runtime: encapsulate checkpoint progress state

src/libthecore/signal.cpp

@@ -1,9 +1,32 @@
 #include "stdafx.h"
 
+#include <atomic>
+
+namespace
+{
+std::atomic<int> s_checkpoint_ticks { 0 };
+
+const char* signal_checkpoint_backend_name_impl(ECheckpointBackend backend)
+{
+	switch (backend)
+	{
+		case CHECKPOINT_BACKEND_NONE:
+			return "none";
+		case CHECKPOINT_BACKEND_VIRTUAL_TIMER:
+			return "virtual-timer";
+		default:
+			return "unknown";
+	}
+}
+}
+
 #ifdef OS_WINDOWS
 void signal_setup() {}
 void signal_timer_disable() {}
 void signal_timer_enable(int timeout_seconds) {}
+void signal_mark_progress() {}
+ECheckpointBackend signal_checkpoint_backend() { return CHECKPOINT_BACKEND_NONE; }
+const char* signal_checkpoint_backend_name(ECheckpointBackend backend) { return signal_checkpoint_backend_name_impl(backend); }
 #else
 #define RETSIGTYPE void
 
@@ -16,13 +39,13 @@ RETSIGTYPE reap(int sig)
 
 RETSIGTYPE checkpointing(int sig)
 {
-    if (!tics.load())
+    if (!s_checkpoint_ticks.load())
     {
         sys_err("CHECKPOINT shutdown: tics did not updated.");
         abort();
     }
     else
-	    tics.store(0);
+	    s_checkpoint_ticks.store(0);
 }
 
 
@@ -81,4 +104,19 @@ void signal_setup(void)
     signal(SIGUSR1, usrsig);
 }
 
+void signal_mark_progress()
+{
+	s_checkpoint_ticks.fetch_add(1, std::memory_order_relaxed);
+}
+
+ECheckpointBackend signal_checkpoint_backend()
+{
+	return CHECKPOINT_BACKEND_VIRTUAL_TIMER;
+}
+
+const char* signal_checkpoint_backend_name(ECheckpointBackend backend)
+{
+	return signal_checkpoint_backend_name_impl(backend);
+}
+
 #endif