mirror of https://gitee.com/bigwinds/arangodb
301 lines
10 KiB
C++
301 lines
10 KiB
C++
////////////////////////////////////////////////////////////////////////////////
|
|
/// DISCLAIMER
|
|
///
|
|
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
|
|
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
|
|
///
|
|
/// Licensed under the Apache License, Version 2.0 (the "License");
|
|
/// you may not use this file except in compliance with the License.
|
|
/// You may obtain a copy of the License at
|
|
///
|
|
/// http://www.apache.org/licenses/LICENSE-2.0
|
|
///
|
|
/// Unless required by applicable law or agreed to in writing, software
|
|
/// distributed under the License is distributed on an "AS IS" BASIS,
|
|
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
/// See the License for the specific language governing permissions and
|
|
/// limitations under the License.
|
|
///
|
|
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
|
|
///
|
|
/// @author Michael Hackstein
|
|
////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef ARANGODB_VOCBASE_PATHENUMERATOR_H
|
|
#define ARANGODB_VOCBASE_PATHENUMERATOR_H 1
|
|
|
|
#include "Basics/Common.h"
|
|
#include <stack>
|
|
|
|
namespace arangodb {
|
|
namespace aql {
|
|
struct AqlValue;
|
|
}
|
|
|
|
namespace velocypack {
|
|
class Builder;
|
|
}
|
|
|
|
namespace traverser {
|
|
class Traverser;
|
|
struct TraverserOptions;
|
|
|
|
struct EnumeratedPath {
|
|
std::vector<std::string> edges;
|
|
std::vector<std::string> vertices;
|
|
EnumeratedPath() {}
|
|
};
|
|
|
|
|
|
class PathEnumerator {
|
|
|
|
protected:
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief This is the class that knows the details on how to
|
|
/// load the data and how to return data in the expected format
|
|
/// NOTE: This class does not known the traverser.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
traverser::Traverser* _traverser;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Indicates if we issue next() the first time.
|
|
/// It shall return an empty path in this case.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
bool _isFirst;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Maximal path length which should be enumerated.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
TraverserOptions const* _opts;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief List of the last path is used to
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
EnumeratedPath _enumeratedPath;
|
|
|
|
public:
|
|
PathEnumerator(Traverser* traverser, std::string const& startVertex,
|
|
TraverserOptions const* opts)
|
|
: _traverser(traverser), _isFirst(true), _opts(opts) {
|
|
_enumeratedPath.vertices.push_back(startVertex);
|
|
TRI_ASSERT(_enumeratedPath.vertices.size() == 1);
|
|
}
|
|
|
|
virtual ~PathEnumerator() {}
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Compute the next Path element from the traversal.
|
|
/// Returns false if there is no next path element.
|
|
/// Only if this is true one can compute the AQL values.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
virtual bool next() = 0;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Prunes the current path prefix, the next function should not return
|
|
/// any path having this prefix anymore.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
virtual void prune() = 0;
|
|
|
|
virtual aql::AqlValue lastVertexToAqlValue() = 0;
|
|
virtual aql::AqlValue lastEdgeToAqlValue() = 0;
|
|
virtual aql::AqlValue pathToAqlValue(arangodb::velocypack::Builder&) = 0;
|
|
};
|
|
|
|
class DepthFirstEnumerator final : public PathEnumerator {
|
|
private:
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief The pointers returned for edge indexes on this path. Used to
|
|
/// continue
|
|
/// the search on respective levels.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::stack<size_t*> _lastEdges;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief An internal index for the edge collection used at each depth level
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::stack<size_t> _lastEdgesIdx;
|
|
|
|
public:
|
|
DepthFirstEnumerator(
|
|
Traverser* traverser,
|
|
std::string const& startVertex, TraverserOptions const* opts)
|
|
: PathEnumerator(traverser, startVertex, opts) {
|
|
_lastEdges.push(nullptr);
|
|
_lastEdgesIdx.push(0);
|
|
TRI_ASSERT(_lastEdges.size() == 1);
|
|
}
|
|
|
|
~DepthFirstEnumerator() {}
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Get the next Path element from the traversal.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
bool next() override;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Prunes the current path prefix, the next function should not return
|
|
/// any path having this prefix anymore.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
void prune() override;
|
|
|
|
aql::AqlValue lastVertexToAqlValue() override;
|
|
|
|
aql::AqlValue lastEdgeToAqlValue() override;
|
|
|
|
aql::AqlValue pathToAqlValue(arangodb::velocypack::Builder& result) override;
|
|
|
|
};
|
|
|
|
class BreadthFirstEnumerator final : public PathEnumerator {
|
|
private:
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief One entry in the schreier vector
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
struct PathStep {
|
|
size_t sourceIdx;
|
|
std::string edge;
|
|
std::string vertex;
|
|
|
|
private:
|
|
PathStep() {}
|
|
|
|
public:
|
|
explicit PathStep(std::string const& vertex) : sourceIdx(0), vertex(vertex) {}
|
|
|
|
PathStep(size_t sourceIdx, std::string const& edge,
|
|
std::string const& vertex)
|
|
: sourceIdx(sourceIdx), edge(edge), vertex(vertex) {}
|
|
};
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Struct to hold all information required to get the list of
|
|
/// connected edges
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
struct NextStep {
|
|
size_t sourceIdx;
|
|
|
|
private:
|
|
NextStep() = delete;
|
|
|
|
public:
|
|
explicit NextStep(size_t sourceIdx)
|
|
: sourceIdx(sourceIdx) {}
|
|
};
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief schreier vector to store the visited vertices
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::vector<PathStep*> _schreier;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Next free index in schreier vector.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
size_t _schreierIndex;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Position of the last returned value in the schreier vector
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
size_t _lastReturned;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Vector to store where to continue search on next depth
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::vector<NextStep> _nextDepth;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Vector storing the position at current search depth
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::vector<NextStep> _toSearch;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Vector storing the position at current search depth
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
std::unordered_set<std::string> _tmpEdges;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Marker for the search depth. Used to abort searching.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
size_t _currentDepth;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief position in _toSerach. If this is >= _toSearch.size() we are done
|
|
/// with this depth.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
size_t _toSearchPos;
|
|
|
|
public:
|
|
BreadthFirstEnumerator(Traverser* traverser,
|
|
std::string const& startVertex, TraverserOptions const* opts);
|
|
|
|
~BreadthFirstEnumerator() {
|
|
for (auto& it : _schreier) {
|
|
delete it;
|
|
}
|
|
}
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Get the next Path element from the traversal.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
bool next() override;
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Prunes the current path prefix, the next function should not return
|
|
/// any path having this prefix anymore.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
void prune() override;
|
|
|
|
aql::AqlValue lastVertexToAqlValue() override;
|
|
|
|
aql::AqlValue lastEdgeToAqlValue() override;
|
|
|
|
aql::AqlValue pathToAqlValue(arangodb::velocypack::Builder& result) override;
|
|
|
|
private:
|
|
|
|
inline size_t getDepth(size_t index) const {
|
|
size_t depth = 0;
|
|
while (index != 0) {
|
|
++depth;
|
|
index = _schreier[index]->sourceIdx;
|
|
}
|
|
return depth;
|
|
}
|
|
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
/// @brief Build the enumerated path for the given index in the schreier
|
|
/// vector.
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
void computeEnumeratedPath(size_t index);
|
|
};
|
|
|
|
|
|
} // namespace traverser
|
|
} // namespace arangodb
|
|
|
|
#endif
|