Reimplement GetTransactionAncestry() to not rely on cached data

In preparation for removing ancestor data from CTxMemPoolEntry, recalculate the
ancestor statistics on demand wherever needed.

src/txmempool.cpp

@@ -1217,15 +1217,31 @@ uint64_t CTxMemPool::CalculateDescendantMaximum(txiter entry) const {
     return maximum;
 }
 
+std::tuple<size_t, size_t, CAmount> CTxMemPool::CalculateAncestorData(const CTxMemPoolEntry& entry) const
+{
+    auto ancestors = m_txgraph->GetAncestors(entry, TxGraph::Level::MAIN);
+
+    size_t ancestor_count = ancestors.size();
+    size_t ancestor_size = 0;
+    CAmount ancestor_fees = 0;
+    for (auto tx: ancestors) {
+        const CTxMemPoolEntry& anc = static_cast<const CTxMemPoolEntry&>(*tx);
+        ancestor_size += anc.GetTxSize();
+        ancestor_fees += anc.GetModifiedFee();
+    }
+    return {ancestor_count, ancestor_size, ancestor_fees};
+}
+
 void CTxMemPool::GetTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& descendants, size_t* const ancestorsize, CAmount* const ancestorfees) const {
     LOCK(cs);
     auto it = mapTx.find(txid);
     ancestors = descendants = 0;
     if (it != mapTx.end()) {
-        ancestors = it->GetCountWithAncestors();
-        if (ancestorsize) *ancestorsize = it->GetSizeWithAncestors();
-        if (ancestorfees) *ancestorfees = it->GetModFeesWithAncestors();
+        auto [ancestor_count, ancestor_size, ancestor_fees] = CalculateAncestorData(*it);
         descendants = CalculateDescendantMaximum(it);
+        ancestors = ancestor_count;
+        if (ancestorsize) *ancestorsize = ancestor_size;
+        if (ancestorfees) *ancestorfees = ancestor_fees;
     }
 }
 

src/txmempool.h

@@ -285,6 +285,9 @@ public:
     using Limits = kernel::MemPoolLimits;
 
     uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+
+    std::tuple<size_t, size_t, CAmount> CalculateAncestorData(const CTxMemPoolEntry& entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+
 private:
     typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;