From 69872195773870de8ee6521c9f555d60395a5ad9 Mon Sep 17 00:00:00 2001
From: Matt Corallo <git@bluematt.me>
Date: Sun, 18 Dec 2016 23:26:20 -0800
Subject: [PATCH] Add a CValidationInterface::NewPoWValidBlock callback

---
 src/validation.cpp          | 5 +++++
 src/validationinterface.cpp | 3 +++
 src/validationinterface.h   | 6 ++++++
 3 files changed, 14 insertions(+)

diff --git a/src/validation.cpp b/src/validation.cpp
index d6bd789647..20d75d957f 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3096,6 +3096,11 @@ static bool AcceptBlock(const std::shared_ptr<const CBlock>& pblock, CValidation
         return error("%s: %s", __func__, FormatStateMessage(state));
     }
 
+    // Header is valid/has work, merkle tree and segwit merkle tree are good...RELAY NOW
+    // (but if it does not build on our best tip, let the SendMessages loop relay it)
+    if (!IsInitialBlockDownload() && chainActive.Tip() == pindex->pprev)
+        GetMainSignals().NewPoWValidBlock(pindex, pblock);
+
     int nHeight = pindex->nHeight;
 
     // Write block to history file
diff --git a/src/validationinterface.cpp b/src/validationinterface.cpp
index 215c342dea..d4121a28bc 100644
--- a/src/validationinterface.cpp
+++ b/src/validationinterface.cpp
@@ -22,6 +22,7 @@ void RegisterValidationInterface(CValidationInterface* pwalletIn) {
     g_signals.BlockChecked.connect(boost::bind(&CValidationInterface::BlockChecked, pwalletIn, _1, _2));
     g_signals.ScriptForMining.connect(boost::bind(&CValidationInterface::GetScriptForMining, pwalletIn, _1));
     g_signals.BlockFound.connect(boost::bind(&CValidationInterface::ResetRequestCount, pwalletIn, _1));
+    g_signals.NewPoWValidBlock.connect(boost::bind(&CValidationInterface::NewPoWValidBlock, pwalletIn, _1, _2));
 }
 
 void UnregisterValidationInterface(CValidationInterface* pwalletIn) {
@@ -34,6 +35,7 @@ void UnregisterValidationInterface(CValidationInterface* pwalletIn) {
     g_signals.UpdatedTransaction.disconnect(boost::bind(&CValidationInterface::UpdatedTransaction, pwalletIn, _1));
     g_signals.SyncTransaction.disconnect(boost::bind(&CValidationInterface::SyncTransaction, pwalletIn, _1, _2, _3));
     g_signals.UpdatedBlockTip.disconnect(boost::bind(&CValidationInterface::UpdatedBlockTip, pwalletIn, _1, _2, _3));
+    g_signals.NewPoWValidBlock.disconnect(boost::bind(&CValidationInterface::NewPoWValidBlock, pwalletIn, _1, _2));
 }
 
 void UnregisterAllValidationInterfaces() {
@@ -46,4 +48,5 @@ void UnregisterAllValidationInterfaces() {
     g_signals.UpdatedTransaction.disconnect_all_slots();
     g_signals.SyncTransaction.disconnect_all_slots();
     g_signals.UpdatedBlockTip.disconnect_all_slots();
+    g_signals.NewPoWValidBlock.disconnect_all_slots();
 }
diff --git a/src/validationinterface.h b/src/validationinterface.h
index 717026389c..594072719c 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -8,6 +8,7 @@
 
 #include <boost/signals2/signal.hpp>
 #include <boost/shared_ptr.hpp>
+#include <memory>
 
 class CBlock;
 class CBlockIndex;
@@ -40,6 +41,7 @@ protected:
     virtual void BlockChecked(const CBlock&, const CValidationState&) {}
     virtual void GetScriptForMining(boost::shared_ptr<CReserveScript>&) {};
     virtual void ResetRequestCount(const uint256 &hash) {};
+    virtual void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& block) {};
     friend void ::RegisterValidationInterface(CValidationInterface*);
     friend void ::UnregisterValidationInterface(CValidationInterface*);
     friend void ::UnregisterAllValidationInterfaces();
@@ -66,6 +68,10 @@ struct CMainSignals {
     boost::signals2::signal<void (boost::shared_ptr<CReserveScript>&)> ScriptForMining;
     /** Notifies listeners that a block has been successfully mined */
     boost::signals2::signal<void (const uint256 &)> BlockFound;
+    /**
+     * Notifies listeners that a block which builds directly on our current tip
+     * has been received and connected to the headers tree, though not validated yet */
+    boost::signals2::signal<void (const CBlockIndex *, const std::shared_ptr<const CBlock>&)> NewPoWValidBlock;
 };
 
 CMainSignals& GetMainSignals();