[fix] fix intermittent crash on incoming connection by guarding shared connection status state across threads

src/gui/panels/remote_peer_panel.cpp

@@ -211,7 +211,7 @@ int Render::ConnectTo(const std::string& remote_id, const char* password,
         props->control_window_max_width_ = title_bar_height_ * 10.0f;
         props->control_window_max_height_ = title_bar_height_ * 7.0f;
 
-        props->connection_status_ = ConnectionStatus::Connecting;
+        props->connection_status_.store(ConnectionStatus::Connecting);
         show_connection_status_window_ = true;
 
         if (!props->peer_) {
@@ -231,7 +231,7 @@ int Render::ConnectTo(const std::string& remote_id, const char* password,
         AddDataStream(props->peer_, props->file_feedback_label_.c_str(), true);
         AddDataStream(props->peer_, props->clipboard_label_.c_str(), true);
 
-        props->connection_status_ = ConnectionStatus::Connecting;
+        props->connection_status_.store(ConnectionStatus::Connecting);
 
         peer_to_init = props->peer_;
         local_id = props->local_id_;

src/gui/render.cpp

@@ -13,6 +13,9 @@
 #include <filesystem>
 #include <fstream>
 #include <iostream>
+#include <memory>
+#include <mutex>
+#include <shared_mutex>
 #include <string>
 #include <thread>
 
@@ -2175,11 +2178,13 @@ void Render::HandleWindowsServiceIntegration() {
     return;
   }
 
-  const bool has_connected_remote =
-      std::any_of(connection_status_.begin(), connection_status_.end(),
-                  [](const auto& entry) {
-                    return entry.second == ConnectionStatus::Connected;
-                  });
+  const bool has_connected_remote = [&] {
+    std::shared_lock lock(connection_status_mutex_);
+    return std::any_of(connection_status_.begin(), connection_status_.end(),
+                       [](const auto& entry) {
+                         return entry.second == ConnectionStatus::Connected;
+                       });
+  }();
   if (!has_connected_remote) {
     ResetLocalWindowsServiceState(false);
     return;

src/gui/render.h

@@ -184,7 +184,11 @@ class Render {
     SDL_Rect stream_render_rect_;
     SDL_Rect stream_render_rect_last_;
     ImVec2 control_window_pos_;
-    ConnectionStatus connection_status_ = ConnectionStatus::Closed;
+    // Written from the minirtc/libnice callback thread (OnConnectionStatusCb)
+    // and the SDL main thread (remote_peer_panel connect button); read from
+    // the SDL main render thread (stream/control windows) and the SDL audio
+    // thread (SdlCaptureAudioIn). Atomic so those reads/writes are defined.
+    std::atomic<ConnectionStatus> connection_status_ = ConnectionStatus::Closed;
     TraversalMode traversal_mode_ = TraversalMode::UnknownMode;
     int fps_ = 0;
     int frame_count_ = 0;
@@ -816,6 +820,11 @@ class Render {
   void WaitForThumbnailSaveTasks();
 
   /* ------ server mode ------ */
+  // connection_status_ / connection_host_names_ are read on the main
+  // render thread (DrawServerWindow, HandleWindowsServiceIntegration) and
+  // written from minirtc/libnice callback threads (OnConnectionStatusCb,
+  // OnReceiveDataBufferCb). Guard every access with this shared mutex.
+  std::shared_mutex connection_status_mutex_;
   std::unordered_map<std::string, ConnectionStatus> connection_status_;
   std::unordered_map<std::string, std::string> connection_host_names_;
   std::string selected_server_remote_id_ = "";

src/gui/render_callback.cpp

@@ -6,6 +6,9 @@
 #include <filesystem>
 #include <fstream>
 #include <limits>
+#include <memory>
+#include <mutex>
+#include <shared_mutex>
 #include <unordered_map>
 #include <unordered_set>
 
@@ -489,7 +492,7 @@ void Render::SendKeyboardHeartbeat(bool force) {
   }
 
   const auto props = props_it->second;
-  if (props->connection_status_ != ConnectionStatus::Connected ||
+  if (props->connection_status_.load() != ConnectionStatus::Connected ||
       !props->peer_) {
     last_keyboard_heartbeat_tick_ = now;
     return;
@@ -531,7 +534,7 @@ int Render::SendKeyCommand(int key_code, bool is_down, uint32_t scan_code,
   if (!target_id.empty()) {
     if (client_properties_.find(target_id) != client_properties_.end()) {
       auto props = client_properties_[target_id];
-      if (props->connection_status_ == ConnectionStatus::Connected &&
+      if (props->connection_status_.load() == ConnectionStatus::Connected &&
           props->peer_) {
         std::string msg = remote_action.to_json();
         int ret = SendReliableDataFrame(props->peer_, msg.c_str(), msg.size(),
@@ -928,10 +931,10 @@ void Render::SdlCaptureAudioIn(void* userdata, Uint8* stream, int len) {
   }
 
   if (1) {
-    // std::shared_lock lock(render->client_properties_mutex_);
+    std::shared_lock lock(render->client_properties_mutex_);
     for (const auto& it : render->client_properties_) {
       auto props = it.second;
-      if (props->connection_status_ == ConnectionStatus::Connected) {
+      if (props->connection_status_.load() == ConnectionStatus::Connected) {
         if (props->peer_) {
           SendAudioFrame(props->peer_, (const char*)stream, len,
                          render->audio_label_.c_str());
@@ -1324,12 +1327,20 @@ void Render::OnReceiveDataBufferCb(const char* data, size_t size,
     return;
   }
 
-  // std::shared_lock lock(render->client_properties_mutex_);
   if (remote_action.type == ControlType::host_infomation) {
-    if (render->client_properties_.find(remote_id) !=
-        render->client_properties_.end()) {
+    bool is_client_mode = false;
+    std::shared_ptr<SubStreamWindowProperties> props;
+    {
+      std::shared_lock lock(render->client_properties_mutex_);
+      auto props_it = render->client_properties_.find(remote_id);
+      if (props_it != render->client_properties_.end()) {
+        is_client_mode = true;
+        props = props_it->second;
+      }
+    }
+
+    if (is_client_mode) {
       // client mode
-      auto props = render->client_properties_.find(remote_id)->second;
       if (props && props->remote_host_name_.empty()) {
         props->remote_host_name_ = std::string(remote_action.i.host_name,
                                                remote_action.i.host_name_size);
@@ -1345,10 +1356,13 @@ void Render::OnReceiveDataBufferCb(const char* data, size_t size,
       FreeRemoteAction(remote_action);
     } else {
       // server mode
-      render->connection_host_names_[remote_id] = std::string(
-          remote_action.i.host_name, remote_action.i.host_name_size);
-      LOG_INFO("Remote hostname: [{}]",
-               render->connection_host_names_[remote_id]);
+      std::string host_name(remote_action.i.host_name,
+                            remote_action.i.host_name_size);
+      {
+        std::unique_lock lock(render->connection_status_mutex_);
+        render->connection_host_names_[remote_id] = host_name;
+      }
+      LOG_INFO("Remote hostname: [{}]", host_name);
       FreeRemoteAction(remote_action);
     }
   } else {
@@ -1480,14 +1494,19 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
   if (!render) return;
 
   std::string remote_id(user_id, user_id_size);
-  // std::shared_lock lock(render->client_properties_mutex_);
-  auto it = render->client_properties_.find(remote_id);
-  auto props = (it != render->client_properties_.end()) ? it->second : nullptr;
+  std::shared_ptr<SubStreamWindowProperties> props;
+  {
+    std::shared_lock lock(render->client_properties_mutex_);
+    auto it = render->client_properties_.find(remote_id);
+    if (it != render->client_properties_.end()) {
+      props = it->second;
+    }
+  }
 
   if (props) {
     render->is_client_mode_ = true;
     render->show_connection_status_window_ = true;
-    props->connection_status_ = status;
+    props->connection_status_.store(status);
 
     switch (status) {
       case ConnectionStatus::Connected: {
@@ -1603,7 +1622,10 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
   } else {
     render->is_client_mode_ = false;
     render->show_connection_status_window_ = true;
-    render->connection_status_[remote_id] = status;
+    {
+      std::unique_lock lock(render->connection_status_mutex_);
+      render->connection_status_[remote_id] = status;
+    }
 
     switch (status) {
       case ConnectionStatus::Connected: {
@@ -1659,11 +1681,14 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
         render->start_speaker_capturer_ = true;
         render->remote_client_id_ = remote_id;
         render->start_mouse_controller_ = true;
-        if (std::all_of(render->connection_status_.begin(),
-                        render->connection_status_.end(), [](const auto& kv) {
-                          return kv.first.find("web") != std::string::npos;
-                        })) {
-          render->show_cursor_ = true;
+        {
+          std::shared_lock lock(render->connection_status_mutex_);
+          if (std::all_of(render->connection_status_.begin(),
+                          render->connection_status_.end(), [](const auto& kv) {
+                            return kv.first.find("web") != std::string::npos;
+                          })) {
+            render->show_cursor_ = true;
+          }
         }
 
         break;
@@ -1672,12 +1697,18 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
       case ConnectionStatus::Failed:
       case ConnectionStatus::Closed: {
         render->ReleaseRemotePressedKeys(remote_id, "connection_closed");
-        if (std::all_of(render->connection_status_.begin(),
-                        render->connection_status_.end(), [](const auto& kv) {
-                          return kv.second == ConnectionStatus::Closed ||
-                                 kv.second == ConnectionStatus::Failed ||
-                                 kv.second == ConnectionStatus::Disconnected;
-                        })) {
+        bool all_disconnected = false;
+        {
+          std::shared_lock lock(render->connection_status_mutex_);
+          all_disconnected = std::all_of(
+              render->connection_status_.begin(),
+              render->connection_status_.end(), [](const auto& kv) {
+                return kv.second == ConnectionStatus::Closed ||
+                       kv.second == ConnectionStatus::Failed ||
+                       kv.second == ConnectionStatus::Disconnected;
+              });
+        }
+        if (all_disconnected) {
           render->need_to_destroy_server_window_ = true;
           render->is_server_mode_ = false;
 #if defined(__linux__) && !defined(__APPLE__)
@@ -1704,18 +1735,24 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
             render->audio_capture_ = false;
           }
 
-          render->connection_status_.erase(remote_id);
-          render->connection_host_names_.erase(remote_id);
+          {
+            std::unique_lock lock(render->connection_status_mutex_);
+            render->connection_status_.erase(remote_id);
+            render->connection_host_names_.erase(remote_id);
+          }
           if (render->screen_capturer_) {
             render->screen_capturer_->ResetToInitialMonitor();
           }
         }
 
-        if (std::all_of(render->connection_status_.begin(),
-                        render->connection_status_.end(), [](const auto& kv) {
-                          return kv.first.find("web") == std::string::npos;
-                        })) {
-          render->show_cursor_ = false;
+        {
+          std::shared_lock lock(render->connection_status_mutex_);
+          if (std::all_of(render->connection_status_.begin(),
+                          render->connection_status_.end(), [](const auto& kv) {
+                            return kv.first.find("web") == std::string::npos;
+                          })) {
+            render->show_cursor_ = false;
+          }
         }
 
         break;

src/gui/toolbars/control_bar.cpp

@@ -191,7 +191,7 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
           RemoteAction remote_action;
           remote_action.type = ControlType::display_id;
           remote_action.d = i;
-          if (props->connection_status_ == ConnectionStatus::Connected) {
+          if (props->connection_status_.load() == ConnectionStatus::Connected) {
             std::string msg = remote_action.to_json();
             SendReliableDataFrame(props->peer_, msg.c_str(), msg.size(),
                                   props->control_data_label_.c_str());
@@ -215,7 +215,7 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
 
     auto send_service_command = [&](ServiceCommandFlag flag,
                                     const char* log_action) {
-      if (props->connection_status_ == ConnectionStatus::Connected &&
+      if (props->connection_status_.load() == ConnectionStatus::Connected &&
           props->peer_) {
         RemoteAction remote_action;
         remote_action.type = ControlType::service_command;

src/gui/windows/connection_status_window.cpp

@@ -31,8 +31,9 @@ bool Render::ConnectionStatusWindow(
 
   ImGui::SetWindowFontScale(0.5f);
   std::string text;
+  const ConnectionStatus status = props->connection_status_.load();
 
-  if (ConnectionStatus::Connecting == props->connection_status_) {
+  if (ConnectionStatus::Connecting == status) {
     text = localization::p2p_connecting[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -48,7 +49,7 @@ bool Render::ConnectionStatusWindow(
       }
       ret_flag = true;
     }
-  } else if (ConnectionStatus::Gathering == props->connection_status_) {
+  } else if (ConnectionStatus::Gathering == status) {
     text = localization::p2p_gathering[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -64,7 +65,7 @@ bool Render::ConnectionStatusWindow(
       }
       ret_flag = true;
     }
-  } else if (ConnectionStatus::Connected == props->connection_status_) {
+  } else if (ConnectionStatus::Connected == status) {
     text = localization::p2p_connected[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -74,7 +75,7 @@ bool Render::ConnectionStatusWindow(
         ImGui::IsKeyPressed(ImGuiKey_Escape)) {
       show_connection_status_window_ = false;
     }
-  } else if (ConnectionStatus::Disconnected == props->connection_status_) {
+  } else if (ConnectionStatus::Disconnected == status) {
     text = localization::p2p_disconnected[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -84,7 +85,7 @@ bool Render::ConnectionStatusWindow(
         ImGui::IsKeyPressed(ImGuiKey_Escape)) {
       show_connection_status_window_ = false;
     }
-  } else if (ConnectionStatus::Failed == props->connection_status_) {
+  } else if (ConnectionStatus::Failed == status) {
     text = localization::p2p_failed[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -94,7 +95,7 @@ bool Render::ConnectionStatusWindow(
         ImGui::IsKeyPressed(ImGuiKey_Escape)) {
       show_connection_status_window_ = false;
     }
-  } else if (ConnectionStatus::Closed == props->connection_status_) {
+  } else if (ConnectionStatus::Closed == status) {
     text = localization::p2p_closed[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
@@ -104,7 +105,7 @@ bool Render::ConnectionStatusWindow(
         ImGui::IsKeyPressed(ImGuiKey_Escape)) {
       show_connection_status_window_ = false;
     }
-  } else if (ConnectionStatus::IncorrectPassword == props->connection_status_) {
+  } else if (ConnectionStatus::IncorrectPassword == status) {
     if (!password_validating_) {
       if (password_validating_time_ == 1) {
         text = localization::input_password[localization_language_index_];
@@ -167,8 +168,7 @@ bool Render::ConnectionStatusWindow(
       ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
       ImGui::SetCursorPosY(connection_status_window_height * 0.67f);
     }
-  } else if (ConnectionStatus::NoSuchTransmissionId ==
-             props->connection_status_) {
+  } else if (ConnectionStatus::NoSuchTransmissionId == status) {
     text = localization::no_such_id[localization_language_index_];
     ImGui::SetCursorPosX(connection_status_window_width * 0.43f);
     ImGui::SetCursorPosY(connection_status_window_height * 0.67f);

src/gui/windows/server_window.cpp

@@ -1,6 +1,8 @@
 #include <algorithm>
 #include <cmath>
 #include <cstdio>
+#include <memory>
+#include <shared_mutex>
 #include <string>
 #include <vector>
 
@@ -149,14 +151,17 @@ int Render::RemoteClientInfoWindow() {
   float font_scale = localization_language_index_ == 0 ? 0.5f : 0.45f;
 
   std::vector<std::pair<std::string, std::string>> remote_entries;
-  remote_entries.reserve(connection_status_.size());
-  for (const auto& kv : connection_status_) {
-    const auto host_it = connection_host_names_.find(kv.first);
-    const std::string display_name =
-        (host_it != connection_host_names_.end() && !host_it->second.empty())
-            ? host_it->second
-            : kv.first;
-    remote_entries.emplace_back(kv.first, display_name);
+  {
+    std::shared_lock lock(connection_status_mutex_);
+    remote_entries.reserve(connection_status_.size());
+    for (const auto& kv : connection_status_) {
+      const auto host_it = connection_host_names_.find(kv.first);
+      const std::string display_name =
+          (host_it != connection_host_names_.end() && !host_it->second.empty())
+              ? host_it->second
+              : kv.first;
+      remote_entries.emplace_back(kv.first, display_name);
+    }
   }
 
   auto find_display_name_by_remote_id =
@@ -220,10 +225,14 @@ int Render::RemoteClientInfoWindow() {
   ImGui::SetWindowFontScale(font_scale);
 
   if (!selected_server_remote_id_.empty()) {
-    auto it = connection_status_.find(selected_server_remote_id_);
-    const ConnectionStatus status = (it == connection_status_.end())
-                                        ? ConnectionStatus::Closed
-                                        : it->second;
+    ConnectionStatus status = ConnectionStatus::Closed;
+    {
+      std::shared_lock lock(connection_status_mutex_);
+      auto it = connection_status_.find(selected_server_remote_id_);
+      if (it != connection_status_.end()) {
+        status = it->second;
+      }
+    }
 
     ImGui::Text(
         "%s",
@@ -376,4 +385,4 @@ int Render::RemoteClientInfoWindow() {
 
   return 0;
 }
-}  // namespace crossdesk
+}  // namespace crossdesk

src/gui/windows/stream_window.cpp

@@ -7,7 +7,7 @@ namespace crossdesk {
 void Render::DrawConnectionStatusText(
     std::shared_ptr<SubStreamWindowProperties>& props) {
   std::string text;
-  switch (props->connection_status_) {
+  switch (props->connection_status_.load()) {
     case ConnectionStatus::Disconnected:
       text = localization::p2p_disconnected[localization_language_index_];
       break;
@@ -34,7 +34,7 @@ void Render::DrawConnectionStatusText(
 void Render::DrawReceivingScreenText(
     std::shared_ptr<SubStreamWindowProperties>& props) {
   if (!props->connection_established_ ||
-      props->connection_status_ != ConnectionStatus::Connected) {
+      props->connection_status_.load() != ConnectionStatus::Connected) {
     return;
   }