From ec2fc59fde61b1eea65de2bd870b390b2c47d9a0 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Sat, 29 Jan 2022 18:33:39 +0100
Subject: [PATCH] App: add a function to document observer to be notified if
 the active document changes

---
 src/App/DocumentObserver.cpp | 13 ++++++++-----
 src/App/DocumentObserver.h   |  7 +++++--
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/src/App/DocumentObserver.cpp b/src/App/DocumentObserver.cpp
index 2aa04a1aa1..927f7d7c8d 100644
--- a/src/App/DocumentObserver.cpp
+++ b/src/App/DocumentObserver.cpp
@@ -656,15 +656,13 @@ DocumentObserver::DocumentObserver() : _document(nullptr)
         (&DocumentObserver::slotCreatedDocument, this, sp::_1));
     this->connectApplicationDeletedDocument = App::GetApplication().signalDeleteDocument.connect(std::bind
         (&DocumentObserver::slotDeletedDocument, this, sp::_1));
+    this->connectApplicationActivateDocument = App::GetApplication().signalActiveDocument.connect(std::bind
+        (&DocumentObserver::slotActivateDocument, this, sp::_1));
 }
 
-DocumentObserver::DocumentObserver(Document* doc) : _document(nullptr)
+DocumentObserver::DocumentObserver(Document* doc) : DocumentObserver()
 {
     // Connect to application and given document
-    this->connectApplicationCreatedDocument = App::GetApplication().signalNewDocument.connect(std::bind
-        (&DocumentObserver::slotCreatedDocument, this, sp::_1));
-    this->connectApplicationDeletedDocument = App::GetApplication().signalDeleteDocument.connect(std::bind
-        (&DocumentObserver::slotDeletedDocument, this, sp::_1));
     attachDocument(doc);
 }
 
@@ -673,6 +671,7 @@ DocumentObserver::~DocumentObserver()
     // disconnect from application and document
     this->connectApplicationCreatedDocument.disconnect();
     this->connectApplicationDeletedDocument.disconnect();
+    this->connectApplicationActivateDocument.disconnect();
     detachDocument();
 }
 
@@ -720,6 +719,10 @@ void DocumentObserver::slotDeletedDocument(const App::Document& /*Doc*/)
 {
 }
 
+void DocumentObserver::slotActivateDocument(const App::Document& /*Doc*/)
+{
+}
+
 void DocumentObserver::slotCreatedObject(const App::DocumentObject& /*Obj*/)
 {
 }
diff --git a/src/App/DocumentObserver.h b/src/App/DocumentObserver.h
index 1cde5f51d5..4f1a47958f 100644
--- a/src/App/DocumentObserver.h
+++ b/src/App/DocumentObserver.h
@@ -437,10 +437,12 @@ public:
     void detachDocument();
 
 private:
-    /** Checks if a new document was created */
+    /** Called when a new document was created */
     virtual void slotCreatedDocument(const App::Document& Doc);
-    /** Checks if the given document is about to be closed */
+    /** Called when a document is about to be closed */
     virtual void slotDeletedDocument(const App::Document& Doc);
+    /** Called when a document is activated */
+    virtual void slotActivateDocument(const App::Document& Doc);
     /** Checks if a new object was added. */
     virtual void slotCreatedObject(const App::DocumentObject& Obj);
     /** Checks if the given object is about to be removed. */
@@ -460,6 +462,7 @@ private:
     typedef boost::signals2::connection Connection;
     Connection connectApplicationCreatedDocument;
     Connection connectApplicationDeletedDocument;
+    Connection connectApplicationActivateDocument;
     Connection connectDocumentCreatedObject;
     Connection connectDocumentDeletedObject;
     Connection connectDocumentChangedObject;