ENH: cleanup autoPtr class (issue #639)

Improve alignment of its behaviour with std::unique_ptr

  - element_type typedef
  - release() method - identical to ptr() method
  - get() method to get the pointer without checking and without releasing it.
  - operator*() for dereferencing

Method name changes

  - renamed rawPtr() to get()
  - renamed rawRef() to ref(), removed unused const version.

Removed methods/operators

  - assignment from a raw pointer was deleted (was rarely used).
    Can be convenient, but uncontrolled and potentially unsafe.
    Do allow assignment from a literal nullptr though, since this
    can never leak (and also corresponds to the unique_ptr API).

Additional methods

  - clone() method: forwards to the clone() method of the underlying
    data object with argument forwarding.

  - reset(autoPtr&&) as an alternative to operator=(autoPtr&&)

STYLE: avoid implicit conversion from autoPtr to object type in many places

- existing implementation has the following:

     operator const T&() const { return operator*(); }

  which means that the following code works:

       autoPtr<mapPolyMesh> map = ...;
       updateMesh(*map);    // OK: explicit dereferencing
       updateMesh(map());   // OK: explicit dereferencing
       updateMesh(map);     // OK: implicit dereferencing

  for clarity it may preferable to avoid the implicit dereferencing

- prefer operator* to operator() when deferenced a return value
  so it is clearer that a pointer is involve and not a function call
  etc    Eg,   return *meshPtr_;  vs.  return meshPtr_();

src/sampling/sampledSet/sampledSet/sampledSet.H

@@ -217,7 +217,7 @@ public:
         autoPtr<sampledSet> clone() const
         {
             NotImplemented;
-            return autoPtr<sampledSet>(nullptr);
+            return autoPtr<sampledSet>();
         }
 
 

src/sampling/sampledSurface/distanceSurface/distanceSurface.H

@@ -209,12 +209,10 @@ public:
         {
             if (cell_)
             {
-                return isoSurfCellPtr_();
-            }
-            else
-            {
-                return isoSurfPtr_();
+                return *isoSurfCellPtr_;
             }
+
+            return *isoSurfPtr_;
         }
 
 

src/sampling/sampledSurface/isoSurface/sampledIsoSurface.H

@@ -157,7 +157,7 @@ public:
 
         const isoSurface& surface() const
         {
-            return surfPtr_();
+            return *surfPtr_;
         }
 
         //- Does the surface need an update?

src/sampling/sampledSurface/sampledCuttingPlane/sampledCuttingPlane.H

@@ -141,7 +141,7 @@ public:
         //const isoSurfaceCell& surface() const
         const isoSurface& surface() const
         {
-            return isoSurfPtr_();
+            return *isoSurfPtr_;
         }
 
         //- Does the surface need an update?

src/sampling/sampledSurface/sampledSurface/sampledSurface.H

@@ -205,7 +205,7 @@ public:
         autoPtr<sampledSurface> clone() const
         {
             NotImplemented;
-            return autoPtr<sampledSurface>(nullptr);
+            return autoPtr<sampledSurface>();
         }
 
 

src/sampling/sampledSurface/sampledTriSurfaceMesh/sampledTriSurfaceMesh.C

@@ -158,7 +158,7 @@ Foam::sampledTriSurfaceMesh::nonCoupledboundaryTree() const
         );
     }
 
-    return boundaryTreePtr_();
+    return *boundaryTreePtr_;
 }
 
 

src/sampling/surfMeshSampler/surfMeshSampler/surfMeshSampler.H

@@ -181,7 +181,7 @@ public:
         autoPtr<surfMeshSampler> clone() const
         {
             NotImplemented;
-            return autoPtr<surfMeshSampler>(nullptr);
+            return autoPtr<surfMeshSampler>();
         }
 
 

src/sampling/surface/triSurfaceMesh/discreteSurface.C

@@ -152,7 +152,7 @@ Foam::discreteSurface::nonCoupledboundaryTree() const
         );
     }
 
-    return boundaryTreePtr_();
+    return *boundaryTreePtr_;
 }