From 949110d73d104309e522c3d5564c43a8ecb41a4b Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Mon, 16 Mar 2020 15:11:11 +0100
Subject: [PATCH] App: [skip ci] implement WekPtrT to simplify using
 DocumentObjectWeakPtrT

---
 src/App/DocumentObserver.cpp | 57 ++++++++++++++++--------
 src/App/DocumentObserver.h   | 84 +++++++++++++++++++++++++++++++++++-
 2 files changed, 121 insertions(+), 20 deletions(-)

diff --git a/src/App/DocumentObserver.cpp b/src/App/DocumentObserver.cpp
index 789386ba8e..299527d838 100644
--- a/src/App/DocumentObserver.cpp
+++ b/src/App/DocumentObserver.cpp
@@ -447,16 +447,7 @@ App::Document* DocumentWeakPtrT::operator->() noexcept
 class DocumentObjectWeakPtrT::Private {
 public:
     Private(App::DocumentObject* obj) : object(obj), indocument(false) {
-        if (obj) {
-            indocument = true;
-            connectApplicationDeletedDocument = App::GetApplication().signalDeleteDocument.connect(boost::bind
-                (&Private::deletedDocument, this, _1));
-            App::Document* doc = obj->getDocument();
-            connectDocumentCreatedObject = doc->signalNewObject.connect(boost::bind
-                (&Private::createdObject, this, _1));
-            connectDocumentDeletedObject = doc->signalDeletedObject.connect(boost::bind
-                (&Private::deletedObject, this, _1));
-        }
+        set(obj);
     }
     void deletedDocument(const App::Document& doc) {
         // When deleting document then there is no way to undo it
@@ -464,13 +455,13 @@ public:
             reset();
         }
     }
-    void createdObject(const App::DocumentObject& obj) {
+    void createdObject(const App::DocumentObject& obj) noexcept {
         // When undoing the removal
         if (object == &obj) {
             indocument = true;
         }
     }
-    void deletedObject(const App::DocumentObject& obj) {
+    void deletedObject(const App::DocumentObject& obj) noexcept {
         if (object == &obj) {
             indocument = false;
         }
@@ -482,7 +473,20 @@ public:
         object = nullptr;
         indocument = false;
     }
-    App::DocumentObject* get() const {
+    void set(App::DocumentObject* obj) {
+        object = obj;
+        if (obj) {
+            indocument = true;
+            connectApplicationDeletedDocument = App::GetApplication().signalDeleteDocument.connect(boost::bind
+            (&Private::deletedDocument, this, _1));
+            App::Document* doc = obj->getDocument();
+            connectDocumentCreatedObject = doc->signalNewObject.connect(boost::bind
+            (&Private::createdObject, this, _1));
+            connectDocumentDeletedObject = doc->signalDeletedObject.connect(boost::bind
+            (&Private::deletedObject, this, _1));
+        }
+    }
+    App::DocumentObject* get() const noexcept {
         return indocument ? object : nullptr;
     }
 
@@ -494,7 +498,7 @@ public:
     Connection connectDocumentDeletedObject;
 };
 
-DocumentObjectWeakPtrT::DocumentObjectWeakPtrT(App::DocumentObject* obj) noexcept
+DocumentObjectWeakPtrT::DocumentObjectWeakPtrT(App::DocumentObject* obj)
   : d(new Private(obj))
 {
 }
@@ -509,7 +513,7 @@ App::DocumentObject* DocumentObjectWeakPtrT::_get() const noexcept
     return d->get();
 }
 
-void DocumentObjectWeakPtrT::reset() noexcept
+void DocumentObjectWeakPtrT::reset()
 {
     d->reset();
 }
@@ -519,14 +523,31 @@ bool DocumentObjectWeakPtrT::expired() const noexcept
     return !d->indocument;
 }
 
+DocumentObjectWeakPtrT& DocumentObjectWeakPtrT::operator= (App::DocumentObject* p)
+{
+    d->reset();
+    d->set(p);
+    return *this;
+}
+
 App::DocumentObject* DocumentObjectWeakPtrT::operator->() noexcept
 {
     return d->get();
 }
 
+bool DocumentObjectWeakPtrT::operator== (const DocumentObjectWeakPtrT& p) const noexcept
+{
+    return d->get() == p.d->get();
+}
+
+bool DocumentObjectWeakPtrT::operator!= (const DocumentObjectWeakPtrT& p) const noexcept
+{
+    return d->get() != p.d->get();
+}
+
 // -----------------------------------------------------------------------------
 
-DocumentObserver::DocumentObserver() : _document(0)
+DocumentObserver::DocumentObserver() : _document(nullptr)
 {
     this->connectApplicationCreatedDocument = App::GetApplication().signalNewDocument.connect(boost::bind
         (&DocumentObserver::slotCreatedDocument, this, _1));
@@ -534,7 +555,7 @@ DocumentObserver::DocumentObserver() : _document(0)
         (&DocumentObserver::slotDeletedDocument, this, _1));
 }
 
-DocumentObserver::DocumentObserver(Document* doc) : _document(0)
+DocumentObserver::DocumentObserver(Document* doc) : _document(nullptr)
 {
     // Connect to application and given document
     this->connectApplicationCreatedDocument = App::GetApplication().signalNewDocument.connect(boost::bind
@@ -579,7 +600,7 @@ void DocumentObserver::attachDocument(Document* doc)
 void DocumentObserver::detachDocument()
 {
     if (this->_document) {
-        this->_document = 0;
+        this->_document = nullptr;
         this->connectDocumentCreatedObject.disconnect();
         this->connectDocumentDeletedObject.disconnect();
         this->connectDocumentChangedObject.disconnect();
diff --git a/src/App/DocumentObserver.h b/src/App/DocumentObserver.h
index 53dea56df7..3fa6329dc2 100644
--- a/src/App/DocumentObserver.h
+++ b/src/App/DocumentObserver.h
@@ -249,24 +249,39 @@ private:
 class AppExport DocumentObjectWeakPtrT
 {
 public:
-    DocumentObjectWeakPtrT(App::DocumentObject*) noexcept;
+    DocumentObjectWeakPtrT(App::DocumentObject*);
     ~DocumentObjectWeakPtrT();
 
     /*!
      * \brief reset
      * Releases the reference to the managed object. After the call *this manages no object.
      */
-    void reset() noexcept;
+    void reset();
     /*!
      * \brief expired
      * \return true if the managed object has already been deleted, false otherwise.
      */
     bool expired() const noexcept;
+    /*!
+     * \brief operator =
+     * Assignment operator
+     */
+    DocumentObjectWeakPtrT& operator= (App::DocumentObject* p);
     /*!
      * \brief operator ->
      * \return pointer to the document
      */
     App::DocumentObject* operator->() noexcept;
+    /*!
+     * \brief operator ==
+     * \return true if both objects are equal, false otherwise
+     */
+    bool operator== (const DocumentObjectWeakPtrT& p) const noexcept;
+    /*!
+     * \brief operator !=
+     * \return true if both objects are inequal, false otherwise
+     */
+    bool operator!= (const DocumentObjectWeakPtrT& p) const noexcept;
     /*! Get a pointer to the object or 0 if it doesn't exist any more or the type doesn't match. */
     template<typename T>
     inline T* get() const noexcept
@@ -285,6 +300,71 @@ private:
     std::unique_ptr<Private> d;
 };
 
+/**
+ * @brief The WeakPtrT class
+ */
+template <class T>
+class WeakPtrT
+{
+public:
+    WeakPtrT(T* t) : ptr(t) {
+    }
+    ~WeakPtrT() {
+    }
+
+    /*!
+     * \brief reset
+     * Releases the reference to the managed object. After the call *this manages no object.
+     */
+    void reset() {
+        ptr.reset();
+    }
+    /*!
+     * \brief expired
+     * \return true if the managed object has already been deleted, false otherwise.
+     */
+    bool expired() const {
+        return ptr.expired();
+    }
+    /*!
+     * \brief operator =
+     * Assignment operator
+     */
+    WeakPtrT<T>& operator= (T* p) {
+        ptr = p;
+        return *this;
+    }
+    /*!
+     * \brief operator ->
+     * \return pointer to the document
+     */
+    T* operator->() {
+        return ptr.get<T>();
+    }
+    /*!
+     * \brief operator ==
+     * \return true if both objects are equal, false otherwise
+     */
+    bool operator== (const WeakPtrT<T>& p) const {
+        return ptr == p.ptr;
+    }
+    /*!
+     * \brief operator !=
+     * \return true if both objects are inequal, false otherwise
+     */
+    bool operator!= (const WeakPtrT<T>& p) const {
+        return ptr != p.ptr;
+    }
+
+private:
+    // disable
+    WeakPtrT(const WeakPtrT&);
+    WeakPtrT& operator=(const WeakPtrT&);
+
+private:
+    DocumentObjectWeakPtrT ptr;
+};
+
 /**
  * The DocumentObserver class simplfies the step to write classes that listen
  * to what happens inside a document.