From 64dea656becd8c914a3c8dc3f3b4f0d71bd3f2d0 Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Wed, 11 Jun 2014 20:05:36 +0200
Subject: Defer PT apply to avoid deadlock

---
 FTNoIR_Tracker_PT/ftnoir_tracker_pt.cpp | 22 ++++++++++++++++++----
 FTNoIR_Tracker_PT/ftnoir_tracker_pt.h   |  6 ++++--
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/FTNoIR_Tracker_PT/ftnoir_tracker_pt.cpp b/FTNoIR_Tracker_PT/ftnoir_tracker_pt.cpp
index cbc1f1dc..787a5128 100644
--- a/FTNoIR_Tracker_PT/ftnoir_tracker_pt.cpp
+++ b/FTNoIR_Tracker_PT/ftnoir_tracker_pt.cpp
@@ -26,7 +26,9 @@ Tracker::Tracker()
     : commands(0),
 	  video_widget(NULL), 
 	  video_frame(NULL),
-	  tracking_valid(false)
+	  tracking_valid(false),
+	  need_apply(false),
+	  new_settings(nullptr)
 {
 	qDebug()<<"Tracker::Tracker";
 }
@@ -73,7 +75,7 @@ void Tracker::run()
         if (commands & ABORT) break;
         if (commands & PAUSE) continue;
         commands = 0;
-        
+	apply_inner();
         dt = time.start() / 1000.0;
 
         new_frame = camera.get_frame(dt, &frame);
@@ -111,11 +113,23 @@ void Tracker::run()
 
 	qDebug()<<"Tracker:: Thread stopping";
 }
-
 void Tracker::apply(settings& s)
 {
-	qDebug()<<"Tracker:: Applying settings";
 	QMutexLocker lock(&mutex);
+	need_apply = true;
+	// caller guarantees object lifetime
+	new_settings = &s;
+}
+
+void Tracker::apply_inner()
+{
+	QMutexLocker lock(&mutex);
+	if (!need_apply)
+		return;
+	qDebug()<<"Tracker:: Applying settings";
+	auto& s = *new_settings;
+	new_settings = nullptr;
+	need_apply = false;
     camera.set_device_index(s.cam_index);
     camera.set_res(s.cam_res_x, s.cam_res_y);
     camera.set_fps(s.cam_fps);
diff --git a/FTNoIR_Tracker_PT/ftnoir_tracker_pt.h b/FTNoIR_Tracker_PT/ftnoir_tracker_pt.h
index 80abbc6a..47a9987b 100644
--- a/FTNoIR_Tracker_PT/ftnoir_tracker_pt.h
+++ b/FTNoIR_Tracker_PT/ftnoir_tracker_pt.h
@@ -44,6 +44,7 @@ public:
     virtual void refreshVideo();
 
     void apply(settings& s);
+	void apply_inner();
 	void center();
 	void reset();	// reset the trackers internal state variables
 	void run();
@@ -81,9 +82,10 @@ protected:
 
     PTVideoWidget* video_widget;
 	QFrame*      video_frame;
-    bool           tracking_valid;
-
+    bool           tracking_valid, need_apply;
+	
     settings s;
+    settings* new_settings;
     Timer time;
 };
 
-- 
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