Factorize handling of asynchronous receives.

[simgrid.git] / examples / c / dht-kademlia / node.c

diff --git a/examples/c/dht-kademlia/node.c b/examples/c/dht-kademlia/node.c
index da155cc..2ad13b2 100644 (file)
--- a/examples/c/dht-kademlia/node.c
+++ b/examples/c/dht-kademlia/node.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010-2020. The SimGrid Team. All rights reserved.          */
+/* Copyright (c) 2010-2021. The SimGrid Team. All rights reserved.          */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
@@ -37,6 +37,19 @@ void node_free(node_t node)
   xbt_free(node);
 }
 
+/**
+  * Try to asynchronously get a new message from given mailbox. Return null if none available.
+  */
+kademlia_message_t receive(node_t node, sg_mailbox_t mailbox)
+{
+  if (node->receive_comm == NULL)
+    node->receive_comm = sg_mailbox_get_async(mailbox, &node->received_msg);
+  if (!sg_comm_test(node->receive_comm))
+    return NULL;
+  node->receive_comm = NULL;
+  return node->received_msg;
+}
+
 /**
  * @brief Tries to join the network
  * @param node node data
@@ -56,14 +69,11 @@ unsigned int join(node_t node, unsigned int id_known)
   /* First step: Send a "FIND_NODE" request to the node we know */
   send_find_node(node, id_known, node->id);
   do {
-    if (node->receive_comm == NULL)
-      node->receive_comm = sg_mailbox_get_async(mailbox, &node->received_msg);
-
-    if (sg_comm_test(node->receive_comm)) {
+    const kademlia_message_t msg = receive(node, mailbox);
+    if (msg) {
       XBT_DEBUG("Received an answer from the node I know.");
       got_answer = 1;
       // retrieve the node list and ping them.
-      const kademlia_message_t msg = (kademlia_message_t)(node->received_msg);
       const s_answer_t* node_list  = msg->answer;
       if (node_list != NULL) {
         node_contact_t contact;
@@ -75,13 +85,12 @@ unsigned int join(node_t node, unsigned int id_known)
       }
       answer_free(msg->answer);
       free(msg);
-      node->receive_comm = NULL;
     } else {
       sg_actor_sleep_for(1);
     }
   } while (got_answer == 0);
 
-  /* Second step: Send a FIND_NODE to a a random node in buckets */
+  /* Second step: Send a FIND_NODE to a random node in buckets */
   unsigned int bucket_id = routing_table_find_bucket(node->table, id_known)->id;
   xbt_assert(bucket_id <= IDENTIFIER_SIZE);
   for (i = 0; ((bucket_id > i) || (bucket_id + i) <= IDENTIFIER_SIZE) && i < JOIN_BUCKETS_QUERIES; i++) {
@@ -203,7 +212,6 @@ answer_t find_closest(const_node_t node, unsigned int destination_id)
 
 unsigned int find_node(node_t node, unsigned int id_to_find, unsigned int count_in_stats)
 {
-  unsigned int i = 0;
   unsigned int queries;
   unsigned int answers;
   unsigned int destination_found = 0;
@@ -228,18 +236,15 @@ unsigned int find_node(node_t node, unsigned int id_to_find, unsigned int count_
     double time_beginreceive = simgrid_get_clock();
 
     do {
-      if (node->receive_comm == NULL)
-        node->receive_comm = sg_mailbox_get_async(mailbox, &node->received_msg);
-
-      if (sg_comm_test(node->receive_comm)) {
+      const kademlia_message_t msg = receive(node, mailbox);
+      if (msg) {
         // Figure out if we received an answer or something else
-        const kademlia_message_t msg = (kademlia_message_t)(node->received_msg);
-
         // Check if what we have received is what we are looking for.
         if (msg->answer != NULL && msg->answer->destination_id == id_to_find) {
           // Handle the answer
           routing_table_update(node, msg->sender_id);
           node_contact_t contact;
+          unsigned int i;
           xbt_dynar_foreach (node_list->nodes, i, contact)
             routing_table_update(node, contact->id);
 
@@ -261,7 +266,6 @@ unsigned int find_node(node_t node, unsigned int id_to_find, unsigned int count_
         }
         answer_free(msg->answer);
         free(msg);
-        node->receive_comm = NULL;
       } else {
         sg_actor_sleep_for(1);
       }