EventManager: add support for timers

src/event_manager.cc

@@ -16,6 +16,23 @@ FDWatcher::~FDWatcher()
     EventManager::instance().m_fd_watchers.remove(this);
 }
 
+Timer::Timer(TimePoint date, Callback callback)
+    : m_date{date}, m_callback{std::move(callback)}
+{
+    EventManager::instance().m_timers.add(this);
+}
+
+Timer::~Timer()
+{
+    EventManager::instance().m_timers.remove(this);
+}
+
+void Timer::run()
+{
+    m_date = TimePoint::max();
+    m_callback(*this);
+}
+
 EventManager::EventManager()
 {
     m_forced_fd.reserve(4);
@@ -24,6 +41,7 @@ EventManager::EventManager()
 EventManager::~EventManager()
 {
     assert(m_fd_watchers.empty());
+    assert(m_timers.empty());
 }
 
 void EventManager::handle_next_events()
@@ -48,6 +66,13 @@ void EventManager::handle_next_events()
                 (*it)->run();
         }
     }
+
+    TimePoint now = Clock::now();
+    for (auto& timer : m_timers)
+    {
+        if (timer->next_date() <= now)
+            timer->run();
+    }
 }
 
 void EventManager::force_signal(int fd)

src/event_manager.hh

@@ -3,6 +3,8 @@
 
 #include "utils.hh"
 
+#include <chrono>
+
 namespace Kakoune
 {
 
@@ -20,6 +22,26 @@ private:
     Callback m_callback;
 };
 
+using Clock = std::chrono::steady_clock;
+using TimePoint = Clock::time_point;
+
+class Timer
+{
+public:
+    using Callback = std::function<void (Timer& timer)>;
+
+    Timer(TimePoint date, Callback callback);
+    ~Timer();
+
+    TimePoint next_date() const { return m_date; }
+    void      set_next_date(TimePoint date) { m_date = date; }
+    void run();
+
+private:
+    TimePoint m_date;
+    Callback  m_callback;
+};
+
 // The EventManager provides an interface to file descriptor
 // based event handling.
 //
@@ -39,8 +61,12 @@ public:
 
 private:
     friend class FDWatcher;
+    friend class Timer;
     Set<FDWatcher*>  m_fd_watchers;
+    Set<Timer*>      m_timers;
     std::vector<int> m_forced_fd;
+
+    TimePoint        m_last;
 };
 
 }