72 lines
2.6 KiB
Go
72 lines
2.6 KiB
Go
/*
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Package neptoken contains RPC wrapper for common NEP-11 and NEP-17 methods.
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All of these methods are safe, read-only.
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*/
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package neptoken
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import (
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"math/big"
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"github.com/nspcc-dev/neo-go/pkg/neorpc/result"
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"github.com/nspcc-dev/neo-go/pkg/rpcclient/unwrap"
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"github.com/nspcc-dev/neo-go/pkg/util"
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)
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const (
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// MaxValidDecimals is the maximum value 'decimals' contract method can
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// return to be considered as valid. It's log10(2^256), higher values
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// don't make any sense on a VM with 256-bit integers. This restriction
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// is not imposed by NEP-17 or NEP-11, but we do it as a sanity check
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// anyway (and return plain int as a result).
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MaxValidDecimals = 77
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)
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// Invoker is used by Base to call various methods.
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type Invoker interface {
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Call(contract util.Uint160, operation string, params ...interface{}) (*result.Invoke, error)
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}
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// Base is a reader interface for common NEP-11 and NEP-17 methods built
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// on top of Invoker.
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type Base struct {
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invoker Invoker
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hash util.Uint160
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}
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// New creates an instance of Base for contract with the given hash using the
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// given invoker.
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func New(invoker Invoker, hash util.Uint160) *Base {
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return &Base{invoker, hash}
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}
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// Decimals implements `decimals` NEP-17 or NEP-11 method and returns the number
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// of decimals used by token. For non-divisible NEP-11 tokens this method always
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// returns zero. Values less than 0 or more than MaxValidDecimals are considered
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// to be invalid (with an appropriate error) even if returned by the contract.
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func (b *Base) Decimals() (int, error) {
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r, err := b.invoker.Call(b.hash, "decimals")
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dec, err := unwrap.LimitedInt64(r, err, 0, MaxValidDecimals)
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return int(dec), err
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}
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// Symbol implements `symbol` NEP-17 or NEP-11 method and returns a short token
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// identifier (like "NEO" or "GAS").
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func (b *Base) Symbol() (string, error) {
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return unwrap.PrintableASCIIString(b.invoker.Call(b.hash, "symbol"))
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}
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// TotalSupply returns the total token supply currently available (the amount
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// of minted tokens).
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func (b *Base) TotalSupply() (*big.Int, error) {
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return unwrap.BigInt(b.invoker.Call(b.hash, "totalSupply"))
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}
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// BalanceOf returns the token balance of the given account. For NEP-17 that's
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// the token balance with decimals (1 TOK with 2 decimals will lead to 100
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// returned from this method). For non-divisible NEP-11 that's the number of
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// NFTs owned by the account, for divisible NEP-11 that's the sum of the parts
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// of all NFTs owned by the account.
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func (b *Base) BalanceOf(account util.Uint160) (*big.Int, error) {
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return unwrap.BigInt(b.invoker.Call(b.hash, "balanceOf", account))
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}
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