# HG changeset patch
# User Chris Cannam
# Date 1429521026 -3600
# Node ID e53a87a5efb2fcf90ca9d97cfe0592b53226d002
# Parent  78c152e4db958ac5a36e0fba3102cb6fdc52dd62
Allow layers to be loaded without models if their layer class explicitly says it's OK (otherwise default template won't load, as it has an empty waveform layer)

diff -r 78c152e4db95 -r e53a87a5efb2 layer/Layer.h
--- a/layer/Layer.h	Mon Apr 20 09:12:17 2015 +0100
+++ b/layer/Layer.h	Mon Apr 20 10:10:26 2015 +0100
@@ -62,7 +62,7 @@
     Model *getModel() {
 	return const_cast<Model *>(const_cast<const Layer *>(this)->getModel());
     }
-
+    
     /**
      * Return a zoom constraint object defining the supported zoom
      * levels for this layer.  If this returns zero, the layer will
@@ -518,6 +518,13 @@
      */
     virtual RangeMapper *getNewVerticalZoomRangeMapper() const { return 0; }
 
+    /**
+     * Return true if this layer type can function without a model
+     * being set. If false (the default), the layer will not be loaded
+     * from a session if its model cannot be found.
+     */
+    virtual bool canExistWithoutModel() const { return false; }
+
 public slots:
     void showLayer(View *, bool show);
 
diff -r 78c152e4db95 -r e53a87a5efb2 layer/TimeRulerLayer.h
--- a/layer/TimeRulerLayer.h	Mon Apr 20 09:12:17 2015 +0100
+++ b/layer/TimeRulerLayer.h	Mon Apr 20 10:10:26 2015 +0100
@@ -60,6 +60,8 @@
 
     void setProperties(const QXmlAttributes &attributes);
 
+    virtual bool canExistWithoutModel() const { return true; }
+
 protected:
     Model *m_model;
     LabelHeight m_labelHeight;
diff -r 78c152e4db95 -r e53a87a5efb2 layer/WaveformLayer.h
--- a/layer/WaveformLayer.h	Mon Apr 20 09:12:17 2015 +0100
+++ b/layer/WaveformLayer.h	Mon Apr 20 10:10:26 2015 +0100
@@ -202,6 +202,8 @@
     virtual int getCurrentVerticalZoomStep() const;
     virtual void setVerticalZoomStep(int);
 
+    virtual bool canExistWithoutModel() const { return true; }
+
 protected:
     int dBscale(double sample, int m) const;