mempool: add notification for added/removed entries

Add notification signals to make it possible to subscribe to mempool
changes:

- NotifyEntryAdded(CTransactionRef)>
- NotifyEntryRemoved(CTransactionRef, MemPoolRemovalReason)>

Also add a mempool removal reason enumeration, which is passed to the
removed notification based on why the transaction was removed from
the mempool.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 881292d613..d382e121bc 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -956,7 +956,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
             if (plTxnReplaced)
                 plTxnReplaced->push_back(it->GetSharedTx());
         }
-        pool.RemoveStaged(allConflicting, false);
+        pool.RemoveStaged(allConflicting, false, MemPoolRemovalReason::REPLACED);
 
         // This transaction should only count for fee estimation if
         // the node is not behind and it is not dependent on any other
@@ -2166,7 +2166,7 @@ bool static DisconnectTip(CValidationState& state, const CChainParams& chainpara
             // ignore validation errors in resurrected transactions
             CValidationState stateDummy;
             if (tx.IsCoinBase() || !AcceptToMemoryPool(mempool, stateDummy, it, false, NULL, NULL, true)) {
-                mempool.removeRecursive(tx);
+                mempool.removeRecursive(tx, MemPoolRemovalReason::REORG);
             } else if (mempool.exists(tx.GetHash())) {
                 vHashUpdate.push_back(tx.GetHash());
             }
@@ -3597,7 +3597,7 @@ bool CVerifyDB::VerifyDB(const CChainParams& chainparams, CCoinsView *coinsview,
             return error("VerifyDB(): *** ReadBlockFromDisk failed at %d, hash=%s", pindex->nHeight, pindex->GetBlockHash().ToString());
         // check level 1: verify block validity
         if (nCheckLevel >= 1 && !CheckBlock(block, state, chainparams.GetConsensus()))
-            return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__, 
+            return error("%s: *** found bad block at %d, hash=%s (%s)\n", __func__,
                          pindex->nHeight, pindex->GetBlockHash().ToString(), FormatStateMessage(state));
         // check level 2: verify undo validity
         if (nCheckLevel >= 2 && pindex) {
@@ -3768,7 +3768,7 @@ bool LoadBlockIndex(const CChainParams& chainparams)
     return true;
 }
 
-bool InitBlockIndex(const CChainParams& chainparams) 
+bool InitBlockIndex(const CChainParams& chainparams)
 {
     LOCK(cs_main);