From 9e7babc707a99b6446f2a277b4efbfc3a14fb855 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Simon=20D=C3=A9saulniers?= <rostydela@gmail.com>
Date: Thu, 7 Jan 2016 15:28:10 -0500
Subject: [PATCH] changed Search::refill to progressive approach

In order to optimize the refill of a search with good SearchNode, the refill is
now done at each call of searchStep(). A "refill" will try to add more good
nodes to the search until the search has reached SEARCH_NODES good nodes.
---
 src/dht.cpp | 64 ++++++++++++++++++++++++++---------------------------
 1 file changed, 31 insertions(+), 33 deletions(-)

diff --git a/src/dht.cpp b/src/dht.cpp
index eda21b13..9ababf84 100644
--- a/src/dht.cpp
+++ b/src/dht.cpp
@@ -948,6 +948,12 @@ Dht::searchStep(Search& sr)
 
     /* Check if the first TARGET_NODES (8) live nodes have replied. */
     if (sr.isSynced(now)) {
+
+        if (sr.nodes.size()-sr.getNumberOfCandidates(now) < SEARCH_NODES and not sr.refilled) {
+            auto added = sr.refill(sr.af == AF_INET ? buckets : buckets6, now);
+            DHT_WARN("[search %s IPv%c] refilled with %u nodes", sr.id.toString().c_str(), (sr.af == AF_INET) ? '4' : '6', added);
+        }
+
         if (not sr.callbacks.empty()) {
             // search is synced but some (newer) get operations are not complete
             // Call callbacks when done
@@ -1057,40 +1063,31 @@ Dht::searchStep(Search& sr)
                     return sn.candidate or sn.node->isExpired(now);
                 }) == sr.nodes.size())
         {
-            unsigned added = 0;
-            if (not sr.refilled) {
-                added = sr.refill(sr.af == AF_INET ? buckets : buckets6, now);
-                sr.refilled = true;
+            DHT_ERROR("[search %s IPv%c] expired", sr.id.toString().c_str(), sr.af == AF_INET ? '4' : '6');
+            // no nodes or all expired nodes
+            sr.expired = true;
+            // reset refilled since the search is now expired.
+            sr.refilled = false;
+            if (sr.announce.empty() && sr.listeners.empty()) {
+                // Listening or announcing requires keeping the cluster up to date.
+                sr.done = true;
             }
-            if (added) {
-                DHT_WARN("[search %s IPv%c] refilled with %u nodes", sr.id.toString().c_str(), (sr.af == AF_INET) ? '4' : '6', added);
-            } else {
-                DHT_ERROR("[search %s IPv%c] expired", sr.id.toString().c_str(), sr.af == AF_INET ? '4' : '6');
-                // no nodes or all expired nodes
-                sr.expired = true;
-                // reset refilled since the search is now expired.
-                sr.refilled = false;
-                if (sr.announce.empty() && sr.listeners.empty()) {
-                    // Listening or announcing requires keeping the cluster up to date.
-                    sr.done = true;
-                }
-                {
-                    auto get_cbs = std::move(sr.callbacks);
-                    for (const auto& g : get_cbs) {
-                        if (g.done_cb)
-                            g.done_cb(false, {});
-                    }
-                }
-                {
-                    std::vector<DoneCallback> a_cbs;
-                    a_cbs.reserve(sr.announce.size());
-                    for (const auto& a : sr.announce)
-                        if (a.callback)
-                            a_cbs.emplace_back(std::move(a.callback));
-                    for (const auto& a : a_cbs)
-                        a(false, {});
+            {
+                auto get_cbs = std::move(sr.callbacks);
+                for (const auto& g : get_cbs) {
+                    if (g.done_cb)
+                        g.done_cb(false, {});
                 }
             }
+            {
+                std::vector<DoneCallback> a_cbs;
+                a_cbs.reserve(sr.announce.size());
+                for (const auto& a : sr.announce)
+                    if (a.callback)
+                        a_cbs.emplace_back(std::move(a.callback));
+                for (const auto& a : a_cbs)
+                    a(false, {});
+            }
         }
     }
 
@@ -1359,7 +1356,7 @@ Dht::Search::refill(const RoutingTable& r, time_point now) {
     auto num_bad_nodes = getNumberOfBadNodes(now);
     auto b = r.findBucket(id);
     auto n = b;
-    while (added < SEARCH_NODES && (std::next(n) != r.end() || b != r.begin())) {
+    while (nodes.size()-num_bad_nodes < SEARCH_NODES && (std::next(n) != r.end() || b != r.begin())) {
         if (std::next(n) != r.end()) {
             added += insertBucket(*std::next(n), now);
             n = std::next(n);
@@ -1369,7 +1366,8 @@ Dht::Search::refill(const RoutingTable& r, time_point now) {
             b = std::prev(b);
         }
     }
-    //DHT_WARN("[search %s IPv%c] refilled with %u nodes", id.toString().c_str(), (af == AF_INET) ? '4' : '6', added);
+    refilled = true;
+
     return added;
 }