From fef1010199b70026fd6d56ebac5c277552757307 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Tue, 4 Oct 2016 13:49:44 -0400
Subject: [PATCH] Use CValidationInterface from chain logic to notify peer
 logic

This adds a new CValidationInterface subclass, defined in main.h,
to receive notifications of UpdatedBlockTip and use that to push
blocks to peers, instead of doing it directly from
ActivateBestChain.
---
 src/init.cpp |  5 +++++
 src/main.cpp | 56 ++++++++++++++++++++++++++++++----------------------
 src/main.h   | 11 +++++++++++
 3 files changed, 48 insertions(+), 24 deletions(-)

diff --git a/src/init.cpp b/src/init.cpp
index eefef7ba0b..7045b3e6e1 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -72,6 +72,7 @@ static const bool DEFAULT_DISABLE_SAFEMODE = false;
 static const bool DEFAULT_STOPAFTERBLOCKIMPORT = false;
 
 std::unique_ptr<CConnman> g_connman;
+std::unique_ptr<PeerLogicValidation> peerLogic;
 
 #if ENABLE_ZMQ
 static CZMQNotificationInterface* pzmqNotificationInterface = NULL;
@@ -200,6 +201,8 @@ void Shutdown()
         pwalletMain->Flush(false);
 #endif
     MapPort(false);
+    UnregisterValidationInterface(peerLogic.get());
+    peerLogic.reset();
     g_connman.reset();
 
     StopTorControl();
@@ -1102,6 +1105,8 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
     g_connman = std::unique_ptr<CConnman>(new CConnman(GetRand(std::numeric_limits<uint64_t>::max()), GetRand(std::numeric_limits<uint64_t>::max())));
     CConnman& connman = *g_connman;
 
+    peerLogic.reset(new PeerLogicValidation(&connman));
+    RegisterValidationInterface(peerLogic.get());
     RegisterNodeSignals(GetNodeSignals());
 
     // sanitize comments per BIP-0014, format user agent and check total size
diff --git a/src/main.cpp b/src/main.cpp
index 2eb641e543..e042a73822 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3073,30 +3073,6 @@ bool ActivateBestChain(CValidationState &state, const CChainParams& chainparams,
         if (pindexFork != pindexNewTip) {
             uiInterface.NotifyBlockTip(fInitialDownload, pindexNewTip);
 
-            if (!fInitialDownload) {
-                // Find the hashes of all blocks that weren't previously in the best chain.
-                std::vector<uint256> vHashes;
-                CBlockIndex *pindexToAnnounce = pindexNewTip;
-                while (pindexToAnnounce != pindexFork) {
-                    vHashes.push_back(pindexToAnnounce->GetBlockHash());
-                    pindexToAnnounce = pindexToAnnounce->pprev;
-                    if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
-                        // Limit announcements in case of a huge reorganization.
-                        // Rely on the peer's synchronization mechanism in that case.
-                        break;
-                    }
-                }
-                // Relay inventory, but don't relay old inventory during initial block download.
-                if(connman) {
-                    connman->ForEachNode([nNewHeight, &vHashes](CNode* pnode) {
-                        if (nNewHeight > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : 0)) {
-                            BOOST_REVERSE_FOREACH(const uint256& hash, vHashes) {
-                                pnode->PushBlockHash(hash);
-                            }
-                        }
-                    });
-                }
-            }
             // Notify external listeners about the new tip.
             GetMainSignals().UpdatedBlockTip(pindexNewTip, pindexFork, fInitialDownload);
         }
@@ -4682,6 +4658,38 @@ std::string GetWarnings(const std::string& strFor)
 
 
 
+//////////////////////////////////////////////////////////////////////////////
+//
+// blockchain -> download logic notification
+//
+
+void PeerLogicValidation::UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) {
+    const int nNewHeight = pindexNew->nHeight;
+
+    if (!fInitialDownload) {
+        // Find the hashes of all blocks that weren't previously in the best chain.
+        std::vector<uint256> vHashes;
+        const CBlockIndex *pindexToAnnounce = pindexNew;
+        while (pindexToAnnounce != pindexFork) {
+            vHashes.push_back(pindexToAnnounce->GetBlockHash());
+            pindexToAnnounce = pindexToAnnounce->pprev;
+            if (vHashes.size() == MAX_BLOCKS_TO_ANNOUNCE) {
+                // Limit announcements in case of a huge reorganization.
+                // Rely on the peer's synchronization mechanism in that case.
+                break;
+            }
+        }
+        // Relay inventory, but don't relay old inventory during initial block download.
+        connman->ForEachNode([nNewHeight, &vHashes](CNode* pnode) {
+            if (nNewHeight > (pnode->nStartingHeight != -1 ? pnode->nStartingHeight - 2000 : 0)) {
+                BOOST_REVERSE_FOREACH(const uint256& hash, vHashes) {
+                    pnode->PushBlockHash(hash);
+                }
+            }
+        });
+    }
+}
+
 //////////////////////////////////////////////////////////////////////////////
 //
 // Messages
diff --git a/src/main.h b/src/main.h
index 3c587569f6..bb5e26b0b2 100644
--- a/src/main.h
+++ b/src/main.h
@@ -16,6 +16,7 @@
 #include "net.h"
 #include "script/script_error.h"
 #include "sync.h"
+#include "validationinterface.h"
 #include "versionbits.h"
 
 #include <algorithm>
@@ -527,6 +528,16 @@ void RegisterNodeSignals(CNodeSignals& nodeSignals);
 /** Unregister a network node */
 void UnregisterNodeSignals(CNodeSignals& nodeSignals);
 
+class PeerLogicValidation : public CValidationInterface {
+private:
+    CConnman* connman;
+
+public:
+    PeerLogicValidation(CConnman* connmanIn) : connman(connmanIn) {}
+
+    virtual void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload);
+};
+
 struct CNodeStateStats {
     int nMisbehavior;
     int nSyncHeight;