net: rearrange so that socket accesses can be grouped together

src/net.cpp

@@ -1152,9 +1152,6 @@ void CConnman::ThreadSocketHandler()
             {
                 if (pnode->hSocket == INVALID_SOCKET)
                     continue;
-                FD_SET(pnode->hSocket, &fdsetError);
-                hSocketMax = std::max(hSocketMax, pnode->hSocket);
-                have_fds = true;
 
                 // Implement the following logic:
                 // * If there is data to send, select() for sending data. As this only
@@ -1166,15 +1163,23 @@ void CConnman::ThreadSocketHandler()
                 //   receiving data.
                 // * Hand off all complete messages to the processor, to be handled without
                 //   blocking here.
+
+                bool select_recv = !pnode->fPauseRecv;
+                bool select_send;
                 {
                     LOCK(pnode->cs_vSend);
-                    if (!pnode->vSendMsg.empty()) {
+                    select_send = !pnode->vSendMsg.empty();
+                }
+
+                FD_SET(pnode->hSocket, &fdsetError);
+                hSocketMax = std::max(hSocketMax, pnode->hSocket);
+                have_fds = true;
+
+                if (select_send) {
                     FD_SET(pnode->hSocket, &fdsetSend);
                     continue;
                 }
-                }
-                {
-                    if (!pnode->fPauseRecv)
+                if (select_recv) {
                     FD_SET(pnode->hSocket, &fdsetRecv);
                 }
             }
@@ -1229,9 +1234,15 @@ void CConnman::ThreadSocketHandler()
             //
             // Receive
             //
+            bool recvSet = false;
+            bool sendSet = false;
+            bool errorSet = false;
             if (pnode->hSocket == INVALID_SOCKET)
                 continue;
-            if (FD_ISSET(pnode->hSocket, &fdsetRecv) || FD_ISSET(pnode->hSocket, &fdsetError))
+            recvSet = FD_ISSET(pnode->hSocket, &fdsetRecv);
+            sendSet = FD_ISSET(pnode->hSocket, &fdsetSend);
+            errorSet = FD_ISSET(pnode->hSocket, &fdsetError);
+            if (recvSet || errorSet)
             {
                 {
                     {
@@ -1286,9 +1297,7 @@ void CConnman::ThreadSocketHandler()
             //
             // Send
             //
-            if (pnode->hSocket == INVALID_SOCKET)
-                continue;
-            if (FD_ISSET(pnode->hSocket, &fdsetSend))
+            if (sendSet)
             {
                 LOCK(pnode->cs_vSend);
                 size_t nBytes = SocketSendData(pnode);