src: remove threadpool and use boost asio thread_pool

src/common/CMakeLists.txt

@@ -42,7 +42,6 @@ set(common_sources
   perf_timer.cpp
   pruning.cpp
   spawn.cpp
-  threadpool.cpp
   updates.cpp
   aligned.c
   timings.cc

src/common/dns_utils.cpp

@@ -35,12 +35,19 @@
 #include <set>
 #include <stdlib.h>
 #include "include_base_utils.h"
-#include "common/threadpool.h"
 #include "crypto/crypto.h"
 #include <boost/thread/mutex.hpp>
 #include <boost/algorithm/string/join.hpp>
 #include <boost/optional.hpp>
 #include <boost/utility/string_ref.hpp>
+#include <boost/bind/bind.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <boost/asio/post.hpp>
+#include <boost/thread/condition_variable.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/thread.hpp>
+#include <thread>
+
 using namespace epee;
 
 #undef MONERO_DEFAULT_LOG_CATEGORY
@@ -487,17 +494,17 @@ bool load_txt_records_from_dns(std::vector<std::string> &good_records, const std
 
   // send all requests in parallel
   std::deque<bool> avail(dns_urls.size(), false), valid(dns_urls.size(), false);
-  tools::threadpool& tpool = tools::threadpool::getInstanceForIO();
-  tools::threadpool::waiter waiter(tpool);
+  int threads = std::thread::hardware_concurrency();
+  boost::asio::thread_pool thread_pool(threads);
   for (size_t n = 0; n < dns_urls.size(); ++n)
   {
-    tpool.submit(&waiter,[n, dns_urls, &records, &avail, &valid](){
+    boost::asio::post(thread_pool, [n, dns_urls, &records, &avail, &valid](){
        const auto res = tools::DNSResolver::instance().get_txt_record(dns_urls[n], avail[n], valid[n]);
        for (const auto &s: res)
          records[n].insert(s);
     });
   }
-  waiter.wait();
+  thread_pool.wait();
 
   size_t cur_index = first_index;
   do