Merge bitcoin#16262: rpc: Allow shutdown while in generateblocks

3b9bf0e rpc: Allow shutdown while in generateblocks (Patrick Strateman)

Pull request description:

  By checking the shutdown flag every loop we can use the entire 32 bit nonce space instead of breaking every 16 bits to check the flag.

  This is possible now because the shutdown flag is an atomic where before it was controlled by a condition variable and lock.

ACKs for top commit:
  kallewoof:
    Re-ACK 3b9bf0e

Tree-SHA512: d0664201a55215130c2e9199a31fb81361daf4102a65cb3418984fd61cb98bfb9136d9ee8d23a85d57e50051f9bb0059bd71fe0488a17f63c38ea5caa6004504

src/rpc/mining.cpp

@@ -113,7 +113,6 @@ static UniValue getnetworkhashps(const JSONRPCRequest& request)
 #if ENABLE_MINER
 UniValue generateBlocks(std::shared_ptr<CReserveScript> coinbaseScript, int nGenerate, uint64_t nMaxTries, bool keepScript)
 {
-    static const int nInnerLoopCount = 0x10000;
     int nHeightEnd = 0;
     int nHeight = 0;
 
@@ -134,14 +133,14 @@ UniValue generateBlocks(std::shared_ptr<CReserveScript> coinbaseScript, int nGen
             LOCK(cs_main);
             IncrementExtraNonce(pblock, chainActive.Tip(), nExtraNonce);
         }
-        while (nMaxTries > 0 && pblock->nNonce < nInnerLoopCount && !CheckProofOfWork(pblock->GetHash(), pblock->nBits, Params().GetConsensus())) {
+        while (nMaxTries > 0 && pblock->nNonce < std::numeric_limits<uint32_t>::max() && !CheckProofOfWork(pblock->GetHash(), pblock->nBits, Params().GetConsensus()) && !ShutdownRequested()) {
             ++pblock->nNonce;
             --nMaxTries;
         }
-        if (nMaxTries == 0) {
+        if (nMaxTries == 0 || ShutdownRequested()) {
             break;
         }
-        if (pblock->nNonce == nInnerLoopCount) {
+        if (pblock->nNonce == std::numeric_limits<uint32_t>::max()) {
             continue;
         }
         std::shared_ptr<const CBlock> shared_pblock = std::make_shared<const CBlock>(*pblock);