1 files changed, 132 insertions, 0 deletions
diff --git a/src/core/DataView.vala b/src/core/DataView.vala
new file mode 100644
index 0000000..07cd4fc
--- /dev/null
+++ b/src/core/DataView.vala
@@ -0,0 +1,132 @@
+/* Copyright 2011-2014 Yorba Foundation
+ *
+ * This software is licensed under the GNU Lesser General Public License
+ * (version 2.1 or later).  See the COPYING file in this distribution.
+ */
+
+public class DataView : DataObject {
+    private DataSource source;
+    private bool selected = false;
+    private bool visible = true;
+    
+    // Indicates that the selection state has changed.
+    public virtual signal void state_changed(bool selected) {
+    }
+    
+    // Indicates the visible state has changed.
+    public virtual signal void visibility_changed(bool visible) {
+    }
+    
+    // Indicates that the display (what is seen by the user) of the DataView has changed.
+    public virtual signal void view_altered() {
+    }
+    
+    // Indicates that the geometry of the DataView has changed (which implies the view has altered,
+    // but only in that the same elements have changed size).
+    public virtual signal void geometry_altered() {
+    }
+    
+    public virtual signal void unsubscribed(DataSource source) {
+    }
+    
+    public DataView(DataSource source) {
+        this.source = source;
+        
+        // subscribe to the DataSource, which sets up signal reflection and gives the DataView
+        // first notification of destruction.
+        source.internal_subscribe(this);
+    }
+    
+    ~DataView() {
+#if TRACE_DTORS
+        debug("DTOR: DataView %s", dbg_to_string);
+#endif
+        source.internal_unsubscribe(this);
+    }
+    
+    public override string get_name() {
+        return "View of %s".printf(source.get_name());
+    }
+    
+    public override string to_string() {
+        return "DataView %s [DataSource %s]".printf(get_name(), source.to_string());
+    }
+    
+    public DataSource get_source() {
+        return source;
+    }
+    
+    public bool is_selected() {
+        return selected;
+    }
+    
+    // This method is only called by ViewCollection.
+    public void internal_set_selected(bool selected) {
+        if (this.selected == selected)
+            return;
+        
+        this.selected = selected;
+        state_changed(selected);
+    }
+    
+    // This method is only called by ViewCollection.  Returns the toggled state.
+    public bool internal_toggle() {
+        selected = !selected;
+        state_changed(selected);
+        
+        return selected;
+    }
+    
+    public bool is_visible() {
+        return visible;
+    }
+    
+    // This method is only called by ViewCollection.
+    public void internal_set_visible(bool visible) {
+        if (this.visible == visible)
+            return;
+        
+        this.visible = visible;
+        visibility_changed(visible);
+    }
+
+    protected virtual void notify_view_altered() {
+        // impossible when not visible
+        if (!visible)
+            return;
+        
+        ViewCollection vc = get_membership() as ViewCollection;
+        if (vc != null) {
+            if (!vc.are_notifications_frozen())
+                view_altered();
+            
+            // notify ViewCollection in any event
+            vc.internal_notify_view_altered(this);
+        } else {
+            view_altered();
+        }
+    }
+    
+    protected virtual void notify_geometry_altered() {
+        // impossible when not visible
+        if (!visible)
+            return;
+        
+        ViewCollection vc = get_membership() as ViewCollection;
+        if (vc != null) {
+            if (!vc.are_notifications_frozen())
+                geometry_altered();
+            
+            // notify ViewCollection in any event
+            vc.internal_notify_geometry_altered(this);
+        } else {
+            geometry_altered();
+        }
+    }
+    
+    // This is only called by DataSource
+    public virtual void notify_unsubscribed(DataSource source) {
+        unsubscribed(source);
+    }
+}
+