Merge bitcoin/bitcoin#24356: refactor: replace CConnman::SocketEvents() with mockable Sock::WaitMany()

6e68ccbefea6509c61fc4405a391a517c6057bb0 net: use Sock::WaitMany() instead of CConnman::SocketEvents() (Vasil Dimov)
ae263460bab9e6aa112dc99790c8ef06a56ec838 net: introduce Sock::WaitMany() (Vasil Dimov)
cc74459768063a923fb6220a4f420eaf211aee7b net: also wait for exceptional events in Sock::Wait() (Vasil Dimov)

Pull request description:

  _This is a piece of #21878, chopped off to ease review._

  `Sock::Wait()` waits for IO events on one socket. Introduce a similar `virtual` method `WaitMany()` that waits simultaneously for IO events on more than one socket.

  Use `WaitMany()` instead of `CConnman::SocketEvents()` (and ditch the latter). Given that the former is a `virtual` method, it can be mocked by unit and fuzz tests. This will help to make bigger parts of `CConnman` testable (unit and fuzz).

ACKs for top commit:
  laanwj:
    Code review ACK 6e68ccbefea6509c61fc4405a391a517c6057bb0
  jonatack:
    re-ACK 6e68ccbefea6509c61fc4405a391a517c6057bb0 per `git range-diff e18fd47 6747729 6e68ccb`, and verified rebase to master and debug build

Tree-SHA512: 917fb6ad880d64d3af1ebb301c06fbd01afd8ff043f49e4055a088ebed6affb7ffe1dcf59292d822f10de5f323b6d52d557cb081dd7434634995f9148efcf08f

1 files changed, 7 insertions, 31 deletions

diff --git a/src/net.h b/src/net.h
index d6b605652b..bf169649c0 100644
--- a/src/net.h
+++ b/src/net.h
@@ -980,28 +980,9 @@ private:
     /**
      * Generate a collection of sockets to check for IO readiness.
      * @param[in] nodes Select from these nodes' sockets.
-     * @param[out] recv_set Sockets to check for read readiness.
-     * @param[out] send_set Sockets to check for write readiness.
-     * @param[out] error_set Sockets to check for errors.
-     * @return true if at least one socket is to be checked (the returned set is not empty)
+     * @return sockets to check for readiness
      */
-    bool GenerateSelectSet(const std::vector<CNode*>& nodes,
-                           std::set<SOCKET>& recv_set,
-                           std::set<SOCKET>& send_set,
-                           std::set<SOCKET>& error_set);
-
-    /**
-     * Check which sockets are ready for IO.
-     * @param[in] nodes Select from these nodes' sockets.
-     * @param[out] recv_set Sockets which are ready for read.
-     * @param[out] send_set Sockets which are ready for write.
-     * @param[out] error_set Sockets which have errors.
-     * This calls `GenerateSelectSet()` to gather a list of sockets to check.
-     */
-    void SocketEvents(const std::vector<CNode*>& nodes,
-                      std::set<SOCKET>& recv_set,
-                      std::set<SOCKET>& send_set,
-                      std::set<SOCKET>& error_set);
+    Sock::EventsPerSock GenerateWaitSockets(Span<CNode* const> nodes);
 
     /**
      * Check connected and listening sockets for IO readiness and process them accordingly.
@@ -1010,23 +991,18 @@ private:
 
     /**
      * Do the read/write for connected sockets that are ready for IO.
-     * @param[in] nodes Nodes to process. The socket of each node is checked against
-     * `recv_set`, `send_set` and `error_set`.
-     * @param[in] recv_set Sockets that are ready for read.
-     * @param[in] send_set Sockets that are ready for send.
-     * @param[in] error_set Sockets that have an exceptional condition (error).
+     * @param[in] nodes Nodes to process. The socket of each node is checked against `what`.
+     * @param[in] events_per_sock Sockets that are ready for IO.
      */
     void SocketHandlerConnected(const std::vector<CNode*>& nodes,
-                                const std::set<SOCKET>& recv_set,
-                                const std::set<SOCKET>& send_set,
-                                const std::set<SOCKET>& error_set)
+                                const Sock::EventsPerSock& events_per_sock)
         EXCLUSIVE_LOCKS_REQUIRED(!m_total_bytes_sent_mutex, !mutexMsgProc);
 
     /**
      * Accept incoming connections, one from each read-ready listening socket.
-     * @param[in] recv_set Sockets that are ready for read.
+     * @param[in] events_per_sock Sockets that are ready for IO.
      */
-    void SocketHandlerListening(const std::set<SOCKET>& recv_set);
+    void SocketHandlerListening(const Sock::EventsPerSock& events_per_sock);
 
     void ThreadSocketHandler() EXCLUSIVE_LOCKS_REQUIRED(!m_total_bytes_sent_mutex, !mutexMsgProc);
     void ThreadDNSAddressSeed() EXCLUSIVE_LOCKS_REQUIRED(!m_addr_fetches_mutex, !m_nodes_mutex);