Add a InputMode::on_replaced virtual method.

Destructors are not a good place to run mode exit hooks, as they
wont be called until the next mode trash clearing, so we now call
this virtual method on the previous mode just before it gets replaced.

src/client.cc

@@ -26,6 +26,7 @@ public:
     InputMode& operator=(const InputMode&) = delete;
 
     virtual void on_key(Key key) = 0;
+    virtual void on_replaced() {}
     Context& context() const { return m_client.context(); }
 
     using Insertion = Client::Insertion;
@@ -54,7 +55,7 @@ public:
         context().hooks().run_hook("NormalBegin", "", context());
     }
 
-    ~Normal()
+    void on_replaced() override
     {
         context().hooks().run_hook("NormalEnd", "", context());
     }
@@ -908,12 +909,10 @@ private:
 
 InputMode& InputMode::reset_normal_mode()
 {
-    m_client.m_mode_trash.emplace_back(std::move(m_client.m_mode));
+    m_client.change_input_mode(new InputModes::Normal(m_client));
-    m_client.m_mode.reset(new InputModes::Normal(m_client));
     return *m_client.m_mode;
 }
 
-
 Client::Client(std::unique_ptr<UserInterface>&& ui, Editor& editor, String name)
     : m_ui(std::move(ui)), m_context(*this, editor), m_mode(new InputModes::Normal(*this)), m_name(name)
 {
@@ -923,10 +922,16 @@ Client::~Client()
 {
 }
 
+void Client::change_input_mode(InputMode* new_mode)
+{
+    m_mode->on_replaced();
+    m_mode_trash.emplace_back(std::move(m_mode));
+    m_mode.reset(new_mode);
+}
+
 void Client::insert(InsertMode mode)
 {
-    m_mode_trash.emplace_back(std::move(m_mode));
+    change_input_mode(new InputModes::Insert(*this, mode));
-    m_mode.reset(new InputModes::Insert(*this, mode));
 }
 
 void Client::repeat_last_insert()
@@ -938,8 +943,7 @@ void Client::repeat_last_insert()
     swap(keys, m_last_insert.second);
     // context.last_insert will be refilled by the new Insert
     // this is very inefficient.
-    m_mode_trash.emplace_back(std::move(m_mode));
+    change_input_mode(new InputModes::Insert(*this, m_last_insert.first));
-    m_mode.reset(new InputModes::Insert(*this, m_last_insert.first));
     for (auto& key : keys)
         m_mode->on_key(key);
     kak_assert(dynamic_cast<InputModes::Normal*>(m_mode.get()) != nullptr);
@@ -948,8 +952,7 @@ void Client::repeat_last_insert()
 void Client::prompt(const String& prompt, ColorPair prompt_colors,
                           Completer completer, PromptCallback callback)
 {
-    m_mode_trash.emplace_back(std::move(m_mode));
+    change_input_mode(new InputModes::Prompt(*this, prompt, prompt_colors,
-    m_mode.reset(new InputModes::Prompt(*this, prompt, prompt_colors,
                                              completer, callback));
 }
 
@@ -963,14 +966,12 @@ void Client::set_prompt_colors(ColorPair prompt_colors)
 void Client::menu(memoryview<String> choices,
                         MenuCallback callback)
 {
-    m_mode_trash.emplace_back(std::move(m_mode));
+    change_input_mode(new InputModes::Menu(*this, choices, callback));
-    m_mode.reset(new InputModes::Menu(*this, choices, callback));
 }
 
 void Client::on_next_key(KeyCallback callback)
 {
-    m_mode_trash.emplace_back(std::move(m_mode));
+    change_input_mode(new InputModes::NextKey(*this, callback));
-    m_mode.reset(new InputModes::NextKey(*this, callback));
 }
 
 bool is_valid(Key key)

src/client.hh

@@ -91,6 +91,8 @@ private:
     std::unique_ptr<InputMode> m_mode;
     std::vector<std::unique_ptr<InputMode>> m_mode_trash;
 
+    void change_input_mode(InputMode* new_mode);
+
     String m_name;
     DisplayLine m_status_line;