trie.h

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#line 1 "S:/jenkins/workspace/ufe-full-windows/ufe/include/trie.h"
#ifndef _ufeTrie
#define _ufeTrie
// =======================================================================
// Copyright 2019 Autodesk, Inc. All rights reserved.
//
// This computer source code and related instructions and comments are the
// unpublished confidential  and proprietary information of Autodesk, Inc.
// and are protected under applicable copyright and trade secret law. They 
// may not be disclosed to, copied  or used by any third party without the 
// prior written consent of Autodesk, Inc.
// =======================================================================

#include "pathComponent.h"
#include "path.h"

#include <memory>
#include <unordered_map>

UFE_NS_DEF {


template<typename T> class Trie;

template<typename T>
class TrieNode : public std::enable_shared_from_this< TrieNode<T> >
{
    friend class Trie<T>;
public:
    typedef std::shared_ptr<TrieNode> Ptr;

    TrieNode(const PathComponent& component);

    // Create a trie node with a null component.
    TrieNode();

    Ptr parent() const;

    // Child addition and removal.
    void add(const Ptr& child);
    void remove(const Ptr& child);

    // Child lookup.
    bool contains(const PathComponent& child) const;
    Ptr operator[](const PathComponent& child) const;

    // Number of children TrieNode's.
    std::size_t size() const;

    // Number of nodes in the tree rooted at this node, including this node.
    std::size_t treeSize() const;

    // Convenience method for size() == 0.
    bool empty() const;

    PathComponent component() const;

    // Change the component of this node, adjusting the parent accordingly.
    void rename(const PathComponent& component);

    // Copy the data into the node, and set the has data flag.
    void setData(const T& data);

    // Access the node's data.  The hasData() method must return true for data
    // to be valid, else the return data is stale.
    const T& data() const;

    bool hasData() const;

    // Called to find the depth of the closest common ancestor to all nodes
    // with data.  Calls itself recursively looking for either multiple children
    // or the first node with associated data.
    // Increments the depth parameter as it moves down the trie which can then
    // be used to create a path that matches the specific node.
    int closestCommonAncestor( int depth ) const;

private:

    typedef std::unordered_map<PathComponent, Ptr> Children;
    typedef std::weak_ptr<TrieNode>                ParentPtr;

    // Clearing out of the TrieNode should be managed by the Trie only,
    // so keeping these private.
    void clear();
    void clearData();

    void setParent(Ptr parent);

    PathComponent fComponent;
    ParentPtr     fParent;
    Children      fChildren;
    bool          fHasData;
    T             fData;
};


template<typename T>
class Trie
{
public:

    Trie();

    Trie(const Trie&) = delete;
    Trie& operator=(const Trie&) = delete;

    // Move assignment and construction.
    Trie(Trie&&);
    Trie& operator=(Trie&&);

    typename TrieNode<T>::Ptr root() const;

    typename TrieNode<T>::Ptr add(const Path& path, const T& data);
    typename TrieNode<T>::Ptr remove(const Path&);
    void                      clear();

    // Lookup. contains() is a convenience for bool(find(path)).
    typename TrieNode<T>::Ptr find(const Path& path) const;
    bool contains(const Path& path) const;

    // Return the trie node corresponding to the path, regardless of whether it
    // has data or not.  If the trie has no such node, returns a null pointer.
    typename TrieNode<T>::Ptr node(const Path& path) const;

    // Query whether the trie contains a descendant of the argument path.  Must
    // be a strict descendant: if the trie contains only the argument
    // itself, returns false.  If the argument path is empty, returns false.
    bool containsDescendant(const Path& path) const;

    // Query whether the trie contains an ancestor of the argument path.
    // Must be a strict ancestor: if the trie contains only the argument
    // itself, returns false.  If the argument path is empty, returns false.
    bool containsAncestor(const Path& path) const;

    // Returns the depth of the closest common ancestor of all leaf nodes.
    // Return -1 if the trie is empty.
    // Return 0 if the common ancestor is the root of the scene graph.
    int closestCommonAncestor() const;

    // Number of nodes in the trie, including the root node.  For testing
    // and debugging purposes, as it traverses the trie and counts nodes.
    std::size_t size() const;

    // Convenience method for size() == 0.
    bool empty() const;

private:

    typename TrieNode<T>::Ptr fRoot;
};

}

#endif  /* _ufeTrie */