FISCO BCOS 源码知识图谱

2.x/docs/articles/7_practice/sourceCode_knowledge_map/libblockchain.md

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+#  libblockchain 模块
+作者：TrustChain [微信公众号]
+
+libblockchain：管理区块、交易、区块链状态等信息的读写。
+
+
+
+## 主要内容有：
+
++ 管理区块、交易、区块链状态等信息的读写。
+
+![](../../../../images/articles/sourceCode_knowledge_map/libblockchain.png)
+
+
+## 涉及知识点：
++ 区块缓存数据结构：
+```
+mutable std::map<dev::h256, std::shared_ptr<dev::eth::Block>> m_blockCache;
+mutable std::deque<dev::h256> m_blockCacheFIFO;  // insert queue log for m_blockCache
+```
++ getBlockHeaderInfoByHash：先查缓存m_blockCache，查不到再查询系统表;
+
++ SYS_HASH_2_BLOCKHEADER，如果查询不到，再getBlock函数获取区块；
+
++ getBlock函数：先查缓存m_blockCache，查不到再查询系统表SYS_HASH_2_BLOCK；
+
++ getBlockRLP函数：访问SYS_NUMBER_2_HASH、SYS_HASH_2_BLOCK获取区块的RLP编码数据；
+
++ initGenesisWorkingSealers：用于共识算法rpbft,初始化共识节点队列，在sealerList随机选择共识节点workingSealers；
+
++ commitBlock函数
+```
+tbb::parallel_invoke([this, block, context]() { writeHash2Block(*block, context); },
+                [this, block, context]() { writeNumber2Hash(*block, context); },
+                [this, block, context]() { writeNumber(*block, context); },
+                [this, block, context]() { writeTotalTransactionCount(*block, context); },
+                [this, block, context]() { writeTxToBlock(*block, context); },
+                [this, block, context]() { writeHash2BlockHeader(*block, context); });
+```
++ 计算区块的交易或者回执的默克尔根
+```
+
+std::pair<dev::eth::BlockNumber, std::shared_ptr<Child2ParentMap>> m_receiptChild2ParentCache;
+ std::pair<dev::eth::BlockNumber, std::shared_ptr<Child2ParentMap>> m_txsChild2ParentCache;
+//获取默克尔根
+void BlockChainImp::getMerkleProof(dev::bytes const& _txHash,
+    const std::map<std::string, std::vector<std::string>>& parent2ChildList,
+    const Child2ParentMap& child2Parent,
+    std::vector<std::pair<std::vector<std::string>, std::vector<std::string>>>& merkleProof)
+{
+    std::string merkleNode = toHex(_txHash);
+    //得到merkleNode的自身节点itChild2Parent，设为A
+    auto itChild2Parent = child2Parent.find(merkleNode);
+    while (itChild2Parent != child2Parent.end())
+    {
+        //itChild2Parent->second，即A的父节点B，itParent2ChildList=<B,[merkleNode,merkleNode兄弟节点]>
+        auto itParent2ChildList = parent2ChildList.find(itChild2Parent->second);
+        if (itParent2ChildList == parent2ChildList.end())
+        {
+            break;
+        }
+        // get index from itParent2ChildList->second by merkleNode
+       //<B,[merkleNode,merkleNode兄弟节点]>，itChildlist= merkleNode
+        auto itChildlist = std::find(
+            itParent2ChildList->second.begin(), itParent2ChildList->second.end(), merkleNode);
+        if (itChildlist == itParent2ChildList->second.end())
+        {
+            break;
+        }
+        // copy to merkle proof path
+        std::vector<std::string> leftpath;
+        std::vector<std::string> rightpath;
+        leftpath.insert(leftpath.end(), itParent2ChildList->second.begin(), itChildlist);
+        rightpath.insert(rightpath.end(), std::next(itChildlist), itParent2ChildList->second.end());
+        merkleProof.push_back(std::make_pair(std::move(leftpath), std::move(rightpath)));
+        //itChild2Parent->second，即A的父节点B，merkleNode指向父节点B
+        merkleNode = itChild2Parent->second;
+        //从下往上计算默克尔树根
+        itChild2Parent = child2Parent.find(merkleNode);
+    }
+}
+```
+参考文献：
+
+[1] https://github.com/FISCO-BCOS/FISCO-BCOS/releases/tag/v2.7.2
+
+[2] https://fisco-bcos-documentation.readthedocs.io/zh_CN/latest/