dht: fix recycling of existing search

src/dht.cpp

@@ -889,10 +889,16 @@ Dht::search(const InfoHash& id,
             sr = std::make_shared<Search>();
             srs.emplace(id, sr);
         } else {
-            for (auto it = srs.begin(); it != srs.end();) {
+            for (auto it = srs.begin(); it != srs.end(); ++it) {
                 auto& s = *it->second;
                 if ((s.done or s.expired) and s.announce.empty() and s.listeners.empty()) {
                     sr = it->second;
+                    if (sr->nextSearchStep)
+                        scheduler.cancel(sr->nextSearchStep);
+                    if (sr->opExpirationJob)
+                        scheduler.cancel(sr->opExpirationJob);
+                    sr->clear();
+                    srs.erase(it);
                     break;
                 }
             }
@@ -901,8 +907,11 @@ Dht::search(const InfoHash& id,
                     logger_->error("[search {} IPv{}] Maximum number of searches reached!",
                                    id.toString(),
                                    (af == AF_INET) ? '4' : '6');
+                if (dcb)
+                    dcb(false, {});
                 return {};
             }
+            srs.emplace(id, sr);
         }
         sr->af = af;
         sr->tid = search_id++;

src/op_cache.cpp

@@ -210,6 +210,13 @@ SearchCache::cancelAll(const std::function<void(size_t)>& onCancel)
     ops.clear();
 }
 
+void
+SearchCache::clear()
+{
+    ops.clear();
+    nextExpiration_ = time_point::max();
+}
+
 time_point
 SearchCache::expire(const time_point& now, const std::function<void(size_t)>& onCancel)
 {

src/op_cache.h

@@ -164,6 +164,7 @@ public:
 
     bool cancelListen(size_t gtoken, const time_point& now);
     void cancelAll(const std::function<void(size_t)>& onCancel);
+    void clear();
 
     time_point expire(const time_point& now, const std::function<void(size_t)>& onCancel);
     time_point getExpiration() const { return nextExpiration_; }

src/search.h

@@ -836,6 +836,7 @@ struct Dht::Search
         listeners.clear();
         nodes.clear();
         nextSearchStep.reset();
+        cache.clear();
     }
 };