ENH: refine definition of PtrList emplace() and HashPtrTable emplace_set()

- like emplace_back(), return a reference to the new element

applications/test/PtrList/Test-PtrList.C

@@ -599,7 +599,9 @@ int main(int argc, char *argv[])
         dynPlanes.set(6, new plane(vector(2,2,1), vector::one));
         dynPlanes.set(10, new plane(vector(4,5,6), vector::one));
 
-        dynPlanes.emplace(12, vector(3,2,1), vector::one);
+        Info<< "emplaced :"
+            << dynPlanes.emplace(12, vector(3,2,1), vector::one) << endl;
+
         dynPlanes.emplace_back(Zero, vector::one);
     }
 

src/OpenFOAM/containers/HashTables/HashPtrTable/HashPtrTable.H

@@ -207,9 +207,9 @@ public:
         inline bool emplace(const Key& key, Args&&... args);
 
         //- Emplace set an entry, overwriting any existing entries.
-        //  \return True, since it always overwrites any entries.
+        //  \return Reference to the new element.
         template<class... Args>
-        inline bool emplace_set(const Key& key, Args&&... args);
+        inline T& emplace_set(const Key& key, Args&&... args);
 
         //- No insert() with raw pointers (potential memory leaks).
         //- Use insert() with autoPtr or set()

src/OpenFOAM/containers/HashTables/HashPtrTable/HashPtrTableI.H

@@ -95,13 +95,15 @@ inline bool Foam::HashPtrTable<T, Key, Hash>::emplace
 
 template<class T, class Key, class Hash>
 template<class... Args>
-inline bool Foam::HashPtrTable<T, Key, Hash>::emplace_set
+inline T& Foam::HashPtrTable<T, Key, Hash>::emplace_set
 (
     const Key& key,
     Args&&... args
 )
 {
-    return this->set(key, new T(std::forward<Args>(args)...));
+    T* ptr = new T(std::forward<Args>(args)...);
+    (void)this->set(key, ptr);
+    return *ptr;
 }
 
 

src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynList.H

@@ -174,9 +174,11 @@ public:
         //- Remove and return the top element. Can be called on an empty list.
         inline autoPtr<T> remove();
 
-        //- Construct and set an element
+        //- Construct and set a new element at given position,
+        //- (discard old element at that location).
+        //- Return reference to the new list element.
         template<class... Args>
-        inline autoPtr<T> emplace(const label i, Args&&... args);
+        inline T& emplace(const label i, Args&&... args);
 
         //- Set element to given pointer and return old element (can be null).
         //- Auto-sizes list as required.

src/OpenFOAM/containers/PtrLists/PtrDynList/PtrDynListI.H

@@ -220,8 +220,9 @@ template<class T, int SizeMin>
 template<class... Args>
 inline T& Foam::PtrDynList<T, SizeMin>::emplace_back(Args&&... args)
 {
-    this->push_back(new T(std::forward<Args>(args)...));
+    T* ptr = new T(std::forward<Args>(args)...);
-    return this->back();
+    this->push_back(ptr);
+    return *ptr;
 }
 
 
@@ -346,13 +347,15 @@ inline Foam::autoPtr<T> Foam::PtrDynList<T, SizeMin>::remove()
 
 template<class T, int SizeMin>
 template<class... Args>
-inline Foam::autoPtr<T> Foam::PtrDynList<T, SizeMin>::emplace
+inline T& Foam::PtrDynList<T, SizeMin>::emplace
 (
     const label i,
     Args&&... args
 )
 {
-    return this->set(i, new T(std::forward<Args>(args)...));
+    T* ptr = new T(std::forward<Args>(args)...);
+    (void)this->set(i, ptr);
+    return *ptr;
 }
 
 

src/OpenFOAM/containers/PtrLists/PtrList/PtrList.H

@@ -172,9 +172,11 @@ public:
         //- Move append another list to the end of this list.
         inline void push_back(PtrList<T>&& other);
 
-        //- Construct and set an element
+        //- Construct and set a new element at given position,
+        //- (discard old element at that location).
+        //- Return reference to the new list element.
         template<class... Args>
-        inline autoPtr<T> emplace(const label i, Args&&... args);
+        inline T& emplace(const label i, Args&&... args);
 
         //- Set element to given pointer and return old element (can be null)
         //  No-op if the new pointer value is identical to the current content.

src/OpenFOAM/containers/PtrLists/PtrList/PtrListI.H

@@ -105,8 +105,9 @@ template<class T>
 template<class... Args>
 inline T& Foam::PtrList<T>::emplace_back(Args&&... args)
 {
-    UPtrList<T>::push_back(new T(std::forward<Args>(args)...));
+    T* ptr = new T(std::forward<Args>(args)...);
-    return this->back();
+    UPtrList<T>::push_back(ptr);
+    return *ptr;
 }
 
 
@@ -171,13 +172,15 @@ inline void Foam::PtrList<T>::push_back(PtrList<T>&& other)
 
 template<class T>
 template<class... Args>
-inline Foam::autoPtr<T> Foam::PtrList<T>::emplace
+inline T& Foam::PtrList<T>::emplace
 (
     const label i,
     Args&&... args
 )
 {
-    return set(i, new T(std::forward<Args>(args)...));
+    T* ptr = new T(std::forward<Args>(args)...);
+    (void)this->set(i, ptr);
+    return *ptr;
 }