Merge #19056: rpc: Make gettxoutsetinfo/GetUTXOStats interruptible

fa756928c3 rpc: Make gettxoutsetinfo/GetUTXOStats interruptible (MarcoFalke)
fa7fc5a8e0 rpc: factor out RpcInterruptionPoint from dumptxoutset (MarcoFalke)

Pull request description:

  Make it interruptible, so that shutdown doesn't block for up to one hour.

  Fixes (partially) #13217

ACKs for top commit:
  Empact:
    Code Review ACK fa756928c3
  laanwj:
    Code review ACK fa756928c3

Tree-SHA512: 298261e0ff7d79fab542b8f6828cc0ac451cbafe396d5f0816c9d36437faba1330f5c4cb2a25c5540e202bfb9783da6ec858bd453056ce488d21e36335d3d42c

src/node/coinstats.cpp

@@ -33,7 +33,7 @@ static void ApplyStats(CCoinsStats &stats, CHashWriter& ss, const uint256& hash,
 }
 
 //! Calculate statistics about the unspent transaction output set
-bool GetUTXOStats(CCoinsView *view, CCoinsStats &stats)
+bool GetUTXOStats(CCoinsView* view, CCoinsStats& stats, const std::function<void()>& interruption_point)
 {
     stats = CCoinsStats();
     std::unique_ptr<CCoinsViewCursor> pcursor(view->Cursor());
@@ -49,6 +49,7 @@ bool GetUTXOStats(CCoinsView *view, CCoinsStats &stats)
     uint256 prevkey;
     std::map<uint32_t, Coin> outputs;
     while (pcursor->Valid()) {
+        interruption_point();
         COutPoint key;
         Coin coin;
         if (pcursor->GetKey(key) && pcursor->GetValue(coin)) {

src/node/coinstats.h

@@ -10,6 +10,7 @@
 #include <uint256.h>
 
 #include <cstdint>
+#include <functional>
 
 class CCoinsView;
 
@@ -29,6 +30,6 @@ struct CCoinsStats
 };
 
 //! Calculate statistics about the unspent transaction output set
-bool GetUTXOStats(CCoinsView* view, CCoinsStats& stats);
+bool GetUTXOStats(CCoinsView* view, CCoinsStats& stats, const std::function<void()>& interruption_point = {});
 
 #endif // BITCOIN_NODE_COINSTATS_H