Add deferred task implementation

3 files changed, 81 insertions, 0 deletions

diff --git a/base/base.pro b/base/base.pro
index 58887276ef..934e3298ac 100644
--- a/base/base.pro
+++ b/base/base.pro
@@ -11,6 +11,7 @@ SOURCES += \
     base.cpp \
     condition.cpp \
     gmtime.cpp \
+    deferred_task.cpp \
     exception.cpp \
     internal/message.cpp \
     logging.cpp \
@@ -42,6 +43,7 @@ HEADERS += \
     collection_cast.hpp \
     condition.hpp \
     const_helper.hpp \
+    deferred_task.hpp \
     exception.hpp \
     gmtime.hpp \
     internal/messagex.hpp \
diff --git a/base/deferred_task.cpp b/base/deferred_task.cpp
new file mode 100644
index 0000000000..c769dab253
--- /dev/null
+++ b/base/deferred_task.cpp
@@ -0,0 +1,44 @@
+#include "deferred_task.hpp"
+
+DeferredTask::DeferredTask(TDuration duration) : m_duration(duration)
+{
+  m_thread = thread([this] {
+    unique_lock<mutex> l(m_mutex);
+    while (!m_terminate)
+    {
+      if (!m_fn)
+      {
+        m_cv.wait(l);
+        continue;
+      }
+
+      if (m_cv.wait_for(l, m_duration) != cv_status::timeout)
+        continue;
+
+      auto local_fn = move(m_fn);
+      m_fn = nullptr;
+      l.unlock();
+      local_fn();
+      l.lock();
+    }
+  });
+}
+
+DeferredTask::~DeferredTask()
+{
+  {
+    unique_lock<mutex> l(m_mutex);
+    m_terminate = true;
+  }
+  m_cv.notify_one();
+  m_thread.join();
+}
+
+void DeferredTask::Drop()
+{
+  {
+    unique_lock<mutex> l(m_mutex);
+    m_fn = nullptr;
+  }
+  m_cv.notify_one();
+}
diff --git a/base/deferred_task.hpp b/base/deferred_task.hpp
new file mode 100644
index 0000000000..517953150d
--- /dev/null
+++ b/base/deferred_task.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include "std/thread.hpp"
+#include "std/chrono.hpp"
+#include "std/mutex.hpp"
+#include "std/condition_variable.hpp"
+#include "std/function.hpp"
+
+
+class DeferredTask
+{
+  using TDuration = duration<double>;
+  thread m_thread;
+  mutex m_mutex;
+  condition_variable m_cv;
+  function<void()> m_fn;
+  TDuration m_duration;
+  bool m_terminate = false;
+
+public:
+  DeferredTask(TDuration duration);
+  ~DeferredTask();
+
+  void Drop();
+
+  template<typename TFn>
+  void RestartWith(TFn const && fn)
+  {
+    {
+      unique_lock<mutex> l(m_mutex);
+      m_fn = fn;
+    }
+    m_cv.notify_one();
+  }
+};