Add client::on_next_key method to run some code when the next key arrives

src/client.cc

@@ -291,6 +291,24 @@ private:
 };
 std::unordered_map<String, std::vector<String>> Client::PromptMode::ms_history;
 
+class Client::NextKeyMode : public Client::Mode
+{
+public:
+    NextKeyMode(Client& client, KeyCallback callback)
+        : Client::Mode(client), m_callback(callback) {}
+
+    void on_key(const Key& key, Context& context) override
+    {
+        // save callback as reset_normal_mode will delete this
+        KeyCallback callback = std::move(m_callback);
+        m_client.reset_normal_mode();
+        callback(key, context);
+   }
+
+private:
+    KeyCallback m_callback;
+};
+
 Client::Client()
     : m_mode(new NormalMode(*this))
 {
@@ -308,6 +326,11 @@ void Client::menu(const memoryview<String>& choices,
     m_mode.reset(new MenuMode(*this, choices, callback));
 }
 
+void Client::on_next_key(KeyCallback callback)
+{
+    m_mode.reset(new NextKeyMode(*this, callback));
+}
+
 void Client::handle_next_input(Context& context)
 {
     m_mode->on_key(get_key(), context);

src/client.hh

@@ -25,6 +25,7 @@ enum class MenuCommand
 
 using MenuCallback = std::function<void (int, Context&)>;
 using PromptCallback = std::function<void (const String&, Context&)>;
+using KeyCallback = std::function<void (const Key&, Context&)>;
 
 class Client : public SafeCountable
 {
@@ -41,11 +42,12 @@ public:
     void menu(const memoryview<String>& choices,
               MenuCallback callback);
 
+    void on_next_key(KeyCallback callback);
+
     void handle_next_input(Context& context);
     virtual Key    get_key() = 0;
 
 private:
-
     virtual void   show_menu(const memoryview<String>& choices) = 0;
     virtual void   menu_ctrl(MenuCommand command) = 0;
 
@@ -56,6 +58,9 @@ private:
     public:
         Mode(Client& client) : m_client(client) {}
         virtual ~Mode() {}
+        Mode(const Mode&) = delete;
+        Mode& operator=(const Mode&) = delete;
+
         virtual void on_key(const Key& key, Context& context) = 0;
     protected:
         Client& m_client;
@@ -65,6 +70,7 @@ private:
     class NormalMode;
     class MenuMode;
     class PromptMode;
+    class NextKeyMode;
 };
 
 struct prompt_aborted {};