SyncTransaction->TxAddedToMempool/BlockConnected/Disconnected

This simplifies fixing the wallet-returns-stale-info issue as we
can now hold cs_wallet across an entire block instead of only
per-tx (though we only actually do so in the next commit).

This change also removes the NOT_IN_BLOCK constant in favor of only
passing the CBlockIndex* parameter to SyncTransactions when a new
block is being connected, instead of also when a block is being
disconnected.

This change adds a parameter to BlockConnectedDisconnected which
lists the transactions which were removed from mempool due to
confliction as a result of this operation. While its somewhat of a
shame to make block-validation-logic generate a list of mempool
changes to be included in its generated callbacks, fixing this isnt
too hard.

Further in this change-set, CValidationInterface starts listening
to mempool directly, placing it in the middle and giving it a bit
of logic to know how to route notifications from block-validation,
mempool, etc (though not listening for conflicted-removals yet).

1 files changed, 14 insertions, 13 deletions

diff --git a/src/validationinterface.h b/src/validationinterface.h
index 7f13a29d23..ddb0afbb4d 100644
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -10,13 +10,14 @@
 #include <boost/shared_ptr.hpp>
 #include <memory>
 
+#include "primitives/transaction.h" // CTransaction(Ref)
+
 class CBlock;
 class CBlockIndex;
 struct CBlockLocator;
 class CBlockIndex;
 class CConnman;
 class CReserveScript;
-class CTransaction;
 class CValidationInterface;
 class CValidationState;
 class uint256;
@@ -33,7 +34,9 @@ void UnregisterAllValidationInterfaces();
 class CValidationInterface {
 protected:
     virtual void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) {}
-    virtual void SyncTransaction(const CTransaction &tx, const CBlockIndex *pindex, int posInBlock) {}
+    virtual void TransactionAddedToMempool(const CTransactionRef &ptxn) {}
+    virtual void BlockConnected(const std::shared_ptr<const CBlock> &block, const CBlockIndex *pindex, const std::vector<CTransactionRef> &txnConflicted) {}
+    virtual void BlockDisconnected(const std::shared_ptr<const CBlock> &block) {}
     virtual void SetBestChain(const CBlockLocator &locator) {}
     virtual void UpdatedTransaction(const uint256 &hash) {}
     virtual void Inventory(const uint256 &hash) {}
@@ -50,17 +53,15 @@ protected:
 struct CMainSignals {
     /** Notifies listeners of updated block chain tip */
     boost::signals2::signal<void (const CBlockIndex *, const CBlockIndex *, bool fInitialDownload)> UpdatedBlockTip;
-    /** A posInBlock value for SyncTransaction calls for transactions not
-     * included in connected blocks such as transactions removed from mempool,
-     * accepted to mempool or appearing in disconnected blocks.*/
-    static const int SYNC_TRANSACTION_NOT_IN_BLOCK = -1;
-    /** Notifies listeners of updated transaction data (transaction, and
-     * optionally the block it is found in). Called with block data when
-     * transaction is included in a connected block, and without block data when
-     * transaction was accepted to mempool, removed from mempool (only when
-     * removal was due to conflict from connected block), or appeared in a
-     * disconnected block.*/
-    boost::signals2::signal<void (const CTransaction &, const CBlockIndex *pindex, int posInBlock)> SyncTransaction;
+    /** Notifies listeners of a transaction having been added to mempool. */
+    boost::signals2::signal<void (const CTransactionRef &)> TransactionAddedToMempool;
+    /**
+     * Notifies listeners of a block being connected.
+     * Provides a vector of transactions evicted from the mempool as a result.
+     */
+    boost::signals2::signal<void (const std::shared_ptr<const CBlock> &, const CBlockIndex *pindex, const std::vector<CTransactionRef> &)> BlockConnected;
+    /** Notifies listeners of a block being disconnected */
+    boost::signals2::signal<void (const std::shared_ptr<const CBlock> &)> BlockDisconnected;
     /** Notifies listeners of an updated transaction without new data (for now: a coinbase potentially becoming visible). */
     boost::signals2::signal<void (const uint256 &)> UpdatedTransaction;
     /** Notifies listeners of a new active block chain. */