src/chain.h

//包含所有的CBlockIndex(一个区块对应一个CBlockIndex)
//所有区块构建的链
/** An in-memory indexed chain of blocks. */
class CChain {
private:
    std::vector<CBlockIndex*> vChain; //vector是一个能够存放任意类型的动态数组，能够增加和压缩数据

public:
    /** Returns the index entry for the genesis block of this chain, or nullptr if none. */
    CBlockIndex *Genesis() const { //返回创世CBlockIndex
        return vChain.size() > 0 ? vChain[0] : nullptr;
    }

    //最后一个CBlockIndex
    /** Returns the index entry for the tip(末梢) of this chain, or nullptr if none. */
    CBlockIndex *Tip() const {
        return vChain.size() > 0 ? vChain[vChain.size() - 1] : nullptr;
    }

    //特定高度的CBlockIndex
    /** Returns the index entry at a particular height in this chain, or nullptr if no such height exists. */
    CBlockIndex *operator[](int nHeight) const {
        if (nHeight < 0 || nHeight >= (int)vChain.size())
            return nullptr;
        return vChain[nHeight];
    }

    //大小相等；最后一个CBlockIndex相等
    /** Compare two chains efficiently. */
    friend bool operator==(const CChain &a, const CChain &b) {
        return a.vChain.size() == b.vChain.size() &&
               a.vChain[a.vChain.size() - 1] == b.vChain[b.vChain.size() - 1];
    }

    /** Efficiently check whether a block is present in this chain. */
    bool Contains(const CBlockIndex *pindex) const {
        return (*this)[pindex->nHeight] == pindex;
    }

    //后续者
    /** Find the successor of a block in this chain, or nullptr if the given index is not found or is the tip. */
    CBlockIndex *Next(const CBlockIndex *pindex) const {
        if (Contains(pindex))
            return (*this)[pindex->nHeight + 1];
        else
            return nullptr;
    }

    //最大高度
    /** Return the maximal height in the chain. Is equal to chain.Tip() ? chain.Tip()->nHeight : -1. */
    int Height() const {
        return vChain.size() - 1;
    }

    /** Set/initialize a chain with a given tip. */
    void SetTip(CBlockIndex *pindex);

    /** Return a CBlockLocator that refers to a block in this chain (by default the tip). */
    CBlockLocator GetLocator(const CBlockIndex *pindex = nullptr) const;

    /** Find the last common block between this chain and a block index entry. */
    const CBlockIndex *FindFork(const CBlockIndex *pindex) const;

    /** Find the earliest block with timestamp equal or greater than the given. */
    CBlockIndex* FindEarliestAtLeast(int64_t nTime) const;
};