Use txgraph to calculate ancestors

diff --git a/src/policy/rbf.cpp b/src/policy/rbf.cpp
index fdf6f53c..c78fed8e 100644
--- a/src/policy/rbf.cpp
+++ b/src/policy/rbf.cpp
@@ -39,7 +39,7 @@ RBFTransactionState IsRBFOptIn(const CTransaction& tx, const CTxMemPool& pool)
     // If all the inputs have nSequence >= maxint-1, it still might be
     // signaled for RBF if any unconfirmed parents have signaled.
     const auto& entry{*Assert(pool.GetEntry(tx.GetHash()))};
-    auto ancestors{pool.CalculateMemPoolAncestors(entry, /*fSearchForParents=*/false)};
+    auto ancestors{pool.CalculateMemPoolAncestors(entry)};
 
     for (CTxMemPool::txiter it : ancestors) {
         if (SignalsOptInRBF(it->GetTx())) {
diff --git a/src/rpc/mempool.cpp b/src/rpc/mempool.cpp
index 01870ef3..7a016335 100644
--- a/src/rpc/mempool.cpp
+++ b/src/rpc/mempool.cpp
@@ -474,7 +474,7 @@ static RPCHelpMan getmempoolancestors()
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Transaction not in mempool");
     }
 
-    auto ancestors{mempool.CalculateMemPoolAncestors(*entry, /*fSearchForParents=*/false)};
+    auto ancestors{mempool.CalculateMemPoolAncestors(*entry)};
 
     if (!fVerbose) {
         UniValue o(UniValue::VARR);
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index f83b4544..2b8bec25 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -99,31 +99,6 @@ void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<Txid>& vHashesToU
     }
 }
 
-CTxMemPool::setEntries CTxMemPool::CalculateAncestors(CTxMemPoolEntry::Parents& staged_ancestors) const
-{
-    setEntries ancestors;
-
-    while (!staged_ancestors.empty()) {
-        const CTxMemPoolEntry& stage = staged_ancestors.begin()->get();
-        txiter stageit = mapTx.iterator_to(stage);
-
-        ancestors.insert(stageit);
-        staged_ancestors.erase(stage);
-
-        const CTxMemPoolEntry::Parents& parents = stageit->GetMemPoolParentsConst();
-        for (const CTxMemPoolEntry& parent : parents) {
-            txiter parent_it = mapTx.iterator_to(parent);
-
-            // If this is a new ancestor, add it.
-            if (ancestors.count(parent_it) == 0) {
-                staged_ancestors.insert(parent);
-            }
-        }
-    }
-
-    return ancestors;
-}
-
 util::Result<void> CTxMemPool::CheckPackageLimits(const Package& package,
                                                   const int64_t total_vsize) const
 {
@@ -138,31 +113,42 @@ bool CTxMemPool::HasDescendants(const Txid& txid) const
     return m_txgraph->GetDescendants(*entry, TxGraph::Level::MAIN).size() > 1;
 }
 
-CTxMemPool::setEntries CTxMemPool::CalculateMemPoolAncestors(
-    const CTxMemPoolEntry &entry,
-    bool fSearchForParents /* = true */) const
+CTxMemPool::setEntries CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry) const
 {
-    CTxMemPoolEntry::Parents staged_ancestors;
+    auto ancestors = m_txgraph->GetAncestors(entry, TxGraph::Level::MAIN);
+    setEntries ret;
+    if (ancestors.size() > 0) {
+        for (auto ancestor : ancestors) {
+            if (ancestor != &entry) {
+                ret.insert(mapTx.iterator_to(static_cast<const CTxMemPoolEntry&>(*ancestor)));
+            }
+        }
+        return ret;
+    }
+
+    // If we didn't get anything back, the transaction is not in the graph.
+    // Find each parent and call GetAncestors on each.
+    setEntries staged_parents;
     const CTransaction &tx = entry.GetTx();
 
-    if (fSearchForParents) {
-        // Get parents of this transaction that are in the mempool
-        // GetMemPoolParents() is only valid for entries in the mempool, so we
-        // iterate mapTx to find parents.
-        for (unsigned int i = 0; i < tx.vin.size(); i++) {
-            std::optional<txiter> piter = GetIter(tx.vin[i].prevout.hash);
-            if (piter) {
-                staged_ancestors.insert(**piter);
-            }
+    // Get parents of this transaction that are in the mempool
+    // GetMemPoolParents() is only valid for entries in the mempool, so we
+    // iterate mapTx to find parents.
+    for (unsigned int i = 0; i < tx.vin.size(); i++) {
+        std::optional<txiter> piter = GetIter(tx.vin[i].prevout.hash);
+        if (piter) {
+            staged_parents.insert(*piter);
+        }
+    }
+
+    for (const auto& parent : staged_parents) {
+        auto parent_ancestors = m_txgraph->GetAncestors(*parent, TxGraph::Level::MAIN);
+        for (auto ancestor : parent_ancestors) {
+            ret.insert(mapTx.iterator_to(static_cast<const CTxMemPoolEntry&>(*ancestor)));
         }
-    } else {
-        // If we're not searching for parents, we require this to already be an
-        // entry in the mempool and use the entry's cached parents.
-        txiter it = mapTx.iterator_to(entry);
-        staged_ancestors = it->GetMemPoolParentsConst();
     }
 
-    return CalculateAncestors(staged_ancestors);
+    return ret;
 }
 
 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it)
diff --git a/src/txmempool.h b/src/txmempool.h
index d2b7f232..3c488215 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -304,17 +304,6 @@ private:
      */
     std::set<Txid> m_unbroadcast_txids GUARDED_BY(cs);
 
-
-    /**
-     * Helper function to calculate all in-mempool ancestors of staged_ancestors
-     *
-     * @param[in]   staged_ancestors    Should contain entries in the mempool.
-     *
-     * @return all in-mempool ancestors
-     */
-    setEntries CalculateAncestors(CTxMemPoolEntry::Parents &staged_ancestors)
-            const EXCLUSIVE_LOCKS_REQUIRED(cs);
-
     static TxMempoolInfo GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it)
     {
         return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), it->GetFee(), it->GetTxSize(), it->GetModifiedFee() - it->GetFee()};
@@ -429,18 +418,13 @@ public:
     }
 
     /**
-     * Calculate all in-mempool ancestors of entry.
-     * (these are all calculated including the tx itself)
+     * Calculate all in-mempool ancestors of entry (not including the tx itself)
      *
      * @param[in]   entry               CTxMemPoolEntry of which all in-mempool ancestors are calculated
-     * @param[in]   fSearchForParents   Whether to search a tx's vin for in-mempool parents, or look
-     *                                  up parents from mapLinks. Must be true for entries not in
-     *                                  the mempool
      *
      * @return all in-mempool ancestors
      */
-    setEntries CalculateMemPoolAncestors(const CTxMemPoolEntry& entry,
-                                   bool fSearchForParents = true) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+    setEntries CalculateMemPoolAncestors(const CTxMemPoolEntry& entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     bool HasDescendants(const Txid& txid) const;