namespace simgrid::mc::odpor {
-struct WakeupTreeIterator
+/**
+ * @brief A forward-iterator that performs a postorder traversal
+ * of the nodes of a WakeupTree
+ *
+ * Inserting a sequence `w` into a wakeup tree `B` with respect to
+ * some execution `E` requires determining the "<-minimal" node `N`
+ * with sequence `v` in the tree such that `v ~_[E] w`. The "<" relation
+ * over a wakeup tree orders its nodes by first recursively ordering all
+ * children of a node `N` followed by the node `N` itself, viz. a postorder.
+ * This iterator provides such a postorder traversal over the nodes in the
+ * wakeup tree.
+ */
+class WakeupTreeIterator
: public boost::iterator_facade<WakeupTreeIterator, WakeupTreeNode*, boost::forward_traversal_tag> {
public:
- WakeupTreeIterator() = default;
+ // Use rule-of-three, and implicitely disable the move constructor which cannot be 'noexcept' (as required by C++ Core
+ // Guidelines), due to the std::list and std:stack<std::deque> members.
+ WakeupTreeIterator() = default;
+ WakeupTreeIterator(const WakeupTreeIterator&) = default;
+ ~WakeupTreeIterator() = default;
+
explicit WakeupTreeIterator(const WakeupTree& tree);
private:
using node_handle = std::list<WakeupTreeNode*>::iterator;
+ /**
+ * @brief A list which is used to "store" the root node of the traversed
+ * wakeup tree
+ *
+ * The root node is, by definition, not the child of any other node. This
+ * means that the root node also is contained in any list into which the
+ * iterator can generate a pointer (iterator). This list takes the role
+ * of allowing the iterator to treat the root node like any other.
+ */
+ std::list<WakeupTreeNode*> root_list;
+
/**
* @brief The current "view" of the iteration in post-order traversal
*/
std::stack<node_handle> post_order_iteration;
/**
+ * @brief The nodes in the current ordering that have already
+ * added their own children
*
+ * We need to be able to determine whether to add the children
+ * of a given node. Eventually, we want to search that node itself,
+ * but we have to first search its children. Later, when we
+ * reach each node in this stack again, we'll remember not to add
+ * its children and will search the node in the stack instead.
+ */
+ std::stack<WakeupTreeNode*> has_added_children;
+
+ /**
+ * @brief Search the wakeup tree until a leaf node appears at the front
+ * of the iteration, pushing all children towards the top of the stack
+ * as the search progresses
*/
void push_until_left_most_found();
