Merge bitcoin#10756: net processing: swap out signals for an interfac…

…e class

2525b97 net: stop both net/net_processing before destroying them (Cory Fields)
80e2e9d net: drop unused connman param (Cory Fields)
8ad663c net: use an interface class rather than signals for message processing (Cory Fields)
28f11e9 net: pass CConnman via pointer rather than reference (Cory Fields)

Pull request description:

  See individual commits.
  Benefits:
  - Allows us to begin moving stuff out of CNode and into CNodeState (after bitcoin#10652 and follow-ups)
  - Drops boost dependency and overhead
  - Drops global signal registration
  - Friendlier backtraces

Tree-SHA512: af2038c959dbec25f0c90c74c88dc6a630e6b9e984adf52aceadd6954aa463b6aadfccf979c2459a9f3354326b5077ee02048128eda2a649236fadb595b66ee3

src/init.cpp

@@ -243,12 +243,14 @@ void PrepareShutdown()
     }
 #endif
     MapPort(false);
+
+    // Because these depend on each-other, we make sure that neither can be
+    // using the other before destroying them.
     UnregisterValidationInterface(peerLogic.get());
-    peerLogic.reset();
     if (g_connman) {
-        // make sure to stop all threads before g_connman is reset to nullptr as these threads might still be accessing it
         g_connman->Stop();
     }
+    peerLogic.reset();
     g_connman.reset();
 
     if (!fLiteMode && !fRPCInWarmup) {
@@ -263,7 +265,6 @@ void PrepareShutdown()
         flatdb6.Dump(sporkManager);
     }
 
-    UnregisterNodeSignals(GetNodeSignals());
     if (fDumpMempoolLater && gArgs.GetArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)) {
         DumpMempool();
     }
@@ -1588,7 +1589,6 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
 
     peerLogic.reset(new PeerLogicValidation(&connman));
     RegisterValidationInterface(peerLogic.get());
-    RegisterNodeSignals(GetNodeSignals());
 
     // sanitize comments per BIP-0014, format user agent and check total size
     std::vector<std::string> uacomments;
@@ -2127,6 +2127,7 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
     connOptions.nMaxFeeler = 1;
     connOptions.nBestHeight = chainActive.Height();
     connOptions.uiInterface = &uiInterface;
+    connOptions.m_msgproc = peerLogic.get();
     connOptions.nSendBufferMaxSize = 1000*gArgs.GetArg("-maxsendbuffer", DEFAULT_MAXSENDBUFFER);
     connOptions.nReceiveFloodSize = 1000*gArgs.GetArg("-maxreceivebuffer", DEFAULT_MAXRECEIVEBUFFER);
 

src/net.cpp

@@ -99,10 +99,6 @@ std::string strSubVersion;
 
 unordered_limitedmap<uint256, int64_t, StaticSaltedHasher> mapAlreadyAskedFor(MAX_INV_SZ, MAX_INV_SZ * 2);
 
-// Signals for message handling
-static CNodeSignals g_signals;
-CNodeSignals& GetNodeSignals() { return g_signals; }
-
 void CConnman::AddOneShot(const std::string& strDest)
 {
     LOCK(cs_vOneShots);
@@ -1201,7 +1197,7 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
     CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addr, CalculateKeyedNetGroup(addr), nonce, addr_bind, "", true);
     pnode->AddRef();
     pnode->fWhitelisted = whitelisted;
-    GetNodeSignals().InitializeNode(pnode, *this);
+    m_msgproc->InitializeNode(pnode);
 
     if (fLogIPs) {
         LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToString());
@@ -2187,7 +2183,7 @@ bool CConnman::OpenNetworkConnection(const CAddress& addrConnect, bool fCountFai
     if (fConnectToMasternode)
         pnode->fMasternode = true;
 
-    GetNodeSignals().InitializeNode(pnode, *this);
+    m_msgproc->InitializeNode(pnode);
     {
         LOCK(cs_vNodes);
         vNodes.push_back(pnode);
@@ -2214,16 +2210,16 @@ void CConnman::ThreadMessageHandler()
                 continue;
 
             // Receive messages
-            bool fMoreNodeWork = GetNodeSignals().ProcessMessages(pnode, *this, flagInterruptMsgProc);
+            bool fMoreNodeWork = m_msgproc->ProcessMessages(pnode, flagInterruptMsgProc);
             fMoreWork |= (fMoreNodeWork && !pnode->fPauseSend);
             if (flagInterruptMsgProc)
                 return;
-
             // Send messages
             {
                 LOCK(pnode->cs_sendProcessing);
-                GetNodeSignals().SendMessages(pnode, *this, flagInterruptMsgProc);
+                m_msgproc->SendMessages(pnode, flagInterruptMsgProc);
             }
+
             if (flagInterruptMsgProc)
                 return;
         }
@@ -2546,6 +2542,7 @@ bool CConnman::Start(CScheduler& scheduler, const Options& connOptions)
     //
     // Start threads
     //
+    assert(m_msgproc);
     InterruptSocks5(false);
     interruptNet.reset();
     flagInterruptMsgProc = false;
@@ -2709,9 +2706,10 @@ void CConnman::DeleteNode(CNode* pnode)
 {
     assert(pnode);
     bool fUpdateConnectionTime = false;
-    GetNodeSignals().FinalizeNode(pnode->GetId(), fUpdateConnectionTime);
-    if(fUpdateConnectionTime)
+    m_msgproc->FinalizeNode(pnode->GetId(), fUpdateConnectionTime);
+    if(fUpdateConnectionTime) {
         addrman.Connected(pnode->addr);
+    }
     delete pnode;
 }
 

src/net.h

@@ -37,7 +37,6 @@
 #include <arpa/inet.h>
 #endif
 
-#include <boost/signals2/signal.hpp>
 
 // "Optimistic send" was introduced in the beginning of the Bitcoin project. I assume this was done because it was
 // thought that "send" would be very cheap when the send buffer is empty. This is not true, as shown by profiling.
@@ -140,7 +139,7 @@ struct CSerializedNetMsg
     std::string command;
 };
 
-
+class NetEventsInterface;
 class CConnman
 {
 public:
@@ -161,6 +160,7 @@ class CConnman
         int nMaxFeeler = 0;
         int nBestHeight = 0;
         CClientUIInterface* uiInterface = nullptr;
+        NetEventsInterface* m_msgproc = nullptr;
         unsigned int nSendBufferMaxSize = 0;
         unsigned int nReceiveFloodSize = 0;
         uint64_t nMaxOutboundTimeframe = 0;
@@ -178,6 +178,7 @@ class CConnman
         nMaxFeeler = connOptions.nMaxFeeler;
         nBestHeight = connOptions.nBestHeight;
         clientInterface = connOptions.uiInterface;
+        m_msgproc = connOptions.m_msgproc;
         nSendBufferMaxSize = connOptions.nSendBufferMaxSize;
         nReceiveFloodSize = connOptions.nReceiveFloodSize;
         nMaxOutboundTimeframe = connOptions.nMaxOutboundTimeframe;
@@ -537,6 +538,7 @@ class CConnman
     int nMaxFeeler;
     std::atomic<int> nBestHeight;
     CClientUIInterface* clientInterface;
+    NetEventsInterface* m_msgproc;
 
     /** SipHasher seeds for deterministic randomness */
     const uint64_t nSeed0, nSeed1;
@@ -584,19 +586,18 @@ struct CombinerAll
     }
 };
 
-// Signals for message handling
-struct CNodeSignals
+/**
+ * Interface for message handling
+ */
+class NetEventsInterface
 {
-    boost::signals2::signal<bool (CNode*, CConnman&, std::atomic<bool>&), CombinerAll> ProcessMessages;
-    boost::signals2::signal<bool (CNode*, CConnman&, std::atomic<bool>&), CombinerAll> SendMessages;
-    boost::signals2::signal<void (CNode*, CConnman&)> InitializeNode;
-    boost::signals2::signal<void (NodeId, bool&)> FinalizeNode;
+public:
+    virtual bool ProcessMessages(CNode* pnode, std::atomic<bool>& interrupt) = 0;
+    virtual bool SendMessages(CNode* pnode, std::atomic<bool>& interrupt) = 0;
+    virtual void InitializeNode(CNode* pnode) = 0;
+    virtual void FinalizeNode(NodeId id, bool& update_connection_time) = 0;
 };
 
-
-CNodeSignals& GetNodeSignals();
-
-
 enum
 {
     LOCAL_NONE,   // unknown