Fix multi-client server suspend

src/main.cc

@@ -477,7 +477,6 @@ void register_options()
 
 static Client* local_client = nullptr;
 static int local_client_exit = 0;
-static UserInterface* local_ui = nullptr;
 static bool convert_to_client_pending = false;
 
 enum class UIType
@@ -550,26 +549,10 @@ std::unique_ptr<UserInterface> create_local_ui(UIType ui_type)
     {
         LocalUI()
         {
-            kak_assert(not local_ui);
+            set_signal_handler(SIGTSTP, [](int) {
-            local_ui = this;
-
-            m_old_sigtstp = set_signal_handler(SIGTSTP, [](int) {
                 if (ClientManager::instance().count() == 1 and
                     *ClientManager::instance().begin() == local_client)
-                {
+                    NCursesUI::instance().suspend();
-                    // Suspend normally if we are the only client
-                    auto current = set_signal_handler(SIGTSTP, static_cast<LocalUI*>(local_ui)->m_old_sigtstp);
-
-                    sigset_t unblock_sigtstp, old_mask;
-                    sigemptyset(&unblock_sigtstp);
-                    sigaddset(&unblock_sigtstp, SIGTSTP);
-                    sigprocmask(SIG_UNBLOCK, &unblock_sigtstp, &old_mask);
-
-                    raise(SIGTSTP);
-
-                    set_signal_handler(SIGTSTP, current);
-                    sigprocmask(SIG_SETMASK, &old_mask, nullptr);
-                }
                 else
                     convert_to_client_pending = true;
            });
@@ -577,23 +560,17 @@ std::unique_ptr<UserInterface> create_local_ui(UIType ui_type)
 
         ~LocalUI() override
         {
-            set_signal_handler(SIGTSTP, m_old_sigtstp);
             local_client = nullptr;
-            local_ui = nullptr;
+            if (convert_to_client_pending or
-            if (not convert_to_client_pending and
+                ClientManager::instance().empty())
-                not ClientManager::instance().empty())
+                return;
-            {
+
             if (fork_server_to_background())
             {
                 this->NCursesUI::~NCursesUI();
                 exit(local_client_exit);
             }
         }
-        }
-
-    private:
-        using SigHandler = void (*)(int);
-        SigHandler m_old_sigtstp;
     };
 
     if (not isatty(1))

src/ncurses_ui.cc

@@ -373,6 +373,7 @@ NCursesUI::NCursesUI()
 
     set_signal_handler(SIGWINCH, &signal_handler<&resize_pending>);
     set_signal_handler(SIGHUP, &signal_handler<&sighup_raised>);
+    set_signal_handler(SIGTSTP, [](int){ NCursesUI::instance().suspend(); });
 
     check_resize(true);
     redraw(false);
@@ -390,6 +391,29 @@ NCursesUI::~NCursesUI()
     tcsetattr(STDIN_FILENO, TCSAFLUSH, &m_original_termios);
     set_signal_handler(SIGWINCH, SIG_DFL);
     set_signal_handler(SIGCONT, SIG_DFL);
+    set_signal_handler(SIGTSTP, SIG_DFL);
+}
+
+void NCursesUI::suspend()
+{
+    bool mouse_enabled = m_mouse_enabled;
+    enable_mouse(false);
+    tcsetattr(STDIN_FILENO, TCSAFLUSH, &m_original_termios);
+
+    auto current = set_signal_handler(SIGTSTP, SIG_DFL);
+    sigset_t unblock_sigtstp, old_mask;
+    sigemptyset(&unblock_sigtstp);
+    sigaddset(&unblock_sigtstp, SIGTSTP);
+    sigprocmask(SIG_UNBLOCK, &unblock_sigtstp, &old_mask);
+
+    raise(SIGTSTP); // suspend here
+
+    set_signal_handler(SIGTSTP, current);
+    sigprocmask(SIG_SETMASK, &old_mask, nullptr);
+
+    check_resize(true);
+    set_raw_mode();
+    enable_mouse(mouse_enabled);
 }
 
 void NCursesUI::set_raw_mode() const
@@ -612,15 +636,7 @@ Optional<Key> NCursesUI::get_next_key()
             return {Key::Backspace};
         if (c == control('z'))
         {
-            bool mouse_enabled = m_mouse_enabled;
-            enable_mouse(false);
-            tcsetattr(STDIN_FILENO, TCSAFLUSH, &m_original_termios);
-
             kill(0, SIGTSTP); // We suspend at this line
-
-            check_resize(true);
-            set_raw_mode();
-            enable_mouse(mouse_enabled);
             return {};
         }
         if (c < 27)

src/ncurses_ui.hh

@@ -17,7 +17,7 @@ namespace Kakoune
 
 struct NCursesWin;
 
-class NCursesUI : public UserInterface
+class NCursesUI : public UserInterface, public Singleton<NCursesUI>
 {
 public:
     NCursesUI();
@@ -57,6 +57,8 @@ public:
 
     static void abort();
 
+    void suspend();
+
     struct Rect
     {
         DisplayCoord pos;
@@ -117,7 +119,7 @@ private:
     Window m_window;
 
     DisplayCoord m_dimensions;
-    termios m_original_termios;
+    termios m_original_termios{};
 
     void set_raw_mode() const;