From d80e2d50917ad85dae21bd954222ba545402219b Mon Sep 17 00:00:00 2001
From: levlam <levlam@telegram.org>
Date: Mon, 21 Jan 2019 20:43:58 +0300
Subject: [PATCH] Optimize FileReferenceManager::merge.

GitOrigin-RevId: a90658d47bacdfd50bf834f54f0b71dd54c375cf
---
 td/telegram/FileReferenceManager.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/td/telegram/FileReferenceManager.cpp b/td/telegram/FileReferenceManager.cpp
index d2d6b809..45388893 100644
--- a/td/telegram/FileReferenceManager.cpp
+++ b/td/telegram/FileReferenceManager.cpp
@@ -95,8 +95,13 @@ void FileReferenceManager::remove_file_source(NodeId node_id, FileSourceId file_
 }
 
 void FileReferenceManager::merge(NodeId to_node_id, NodeId from_node_id) {
+  auto from_it = nodes_.find(from_node_id);
+  if (from_it == nodes_.end()) {
+    return;
+  }
+
   auto &to = nodes_[to_node_id];
-  auto &from = nodes_[from_node_id];
+  auto &from = from_it->second;
   VLOG(file_references) << "Merge " << to.file_source_ids.size() << " and " << from.file_source_ids.size()
                         << " sources of files " << to_node_id << " and " << from_node_id;
   CHECK(!to.query || to.query->proxy.empty());