neo-go/pkg/rpc/request/param.go

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package request
import (
"bytes"
"encoding/hex"
"encoding/json"
"fmt"
"strconv"
"github.com/nspcc-dev/neo-go/pkg/core/transaction"
"github.com/nspcc-dev/neo-go/pkg/encoding/address"
"github.com/nspcc-dev/neo-go/pkg/smartcontract"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/pkg/errors"
)
type (
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// Param represents a param either passed to
// the server or to send to a server using
// the client.
Param struct {
Type paramType
Value interface{}
}
paramType int
// FuncParam represents a function argument parameter used in the
// invokefunction RPC method.
FuncParam struct {
Type smartcontract.ParamType `json:"type"`
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Value Param `json:"value"`
}
// TxFilter is a wrapper structure for transaction event filter. The only
// allowed filter is a transaction type for now.
TxFilter struct {
Type transaction.TXType `json:"type"`
}
// NotificationFilter is a wrapper structure representing filter used for
// notifications generated during transaction execution. Notifications can
// only be filtered by contract hash.
NotificationFilter struct {
Contract util.Uint160 `json:"contract"`
}
// ExecutionFilter is a wrapper structure used for transaction execution
// events. It allows to choose failing or successful transactions based
// on their VM state.
ExecutionFilter struct {
State string `json:"state"`
}
)
// These are parameter types accepted by RPC server.
const (
defaultT paramType = iota
StringT
NumberT
ArrayT
FuncParamT
TxFilterT
NotificationFilterT
ExecutionFilterT
)
var errMissingParameter = errors.New("parameter is missing")
func (p Param) String() string {
return fmt.Sprintf("%v", p.Value)
}
// GetString returns string value of the parameter.
func (p *Param) GetString() (string, error) {
if p == nil {
return "", errMissingParameter
}
str, ok := p.Value.(string)
if !ok {
return "", errors.New("not a string")
}
return str, nil
}
// GetInt returns int value of te parameter.
func (p *Param) GetInt() (int, error) {
if p == nil {
return 0, errMissingParameter
}
i, ok := p.Value.(int)
if ok {
return i, nil
} else if s, ok := p.Value.(string); ok {
return strconv.Atoi(s)
}
return 0, errors.New("not an integer")
}
// GetArray returns a slice of Params stored in the parameter.
func (p *Param) GetArray() ([]Param, error) {
if p == nil {
return nil, errMissingParameter
}
a, ok := p.Value.([]Param)
if !ok {
return nil, errors.New("not an array")
}
return a, nil
}
// GetUint256 returns Uint256 value of the parameter.
func (p *Param) GetUint256() (util.Uint256, error) {
s, err := p.GetString()
if err != nil {
return util.Uint256{}, err
}
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return util.Uint256DecodeStringLE(s)
}
// GetUint160FromHex returns Uint160 value of the parameter encoded in hex.
func (p *Param) GetUint160FromHex() (util.Uint160, error) {
s, err := p.GetString()
if err != nil {
return util.Uint160{}, err
}
if len(s) == 2*util.Uint160Size+2 && s[0] == '0' && s[1] == 'x' {
s = s[2:]
}
return util.Uint160DecodeStringLE(s)
}
// GetUint160FromAddress returns Uint160 value of the parameter that was
// supplied as an address.
func (p *Param) GetUint160FromAddress() (util.Uint160, error) {
s, err := p.GetString()
if err != nil {
return util.Uint160{}, err
}
return address.StringToUint160(s)
}
// GetFuncParam returns current parameter as a function call parameter.
func (p *Param) GetFuncParam() (FuncParam, error) {
if p == nil {
return FuncParam{}, errMissingParameter
}
fp, ok := p.Value.(FuncParam)
if !ok {
return FuncParam{}, errors.New("not a function parameter")
}
return fp, nil
}
// GetBytesHex returns []byte value of the parameter if
// it is a hex-encoded string.
func (p *Param) GetBytesHex() ([]byte, error) {
s, err := p.GetString()
if err != nil {
return nil, err
}
return hex.DecodeString(s)
}
// UnmarshalJSON implements json.Unmarshaler interface.
func (p *Param) UnmarshalJSON(data []byte) error {
var s string
var num float64
// To unmarshal correctly we need to pass pointers into the decoder.
var attempts = [...]Param{
{NumberT, &num},
{StringT, &s},
{FuncParamT, &FuncParam{}},
{TxFilterT, &TxFilter{}},
{NotificationFilterT, &NotificationFilter{}},
{ExecutionFilterT, &ExecutionFilter{}},
{ArrayT, &[]Param{}},
}
for _, cur := range attempts {
r := bytes.NewReader(data)
jd := json.NewDecoder(r)
jd.DisallowUnknownFields()
if err := jd.Decode(cur.Value); err == nil {
p.Type = cur.Type
// But we need to store actual values, not pointers.
switch val := cur.Value.(type) {
case *float64:
p.Value = int(*val)
case *string:
p.Value = *val
case *FuncParam:
p.Value = *val
case *TxFilter:
p.Value = *val
case *NotificationFilter:
p.Value = *val
case *ExecutionFilter:
if (*val).State == "HALT" || (*val).State == "FAULT" {
p.Value = *val
} else {
continue
}
case *[]Param:
p.Value = *val
}
return nil
}
}
return errors.New("unknown type")
}