update/finish app1 go and md
This commit is contained in:
Ethan Buchman
parent
354f9760f8
commit
fc81c14a16
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@ -243,7 +243,7 @@ Note this handler has unfettered access to the store specified by the capability
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For this first example, we will define a simple account that is JSON encoded:
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```go
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type acc struct {
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type app1Account struct {
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Coins sdk.Coins `json:"coins"`
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}
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```
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@ -256,35 +256,105 @@ Now we're ready to handle the MsgSend:
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```go
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// Handle MsgSend.
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// NOTE: msg.From, msg.To, and msg.Amount were already validated
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func handleMsgSend(ctx sdk.Context, key *sdk.KVStoreKey, msg MsgSend) sdk.Result {
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// NOTE: from, to, and amount were already validated
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// Load the store.
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store := ctx.KVStore(key)
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bz := store.Get(msg.From)
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if bz == nil {
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// TODO
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// Debit from the sender.
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if res := handleFrom(store, msg.From, msg.Amount); !res.IsOK() {
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return res
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}
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var acc acc
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err := json.Unmarshal(bz, &acc)
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if err != nil {
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// InternalError
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// Credit the receiver.
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if res := handleTo(store, msg.To, msg.Amount); !res.IsOK() {
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return res
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}
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// TODO: finish the logic
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// Return a success (Code 0).
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// Add list of key-value pair descriptors ("tags").
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return sdk.Result{
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// TODO: Tags
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Tags: msg.Tags(),
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}
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}
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```
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The handler is straight forward:
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The handler is straight forward. We first load the KVStore from the context using the granted capability key.
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Then we make two state transitions: one for the sender, one for the receiver.
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Each one involves JSON unmarshalling the account bytes from the store, mutating
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the `Coins`, and JSON marshalling back into the store:
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- get the KVStore from the context using the granted capability key
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- lookup the From address in the KVStore, and JSON unmarshal it into an `acc`,
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- check that the account balance is greater than the `msg.Amount`
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- transfer the `msg.Amount`
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```go
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func handleFrom(store sdk.KVStore, from sdk.Address, amt sdk.Coins) sdk.Result {
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// Get sender account from the store.
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accBytes := store.Get(from)
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if accBytes == nil {
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// Account was not added to store. Return the result of the error.
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return sdk.NewError(2, 101, "Account not added to store").Result()
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}
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// Unmarshal the JSON account bytes.
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var acc app1Account
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err := json.Unmarshal(accBytes, &acc)
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if err != nil {
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// InternalError
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return sdk.ErrInternal("Error when deserializing account").Result()
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}
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// Deduct msg amount from sender account.
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senderCoins := acc.Coins.Minus(amt)
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// If any coin has negative amount, return insufficient coins error.
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if !senderCoins.IsNotNegative() {
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return sdk.ErrInsufficientCoins("Insufficient coins in account").Result()
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}
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// Set acc coins to new amount.
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acc.Coins = senderCoins
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// Encode sender account.
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accBytes, err = json.Marshal(acc)
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if err != nil {
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return sdk.ErrInternal("Account encoding error").Result()
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}
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// Update store with updated sender account
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store.Set(from, accBytes)
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return sdk.Result{}
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}
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func handleTo(store sdk.KVStore, to sdk.Address, amt sdk.Coins) sdk.Result {
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// Add msg amount to receiver account
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accBytes := store.Get(to)
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var acc app1Account
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if accBytes == nil {
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// Receiver account does not already exist, create a new one.
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acc = app1Account{}
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} else {
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// Receiver account already exists. Retrieve and decode it.
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err := json.Unmarshal(accBytes, &acc)
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if err != nil {
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return sdk.ErrInternal("Account decoding error").Result()
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}
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}
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// Add amount to receiver's old coins
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receiverCoins := acc.Coins.Plus(amt)
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// Update receiver account
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acc.Coins = receiverCoins
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// Encode receiver account
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accBytes, err := json.Marshal(acc)
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if err != nil {
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return sdk.ErrInternal("Account encoding error").Result()
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}
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// Update store with updated receiver account
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store.Set(to, accBytes)
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return sdk.Result{}
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}
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```
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And that's that!
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@ -96,6 +96,12 @@ func (msg MsgSend) GetSigners() []sdk.Address {
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return []sdk.Address{msg.From}
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}
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// Returns the sdk.Tags for the message
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func (msg MsgSend) Tags() sdk.Tags {
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return sdk.NewTags("sender", []byte(msg.From.String())).
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AppendTag("receiver", []byte(msg.To.String()))
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}
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//------------------------------------------------------------------
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// Handler for the message
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@ -112,78 +118,99 @@ func NewApp1Handler(keyAcc *sdk.KVStoreKey) sdk.Handler {
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}
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// Handle MsgSend.
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// NOTE: msg.From, msg.To, and msg.Amount were already validated
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func handleMsgSend(ctx sdk.Context, key *sdk.KVStoreKey, msg MsgSend) sdk.Result {
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// NOTE: from, to, and amount were already validated
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// Load the store.
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store := ctx.KVStore(key)
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// deduct msg amount from sender account
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bz := store.Get(msg.From)
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if bz == nil {
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// Debit from the sender.
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if res := handleFrom(store, msg.From, msg.Amount); !res.IsOK() {
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return res
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}
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// Credit the receiver.
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if res := handleTo(store, msg.To, msg.Amount); !res.IsOK() {
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return res
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}
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// Return a success (Code 0).
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// Add list of key-value pair descriptors ("tags").
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return sdk.Result{
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Tags: msg.Tags(),
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}
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}
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func handleFrom(store sdk.KVStore, from sdk.Address, amt sdk.Coins) sdk.Result {
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// Get sender account from the store.
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accBytes := store.Get(from)
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if accBytes == nil {
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// Account was not added to store. Return the result of the error.
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return sdk.NewError(2, 101, "Account not added to store").Result()
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}
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var acc account
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err := json.Unmarshal(bz, &acc)
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// Unmarshal the JSON account bytes.
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var acc app1Account
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err := json.Unmarshal(accBytes, &acc)
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if err != nil {
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// InternalError
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return sdk.ErrInternal("Error when deserializing account").Result()
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}
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// TODO: finish the logic
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senderCoins := acc.Coins.Minus(msg.Amount)
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// Deduct msg amount from sender account.
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senderCoins := acc.Coins.Minus(amt)
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// If any coin has negative amount, return insufficient coins error.
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if !senderCoins.IsNotNegative() {
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return sdk.ErrInsufficientCoins("Insufficient coins in account").Result()
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}
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// set acc coins to new amount
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// Set acc coins to new amount.
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acc.Coins = senderCoins
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// Encode sender account
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val, err := json.Marshal(acc)
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// Encode sender account.
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accBytes, err = json.Marshal(acc)
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if err != nil {
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return sdk.ErrInternal("Account encoding error").Result()
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}
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// Update store with updated sender account
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store.Set(msg.From, val)
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store.Set(from, accBytes)
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return sdk.Result{}
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}
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func handleTo(store sdk.KVStore, to sdk.Address, amt sdk.Coins) sdk.Result {
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// Add msg amount to receiver account
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bz = store.Get(msg.To)
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var acc2 account
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if bz == nil {
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accBytes := store.Get(to)
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var acc app1Account
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if accBytes == nil {
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// Receiver account does not already exist, create a new one.
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acc2 = account{}
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acc = app1Account{}
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} else {
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// Receiver account already exists. Retrieve and decode it.
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err = json.Unmarshal(bz, &acc2)
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err := json.Unmarshal(accBytes, &acc)
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if err != nil {
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return sdk.ErrInternal("Account decoding error").Result()
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}
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}
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// Add amount to receiver's old coins
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receiverCoins := acc2.Coins.Plus(msg.Amount)
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receiverCoins := acc.Coins.Plus(amt)
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// Update receiver account
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acc2.Coins = receiverCoins
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acc.Coins = receiverCoins
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// Encode receiver account
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val, err = json.Marshal(acc2)
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accBytes, err := json.Marshal(acc)
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if err != nil {
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return sdk.ErrInternal("Account encoding error").Result()
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}
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store.Set(msg.To, val)
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return sdk.Result{
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// TODO: Tags
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}
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// Update store with updated receiver account
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store.Set(to, accBytes)
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return sdk.Result{}
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}
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type account struct {
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type app1Account struct {
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Coins sdk.Coins `json:"coins"`
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}
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@ -200,11 +227,6 @@ func (tx app1Tx) GetMsgs() []sdk.Msg {
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return []sdk.Msg{tx.MsgSend}
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}
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// TODO: remove the need for this
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func (tx app1Tx) GetMemo() string {
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return ""
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}
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// JSON decode MsgSend.
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func txDecoder(txBytes []byte) (sdk.Tx, sdk.Error) {
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var tx app1Tx
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