Merge #19056: rpc: Make gettxoutsetinfo/GetUTXOStats interruptible

fa75692 rpc: Make gettxoutsetinfo/GetUTXOStats interruptible (MarcoFalke)
fa7fc5a 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 bitcoin/bitcoin@fa75692
  laanwj:
    Code review ACK fa75692

Tree-SHA512: 298261e0ff7d79fab542b8f6828cc0ac451cbafe396d5f0816c9d36437faba1330f5c4cb2a25c5540e202bfb9783da6ec858bd453056ce488d21e36335d3d42c

Author: MarcoFalke

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

src/rpc/blockchain.cpp

@@ -996,7 +996,7 @@ static UniValue gettxoutsetinfo(const JSONRPCRequest& request)
     ::ChainstateActive().ForceFlushStateToDisk();
 
     CCoinsView* coins_view = WITH_LOCK(cs_main, return &ChainstateActive().CoinsDB());
-    if (GetUTXOStats(coins_view, stats)) {
+    if (GetUTXOStats(coins_view, stats, RpcInterruptionPoint)) {
         ret.pushKV("height", (int64_t)stats.nHeight);
         ret.pushKV("bestblock", stats.hashBlock.GetHex());
         ret.pushKV("transactions", (int64_t)stats.nTransactions);
@@ -1974,6 +1974,7 @@ bool FindScriptPubKey(std::atomic<int>& scan_progress, const std::atomic<bool>&
         Coin coin;
         if (!cursor->GetKey(key) || !cursor->GetValue(coin)) return false;
         if (++count % 8192 == 0) {
+            RpcInterruptionPoint();
             if (should_abort) {
                 // allow to abort the scan via the abort reference
                 return false;
@@ -2317,7 +2318,7 @@ UniValue dumptxoutset(const JSONRPCRequest& request)
 
         ::ChainstateActive().ForceFlushStateToDisk();
 
-        if (!GetUTXOStats(&::ChainstateActive().CoinsDB(), stats)) {
+        if (!GetUTXOStats(&::ChainstateActive().CoinsDB(), stats, RpcInterruptionPoint)) {
             throw JSONRPCError(RPC_INTERNAL_ERROR, "Unable to read UTXO set");
         }
 
@@ -2335,9 +2336,7 @@ UniValue dumptxoutset(const JSONRPCRequest& request)
     unsigned int iter{0};
 
     while (pcursor->Valid()) {
-        if (iter % 5000 == 0 && !IsRPCRunning()) {
-            throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Shutting down");
-        }
+        if (iter % 5000 == 0) RpcInterruptionPoint();
         ++iter;
         if (pcursor->GetKey(key) && pcursor->GetValue(coin)) {
             afile << key;

src/rpc/server.cpp

@@ -11,9 +11,9 @@
 #include <util/strencodings.h>
 #include <util/system.h>
 
-#include <boost/signals2/signal.hpp>
 #include <boost/algorithm/string/classification.hpp>
 #include <boost/algorithm/string/split.hpp>
+#include <boost/signals2/signal.hpp>
 
 #include <memory> // for unique_ptr
 #include <unordered_map>
@@ -309,6 +309,11 @@ bool IsRPCRunning()
     return g_rpc_running;
 }
 
+void RpcInterruptionPoint()
+{
+    if (!IsRPCRunning()) throw JSONRPCError(RPC_CLIENT_NOT_CONNECTED, "Shutting down");
+}
+
 void SetRPCWarmupStatus(const std::string& newStatus)
 {
     LOCK(cs_rpcWarmup);

src/rpc/server.h

@@ -9,10 +9,10 @@
 #include <amount.h>
 #include <rpc/request.h>
 
+#include <functional>
 #include <map>
 #include <stdint.h>
 #include <string>
-#include <functional>
 
 #include <univalue.h>
 
@@ -29,6 +29,9 @@ namespace RPCServer
 /** Query whether RPC is running */
 bool IsRPCRunning();
 
+/** Throw JSONRPCError if RPC is not running */
+void RpcInterruptionPoint();
+
 /**
  * Set the RPC warmup status.  When this is done, all RPC calls will error out
  * immediately with RPC_IN_WARMUP.