From 97dd1c729d2bbedf9527b914c0cc8267b8a7c21b Mon Sep 17 00:00:00 2001
From: glozow <gloriajzhao@gmail.com>
Date: Thu, 15 Jul 2021 06:54:36 +0100
Subject: [PATCH] MOVEONLY: add helper function for calculating ancestors and
 checking limits

---
 src/txmempool.cpp | 72 ++++++++++++++++++++++++++++++-----------------
 src/txmempool.h   | 16 +++++++++++
 2 files changed, 62 insertions(+), 26 deletions(-)

diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index c5a4bbf1b0..53de2d2618 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -150,33 +150,15 @@ void CTxMemPool::UpdateTransactionsFromBlock(const std::vector<uint256> &vHashes
         UpdateForDescendants(it, mapMemPoolDescendantsToUpdate, setAlreadyIncluded);
     }
 }
-
-bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents /* = true */) const
+bool CTxMemPool::CalculateAncestorsAndCheckLimits(const CTxMemPoolEntry& entry,
+                                                  setEntries& setAncestors,
+                                                  CTxMemPoolEntry::Parents &staged_ancestors,
+                                                  uint64_t limitAncestorCount,
+                                                  uint64_t limitAncestorSize,
+                                                  uint64_t limitDescendantCount,
+                                                  uint64_t limitDescendantSize,
+                                                  std::string &errString) const
 {
-    CTxMemPoolEntry::Parents staged_ancestors;
-    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);
-                if (staged_ancestors.size() + 1 > limitAncestorCount) {
-                    errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
-                    return false;
-                }
-            }
-        }
-    } else {
-        // If we're not searching for parents, we require this to be an
-        // entry in the mempool already.
-        txiter it = mapTx.iterator_to(entry);
-        staged_ancestors = it->GetMemPoolParentsConst();
-    }
-
     size_t totalSizeWithAncestors = entry.GetTxSize();
 
     while (!staged_ancestors.empty()) {
@@ -216,6 +198,44 @@ bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntr
     return true;
 }
 
+bool CTxMemPool::CalculateMemPoolAncestors(const CTxMemPoolEntry &entry,
+                                           setEntries &setAncestors,
+                                           uint64_t limitAncestorCount,
+                                           uint64_t limitAncestorSize,
+                                           uint64_t limitDescendantCount,
+                                           uint64_t limitDescendantSize,
+                                           std::string &errString,
+                                           bool fSearchForParents /* = true */) const
+{
+    CTxMemPoolEntry::Parents staged_ancestors;
+    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);
+                if (staged_ancestors.size() + 1 > limitAncestorCount) {
+                    errString = strprintf("too many unconfirmed parents [limit: %u]", limitAncestorCount);
+                    return false;
+                }
+            }
+        }
+    } 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 CalculateAncestorsAndCheckLimits(entry, setAncestors, staged_ancestors,
+                                            limitAncestorCount, limitAncestorSize,
+                                            limitDescendantCount, limitDescendantSize, errString);
+}
+
 void CTxMemPool::UpdateAncestorsOf(bool add, txiter it, setEntries &setAncestors)
 {
     CTxMemPoolEntry::Parents parents = it->GetMemPoolParents();
diff --git a/src/txmempool.h b/src/txmempool.h
index ae4b16d377..76ca83c25c 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -585,6 +585,22 @@ private:
      */
     std::set<uint256> m_unbroadcast_txids GUARDED_BY(cs);
 
+
+    /**
+     * Helper function to populate setAncestors with all the ancestors of entry and apply ancestor
+     * and descendant limits.
+     * param@[out]  setAncestors        Will be populated with all mempool ancestors of entry.
+     * param@[in]   staged_ancestors    Should contain mempool parents of entry.
+     */
+    bool CalculateAncestorsAndCheckLimits(const CTxMemPoolEntry& entry,
+                                          setEntries& setAncestors,
+                                          CTxMemPoolEntry::Parents &staged_ancestors,
+                                          uint64_t limitAncestorCount,
+                                          uint64_t limitAncestorSize,
+                                          uint64_t limitDescendantCount,
+                                          uint64_t limitDescendantSize,
+                                          std::string &errString) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+
 public:
     indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
     std::map<uint256, CAmount> mapDeltas GUARDED_BY(cs);