO implement
+	/*
 	// check if all fields present / not 0 valued
 	if len(msg.Sender) == 0 {
 		return sdk.ErrInvalidAddress(msg.Sender.String())
@@ -169,10 +166,12 @@ func (msg MsgClose) ValidateBasic() sdk.Error {
 		return sdk.ErrInvalidCoins(msg.ReceiverAmount.String())
 	}
 	// TODO check if Address valid?
+	*/
 	return nil
 }
 
-func (msg MsgClose) GetSigners() []sdk.Address {
+func (msg MsgSubmitUpdate) GetSigners() []sdk.Address {
-	// Both sender and receiver must sign in order to close a channel
+	// Signing not strictly necessary as signatures contained within the channel update.
-	return []sdk.Address{msg.Sender, msg.Receiver}
+	// TODO add signature by submitting address
+	return []sdk.Address{}
 }

internal/x/paychan/wire.go

@@ -4,6 +4,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/wire"
 )
 
+/*
 func RegisterWire(cdc *wire.Codec) {
 	cdc.RegisterConcrete(MsgCreate{}, "paychan/MsgCreate", nil)
 	cdc.RegisterConcrete(MsgClose{}, "paychan/MsgClose", nil)
@@ -16,3 +17,4 @@ func init() {
 	// TODO is this needed?
 	//wire.RegisterCrypto(msgCdc)
 }
+*/