From c9ab56cf69cef0501efdace082019c57ae42a631 Mon Sep 17 00:00:00 2001
From: David Capello <davidcapello@gmail.com>
Date: Sun, 10 Nov 2013 20:29:51 -0300
Subject: [PATCH] Timeline: we've to observe the Context to know if the
 Document is destroyed

In this way the timeline can stop observing the Document when it's closed.
---
 src/app/ui/timeline.cpp | 31 +++++++++++++++++++++++++------
 src/app/ui/timeline.h   |  6 ++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/app/ui/timeline.cpp b/src/app/ui/timeline.cpp
index 84c3bcd2d..78db884c1 100644
--- a/src/app/ui/timeline.cpp
+++ b/src/app/ui/timeline.cpp
@@ -115,23 +115,28 @@ Timeline::Timeline()
   , m_context(UIContext::instance())
   , m_document(NULL)
 {
+  m_context->addObserver(this);
 }
 
 Timeline::~Timeline()
 {
-  if (m_document)
-    m_document->removeObserver(this);
+  detachDocument();
+
+  m_context->removeObserver(this);
 }
 
 void Timeline::updateUsingEditor(Editor* editor)
 {
-  if (m_document)
-    m_document->removeObserver(this);
-
   DocumentView* view = editor->getDocumentView();
   DocumentLocation location;
   view->getDocumentLocation(&location);
 
+  // Do nothing, we've already viewing this document in the timeline.
+  if (m_document == location.document())
+    return;
+
+  detachDocument();
+
   m_document = location.document();
   m_sprite = location.sprite();
   m_layer = location.layer();
@@ -147,8 +152,16 @@ void Timeline::updateUsingEditor(Editor* editor)
 
   setFocusStop(true);
   regenerateLayers();
+}
 
-  m_document->addObserver(this);
+void Timeline::detachDocument()
+{
+  if (m_document) {
+    m_document->removeObserver(this);
+    m_document = NULL;
+
+    invalidate();
+  }
 }
 
 bool Timeline::isMovingCel() const
@@ -739,6 +752,12 @@ void Timeline::onPreferredSize(PreferredSizeEvent& ev)
   ev.setPreferredSize(Size(32, 32));
 }
 
+void Timeline::onRemoveDocument(Context* context, Document* document)
+{
+  if (document == m_document)
+    detachDocument();
+}
+
 void Timeline::onAddLayer(DocumentEvent& ev)
 {
   ASSERT(ev.layer() != NULL);
diff --git a/src/app/ui/timeline.h b/src/app/ui/timeline.h
index ca13d2e93..70c6b1770 100644
--- a/src/app/ui/timeline.h
+++ b/src/app/ui/timeline.h
@@ -19,6 +19,7 @@
 #ifndef APP_UI_TIMELINE_H_INCLUDED
 #define APP_UI_TIMELINE_H_INCLUDED
 
+#include "app/context_observer.h"
 #include "app/document_observer.h"
 #include "base/compiler_specific.h"
 #include "raster/frame_number.h"
@@ -40,6 +41,7 @@ namespace app {
   class Editor;
 
   class Timeline : public ui::Widget
+                 , public ContextObserver
                  , public DocumentObserver {
   public:
     enum State {
@@ -78,7 +80,11 @@ namespace app {
     void onRemoveFrame(DocumentEvent& ev) OVERRIDE;
     void onTotalFramesChanged(DocumentEvent& ev) OVERRIDE;
 
+    // ContextObserver impl.
+    void onRemoveDocument(Context* context, Document* document) OVERRIDE;
+
   private:
+    void detachDocument();
     void setCursor(int x, int y);
     void getDrawableLayers(const gfx::Rect& clip, int* first_layer, int* last_layer);
     void getDrawableFrames(const gfx::Rect& clip, FrameNumber* first_frame, FrameNumber* last_frame);