diff data/model/DeferredNotifier.h @ 1651:7a56bb85030f single-point

Introduce deferred notifier, + start converting sparse time-value model (perhaps we should rename it too)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/data/model/DeferredNotifier.h	Mon Mar 18 14:17:20 2019 +0000
@@ -0,0 +1,76 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef SV_DEFERRED_NOTIFIER_H
+#define SV_DEFERRED_NOTIFIER_H
+
+#include "Model.h"
+
+#include "base/Extents.h"
+
+#include <QMutex>
+#include <QMutexLocker>
+
+class DeferredNotifier
+{
+public:
+    enum Mode {
+        NOTIFY_ALWAYS,
+        NOTIFY_DEFERRED
+    };
+    
+    DeferredNotifier(Model *m, Mode mode) : m_model(m), m_mode(mode) { }
+
+    Mode getMode() const {
+        return m_mode;
+    }
+    void switchMode(Mode newMode) {
+        m_mode = newMode;
+    }
+    
+    void update(sv_frame_t frame, sv_frame_t duration) {
+        if (m_mode == NOTIFY_ALWAYS) {
+            m_model->modelChangedWithin(frame, frame + duration);
+        } else {
+            QMutexLocker locker(&m_mutex);
+            m_extents.sample(frame);
+            m_extents.sample(frame + duration);
+        }
+    }
+    
+    void makeDeferredNotifications() {
+        bool shouldEmit = false;
+        sv_frame_t from, to;
+        {   QMutexLocker locker(&m_mutex);
+            if (m_extents.isSet()) {
+                shouldEmit = true;
+                from = m_extents.getMin();
+                to = m_extents.getMax();
+            }
+        }
+        if (shouldEmit) {
+            m_model->modelChangedWithin(from, to);
+            QMutexLocker locker(&m_mutex);
+            m_extents.reset();
+        }
+    }
+
+private:
+    Model *m_model;
+    Mode m_mode;
+    QMutex m_mutex;
+    Extents<sv_frame_t> m_extents;
+};
+
+#endif