ENH: refactored regIOobject searching in object registry

- The findObject() methods are template-typed and used to locate a
  particular Type/name combination.

  Eg,

      volScalarField* ptr = obr.findObject<volScalarField>("xyz");

- The findIOobject() methods are un-typed and use the name only.

  Eg,

      regIOobject* ptr = obr.findIOobject("xyz");

The typed versions will be most commonly used, but the un-typed lookup
can be useful in a templating.

- Simplified findObject* methods to use findIOobject* as the backend.

src/OpenFOAM/db/objectRegistry/objectRegistry.C

@@ -373,6 +373,67 @@ void Foam::objectRegistry::rename(const word& newName)
 }
 
 
+bool Foam::objectRegistry::found
+(
+    const word& name,
+    const bool recursive
+) const
+{
+    return cfindIOobject(name, recursive);
+}
+
+
+const Foam::regIOobject* Foam::objectRegistry::cfindIOobject
+(
+    const word& name,
+    const bool recursive
+) const
+{
+    const_iterator iter = cfind(name);
+
+    if (iter.found())
+    {
+        return iter.val();
+    }
+    else if (recursive && this->parentNotTime())
+    {
+        return parent_.cfindIOobject(name, recursive);
+    }
+
+    return nullptr;
+}
+
+
+const Foam::regIOobject* Foam::objectRegistry::findIOobject
+(
+    const word& name,
+    const bool recursive
+) const
+{
+    return cfindIOobject(name, recursive);
+}
+
+
+Foam::regIOobject* Foam::objectRegistry::findIOobject
+(
+    const word& name,
+    const bool recursive
+)
+{
+    return const_cast<regIOobject*>(cfindIOobject(name, recursive));
+}
+
+
+Foam::regIOobject* Foam::objectRegistry::getIOobjectPtr
+(
+    const word& name,
+    const bool recursive
+) const
+{
+    return const_cast<regIOobject*>(cfindIOobject(name, recursive));
+}
+
+
 bool Foam::objectRegistry::modified() const
 {
     for (const_iterator iter = cbegin(); iter != cend(); ++iter)

src/OpenFOAM/db/objectRegistry/objectRegistry.H

@@ -340,6 +340,59 @@ public:
         template<class Type>
         HashTable<Type*> lookupClass(const bool strict = false);
 
+
+        //- Can the regIOobject object be found (by name).
+        //
+        //  \param recursive search parent registries
+        bool found(const word& name, const bool recursive = false) const;
+
+
+        //- Return const pointer to the regIOobject.
+        //
+        //  \param recursive search parent registries
+        //
+        //  \return nullptr if the object was not found.
+        const regIOobject* cfindIOobject
+        (
+            const word& name,
+            const bool recursive = false
+        ) const;
+
+        //- Return const pointer to the regIOobject.
+        //
+        //  \param recursive search parent registries
+        //
+        //  \return nullptr if the object was not found.
+        const regIOobject* findIOobject
+        (
+            const word& name,
+            const bool recursive = false
+        ) const;
+
+        //- Return non-const pointer to the regIOobject.
+        //
+        //  \param recursive search parent registries
+        //
+        //  \return nullptr if the object was not found.
+        regIOobject* findIOobject
+        (
+            const word& name,
+            const bool recursive = false
+        );
+
+        //- Return non-const pointer to the regIOobject,
+        //- using a const-cast to have it behave like a mutable.
+        //  Exercise caution when using.
+        //
+        //  \param recursive search parent registries.
+        //
+        //  \return nullptr if the object was not found.
+        regIOobject* getIOobjectPtr
+        (
+            const word& name,
+            const bool recursive = false
+        ) const;
+
         //- Is the named Type found?
         //
         //  \param recursive search parent registries

src/OpenFOAM/db/objectRegistry/objectRegistryTemplates.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2016-2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2016-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2015 OpenFOAM Foundation
@@ -391,23 +391,7 @@ const Type* Foam::objectRegistry::cfindObject
     const bool recursive
 ) const
 {
-    const_iterator iter = cfind(name);
-
-    if (iter.found())
-    {
-        const Type* ptr = dynamic_cast<const Type*>(iter());
-
-        if (ptr)
-        {
-            return ptr;
-        }
-    }
-    else if (recursive && this->parentNotTime())
-    {
-        return parent_.cfindObject<Type>(name, recursive);
-    }
-
-    return nullptr;
+    return dynamic_cast<const Type*>(this->cfindIOobject(name, recursive));
 }
 
 
@@ -429,9 +413,7 @@ Type* Foam::objectRegistry::findObject
     const bool recursive
 )
 {
-    const Type* ptr = this->cfindObject<Type>(name, recursive);
-
-    return const_cast<Type*>(ptr);
+    return const_cast<Type*>(this->cfindObject<Type>(name, recursive));
 }
 
 
@@ -442,9 +424,7 @@ Type* Foam::objectRegistry::getObjectPtr
     const bool recursive
 ) const
 {
-    const Type* ptr = this->cfindObject<Type>(name, recursive);
-
-    return const_cast<Type*>(ptr);
+    return const_cast<Type*>(this->cfindObject<Type>(name, recursive));
 }