Recognizing standard Bitcoin output script patterns

1// Copyright (c) 2009-2010 Satoshi Nakamoto
2// Copyright (c) 2009-present The Bitcoin Core developers
3// Distributed under the MIT software license, see the accompanying
4// file COPYING or http://www.opensource.org/licenses/mit-license.php.
5
6// The Solver functions are used by policy and the wallet, but not consensus.
7
8#ifndef BITCOIN_SCRIPT_SOLVER_H
9#define BITCOIN_SCRIPT_SOLVER_H
10
11#include <attributes.h>
12#include <script/script.h>
13
14#include <optional>
15#include <span>
16#include <string>
17#include <utility>
18#include <vector>
19
20class CPubKey;
21
22enum class TxoutType {
23    NONSTANDARD,
24    // 'standard' transaction types:
25    ANCHOR, //!< anyone can spend script
26    PUBKEY,
27    PUBKEYHASH,
28    SCRIPTHASH,
29    MULTISIG,
30    NULL_DATA, //!< unspendable OP_RETURN script that carries data
31    WITNESS_V0_SCRIPTHASH,
32    WITNESS_V0_KEYHASH,
33    WITNESS_V1_TAPROOT,
34    WITNESS_UNKNOWN, //!< Only for Witness versions not already defined above
35};
36
37/** Get the name of a TxoutType as a string */
38std::string GetTxnOutputType(TxoutType t);
39
40constexpr bool IsPushdataOp(opcodetype opcode)
41{
42    return opcode > OP_FALSE && opcode <= OP_PUSHDATA4;
43}
44
45/**
46 * Parse a scriptPubKey and identify script type for standard scripts. If
47 * successful, returns script type and parsed pubkeys or hashes, depending on
48 * the type. For example, for a P2SH script, vSolutionsRet will contain the
49 * script hash, for P2PKH it will contain the key hash, etc.
50 *
51 * @param[in]   scriptPubKey   Script to parse
52 * @param[out]  vSolutionsRet  Vector of parsed pubkeys and hashes
53 * @return                     The script type. TxoutType::NONSTANDARD represents a failed solve.
54 */
55TxoutType Solver(const CScript& scriptPubKey, std::vector<std::vector<unsigned char>>& vSolutionsRet);
56
57/** Generate a P2PK script for the given pubkey. */
58CScript GetScriptForRawPubKey(const CPubKey& pubkey);
59
60/** Determine if script is a "multi_a" script. Returns (threshold, keyspans) if so, and nullopt otherwise.
61 *  The keyspans refer to bytes in the passed script. */
62std::optional<std::pair<int, std::vector<std::span<const unsigned char>>>> MatchMultiA(const CScript& script LIFETIMEBOUND);
63
64/** Generate a multisig script. */
65CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys);
66
67#endif // BITCOIN_SCRIPT_SOLVER_H
68