forked from TrueCloudLab/neoneo-go
113 lines
2.5 KiB
Go
113 lines
2.5 KiB
Go
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package nep5
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import (
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"github.com/CityOfZion/neo-storm/interop/engine"
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"github.com/CityOfZion/neo-storm/interop/runtime"
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"github.com/CityOfZion/neo-storm/interop/storage"
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)
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// Token holds all token info
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type Token struct {
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// Token name
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Name string
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// Ticker symbol
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Symbol string
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// Amount of decimals
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Decimals int
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// Token owner address
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Owner []byte
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// Total tokens * multiplier
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TotalSupply int
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// Storage key for circulation value
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CirculationKey string
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}
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// GetSupply gets the token totalSupply value from VM storage
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func (t Token) GetSupply(ctx storage.Context) interface{} {
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return storage.Get(ctx, t.CirculationKey)
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}
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// BalanceOf gets the token balance of a specific address
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func (t Token) BalanceOf(ctx storage.Context, hodler []byte) interface{} {
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return storage.Get(ctx, hodler)
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}
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// Transfer token from one user to another
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func (t Token) Transfer(ctx storage.Context, from []byte, to []byte, amount int) bool {
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amountFrom := t.CanTransfer(ctx, from, to, amount)
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if amountFrom == -1 {
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return false
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}
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if amountFrom == 0 {
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storage.Delete(ctx, from)
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}
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if amountFrom > 0 {
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diff := amountFrom - amount
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storage.Put(ctx, from, diff)
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}
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amountTo := storage.Get(ctx, to).(int)
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totalAmountTo := amountTo + amount
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storage.Put(ctx, to, totalAmountTo)
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runtime.Notify("transfer", from, to, amount)
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return true
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}
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// CanTransfer returns the amount it can transfer
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func (t Token) CanTransfer(ctx storage.Context, from []byte, to []byte, amount int) int {
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if len(to) != 20 && !IsUsableAddress(from) {
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return -1
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}
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amountFrom := storage.Get(ctx, from).(int)
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if amountFrom < amount {
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return -1
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}
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// Tell Transfer the result is equal - special case since it uses Delete
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if amountFrom == amount {
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return 0
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}
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// return amountFrom value back to Transfer, reduces extra Get
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return amountFrom
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}
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// IsUsableAddress checks if the sender is either the correct NEO address or SC address
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func IsUsableAddress(addr []byte) bool {
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if len(addr) == 20 {
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if runtime.CheckWitness(addr) {
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return true
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}
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// Check if a smart contract is calling scripthash
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callingScriptHash := engine.GetCallingScriptHash()
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if EqualAddresses(callingScriptHash, addr) {
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return true
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}
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}
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return false
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}
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// EqualAddresses compares two addresses if they're equal
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// also returns false if one of the two - or both - aren't actual addresses
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func EqualAddresses(a []byte, b []byte) bool {
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aLen := len(a)
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bLen := len(b)
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if aLen != bLen || aLen != 20 || bLen != 20 {
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return false
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}
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for i := 0; i < aLen; i++ {
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if a[i] != b[i] {
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return false
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}
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}
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return true
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}
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