From 0f7123d33a1ab879191046b86d382318f35fd570 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Tue, 25 Sep 2018 11:53:52 -0400
Subject: [PATCH] more objectification for SafeTime

---
 libs/ardour/ardour/transport_master.h | 30 +++++++++++++++++++--------
 libs/ardour/mtc_slave.cc              | 25 +++-------------------
 2 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/libs/ardour/ardour/transport_master.h b/libs/ardour/ardour/transport_master.h
index da30abfae9..81d250dda9 100644
--- a/libs/ardour/ardour/transport_master.h
+++ b/libs/ardour/ardour/transport_master.h
@@ -26,9 +26,11 @@
 #include <boost/atomic.hpp>
 
 #include <glibmm/threads.h>
+#include <glibmm/timer.h>
 
 #include <ltc.h>
 
+#include "pbd/i18n.h"
 #include "pbd/properties.h"
 #include "pbd/signals.h"
 #include "pbd/stateful.h"
@@ -305,15 +307,6 @@ struct LIBARDOUR_API SafeTime {
 		, guard2 (other.guard2.load (boost::memory_order_acquire))
 	{}
 
-	SafeTime& operator= (SafeTime const & other) {
-		guard1 = other.guard1.load (boost::memory_order_acquire);
-		position = other.position;
-		timestamp = other.timestamp;
-		speed = other.speed;
-		guard2 = other.guard2.load (boost::memory_order_acquire);
-		return *this;
-	}
-
 	void update (samplepos_t p, samplepos_t t, double s) {
 		guard1.fetch_add (1, boost::memory_order_acquire);
 		position = p;
@@ -321,6 +314,25 @@ struct LIBARDOUR_API SafeTime {
 		speed = s;
 		guard2.fetch_add (1, boost::memory_order_acquire);
 	}
+
+	void safe_read (SafeTime& dst) const {
+		int tries = 0;
+
+		do {
+			if (tries == 10) {
+				std::cerr << X_("SafeTime: atomic read of current time failed, sleeping!") << std::endl;
+				Glib::usleep (20);
+				tries = 0;
+			}
+			dst.guard1.store (guard1.load (boost::memory_order_seq_cst), boost::memory_order_seq_cst);
+			dst.position = position;
+			dst.timestamp = timestamp;
+			dst.speed = speed;
+			dst.guard2.store (guard2.load (boost::memory_order_seq_cst), boost::memory_order_seq_cst);
+			tries++;
+
+		} while (dst.guard1.load (boost::memory_order_seq_cst) != dst.guard2.load (boost::memory_order_seq_cst));
+	}
 };
 
 /** a helper class for any TransportMaster that receives its input via a MIDI
diff --git a/libs/ardour/mtc_slave.cc b/libs/ardour/mtc_slave.cc
index 7a6d6a6ed6..d110c2a32d 100644
--- a/libs/ardour/mtc_slave.cc
+++ b/libs/ardour/mtc_slave.cc
@@ -32,8 +32,6 @@
 #include "ardour/session.h"
 #include "ardour/transport_master.h"
 
-#include <glibmm/timer.h>
-
 #include "pbd/i18n.h"
 
 using namespace std;
@@ -259,23 +257,6 @@ MTC_TransportMaster::handle_locate (const MIDI::byte* mmc_tc)
 	update_mtc_time (mtc, true, 0);
 }
 
-void
-MTC_TransportMaster::read_current (SafeTime *st) const
-{
-	int tries = 0;
-
-	do {
-		if (tries == 10) {
-			error << _("MTC Slave: atomic read of current time failed, sleeping!") << endmsg;
-			Glib::usleep (20);
-			tries = 0;
-		}
-		*st = current;
-		tries++;
-
-	} while (st->guard1.load (boost::memory_order_acquire) != st->guard2.load (boost::memory_order_acquire));
-}
-
 void
 MTC_TransportMaster::init_mtc_dll(samplepos_t tme, double qtr)
 {
@@ -579,7 +560,7 @@ MTC_TransportMaster::speed_and_position (double& speed, samplepos_t& pos, sample
 		return false;
 	}
 
-	read_current (&last);
+	current.safe_read (last);
 
 	DEBUG_TRACE (DEBUG::MTC, string_compose ("speed&pos: timestamp %1 speed %2 dir %4 now %5 last-in %6\n",
 						 last.timestamp,
@@ -634,7 +615,7 @@ std::string
 MTC_TransportMaster::position_string() const
 {
 	SafeTime last;
-	read_current (&last);
+	current.safe_read (last);
 	if (last.timestamp == 0 || reset_pending) {
 		return " --:--:--:--";
 	}
@@ -650,7 +631,7 @@ MTC_TransportMaster::delta_string () const
 {
 	char delta[80];
 	SafeTime last;
-	read_current (&last);
+	current.safe_read (last);
 
 	delta[0] = '\0';