[refactor] Add helper for iterating through mempool entries

Instead of reaching into the mapTx data structure, use a helper method
that provides the required vector of CTxMemPoolEntry pointers.

Author: stickies-v

src/kernel/mempool_entry.h

@@ -176,4 +176,6 @@ class CTxMemPoolEntry
     mutable Epoch::Marker m_epoch_marker; //!< epoch when last touched, useful for graph algorithms
 };
 
+using CTxMemPoolEntryRef = CTxMemPoolEntry::CTxMemPoolEntryRef;
+
 #endif // BITCOIN_KERNEL_MEMPOOL_ENTRY_H

src/node/interfaces.cpp

@@ -806,7 +806,7 @@ class ChainImpl : public Chain
     {
         if (!m_node.mempool) return;
         LOCK2(::cs_main, m_node.mempool->cs);
-        for (const CTxMemPoolEntry& entry : m_node.mempool->mapTx) {
+        for (const CTxMemPoolEntry& entry : m_node.mempool->entryAll()) {
             notifications.transactionAddedToMempool(entry.GetSharedTx());
         }
     }

src/rpc/mempool.cpp

@@ -344,14 +344,13 @@ UniValue MempoolToJSON(const CTxMemPool& pool, bool verbose, bool include_mempoo
         }
         LOCK(pool.cs);
         UniValue o(UniValue::VOBJ);
-        for (const CTxMemPoolEntry& e : pool.mapTx) {
-            const uint256& hash = e.GetTx().GetHash();
+        for (const CTxMemPoolEntry& e : pool.entryAll()) {
             UniValue info(UniValue::VOBJ);
             entryToJSON(pool, info, e);
             // Mempool has unique entries so there is no advantage in using
             // UniValue::pushKV, which checks if the key already exists in O(N).
             // UniValue::pushKVEnd is used instead which currently is O(1).
-            o.pushKVEnd(hash.ToString(), info);
+            o.pushKVEnd(e.GetTx().GetHash().ToString(), info);
         }
         return o;
     } else {

src/txmempool.cpp

@@ -836,6 +836,18 @@ static TxMempoolInfo GetInfo(CTxMemPool::indexed_transaction_set::const_iterator
     return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), it->GetFee(), it->GetTxSize(), it->GetModifiedFee() - it->GetFee()};
 }
 
+std::vector<CTxMemPoolEntryRef> CTxMemPool::entryAll() const
+{
+    AssertLockHeld(cs);
+
+    std::vector<CTxMemPoolEntryRef> ret;
+    ret.reserve(mapTx.size());
+    for (const auto& it : GetSortedDepthAndScore()) {
+        ret.emplace_back(*it);
+    }
+    return ret;
+}
+
 std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
 {
     LOCK(cs);

src/txmempool.h

@@ -695,6 +695,7 @@ class CTxMemPool
     /** Returns info for a transaction if its entry_sequence < last_sequence */
     TxMempoolInfo info_for_relay(const GenTxid& gtxid, uint64_t last_sequence) const;
 
+    std::vector<CTxMemPoolEntryRef> entryAll() const EXCLUSIVE_LOCKS_REQUIRED(cs);
     std::vector<TxMempoolInfo> infoAll() const;
 
     size_t DynamicMemoryUsage() const;