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lnwallet: drop some comments upon script_utils.go

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This commit is contained in:
Olaoluwa Osuntokun 2015-12-28 23:55:36 -06:00
parent 7648fee903
commit 1c4887e746
1 changed files with 22 additions and 18 deletions
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40
lnwallet/script_utils.go
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@ -9,11 +9,12 @@ import (
"github.com/btcsuite/btcutil" "github.com/btcsuite/btcutil"
) )
// scriptHashPkScript... // scriptHashPkScript generates a pay-to-script-hash public key script paying
func scriptHashPkScript(scriptBytes []byte) ([]byte, error) { // to the hash160 of the passed redeem script.
func scriptHashPkScript(redeemScript []byte) ([]byte, error) {
bldr := txscript.NewScriptBuilder() bldr := txscript.NewScriptBuilder()
bldr.AddOp(txscript.OP_HASH160) bldr.AddOp(txscript.OP_HASH160)
bldr.AddData(btcutil.Hash160(scriptBytes)) bldr.AddData(btcutil.Hash160(redeemScript))
bldr.AddOp(txscript.OP_EQUAL) bldr.AddOp(txscript.OP_EQUAL)
return bldr.Script() return bldr.Script()
} }
@ -25,31 +26,31 @@ func genFundingPkScript(aPub, bPub []byte) ([]byte, error) {
return nil, fmt.Errorf("Pubkey size error. Compressed pubkeys only") return nil, fmt.Errorf("Pubkey size error. Compressed pubkeys only")
} }
if bytes.Compare(aPub, bPub) == -1 { // swap to sort pubkeys if needed // Swap to sort pubkeys if needed. Keys are sorted in lexicographical
// order. The signatures within the scriptSig must also adhere to the
// order, ensuring that the signatures for each public key appears
// in the proper order on the stack.
if bytes.Compare(aPub, bPub) == -1 {
aPub, bPub = bPub, aPub aPub, bPub = bPub, aPub
} }
bldr := txscript.NewScriptBuilder() bldr := txscript.NewScriptBuilder()
// Require 2 signatures, so from both of the pubkeys
bldr.AddOp(txscript.OP_2) bldr.AddOp(txscript.OP_2)
// add both pubkeys (sorted) bldr.AddData(aPub) // Add both pubkeys (sorted).
bldr.AddData(aPub)
bldr.AddData(bPub) bldr.AddData(bPub)
// 2 keys total. In case that wasn't obvious.
bldr.AddOp(txscript.OP_2) bldr.AddOp(txscript.OP_2)
// Good ol OP_CHECKMULTISIG. Don't forget the zero!
bldr.AddOp(txscript.OP_CHECKMULTISIG) bldr.AddOp(txscript.OP_CHECKMULTISIG)
// get byte slice
return bldr.Script() return bldr.Script()
} }
// fundMultiSigOut creates a TxOut for the funding transaction. // fundMultiSigOut create the redeemScript for the funding transaction, and
// Give it the two pubkeys and it'll give you the p2sh'd txout. // also a TxOut paying to the p2sh of the multi-sig redeemScript. Give it the
// You don't have to remember the p2sh preimage, as long as you remember the // two pubkeys and it'll give you the p2sh'd txout. You don't have to remember
// pubkeys involved. // the p2sh preimage, as long as you remember the pubkeys involved.
func fundMultiSigOut(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) { func fundMultiSigOut(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error) {
if amt < 0 { if amt < 0 {
return nil, nil, fmt.Errorf("Can't create FundTx script with negative coins") return nil, nil, fmt.Errorf("can't create FundTx script with " +
"negative coins")
} }
// p2shify // p2shify
@ -65,7 +66,8 @@ func fundMultiSigOut(aPub, bPub []byte, amt int64) ([]byte, *wire.TxOut, error)
return redeemScript, wire.NewTxOut(amt, pkScript), nil return redeemScript, wire.NewTxOut(amt, pkScript), nil
} }
// the scriptsig to put on a P2SH input // spendMultiSig generates the scriptSig required to redeem the 2-of-2 p2sh
// multi-sig output.
func spendMultiSig(redeemScript, sigA, sigB []byte) ([]byte, error) { func spendMultiSig(redeemScript, sigA, sigB []byte) ([]byte, error) {
bldr := txscript.NewScriptBuilder() bldr := txscript.NewScriptBuilder()
@ -84,8 +86,10 @@ func spendMultiSig(redeemScript, sigA, sigB []byte) ([]byte, error) {
return bldr.Script() return bldr.Script()
} }
// findScriptOutputIndex... // findScriptOutputIndex finds the index of the public key script output
// only finds first matchin, assumes unique pkScripts // matching 'script'. Additionally, a boolean is returned indicating if
// a matching output was found at all.
// NOTE: The search stops after the first matching script is found.
func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) { func findScriptOutputIndex(tx *wire.MsgTx, script []byte) (bool, uint32) {
found := false found := false
index := uint32(0) index := uint32(0)