From d6474dc83d55dbafc8eb113738d2626cc1a375c3 Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Tue, 5 Feb 2019 01:32:37 +0300
Subject: [PATCH] Lazy GetHostByNameActor creation.

GitOrigin-RevId: 423a126e40a77d47cfa8d16889729f3102194724
---
 td/telegram/net/ConnectionCreator.cpp | 31 +++++++++++++++++----------
 td/telegram/net/ConnectionCreator.h   |  2 +-
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/td/telegram/net/ConnectionCreator.cpp b/td/telegram/net/ConnectionCreator.cpp
index 99d0fb00..7c1d31f3 100644
--- a/td/telegram/net/ConnectionCreator.cpp
+++ b/td/telegram/net/ConnectionCreator.cpp
@@ -457,10 +457,27 @@ void ConnectionCreator::get_proxy_link(int32 proxy_id, Promise<string> promise)
   promise.set_value(std::move(url));
 }
 
-ActorId<GetHostByNameActor> ConnectionCreator::get_resolver() const {
+ActorId<GetHostByNameActor> ConnectionCreator::get_dns_resolver() {
   if (G()->shared_config().get_option_boolean("expect_blocking", true)) {
+    if (block_get_host_by_name_actor_.empty()) {
+      VLOG(connections) << "Init block bypass DNS resolver";
+      GetHostByNameActor::Options options;
+      options.scheduler_id = G()->get_gc_scheduler_id();
+      options.resolver_types = {GetHostByNameActor::ResolverType::Google, GetHostByNameActor::ResolverType::Native};
+      options.ok_timeout = 60;
+      options.error_timeout = 0;
+      block_get_host_by_name_actor_ = create_actor<GetHostByNameActor>("BlockDnsResolverActor", std::move(options));
+    }
     return block_get_host_by_name_actor_.get();
   } else {
+    if (get_host_by_name_actor_.empty()) {
+      VLOG(connections) << "Init DNS resolver";
+      GetHostByNameActor::Options options;
+      options.scheduler_id = G()->get_gc_scheduler_id();
+      options.ok_timeout = 5 * 60 - 1;
+      options.error_timeout = 0;
+      get_host_by_name_actor_ = create_actor<GetHostByNameActor>("DnsResolverActor", std::move(options));
+    }
     return get_host_by_name_actor_.get();
   }
 }
@@ -515,7 +532,7 @@ void ConnectionCreator::ping_proxy(int32 proxy_id, Promise<double> promise) {
   }
   const Proxy &proxy = it->second;
   bool prefer_ipv6 = G()->shared_config().get_option_boolean("prefer_ipv6");
-  send_closure(get_resolver(), &GetHostByNameActor::run, proxy.server().str(), proxy.port(), prefer_ipv6,
+  send_closure(get_dns_resolver(), &GetHostByNameActor::run, proxy.server().str(), proxy.port(), prefer_ipv6,
                PromiseCreator::lambda([actor_id = actor_id(this), promise = std::move(promise),
                                        proxy_id](Result<IPAddress> result) mutable {
                  if (result.is_error()) {
@@ -1249,14 +1266,6 @@ void ConnectionCreator::start_up() {
     on_proxy_changed(true);
   }
 
-  GetHostByNameActor::Options options;
-  options.scheduler_id = G()->get_gc_scheduler_id();
-  options.ok_timeout = 5 * 60 - 1;
-  options.error_timeout = 0;
-  get_host_by_name_actor_ = create_actor<GetHostByNameActor>("GetHostByNameActor", options);
-  options.resolver_types = {GetHostByNameActor::ResolverType::Google, GetHostByNameActor::ResolverType::Native};
-  block_get_host_by_name_actor_ = create_actor<GetHostByNameActor>("GetHostByNameActor", options);
-
   ref_cnt_guard_ = create_reference(-1);
 
   is_inited_ = true;
@@ -1382,7 +1391,7 @@ void ConnectionCreator::loop() {
         bool prefer_ipv6 = G()->shared_config().get_option_boolean("prefer_ipv6");
         VLOG(connections) << "Resolve IP address " << resolve_proxy_query_token_ << " of " << proxy.server();
         send_closure(
-            get_resolver(), &GetHostByNameActor::run, proxy.server().str(), proxy.port(), prefer_ipv6,
+            get_dns_resolver(), &GetHostByNameActor::run, proxy.server().str(), proxy.port(), prefer_ipv6,
             PromiseCreator::lambda([actor_id = create_reference(resolve_proxy_query_token_)](Result<IPAddress> result) {
               send_closure(std::move(actor_id), &ConnectionCreator::on_proxy_resolved, std::move(result), false);
             }));
diff --git a/td/telegram/net/ConnectionCreator.h b/td/telegram/net/ConnectionCreator.h
index e9cc76e5..41cafe4a 100644
--- a/td/telegram/net/ConnectionCreator.h
+++ b/td/telegram/net/ConnectionCreator.h
@@ -323,7 +323,7 @@ class ConnectionCreator : public NetQueryCallback {
   Result<SocketFd> find_connection(const ProxyInfo &proxy, DcId dc_id, bool allow_media_only,
                                    FindConnectionExtra &extra);
 
-  ActorId<GetHostByNameActor> get_resolver() const;
+  ActorId<GetHostByNameActor> get_dns_resolver();
 
   void ping_proxy_resolved(int32 proxy_id, IPAddress ip_address, Promise<double> promise);