dune-typetree  2.4-dev
compositenode.hh
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1 // -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
2 // vi: set et ts=4 sw=2 sts=2:
3 
4 #ifndef DUNE_TYPETREE_COMPOSITENODE_HH
5 #define DUNE_TYPETREE_COMPOSITENODE_HH
6 
7 #include <tuple>
8 #include <memory>
9 
12 
13 namespace Dune {
14  namespace TypeTree {
15 
21  template<typename... Children>
24  {
25 
26  public:
27 
30 
32  typedef std::tuple<std::shared_ptr<Children>... > NodeStorage;
33 
35  typedef std::tuple<Children...> ChildTypes;
36 
38  static const bool isLeaf = false;
39 
41  static const bool isPower = false;
42 
44  static const bool isComposite = true;
45 
47  static const std::size_t CHILDREN = sizeof...(Children);
48 
50  template<std::size_t k>
51  struct Child {
52 
53  static_assert((k < CHILDREN), "child index out of range");
54 
56  typedef typename std::tuple_element<k,ChildTypes>::type Type;
57 
59  typedef typename std::tuple_element<k,ChildTypes>::type type;
60 
62  typedef typename std::tuple_element<k,NodeStorage>::type Storage;
63 
65  typedef std::shared_ptr<const typename std::tuple_element<k,ChildTypes>::type> ConstStorage;
66  };
67 
70 
72 
75  template<std::size_t k>
77  {
78  return *std::get<k>(_children);
79  }
80 
82 
85  template<std::size_t k>
86  const typename Child<k>::Type& child(index_constant<k> = {}) const
87  {
88  return *std::get<k>(_children);
89  }
90 
92 
95  template<std::size_t k>
97  {
98  return std::get<k>(_children);
99  }
100 
102 
108  template<std::size_t k>
110  {
111  return std::get<k>(_children);
112  }
113 
115  template<std::size_t k>
117  {
118  std::get<k>(_children) = stackobject_to_shared_ptr(child);
119  }
120 
122  template<std::size_t k>
123  void setChild(typename Child<k>::Storage child, index_constant<k> = {})
124  {
125  std::get<k>(_children) = child;
126  }
127 
128  const NodeStorage& nodeStorage() const
129  {
130  return _children;
131  }
132 
134 
137 
138  // The following two methods require a little bit of SFINAE trickery to work correctly:
139  // We have to make sure that they don't shadow the methods for direct child access because
140  // those get called by the generic child() machinery. If that machinery picks up the methods
141  // defined below, we have an infinite recursion.
142  // So the methods make sure that either
143  //
144  // * there are more than one argument. In that case, we got multiple indices and can forward
145  // to the general machine.
146  //
147  // * the first argument is not a valid flat index, i.e. either a std::size_t or an index_constant.
148  // The argument thus has to be some kind of TreePath instance that we can also pass to the
149  // generic machine.
150  //
151  // The above SFINAE logic works, but there is still a problem with the return type deduction.
152  // We have to do a lazy lookup of the return type after SFINAE has succeeded, otherwise the return
153  // type deduction will trigger the infinite recursion.
154 
156 
160 #ifdef DOXYGEN
161  template<typename... Indices>
162  ImplementationDefined& child(Indices... indices)
163 #else
164  template<typename I0, typename... I>
165  auto child(I0 i0, I... i)
166  -> typename std::enable_if<
167  (sizeof...(I) > 0) || !is_flat_index<I0>{},
168  impl::_lazy_member_child_decltype<CompositeNode>
169  >::type::template evaluate<I0,I...>::type
170 #endif
171  {
172  static_assert(sizeof...(I) > 0 || impl::_non_empty_tree_path(I0{}),
173  "You cannot use the member function child() with an empty TreePath, use the freestanding version child(node,treePath) instead."
174  );
175  return Dune::TypeTree::child(*this,i0,i...);
176  }
177 
179 
183 #ifdef DOXYGEN
184  template<typename... Indices>
185  const ImplementationDefined& child(Indices... indices)
186 #else
187  template<typename I0, typename... I>
188  auto child(I0 i0, I... i) const
189  -> typename std::enable_if<
190  (sizeof...(I) > 0) || !is_flat_index<I0>{},
191  impl::_lazy_member_child_decltype<const CompositeNode>
192  >::type::template evaluate<I0,I...>::type
193 #endif
194  {
195  static_assert(sizeof...(I) > 0 || impl::_non_empty_tree_path(I0{}),
196  "You cannot use the member function child() with an empty TreePath, use the freestanding version child(node,treePath) instead."
197  );
198  return Dune::TypeTree::child(*this,i0,i...);
199  }
200 
202 
203  protected:
204 
207 
209 
217  {}
218 
220  template<typename... Args, typename = typename enable_if<(sizeof...(Args) == CHILDREN)>::type>
221  CompositeNode(Args&&... args)
222  : _children(convert_arg(std::forward<Args>(args))...)
223  {}
224 
226  CompositeNode(std::shared_ptr<Children>... children)
227  : _children(children...)
228  {}
229 
231  CompositeNode(const NodeStorage& children)
232  : _children(children)
233  {}
234 
236 
237  private:
238  NodeStorage _children;
239  };
240 
242 
243  } // namespace TypeTree
244 } //namespace Dune
245 
246 #endif // DUNE_TYPETREE_COMPOSITENODE_HH
static const bool isPower
Mark this class as a non power in the dune-typetree.
Definition: compositenode.hh:41
std::shared_ptr< const typename std::tuple_element< k, ChildTypes >::type > ConstStorage
The const storage type of the child.
Definition: compositenode.hh:65
std::tuple_element< k, NodeStorage >::type Storage
The storage type of the child.
Definition: compositenode.hh:62
Definition: accumulate_static.hh:12
CompositeNode(const NodeStorage &children)
Initialize the CompositeNode with a copy of the passed-in storage type.
Definition: compositenode.hh:231
const NodeStorage & nodeStorage() const
Definition: compositenode.hh:128
CompositeNodeTag NodeTag
The type tag that describes a CompositeNode.
Definition: compositenode.hh:29
Tag designating a composite node.
Definition: nodetags.hh:22
const ImplementationDefined & child(Indices...indices)
Returns the child given by the list of indices.
Definition: compositenode.hh:185
ImplementationDefined child(Node &&node, Indices...indices)
Extracts the child of a node given by a sequence of compile-time and run-time indices.
Definition: childextraction.hh:472
STL namespace.
std::integral_constant< std::size_t, i > index_constant
An index constant with value i.
Definition: utility.hh:312
void setChild(typename Child< k >::Type &child, index_constant< k >={})
Sets the i-th child to the passed-in value.
Definition: compositenode.hh:116
CompositeNode()
Default constructor.
Definition: compositenode.hh:216
CompositeNode(std::shared_ptr< Children >...children)
Initialize the CompositeNode with copies of the passed in Storage objects.
Definition: compositenode.hh:226
typename impl::_is_flat_index< typename std::decay< T >::type >::type is_flat_index
Type trait that determines whether T is a flat index in the context of child extraction.
Definition: childextraction.hh:627
std::tuple< Children...> ChildTypes
A tuple storing the types of all children.
Definition: compositenode.hh:35
Base class for composite nodes based on variadic templates.
Definition: compositenode.hh:23
Access to the type and storage type of the i-th child.
Definition: compositenode.hh:51
static const bool isComposite
Mark this class as a composite in the dune-typetree.
Definition: compositenode.hh:44
static const bool isLeaf
Mark this class as non leaf in the dune-typetree.
Definition: compositenode.hh:38
std::tuple< std::shared_ptr< Children >... > NodeStorage
The type used for storing the children.
Definition: compositenode.hh:32
Child< k >::ConstStorage childStorage(index_constant< k >={}) const
Returns the storage of the i-th child (const version).
Definition: compositenode.hh:109
Child< k >::Type & child(index_constant< k >={})
Returns the i-th child.
Definition: compositenode.hh:76
void setChild(typename Child< k >::Storage child, index_constant< k >={})
Sets the storage of the i-th child to the passed-in value.
Definition: compositenode.hh:123
CompositeNode(Args &&...args)
Initialize all children with the passed-in objects.
Definition: compositenode.hh:221
std::tuple_element< k, ChildTypes >::type type
The type of the child.
Definition: compositenode.hh:59
ImplementationDefined & child(Indices...indices)
Returns the child given by the list of indices.
Definition: compositenode.hh:162
static const std::size_t CHILDREN
The number of children.
Definition: compositenode.hh:47
std::tuple_element< k, ChildTypes >::type Type
The type of the child.
Definition: compositenode.hh:53
Child< k >::Storage childStorage(index_constant< k >={})
Returns the storage of the i-th child.
Definition: compositenode.hh:96
const Child< k >::Type & child(index_constant< k >={}) const
Returns the i-th child (const version).
Definition: compositenode.hh:86