224 lines
6.6 KiB
Go
224 lines
6.6 KiB
Go
package txscript
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import (
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"bytes"
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"fmt"
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"unicode/utf8"
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"github.com/btcsuite/btcd/wire"
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)
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const (
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// MinFeePerNameclaimChar is the minimum claim fee per character in the name of an OP_CLAIM_NAME
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// command that must be attached to transactions for it to be accepted into the memory pool.
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// Rationale: current implementation of the claim trie uses more memory for longer name claims
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// due to the fact that each chracater is assigned a trie node regardless of whether it contains
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// any claims or not. In the future, we can switch to a radix tree implementation where empty
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// nodes do not take up any memory and the minimum fee can be priced on a per claim basis.
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MinFeePerNameclaimChar int64 = 200000
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// MaxClaimScriptSize is the max claim script size in bytes, not including the script pubkey part of the script.
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MaxClaimScriptSize = 8192
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// MaxClaimNameSize is the max claim name size in bytes, for all claim trie transactions.
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MaxClaimNameSize = 255
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)
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var (
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// ErrNotClaimScript is returned when the script does not have a ClaimScript Opcode.
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ErrNotClaimScript = fmt.Errorf("not a claim script")
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// ErrInvalidClaimScript is returned when a script has a ClaimScript Opcode,
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// but does not conform to the format.
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ErrInvalidClaimScript = fmt.Errorf("invalid claim script")
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)
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// ClaimNameScript ...
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func ClaimNameScript(name string, value string) ([]byte, error) {
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return NewScriptBuilder().AddOp(OP_CLAIMNAME).AddData([]byte(name)).AddData([]byte(value)).
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AddOp(OP_2DROP).AddOp(OP_DROP).AddOp(OP_TRUE).Script()
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}
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// SupportClaimScript ...
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func SupportClaimScript(name string, claimID []byte, value []byte) ([]byte, error) {
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builder := NewScriptBuilder().AddOp(OP_SUPPORTCLAIM).AddData([]byte(name)).AddData(claimID)
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if len(value) > 0 {
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return builder.addData(value).AddOp(OP_2DROP).AddOp(OP_2DROP).AddOp(OP_TRUE).Script()
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}
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return builder.AddOp(OP_2DROP).AddOp(OP_DROP).AddOp(OP_TRUE).Script()
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}
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// UpdateClaimScript ...
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func UpdateClaimScript(name string, claimID []byte, value string) ([]byte, error) {
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return NewScriptBuilder().AddOp(OP_UPDATECLAIM).AddData([]byte(name)).AddData(claimID).AddData([]byte(value)).
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AddOp(OP_2DROP).AddOp(OP_2DROP).AddOp(OP_TRUE).Script()
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}
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// DecodeClaimScript ...
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func DecodeClaimScript(script []byte) (*ClaimScript, error) {
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if len(script) == 0 {
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return nil, ErrNotClaimScript
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}
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op := script[0]
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if op != OP_CLAIMNAME && op != OP_SUPPORTCLAIM && op != OP_UPDATECLAIM {
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return nil, ErrNotClaimScript
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}
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pops, err := parseScript(script)
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if err != nil {
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return nil, err
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}
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if isClaimName(pops) || isSupportClaim(pops) || isUpdateClaim(pops) {
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cs := &ClaimScript{op: op, pops: pops}
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if cs.Size() > MaxClaimScriptSize {
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log.Infof("claim script of %d bytes is larger than %d", cs.Size(), MaxClaimScriptSize)
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return nil, ErrInvalidClaimScript
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}
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return cs, nil
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}
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return nil, ErrInvalidClaimScript
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}
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// ClaimScript ...
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// OP_CLAIMNAME <Name> <Value> OP_2DROP OP_DROP <P2PKH>
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// OP_SUPPORTCLAIM <Name> <ClaimID> OP_2DROP OP_DROP <P2PKH>
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// OP_UPDATECLAIM <Name> <ClaimID> <Value> OP_2DROP OP_2DROP <P2PKH>
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type ClaimScript struct {
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op byte
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pops []parsedOpcode
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}
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// Opcode ...
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func (cs *ClaimScript) Opcode() byte {
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return cs.op
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}
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// Name ...
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func (cs *ClaimScript) Name() []byte {
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return cs.pops[1].data
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}
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// ClaimID ...
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func (cs *ClaimScript) ClaimID() []byte {
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if cs.op == OP_CLAIMNAME {
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return nil
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}
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return cs.pops[2].data
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}
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// Value ...
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func (cs *ClaimScript) Value() []byte {
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if cs.pops[0].opcode.value == OP_CLAIMNAME {
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return cs.pops[2].data
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}
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return cs.pops[3].data
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}
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// Size ...
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func (cs *ClaimScript) Size() int {
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ops := 5
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if cs.pops[0].opcode.value == OP_UPDATECLAIM {
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ops++
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}
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size := 0
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for _, op := range cs.pops[:ops] {
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if op.opcode.length > 0 {
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size += op.opcode.length
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continue
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}
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size += 1 - op.opcode.length + len(op.data)
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}
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return size
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}
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// StripClaimScriptPrefix ...
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func StripClaimScriptPrefix(script []byte) []byte {
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cs, err := DecodeClaimScript(script)
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if err != nil {
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return script
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}
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return script[cs.Size():]
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}
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// claimNameSize returns size of the name in a claim script or 0 if script is not a claimtrie transaction.
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func claimNameSize(script []byte) int {
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cs, err := DecodeClaimScript(script)
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if err != nil {
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return 0
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}
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return len(cs.Name())
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}
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// CalcMinClaimTrieFee calculates the minimum fee (mempool rule) required for transaction.
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func CalcMinClaimTrieFee(tx *wire.MsgTx, minFeePerNameClaimChar int64) int64 {
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var minFee int64
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for _, txOut := range tx.TxOut {
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// TODO maybe: lbrycrd ignored transactions that weren't OP_CLAIMNAME
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minFee += int64(claimNameSize(txOut.PkScript))
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}
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return minFee * minFeePerNameClaimChar
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}
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func isClaimName(pops []parsedOpcode) bool {
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return len(pops) > 5 &&
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pops[0].opcode.value == OP_CLAIMNAME &&
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// canonicalPush(pops[1]) &&
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len(pops[1].data) <= MaxClaimNameSize &&
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// canonicalPush(pops[2]) &&
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pops[3].opcode.value == OP_2DROP &&
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pops[4].opcode.value == OP_DROP
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}
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func isSupportClaim(pops []parsedOpcode) bool {
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prefixed := len(pops) > 5 &&
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pops[0].opcode.value == OP_SUPPORTCLAIM &&
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// canonicalPush(pops[1]) &&
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len(pops[1].data) <= MaxClaimNameSize &&
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// canonicalPush(pops[2]) &&
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len(pops[2].data) == 160/8
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if prefixed && pops[3].opcode.value == OP_2DROP && pops[4].opcode.value == OP_DROP {
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return true
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}
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if prefixed && pops[4].opcode.value == OP_2DROP && pops[5].opcode.value == OP_2DROP {
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return len(pops[3].data) > 0 // is this robust enough?
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}
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return false
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}
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func isUpdateClaim(pops []parsedOpcode) bool {
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return len(pops) > 6 &&
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pops[0].opcode.value == OP_UPDATECLAIM &&
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// canonicalPush(pops[1]) &&
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len(pops[1].data) <= MaxClaimNameSize &&
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// canonicalPush(pops[2]) &&
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len(pops[2].data) == 160/8 &&
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// canonicalPush(pops[3]) &&
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pops[4].opcode.value == OP_2DROP &&
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pops[5].opcode.value == OP_2DROP
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}
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const illegalChars = "=&#:*$@%?/\x00"
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func AllClaimsAreSane(script []byte, enforceSoftFork bool) error {
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cs, err := DecodeClaimScript(script)
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if err != ErrNotClaimScript {
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if err != nil {
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return fmt.Errorf("invalid claim script: %s", err.Error())
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}
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if cs.Size() > MaxClaimScriptSize {
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return fmt.Errorf("claimscript exceeds max size of %v", MaxClaimScriptSize)
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}
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if len(cs.Name()) > MaxClaimNameSize {
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return fmt.Errorf("claim name exceeds max size of %v", MaxClaimNameSize)
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}
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if enforceSoftFork {
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if !utf8.Valid(cs.Name()) {
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return fmt.Errorf("claim name is not valid UTF-8")
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}
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if bytes.ContainsAny(cs.Name(), illegalChars) {
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return fmt.Errorf("claim name has illegal chars; it should not contain any of these: %s", illegalChars)
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}
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}
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}
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return nil
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}
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