rpc: Remove cs_main lock from blockToJSON and blockHeaderToJSON

Author: promag

src/rest.cpp

@@ -144,10 +144,12 @@ static bool rest_headers(HTTPRequest* req,
     if (!ParseHashStr(hashStr, hash))
         return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
 
+    const CBlockIndex* tip = nullptr;
     std::vector<const CBlockIndex *> headers;
     headers.reserve(count);
     {
         LOCK(cs_main);
+        tip = chainActive.Tip();
         const CBlockIndex* pindex = LookupBlockIndex(hash);
         while (pindex != nullptr && chainActive.Contains(pindex)) {
             headers.push_back(pindex);
@@ -178,11 +180,8 @@ static bool rest_headers(HTTPRequest* req,
     }
     case RetFormat::JSON: {
         UniValue jsonHeaders(UniValue::VARR);
-        {
-            LOCK(cs_main);
-            for (const CBlockIndex *pindex : headers) {
-                jsonHeaders.push_back(blockheaderToJSON(pindex));
-            }
+        for (const CBlockIndex *pindex : headers) {
+            jsonHeaders.push_back(blockheaderToJSON(tip, pindex));
         }
         std::string strJSON = jsonHeaders.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
@@ -210,8 +209,10 @@ static bool rest_block(HTTPRequest* req,
 
     CBlock block;
     CBlockIndex* pblockindex = nullptr;
+    CBlockIndex* tip = nullptr;
     {
         LOCK(cs_main);
+        tip = chainActive.Tip();
         pblockindex = LookupBlockIndex(hash);
         if (!pblockindex) {
             return RESTERR(req, HTTP_NOT_FOUND, hashStr + " not found");
@@ -243,11 +244,7 @@ static bool rest_block(HTTPRequest* req,
     }
 
     case RetFormat::JSON: {
-        UniValue objBlock;
-        {
-            LOCK(cs_main);
-            objBlock = blockToJSON(block, pblockindex, showTxDetails);
-        }
+        UniValue objBlock = blockToJSON(block, tip, pblockindex, showTxDetails);
         std::string strJSON = objBlock.write() + "\n";
         req->WriteHeader("Content-Type", "application/json");
         req->WriteReply(HTTP_OK, strJSON);

src/rpc/blockchain.cpp

@@ -78,15 +78,22 @@ double GetDifficulty(const CBlockIndex* blockindex)
     return dDiff;
 }
 
-UniValue blockheaderToJSON(const CBlockIndex* blockindex)
+static int ComputeNextBlockAndDepth(const CBlockIndex* tip, const CBlockIndex* blockindex, const CBlockIndex*& next)
+{
+    next = tip->GetAncestor(blockindex->nHeight + 1);
+    if (next && next->pprev == blockindex) {
+        return tip->nHeight - blockindex->nHeight + 1;
+    }
+    next = nullptr;
+    return blockindex == tip ? 1 : -1;
+}
+
+UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex)
 {
-    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
-    int confirmations = -1;
-    // Only report confirmations if the block is on the main chain
-    if (chainActive.Contains(blockindex))
-        confirmations = chainActive.Height() - blockindex->nHeight + 1;
+    const CBlockIndex* pnext;
+    int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("height", blockindex->nHeight);
     result.pushKV("version", blockindex->nVersion);
@@ -102,21 +109,17 @@ UniValue blockheaderToJSON(const CBlockIndex* blockindex)
 
     if (blockindex->pprev)
         result.pushKV("previousblockhash", blockindex->pprev->GetBlockHash().GetHex());
-    CBlockIndex *pnext = chainActive.Next(blockindex);
     if (pnext)
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     return result;
 }
 
-UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails)
+UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails)
 {
-    AssertLockHeld(cs_main);
     UniValue result(UniValue::VOBJ);
     result.pushKV("hash", blockindex->GetBlockHash().GetHex());
-    int confirmations = -1;
-    // Only report confirmations if the block is on the main chain
-    if (chainActive.Contains(blockindex))
-        confirmations = chainActive.Height() - blockindex->nHeight + 1;
+    const CBlockIndex* pnext;
+    int confirmations = ComputeNextBlockAndDepth(tip, blockindex, pnext);
     result.pushKV("confirmations", confirmations);
     result.pushKV("strippedsize", (int)::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION | SERIALIZE_TRANSACTION_NO_WITNESS));
     result.pushKV("size", (int)::GetSerializeSize(block, SER_NETWORK, PROTOCOL_VERSION));
@@ -148,7 +151,6 @@ UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool tx
 
     if (blockindex->pprev)
         result.pushKV("previousblockhash", blockindex->pprev->GetBlockHash().GetHex());
-    CBlockIndex *pnext = chainActive.Next(blockindex);
     if (pnext)
         result.pushKV("nextblockhash", pnext->GetBlockHash().GetHex());
     return result;
@@ -744,7 +746,7 @@ static UniValue getblockheader(const JSONRPCRequest& request)
         return strHex;
     }
 
-    return blockheaderToJSON(pblockindex);
+    return blockheaderToJSON(chainActive.Tip(), pblockindex);
 }
 
 static CBlock GetBlockChecked(const CBlockIndex* pblockindex)
@@ -845,7 +847,7 @@ static UniValue getblock(const JSONRPCRequest& request)
         return strHex;
     }
 
-    return blockToJSON(block, pblockindex, verbosity >= 2);
+    return blockToJSON(block, chainActive.Tip(), pblockindex, verbosity >= 2);
 }
 
 struct CCoinsStats

src/rpc/blockchain.h

@@ -27,7 +27,7 @@ double GetDifficulty(const CBlockIndex* blockindex);
 void RPCNotifyBlockChange(bool ibd, const CBlockIndex *);
 
 /** Block description to JSON */
-UniValue blockToJSON(const CBlock& block, const CBlockIndex* blockindex, bool txDetails = false);
+UniValue blockToJSON(const CBlock& block, const CBlockIndex* tip, const CBlockIndex* blockindex, bool txDetails = false);
 
 /** Mempool information to JSON */
 UniValue mempoolInfoToJSON();
@@ -36,7 +36,7 @@ UniValue mempoolInfoToJSON();
 UniValue mempoolToJSON(bool fVerbose = false);
 
 /** Block header to JSON */
-UniValue blockheaderToJSON(const CBlockIndex* blockindex);
+UniValue blockheaderToJSON(const CBlockIndex* tip, const CBlockIndex* blockindex);
 
 /** Used by getblockstats to get feerates at different percentiles by weight  */
 void CalculatePercentilesByWeight(CAmount result[NUM_GETBLOCKSTATS_PERCENTILES], std::vector<std::pair<CAmount, int64_t>>& scores, int64_t total_weight);