diff options
Diffstat (limited to 'src/script/standard.h')
| -rw-r--r-- | src/script/standard.h | 54 |
1 files changed, 51 insertions, 3 deletions
diff --git a/src/script/standard.h b/src/script/standard.h index d7ea5cef27..ac4e2f3276 100644 --- a/src/script/standard.h +++ b/src/script/standard.h @@ -11,6 +11,7 @@ #include <uint256.h> #include <util/hash_type.h> +#include <map> #include <string> #include <variant> @@ -209,15 +210,50 @@ CScript GetScriptForRawPubKey(const CPubKey& pubkey); /** Generate a multisig script. */ CScript GetScriptForMultisig(int nRequired, const std::vector<CPubKey>& keys); +struct ShortestVectorFirstComparator +{ + bool operator()(const std::vector<unsigned char>& a, const std::vector<unsigned char>& b) const + { + if (a.size() < b.size()) return true; + if (a.size() > b.size()) return false; + return a < b; + } +}; + +struct TaprootSpendData +{ + /** The BIP341 internal key. */ + XOnlyPubKey internal_key; + /** The Merkle root of the script tree (0 if no scripts). */ + uint256 merkle_root; + /** Map from (script, leaf_version) to (sets of) control blocks. + * The control blocks are sorted by size, so that the signing logic can + * easily prefer the cheapest one. */ + std::map<std::pair<CScript, int>, std::set<std::vector<unsigned char>, ShortestVectorFirstComparator>> scripts; + /** Merge other TaprootSpendData (for the same scriptPubKey) into this. */ + void Merge(TaprootSpendData other); +}; + /** Utility class to construct Taproot outputs from internal key and script tree. */ class TaprootBuilder { private: + /** Information about a tracked leaf in the Merkle tree. */ + struct LeafInfo + { + CScript script; //!< The script. + int leaf_version; //!< The leaf version for that script. + std::vector<uint256> merkle_branch; //!< The hashing partners above this leaf. + }; + /** Information associated with a node in the Merkle tree. */ struct NodeInfo { /** Merkle hash of this node. */ uint256 hash; + /** Tracked leaves underneath this node (either from the node itself, or its children). + * The merkle_branch field for each is the partners to get to *this* node. */ + std::vector<LeafInfo> leaves; }; /** Whether the builder is in a valid state so far. */ bool m_valid = true; @@ -260,7 +296,8 @@ private: std::vector<std::optional<NodeInfo>> m_branch; XOnlyPubKey m_internal_key; //!< The internal key, set when finalizing. - XOnlyPubKey m_output_key; //!< The output key, computed when finalizing. */ + XOnlyPubKey m_output_key; //!< The output key, computed when finalizing. + bool m_parity; //!< The tweak parity, computed when finalizing. /** Combine information about a parent Merkle tree node from its child nodes. */ static NodeInfo Combine(NodeInfo&& a, NodeInfo&& b); @@ -269,8 +306,9 @@ private: public: /** Add a new script at a certain depth in the tree. Add() operations must be called - * in depth-first traversal order of binary tree. */ - TaprootBuilder& Add(int depth, const CScript& script, int leaf_version); + * in depth-first traversal order of binary tree. If track is true, it will be included in + * the GetSpendData() output. */ + TaprootBuilder& Add(int depth, const CScript& script, int leaf_version, bool track = true); /** Like Add(), but for a Merkle node with a given hash to the tree. */ TaprootBuilder& AddOmitted(int depth, const uint256& hash); /** Finalize the construction. Can only be called when IsComplete() is true. @@ -285,6 +323,16 @@ public: WitnessV1Taproot GetOutput(); /** Check if a list of depths is legal (will lead to IsComplete()). */ static bool ValidDepths(const std::vector<int>& depths); + /** Compute spending data (after Finalize()). */ + TaprootSpendData GetSpendData() const; }; +/** Given a TaprootSpendData and the output key, reconstruct its script tree. + * + * If the output doesn't match the spenddata, or if the data in spenddata is incomplete, + * std::nullopt is returned. Otherwise, a vector of (depth, script, leaf_ver) tuples is + * returned, corresponding to a depth-first traversal of the script tree. + */ +std::optional<std::vector<std::tuple<int, CScript, int>>> InferTaprootTree(const TaprootSpendData& spenddata, const XOnlyPubKey& output); + #endif // BITCOIN_SCRIPT_STANDARD_H |