addrman: Introduce helper to generalize looking up an addrman entry

Unused until later commit.

Co-authored-by: Martin Zumsande <mzumsande@gmail.com>

src/addrman.cpp

@@ -792,6 +792,21 @@ std::pair<CAddress, NodeSeconds> AddrManImpl::Select_(bool newOnly) const
     }
 }
 
+int AddrManImpl::GetEntry(bool use_tried, size_t bucket, size_t position) const
+{
+    AssertLockHeld(cs);
+
+    assert(position < ADDRMAN_BUCKET_SIZE);
+
+    if (use_tried) {
+        assert(bucket < ADDRMAN_TRIED_BUCKET_COUNT);
+        return vvTried[bucket][position];
+    } else {
+        assert(bucket < ADDRMAN_NEW_BUCKET_COUNT);
+        return vvNew[bucket][position];
+    }
+}
+
 std::vector<CAddress> AddrManImpl::GetAddr_(size_t max_addresses, size_t max_pct, std::optional<Network> network) const
 {
     AssertLockHeld(cs);

src/addrman_impl.h

@@ -253,6 +253,12 @@ private:
 
     std::pair<CAddress, NodeSeconds> Select_(bool newOnly) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
+    /** Helper to generalize looking up an addrman entry from either table.
+     *
+     *  @return  int The nid of the entry or -1 if the addrman position is empty.
+     * */
+    int GetEntry(bool use_tried, size_t bucket, size_t position) const EXCLUSIVE_LOCKS_REQUIRED(cs);
+
     std::vector<CAddress> GetAddr_(size_t max_addresses, size_t max_pct, std::optional<Network> network) const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     void Connected_(const CService& addr, NodeSeconds time) EXCLUSIVE_LOCKS_REQUIRED(cs);