Enable move constructor/assignment for ref-counted pointers

Author: mgreter

src/memory/SharedPtr.cpp

@@ -37,22 +37,20 @@ namespace Sass {
     , dbg(false)
     #endif
   {
-      refcounter = 0;
-      #ifdef DEBUG_SHARED_PTR
-        if (taint) all.push_back(this);
-      #endif
-    };
-
-    SharedObj::~SharedObj() {
-      #ifdef DEBUG_SHARED_PTR
-          if (dbg) std::cerr << "Destruct " << this << "\n";
-          if(!all.empty()) { // check needed for MSVC (no clue why?)
-            all.erase(std::remove(all.begin(), all.end(), this), all.end());
-          }
-      #endif
-    };
-
+    refcounter = 0;
+    #ifdef DEBUG_SHARED_PTR
+      if (taint) all.push_back(this);
+    #endif
+  };
 
+  SharedObj::~SharedObj() {
+    #ifdef DEBUG_SHARED_PTR
+      if (dbg) std::cerr << "Destruct " << this << "\n";
+      if(!all.empty()) { // check needed for MSVC (no clue why?)
+        all.erase(std::remove(all.begin(), all.end(), this), all.end());
+      }
+    #endif
+  };
 
   void SharedPtr::decRefCount() {
     if (node) {

src/memory/SharedPtr.hpp

@@ -86,9 +86,9 @@ namespace Sass {
 
 
   class SharedPtr {
-  private:
+  protected:
     SharedObj* node;
-  private:
+  protected:
     void decRefCount();
     void incRefCount();
   public:
@@ -97,16 +97,16 @@ namespace Sass {
     : node(NULL) {};
     // the create constructor
     SharedPtr(SharedObj* ptr);
-    // copy assignment operator
-    SharedPtr& operator=(const SharedPtr& rhs);
-    // move assignment operator
-    /* SharedPtr& operator=(SharedPtr&& rhs); */
     // the copy constructor
     SharedPtr(const SharedPtr& obj);
     // the move constructor
-    /* SharedPtr(SharedPtr&& obj); */
-    // destructor
-    ~SharedPtr();
+    SharedPtr(SharedPtr&& obj);
+    // copy assignment operator
+    SharedPtr& operator=(const SharedPtr& obj);
+    // move assignment operator
+    SharedPtr& operator=(SharedPtr&& obj);
+    // pure virtual destructor
+    virtual ~SharedPtr() = 0;
   public:
     SharedObj* obj () const {
       return node;
@@ -146,6 +146,29 @@ namespace Sass {
     : SharedPtr(node) {};
     SharedImpl(const T& node)
     : SharedPtr(node) {};
+    // the copy constructor
+    SharedImpl(const SharedImpl<T>& impl)
+    : SharedPtr(impl.node) {};
+    // the move constructor
+    SharedImpl(SharedImpl<T>&& impl)
+    : SharedPtr(impl.node) {};
+    // copy assignment operator
+    SharedImpl<T>& operator=(const SharedImpl<T>& rhs) {
+      if (node) decRefCount();
+      node = rhs.node;
+      incRefCount();
+      return *this;
+    }
+    // move assignment operator
+    SharedImpl<T>& operator=(SharedImpl<T>&& rhs) {
+      // don't move our self
+      if (this != &rhs) {
+        if (node) decRefCount();
+        node = std::move(rhs.node);
+        rhs.node = NULL;
+      }
+      return *this;
+    }
     ~SharedImpl() {};
   public:
     operator T*() const {