[ease] [general] Document, Slide, and Element are now UndoSources

[Nate Stedman <natesm src gnome org>]

commit 8ad67820a01b65676137e5c0181fcfc73ad89bfc
Author: Nate Stedman <natesm gmail com>
Date:   Mon Jul 26 19:41:59 2010 -0400

    [general] Document, Slide, and Element are now UndoSources
    
    Added some convenience methods to UndoSource:
    - forward: passes along an UndoAction
    - listen: starts forwarding from an UndoSource
    - silence: stops listening

 src/ease-document.vala      |    4 +++-
 src/ease-editor-window.vala |    6 +++---
 src/ease-element.vala       |    2 +-
 src/ease-image-element.vala |    2 +-
 src/ease-inspector.vala     |    2 +-
 src/ease-slide.vala         |    7 +++++--
 src/ease-text-element.vala  |    6 +++---
 src/ease-undo-source.vala   |   26 ++++++++++++++++++++++++++
 8 files changed, 43 insertions(+), 12 deletions(-)
---
diff --git a/src/ease-document.vala b/src/ease-document.vala
index 37ebf04..2384bdd 100644
--- a/src/ease-document.vala
+++ b/src/ease-document.vala
@@ -235,6 +235,7 @@ public class Ease.Document : GLib.Object, UndoSource
 		slides.insert(out itr, index);
 		slides.set(itr, COL_SLIDE, s);
 		slide_added(s, index);
+		listen(s);
 	}
 	
 	/**
@@ -262,10 +263,11 @@ public class Ease.Document : GLib.Object, UndoSource
 			{
 				slides.remove(itr);
 				slide_deleted(s, index);
+				silence(s);
 				break;
 			}
 			index++;
-		}
+		}		
 		
 		Slide ret;
 		Gtk.TreeIter itr;
diff --git a/src/ease-editor-window.vala b/src/ease-editor-window.vala
index bd4fab8..959468b 100644
--- a/src/ease-editor-window.vala
+++ b/src/ease-editor-window.vala
@@ -127,6 +127,7 @@ public class Ease.EditorWindow : Gtk.Window
 		set_default_size(1024, 768);
 		
 		document = doc;
+		document.undo.connect(add_undo_action);
 		
 		var builder = new Gtk.Builder();
 		try
@@ -152,18 +153,17 @@ public class Ease.EditorWindow : Gtk.Window
 		// main editor
 		embed = new EditorEmbed(document, this);
 		(builder.get_object("Embed Align") as Gtk.Alignment).add(embed);
-		embed.undo.connect((action) => add_undo_action(action));
+		embed.undo.connect(add_undo_action);
 		
 		// the inspector
 		inspector = new Inspector();
 		(builder.get_object("Inspector Align") as Gtk.Alignment).add(inspector);
-		inspector.undo.connect((action) => add_undo_action(action));
+		inspector.undo.connect(add_undo_action);
 		embed.element_selected.connect(
 			inspector.element_pane.on_element_selected);
 		embed.element_deselected.connect(
 			inspector.element_pane.on_element_deselected);
 		
-		
 		// zoom slider
 		(builder.get_object("Zoom Slider Item") as Gtk.ToolItem).
 			add(create_zoom_slider());
diff --git a/src/ease-element.vala b/src/ease-element.vala
index c4ab1c3..9c7dc0a 100644
--- a/src/ease-element.vala
+++ b/src/ease-element.vala
@@ -22,7 +22,7 @@
  * abstract, so each type of element is represented by a subclass. The Element
  * base class contains properties common to all types of element.
  */
-public abstract class Ease.Element : GLib.Object
+public abstract class Ease.Element : GLib.Object, UndoSource
 {
 	/**
 	 * The default width of { link Theme} master slides.
diff --git a/src/ease-image-element.vala b/src/ease-image-element.vala
index 8560fc9..edacf44 100644
--- a/src/ease-image-element.vala
+++ b/src/ease-image-element.vala
@@ -68,7 +68,7 @@ public class Ease.ImageElement : MediaElement
 			{
 				filename = parent.parent.add_media_file(file_b.get_filename());
 				source_filename = file_b.get_filename();
-				(widget_window(button) as EditorWindow).add_undo_action(action);
+				undo(action);
 			}
 			catch (Error e)
 			{
diff --git a/src/ease-inspector.vala b/src/ease-inspector.vala
index 0ac9ea7..fa5048c 100644
--- a/src/ease-inspector.vala
+++ b/src/ease-inspector.vala
@@ -64,7 +64,7 @@ public class Ease.Inspector : Gtk.Notebook, UndoSource
 	{
 		append_page(i, new Gtk.Image.from_stock(stock_id,
 		                                        Gtk.IconSize.SMALL_TOOLBAR));
-		i.undo.connect((action) => undo(action));
+		listen(i);
 	}
 }
 
diff --git a/src/ease-slide.vala b/src/ease-slide.vala
index 9c74e0d..87916a5 100644
--- a/src/ease-slide.vala
+++ b/src/ease-slide.vala
@@ -22,7 +22,7 @@
  * children. The currently selected Slide is often acted upon by an
  * { link EditorWindow}.
  */
-public class Ease.Slide : GLib.Object
+public class Ease.Slide : GLib.Object, UndoSource
 {
 	public const string IMAGE_TYPE = "EaseImageElement";
 
@@ -371,6 +371,7 @@ public class Ease.Slide : GLib.Object
 		e.parent = this;
 		elements.insert(index, e);
 		element_added(this, e, index);
+		listen(e);
 	}
 	
 	/**
@@ -390,7 +391,8 @@ public class Ease.Slide : GLib.Object
 	{
 		var index = index_of(e);
 		elements.remove(e);
-		element_removed(this, e, index); 
+		element_removed(this, e, index);
+		silence(e);
 	}
 	
 	/**
@@ -401,6 +403,7 @@ public class Ease.Slide : GLib.Object
 		var e = elements.get(index);
 		elements.remove_at(index);
 		element_removed(this, e, index);
+		silence(e);
 	}
 	
 	/**
diff --git a/src/ease-text-element.vala b/src/ease-text-element.vala
index b8de459..83b5ce4 100644
--- a/src/ease-text-element.vala
+++ b/src/ease-text-element.vala
@@ -148,7 +148,7 @@ public class Ease.TextElement : Element
 		
 		font.font_set.connect((button) => {
 			var action = new UndoAction(this, "font-description");
-			(widget_window(button) as EditorWindow).add_undo_action(action);
+			undo(action);
 			font_description =
 				Pango.FontDescription.from_string(font.font_name);
 		});
@@ -163,7 +163,7 @@ public class Ease.TextElement : Element
 		
 		color_b.color_set.connect((button) => {
 			var action = new UndoAction(this, "color");
-			(widget_window(button) as EditorWindow).add_undo_action(action);
+			undo(action);
 			color = new Color.from_gdk(color_b.color);
 		});
 		
@@ -192,7 +192,7 @@ public class Ease.TextElement : Element
 		
 		if (text_align != old)
 		{
-			(widget_window(sender) as EditorWindow).add_undo_action(action);
+			undo(action);
 		}
 	}
 
diff --git a/src/ease-undo-source.vala b/src/ease-undo-source.vala
index fcace0a..4cffb98 100644
--- a/src/ease-undo-source.vala
+++ b/src/ease-undo-source.vala
@@ -26,4 +26,30 @@ public interface Ease.UndoSource : GLib.Object
 	 * UndoAction.
 	 */
 	public signal void undo(UndoItem action);
+	
+	/**
+	 * Forwards an { link UndoItem} downwards, to any object listening to this
+	 * UndoSource's "undo" signal".
+	 */
+	protected void forward(UndoItem action)
+	{
+		undo(action);
+	}
+	
+	/**
+	 * Listens for incoming UndoItems from the specified UndoSource, and
+	 * { link forward}s them downwards.
+	 */
+	protected void listen(UndoSource source)
+	{
+		source.undo.connect(forward);
+	}
+	
+	/**
+	 * Stops listening to an UndoSource.
+	 */
+	protected void silence(UndoSource source)
+	{
+		source.undo.disconnect(forward);
+	}
 }