ENH: add non-const field access without triggering update counter (#1081)

- can now things like ref(), boundaryFieldRef(), primitiveFieldRef()
  with an optional argument that avoids triggering any update events

  Instead of

      Field<Type>& iF = const_cast<Field<Type>&>(fld.primitiveField());

  can now write

      Field<Type>& iF = fld.primitiveFieldRef(false);

  or simply

      auto& iF = fld.primitiveFieldRef(false);

src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.C

@@ -3,7 +3,7 @@
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
     \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
-     \\/     M anipulation  | Copyright (C) 2015-2016 OpenCFD Ltd.
+     \\/     M anipulation  | Copyright (C) 2015-2018 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -719,10 +719,16 @@ Foam::GeometricField<Type, PatchField, GeoMesh>::~GeometricField()
 template<class Type, template<class> class PatchField, class GeoMesh>
 typename
 Foam::GeometricField<Type, PatchField, GeoMesh>::Internal&
-Foam::GeometricField<Type, PatchField, GeoMesh>::ref()
+Foam::GeometricField<Type, PatchField, GeoMesh>::ref
+(
+    const bool updateAccessTime
+)
 {
-    this->setUpToDate();
-    storeOldTimes();
+    if (updateAccessTime)
+    {
+        this->setUpToDate();
+        storeOldTimes();
+    }
     return *this;
 }
 
@@ -730,10 +736,16 @@ Foam::GeometricField<Type, PatchField, GeoMesh>::ref()
 template<class Type, template<class> class PatchField, class GeoMesh>
 typename
 Foam::GeometricField<Type, PatchField, GeoMesh>::Internal::FieldType&
-Foam::GeometricField<Type, PatchField, GeoMesh>::primitiveFieldRef()
+Foam::GeometricField<Type, PatchField, GeoMesh>::primitiveFieldRef
+(
+    const bool updateAccessTime
+)
 {
-    this->setUpToDate();
-    storeOldTimes();
+    if (updateAccessTime)
+    {
+        this->setUpToDate();
+        storeOldTimes();
+    }
     return *this;
 }
 
@@ -741,10 +753,16 @@ Foam::GeometricField<Type, PatchField, GeoMesh>::primitiveFieldRef()
 template<class Type, template<class> class PatchField, class GeoMesh>
 typename
 Foam::GeometricField<Type, PatchField, GeoMesh>::Boundary&
-Foam::GeometricField<Type, PatchField, GeoMesh>::boundaryFieldRef()
+Foam::GeometricField<Type, PatchField, GeoMesh>::boundaryFieldRef
+(
+    const bool updateAccessTime
+)
 {
-    this->setUpToDate();
-    storeOldTimes();
+    if (updateAccessTime)
+    {
+        this->setUpToDate();
+        storeOldTimes();
+    }
     return boundaryField_;
 }
 
@@ -796,10 +814,8 @@ Foam::label Foam::GeometricField<Type, PatchField, GeoMesh>::nOldTimes() const
     {
         return field0Ptr_->nOldTimes() + 1;
     }
-    else
-    {
-        return 0;
-    }
+
+    return 0;
 }
 
 

src/OpenFOAM/fields/GeometricFields/GeometricField/GeometricField.H

@@ -266,7 +266,7 @@ private:
     // Private Member Functions
 
         //- Read the field from the dictionary
-        void readFields(const dictionary&);
+        void readFields(const dictionary& dict);
 
         //- Read the field - create the field dictionary on-the-fly
         void readFields();
@@ -475,30 +475,39 @@ public:
     // Member Functions
 
         //- Return a reference to the dimensioned internal field
-        //  Note: this increments the event counter and checks the
-        //  old-time fields; avoid in loops.
-        Internal& ref();
+        //  \param updateAccessTime update event counter and check
+        //      old-time fields
+        //
+        //  \note Should avoid using updateAccessTime = true within loops.
+        Internal& ref(const bool updateAccessTime = true);
 
         //- Return a const-reference to the dimensioned internal field
         inline const Internal& internalField() const;
 
         //- Return a const-reference to the dimensioned internal field
-        //  of a "vol" field.  Useful in the formulation of source-terms
-        //  for FV equations
+        //- of a "vol" field.
+        //  Useful in the formulation of source-terms for FV equations
         inline const Internal& v() const;
 
         //- Return a reference to the internal field
-        //  Note: this increments the event counter and checks the
-        //  old-time fields; avoid in loops.
-        typename Internal::FieldType& primitiveFieldRef();
+        //  \param updateAccessTime update event counter and check
+        //      old-time fields
+        //
+        //  \note Should avoid using updateAccessTime = true within loops.
+        typename Internal::FieldType& primitiveFieldRef
+        (
+            const bool updateAccessTime = true
+        );
 
         //- Return a const-reference to the  internal field
         inline const typename Internal::FieldType& primitiveField() const;
 
         //- Return a reference to the boundary field
-        //  Note: this increments the event counter and checks the
-        //  old-time fields; avoid in loops.
-        Boundary& boundaryFieldRef();
+        //  \param updateAccessTime update event counter and check
+        //      old-time fields
+        //
+        //  \note Should avoid using updateAccessTime = true within loops.
+        Boundary& boundaryFieldRef(const bool updateAccessTime = true);
 
         //- Return const-reference to the boundary field
         inline const Boundary& boundaryField() const;