Defer deletion of buffers to after the event loop

We can have SelectionList in flights on the buffer, so mark
it for deletion by moving it in a buffer trash, and effectively
delete it later, at a point where there should not be any further
access to it.

src/buffer_manager.cc

@@ -41,6 +41,14 @@ void BufferManager::unregister_buffer(Buffer& buffer)
             return;
         }
     }
+    for (auto it = m_buffer_trash.begin(); it != m_buffer_trash.end(); ++it)
+    {
+        if (*it == &buffer)
+        {
+            m_buffer_trash.erase(it);
+            return;
+        }
+    }
     kak_assert(false);
 }
 
@@ -52,7 +60,9 @@ void BufferManager::delete_buffer(Buffer& buffer)
         {
             if (ClientManager::has_instance())
                 ClientManager::instance().ensure_no_client_uses_buffer(buffer);
-            delete it->get();
+
+            m_buffers.erase(it);
+            m_buffer_trash.emplace_back(&buffer);
             return;
         }
     }
@@ -121,4 +131,10 @@ CandidateList BufferManager::complete_buffer_name(StringView prefix,
     return result.empty() ? subsequence_result : result;
 }
 
+void BufferManager::clear_buffer_trash()
+{
+    while (not m_buffer_trash.empty())
+        delete m_buffer_trash.back().get();
+}
+
 }

src/buffer_manager.hh

@@ -37,8 +37,10 @@ public:
     CandidateList complete_buffer_name(StringView prefix,
                                        ByteCount cursor_pos = -1);
 
+    void clear_buffer_trash();
 private:
     BufferList m_buffers;
+    BufferList m_buffer_trash;
 };
 
 }

src/client.hh

@@ -39,6 +39,9 @@ public:
     Context& context() { return m_input_handler.context(); }
     const Context& context() const { return m_input_handler.context(); }
 
+    InputHandler& input_handler() { return m_input_handler; }
+    const InputHandler& input_handler() const { return m_input_handler; }
+
     void change_buffer(Buffer& buffer);
 
     const String& get_env_var(const String& name) const;

src/client_manager.cc

@@ -170,6 +170,12 @@ void ClientManager::redraw_clients() const
         client->redraw_ifn();
 }
 
+void ClientManager::clear_mode_trashes() const
+{
+    for (auto& client : m_clients)
+        client->input_handler().clear_mode_trash();
+}
+
 CandidateList ClientManager::complete_client_name(StringView prefix,
                                                   ByteCount cursor_pos) const
 {

src/client_manager.hh

@@ -34,6 +34,7 @@ public:
     void add_free_window(std::unique_ptr<Window>&& window, SelectionList selections);
 
     void redraw_clients() const;
+    void clear_mode_trashes() const;
 
     Client*  get_client_ifp(const String& name);
     Client&  get_client(const String& name);

src/event_manager.cc

@@ -1,5 +1,4 @@
 #include "event_manager.hh"
-#include "client_manager.hh"
 
 #include <poll.h>
 
@@ -82,9 +81,6 @@ void EventManager::handle_next_events()
         if (timer->next_date() <= now)
             timer->run();
     }
-
-    if (ClientManager::has_instance())
-        ClientManager::instance().redraw_clients();
 }
 
 void EventManager::force_signal(int fd)

src/main.cc

@@ -421,7 +421,12 @@ int kakoune(const ParametersParser& parser)
         create_local_client(init_command);
 
     while (not terminate and (not client_manager.empty() or daemon))
+    {
         event_manager.handle_next_events();
+        client_manager.clear_mode_trashes();
+        buffer_manager.clear_buffer_trash();
+        client_manager.redraw_clients();
+    }
 
     {
         Context empty_context;