git / moonbite-core / src/merkleblock.h · raw

// Copyright (c) 2009-2010 Satoshi Nakamoto// Copyright (c) 2009-2018 The Bitcoin Core developers// Distributed under the MIT software license, see the accompanying// file COPYING or http://www.opensource.org/licenses/mit-license.php.#ifndef BITCOIN_MERKLEBLOCK_H#define BITCOIN_MERKLEBLOCK_H#include <serialize.h>#include <uint256.h>#include <primitives/block.h>#include <bloom.h>#include <vector>// Helper functions for serialization.std::vector<unsigned char> BitsToBytes(const std::vector<bool>& bits);std::vector<bool> BytesToBits(const std::vector<unsigned char>& bytes);/** Data structure that represents a partial merkle tree. * * It represents a subset of the txid's of a known block, in a way that * allows recovery of the list of txid's and the merkle root, in an * authenticated way. * * The encoding works as follows: we traverse the tree in depth-first order, * storing a bit for each traversed node, signifying whether the node is the * parent of at least one matched leaf txid (or a matched txid itself). In * case we are at the leaf level, or this bit is 0, its merkle node hash is * stored, and its children are not explored further. Otherwise, no hash is * stored, but we recurse into both (or the only) child branch. During * decoding, the same depth-first traversal is performed, consuming bits and * hashes as they written during encoding. * * The serialization is fixed and provides a hard guarantee about the * encoded size: * *   SIZE <= 10 + ceil(32.25*N) * * Where N represents the number of leaf nodes of the partial tree. N itself * is bounded by: * *   N <= total_transactions *   N <= 1 + matched_transactions*tree_height * * The serialization format: *  - uint32     total_transactions (4 bytes) *  - varint     number of hashes   (1-3 bytes) *  - uint256[]  hashes in depth-first order (<= 32*N bytes) *  - varint     number of bytes of flag bits (1-3 bytes) *  - byte[]     flag bits, packed per 8 in a byte, least significant bit first (<= 2*N-1 bits) * The size constraints follow from this. */class CPartialMerkleTree{protected:    /** the total number of transactions in the block */    unsigned int nTransactions;    /** node-is-parent-of-matched-txid bits */    std::vector<bool> vBits;    /** txids and internal hashes */    std::vector<uint256> vHash;    /** flag set when encountering invalid data */    bool fBad;    /** helper function to efficiently calculate the number of nodes at given height in the merkle tree */    unsigned int CalcTreeWidth(int height) const {        return (nTransactions+(1 << height)-1) >> height;    }    /** calculate the hash of a node in the merkle tree (at leaf level: the txid's themselves) */    uint256 CalcHash(int height, unsigned int pos, const std::vector<uint256> &vTxid);    /** recursive function that traverses tree nodes, storing the data as bits and hashes */    void TraverseAndBuild(int height, unsigned int pos, const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch);    /**     * recursive function that traverses tree nodes, consuming the bits and hashes produced by TraverseAndBuild.     * it returns the hash of the respective node and its respective index.     */    uint256 TraverseAndExtract(int height, unsigned int pos, unsigned int &nBitsUsed, unsigned int &nHashUsed, std::vector<uint256> &vMatch, std::vector<unsigned int> &vnIndex);public:    SERIALIZE_METHODS(CPartialMerkleTree, obj)    {        READWRITE(obj.nTransactions, obj.vHash);        std::vector<unsigned char> bytes;        SER_WRITE(obj, bytes = BitsToBytes(obj.vBits));        READWRITE(bytes);        SER_READ(obj, obj.vBits = BytesToBits(bytes));        SER_READ(obj, obj.fBad = false);    }    /** Construct a partial merkle tree from a list of transaction ids, and a mask that selects a subset of them */    CPartialMerkleTree(const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch);    CPartialMerkleTree();    /**     * extract the matching txid's represented by this partial merkle tree     * and their respective indices within the partial tree.     * returns the merkle root, or 0 in case of failure     */    uint256 ExtractMatches(std::vector<uint256> &vMatch, std::vector<unsigned int> &vnIndex);    /** Get number of transactions the merkle proof is indicating for cross-reference with     * local blockchain knowledge.     */    unsigned int GetNumTransactions() const { return nTransactions; };};/** * Used to relay blocks as header + vector<merkle branch> * to filtered nodes. * * NOTE: The class assumes that the given CBlock has *at least* 1 transaction. If the CBlock has 0 txs, it will hit an assertion. */class CMerkleBlock{public:    /** Public only for unit testing */    CBlockHeader header;    CPartialMerkleTree txn;    /**     * Public only for unit testing and relay testing (not relayed).     *     * Used only when a bloom filter is specified to allow     * testing the transactions which matched the bloom filter.     */    std::vector<std::pair<unsigned int, uint256> > vMatchedTxn;    /**     * Create from a CBlock, filtering transactions according to filter     * Note that this will call IsRelevantAndUpdate on the filter for each transaction,     * thus the filter will likely be modified.     */    CMerkleBlock(const CBlock& block, CBloomFilter& filter) : CMerkleBlock(block, &filter, nullptr) { }    // Create from a CBlock, matching the txids in the set    CMerkleBlock(const CBlock& block, const std::set<uint256>& txids) : CMerkleBlock(block, nullptr, &txids) { }    CMerkleBlock() {}    SERIALIZE_METHODS(CMerkleBlock, obj) { READWRITE(obj.header, obj.txn); }private:    // Combined constructor to consolidate code    CMerkleBlock(const CBlock& block, CBloomFilter* filter, const std::set<uint256>* txids);};/** * Can be requested by MWEB light clients to retrieve and verify MWEB headers. *  * Serializes as merkleblock + tx (HogEx) + MWEB header: *  * Merkle Block *  - uint32         version (4 bytes) *  - uint256        prev_block (32 bytes) *  - uint256        merkle_root (32 bytes) *  - uint32         timestamp (4 bytes) *  - uint32         bits (4 bytes) *  - uint32         nonce (4 bytes) *  - uint32         total_transactions (4 bytes) *  - varint         number of hashes   (1-3 bytes) *  - uint256[]      hashes in depth-first order (<= 32*N bytes) *  - varint         number of bytes of flag bits (1-3 bytes) *  - byte[]         flag bits, packed per 8 in a byte, least significant bit first (<= 2*N-1 bits) *  * HogEx Transaction *  - CTransaction   hogex transaction (? bytes) *  * MWEB Header *  - int32          height (4 bytes) *  - uint256        output_root (32 bytes) *  - uint256        kernel_root (32 bytes) *  - uint256        leafset_root (32 bytes) *  - uint256        kernel_offset (32 bytes) *  - uint256        stealth_offset (32 bytes) *  - uint64         output_mmr_size (8 bytes) *  - uint64         kernel_mmr_size (8 bytes) *  * NOTE: The class assumes that the given CBlock contains a hogex transaction and MWEB block data. * If it does not, an assertion will be hit. */class CMerkleBlockWithMWEB{private:    CMerkleBlock merkle;    CTransactionRef hogex;    mw::Header::CPtr mweb_header;public:    CMerkleBlockWithMWEB() { }    CMerkleBlockWithMWEB(const CBlock& block);    SERIALIZE_METHODS(CMerkleBlockWithMWEB, obj) { READWRITE(obj.merkle, obj.hogex, obj.mweb_header); }};#endif // BITCOIN_MERKLEBLOCK_H