From 46fa7e18cf212af34eb7434b82c46d0349112396 Mon Sep 17 00:00:00 2001
From: David Capello <davidcapello@gmail.com>
Date: Wed, 29 Jul 2015 16:48:34 -0300
Subject: [PATCH] Remove MovingPixelsState as an Editor observer when the
 editor is destroyed

---
 src/app/ui/editor/moving_pixels_state.cpp | 19 ++++++++++++++++++-
 src/app/ui/editor/moving_pixels_state.h   |  4 ++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/app/ui/editor/moving_pixels_state.cpp b/src/app/ui/editor/moving_pixels_state.cpp
index cbdae7e6b..85840ab90 100644
--- a/src/app/ui/editor/moving_pixels_state.cpp
+++ b/src/app/ui/editor/moving_pixels_state.cpp
@@ -53,6 +53,7 @@ using namespace ui;
 
 MovingPixelsState::MovingPixelsState(Editor* editor, MouseMessage* msg, PixelsMovementPtr pixelsMovement, HandleType handle)
   : m_editor(editor)
+  , m_observingEditor(false)
   , m_discarded(false)
 {
   // MovingPixelsState needs a selection tool to avoid problems
@@ -97,6 +98,7 @@ MovingPixelsState::MovingPixelsState(Editor* editor, MouseMessage* msg, PixelsMo
   m_editor->getManager()->addMessageFilter(kKeyDownMessage, m_editor);
   m_editor->getManager()->addMessageFilter(kKeyUpMessage, m_editor);
   m_editor->addObserver(this);
+  m_observingEditor = true;
 
   ContextBar* contextBar = App::instance()->getMainWindow()->getContextBar();
   contextBar->updateForMovingPixels();
@@ -111,7 +113,7 @@ MovingPixelsState::~MovingPixelsState()
 
   m_pixelsMovement.reset(NULL);
 
-  m_editor->removeObserver(this);
+  removeAsEditorObserver();
   m_editor->getManager()->removeMessageFilter(kKeyDownMessage, m_editor);
   m_editor->getManager()->removeMessageFilter(kKeyUpMessage, m_editor);
 
@@ -486,6 +488,13 @@ void MovingPixelsState::onBeforeCommandExecution(Command* command)
     dropPixels();
 }
 
+void MovingPixelsState::onDestroyEditor(Editor* editor)
+{
+  // TODO we should call ~MovingPixelsState(), we should delete the
+  //      whole "m_statesHistory" when an editor is deleted.
+  removeAsEditorObserver();
+}
+
 void MovingPixelsState::onBeforeFrameChanged(Editor* editor)
 {
   if (!isActiveDocument())
@@ -570,4 +579,12 @@ bool MovingPixelsState::isActiveEditor() const
   return (targetEditor == m_editor);
 }
 
+void MovingPixelsState::removeAsEditorObserver()
+{
+  if (m_observingEditor) {
+    m_observingEditor = false;
+    m_editor->removeObserver(this);
+  }
+}
+
 } // namespace app
diff --git a/src/app/ui/editor/moving_pixels_state.h b/src/app/ui/editor/moving_pixels_state.h
index 5307e8080..1cb52e882 100644
--- a/src/app/ui/editor/moving_pixels_state.h
+++ b/src/app/ui/editor/moving_pixels_state.h
@@ -50,6 +50,7 @@ namespace app {
     virtual bool requireBrushPreview() override { return false; }
 
     // EditorObserver
+    virtual void onDestroyEditor(Editor* editor) override;
     virtual void onBeforeFrameChanged(Editor* editor) override;
     virtual void onBeforeLayerChanged(Editor* editor) override;
 
@@ -70,9 +71,12 @@ namespace app {
     bool isActiveDocument() const;
     bool isActiveEditor() const;
 
+    void removeAsEditorObserver();
+
     // Helper member to move/translate selection and pixels.
     PixelsMovementPtr m_pixelsMovement;
     Editor* m_editor;
+    bool m_observingEditor;
 
     // True if the image was discarded (e.g. when a "Cut" command was
     // used to remove the dragged image).