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Make count sigops always count up to the point of parse failure.

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We do this by allowing the parser to return the list of parsed objects
(it is an internal only api anyway) and then we use this in the sigops
counting and ignore the error. This change due to bitcoind
compatability.
This commit is contained in:
Owain G. Ainsworth 2013-07-25 15:40:11 +01:00
parent e7f9415e4f
commit fe2233c851
1 changed files with 20 additions and 19 deletions
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39
script.go
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@ -272,14 +272,15 @@ func parseScript(script []byte) ([]parsedOpcode, error) {
}
// parseScriptTemplate is the same as parseScript but allows the passing of the
// template list for testing purposes.
// template list for testing purposes. On error we return the list of parsed
// opcodes so far.
func parseScriptTemplate(script []byte, opcodemap map[byte]*opcode) ([]parsedOpcode, error) {
retScript := []parsedOpcode{}
for i := 0; i < len(script); {
instr := script[i]
op, ok := opcodemap[instr]
if !ok {
return nil, StackErrInvalidOpcode
return retScript, StackErrInvalidOpcode
}
pop := parsedOpcode{opcode: op}
// parse data out of instruction.
@ -289,7 +290,7 @@ func parseScriptTemplate(script []byte, opcodemap map[byte]*opcode) ([]parsedOpc
i++
case op.length > 1:
if len(script[i:]) < op.length {
return nil, StackErrShortScript
return retScript, StackErrShortScript
}
// slice out the data.
pop.data = script[i+1 : i+op.length]
@ -306,7 +307,9 @@ func parseScriptTemplate(script []byte, opcodemap map[byte]*opcode) ([]parsedOpc
case -4:
l, err = scriptUInt32(script[off:])
default:
return nil, fmt.Errorf("invalid opcode length %d", op.length)
return retScript,
fmt.Errorf("invalid opcode length %d",
op.length)
}
if err != nil {
@ -314,10 +317,10 @@ func parseScriptTemplate(script []byte, opcodemap map[byte]*opcode) ([]parsedOpc
}
off = i + 1 - op.length // beginning of data
if int(l) > len(script[off:]) {
return nil, StackErrShortScript
return retScript, StackErrShortScript
}
if l > MaxScriptElementSize {
return nil, StackErrElementTooBig
return retScript, StackErrElementTooBig
}
pop.data = script[off : off+int(l)]
i += 1 - op.length + int(l)
@ -763,11 +766,12 @@ func (s *Script) SetAltStack(data [][]byte) {
// GetSigOpCount provides a quick count of the number of signature operations
// in a script. a CHECKSIG operations counts for 1, and a CHECK_MULTISIG for 20.
// If the script fails to parse, then the count up to the point of failure is
// returned.
func GetSigOpCount(script []byte) int {
pops, err := parseScript(script)
if err != nil {
return 0
}
// We don't check error since parseScript returns the parsed-up-to-error
// list of pops.
pops, _ := parseScript(script)
return getSigOpCount(pops, false)
}
@ -775,12 +779,12 @@ func GetSigOpCount(script []byte) int {
// GetPreciseSigOpCount returns the number of signature operations in
// scriptPubKey. If bip16 is true then scriptSig may be searched for the
// Pay-To-Script-Hash script in order to find the precise number of signature
// operations in the transaction.
// operations in the transaction. If the script fails to parse, then the
// count up to the point of failure is returned.
func GetPreciseSigOpCount(scriptSig, scriptPubKey []byte, bip16 bool) int {
pops, err := parseScript(scriptPubKey)
if err != nil {
return 0
}
// We don't check error since parseScript returns the parsed-up-to-error
// list of pops.
pops, _ := parseScript(scriptPubKey)
// non P2SH transactions just treated as normal.
if !(bip16 && isScriptHash(pops)) {
return getSigOpCount(pops, true)
@ -802,10 +806,7 @@ func GetPreciseSigOpCount(scriptSig, scriptPubKey []byte, bip16 bool) int {
return 0
}
shPops, err := parseScript(shScript)
if err != nil {
return 0
}
shPops, _ := parseScript(shScript)
return getSigOpCount(shPops, true)
}