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arangodb/arangod/V8Server/V8Traverser.h

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////////////////////////////////////////////////////////////////////////////////
/// 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 ARANGOD_V8_SERVER_V8_TRAVERSER_H
#define ARANGOD_V8_SERVER_V8_TRAVERSER_H 1
#include "Basics/VelocyPackHelper.h"
#include "VocBase/ExampleMatcher.h"
#include "VocBase/Traverser.h"
namespace arangodb {
struct OperationCursor;
namespace velocypack {
class Slice;
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief typedef the template instantiation of the PathFinder
////////////////////////////////////////////////////////////////////////////////
typedef arangodb::basics::PathFinder<arangodb::velocypack::Slice,
arangodb::velocypack::Slice,
double> ArangoDBPathFinder;
typedef arangodb::basics::ConstDistanceFinder<arangodb::velocypack::Slice,
arangodb::velocypack::Slice>
ArangoDBConstDistancePathFinder;
namespace arangodb {
namespace traverser {
// Forward declaration
class DepthFirstTraverser;
// A collection of shared options used in several functions.
// Should not be used directly, use specialization instead.
struct BasicOptions {
arangodb::Transaction* _trx;
protected:
std::unordered_map<std::string, arangodb::ExampleMatcher*> _edgeFilter;
std::unordered_map<std::string, arangodb::ExampleMatcher*> _vertexFilter;
explicit BasicOptions(arangodb::Transaction* trx)
: _trx(trx), useEdgeFilter(false), useVertexFilter(false) {}
virtual ~BasicOptions() {
// properly clean up the mess
for (auto& it : _edgeFilter) {
delete it.second;
}
for (auto& it : _vertexFilter) {
delete it.second;
}
}
public:
std::string start;
bool useEdgeFilter;
bool useVertexFilter;
public:
arangodb::Transaction* trx() { return _trx; }
void addEdgeFilter(v8::Isolate* isolate, v8::Handle<v8::Value> const& example,
std::string const&,
std::string& errorMessage);
void addEdgeFilter(arangodb::velocypack::Slice const& example,
std::string const&);
void addVertexFilter(v8::Isolate* isolate,
v8::Handle<v8::Value> const& example,
arangodb::Transaction* trx,
std::string const&,
std::string& errorMessage);
bool matchesEdge(arangodb::velocypack::Slice) const;
virtual bool matchesVertex(std::string const&, std::string const&,
arangodb::velocypack::Slice) const;
};
struct NeighborsOptions : BasicOptions {
private:
std::unordered_set<std::string> _explicitCollections;
public:
TRI_edge_direction_e direction;
uint64_t minDepth;
uint64_t maxDepth;
arangodb::velocypack::Builder startBuilder;
explicit NeighborsOptions(arangodb::Transaction* trx)
: BasicOptions(trx), direction(TRI_EDGE_OUT), minDepth(1), maxDepth(1) {}
bool matchesVertex(std::string const&, std::string const&,
arangodb::velocypack::Slice) const override;
bool matchesVertex(std::string const&) const;
bool matchesVertex(arangodb::velocypack::Slice const&) const;
void addCollectionRestriction(std::string const&);
void setStart(std::string const& id);
arangodb::velocypack::Slice getStart() const;
};
struct ShortestPathOptions : BasicOptions {
public:
std::string direction;
bool useWeight;
std::string weightAttribute;
double defaultWeight;
bool bidirectional;
bool multiThreaded;
std::string end;
arangodb::velocypack::Builder startBuilder;
arangodb::velocypack::Builder endBuilder;
explicit ShortestPathOptions(arangodb::Transaction* trx);
bool matchesVertex(std::string const&, std::string const&,
arangodb::velocypack::Slice) const override;
void setStart(std::string const&);
void setEnd(std::string const&);
arangodb::velocypack::Slice getStart() const;
arangodb::velocypack::Slice getEnd() const;
};
class SingleServerTraversalPath : public TraversalPath {
public:
explicit SingleServerTraversalPath(
arangodb::basics::EnumeratedPath<std::string, std::string> const& path,
DepthFirstTraverser* traverser)
: _traverser(traverser), _path(path) {}
~SingleServerTraversalPath() {}
void pathToVelocyPack(arangodb::Transaction*,
arangodb::velocypack::Builder&) override;
void lastEdgeToVelocyPack(arangodb::Transaction*,
arangodb::velocypack::Builder&) override;
void lastVertexToVelocyPack(arangodb::Transaction*,
arangodb::velocypack::Builder&) override;
private:
void getDocumentByIdentifier(Transaction*, std::string const&,
arangodb::velocypack::Builder&);
DepthFirstTraverser* _traverser;
arangodb::basics::EnumeratedPath<std::string, std::string> _path;
arangodb::velocypack::Builder _searchBuilder;
};
class DepthFirstTraverser : public Traverser {
friend class SingleServerTraversalPath;
private:
//////////////////////////////////////////////////////////////////////////////
/// @brief callable class to load edges based on opts.
//////////////////////////////////////////////////////////////////////////////
class EdgeGetter {
public:
EdgeGetter(DepthFirstTraverser* traverser,
TraverserOptions const& opts,
Transaction* trx)
: _traverser(traverser), _opts(opts), _trx(trx) {}
//////////////////////////////////////////////////////////////////////////////
/// @brief Function to fill the list of edges properly.
//////////////////////////////////////////////////////////////////////////////
void operator()(std::string const&, std::vector<std::string>&,
arangodb::velocypack::ValueLength*&, size_t&, bool&);
private:
//////////////////////////////////////////////////////////////////////////////
/// @brief Get the next valid cursor
//////////////////////////////////////////////////////////////////////////////
bool nextCursor(std::string const&, size_t&,
arangodb::velocypack::ValueLength*&);
//////////////////////////////////////////////////////////////////////////////
/// @brief Get the next edge
//////////////////////////////////////////////////////////////////////////////
void nextEdge(std::string const&, size_t&,
arangodb::velocypack::ValueLength*&,
std::vector<std::string>&);
DepthFirstTraverser* _traverser;
//////////////////////////////////////////////////////////////////////////////
/// @brief Cache for indexes. Maps collectionName to Index
//////////////////////////////////////////////////////////////////////////////
std::unordered_map<std::string, std::pair<TRI_voc_cid_t, EdgeIndex*>>
_indexCache;
//////////////////////////////////////////////////////////////////////////////
/// @brief Traverser options
//////////////////////////////////////////////////////////////////////////////
TraverserOptions _opts;
//////////////////////////////////////////////////////////////////////////////
/// @brief Pointer to active transaction
/// All Edge Collections have to be properly locked before traversing!
//////////////////////////////////////////////////////////////////////////////
Transaction* _trx;
//////////////////////////////////////////////////////////////////////////////
/// @brief Stack of all active cursors
//////////////////////////////////////////////////////////////////////////////
std::stack<std::shared_ptr<OperationCursor>> _cursors;
//////////////////////////////////////////////////////////////////////////////
/// @brief Stack of all active cursor batches
//////////////////////////////////////////////////////////////////////////////
std::stack<std::shared_ptr<OperationResult>> _results;
//////////////////////////////////////////////////////////////////////////////
/// @brief Stack of positions in the cursors
//////////////////////////////////////////////////////////////////////////////
std::stack<arangodb::velocypack::ValueLength> _posInCursor;
//////////////////////////////////////////////////////////////////////////////
/// @brief velocyPack builder to create temporary search values
//////////////////////////////////////////////////////////////////////////////
arangodb::velocypack::Builder _builder;
};
//////////////////////////////////////////////////////////////////////////////
/// @brief internal cursor to enumerate the paths of a graph
//////////////////////////////////////////////////////////////////////////////
std::unique_ptr<arangodb::basics::PathEnumerator<
std::string, std::string, arangodb::velocypack::ValueLength>> _enumerator;
//////////////////////////////////////////////////////////////////////////////
/// @brief internal getter to extract an edge
//////////////////////////////////////////////////////////////////////////////
EdgeGetter _edgeGetter;
//////////////////////////////////////////////////////////////////////////////
/// @brief internal function to extract vertex information
//////////////////////////////////////////////////////////////////////////////
std::function<bool(std::string const&, std::string const&,
size_t, std::string&)> _getVertex;
//////////////////////////////////////////////////////////////////////////////
/// @brief a vector containing all required edge collection structures
//////////////////////////////////////////////////////////////////////////////
std::vector<TRI_document_collection_t*> _edgeCols;
//////////////////////////////////////////////////////////////////////////////
/// @brief Outer top level transaction
//////////////////////////////////////////////////////////////////////////////
Transaction* _trx;
//////////////////////////////////////////////////////////////////////////////
/// @brief Cache for vertex documents
//////////////////////////////////////////////////////////////////////////////
std::unordered_map<std::string,
std::shared_ptr<arangodb::velocypack::Buffer<uint8_t>>>
_vertices;
//////////////////////////////////////////////////////////////////////////////
/// @brief Cache for edge documents
//////////////////////////////////////////////////////////////////////////////
std::unordered_map<std::string,
std::shared_ptr<arangodb::velocypack::Buffer<uint8_t>>>
_edges;
//////////////////////////////////////////////////////////////////////////////
/// @brief Shared builder to create temporary objects like search values
//////////////////////////////////////////////////////////////////////////////
arangodb::velocypack::Builder _builder;
//////////////////////////////////////////////////////////////////////////////
/// @brief Shared operation Options
//////////////////////////////////////////////////////////////////////////////
arangodb::OperationOptions _operationOptions;
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
/// @brief internal function to define the _getVertex and _getEdge functions
//////////////////////////////////////////////////////////////////////////////
void _defInternalFunctions();
public:
DepthFirstTraverser(
TraverserOptions&, Transaction*,
std::unordered_map<size_t, std::vector<TraverserExpression*>> const*);
//////////////////////////////////////////////////////////////////////////////
/// @brief Reset the traverser to use another start vertex
//////////////////////////////////////////////////////////////////////////////
void setStartVertex(std::string const& v) override;
//////////////////////////////////////////////////////////////////////////////
/// @brief Get the next possible path in the graph.
//////////////////////////////////////////////////////////////////////////////
TraversalPath* next() override;
private:
bool edgeMatchesConditions(arangodb::velocypack::Slice, size_t);
bool vertexMatchesConditions(std::string const&, size_t);
std::shared_ptr<arangodb::velocypack::Buffer<uint8_t>> fetchVertexData(
std::string const&);
};
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief callback to weight an edge
////////////////////////////////////////////////////////////////////////////////
typedef std::function<double(arangodb::velocypack::Slice const)>
WeightCalculatorFunction;
////////////////////////////////////////////////////////////////////////////////
/// @brief Information required internally of the traverser.
/// Used to easily pass around collections.
/// Also offer abstraction to extract edges.
////////////////////////////////////////////////////////////////////////////////
class EdgeCollectionInfo {
private:
//////////////////////////////////////////////////////////////////////////////
/// @brief the underlying transaction
//////////////////////////////////////////////////////////////////////////////
arangodb::Transaction* _trx;
//////////////////////////////////////////////////////////////////////////////
/// @brief edge collection name
//////////////////////////////////////////////////////////////////////////////
std::string _collectionName;
//////////////////////////////////////////////////////////////////////////////
/// @brief index id
//////////////////////////////////////////////////////////////////////////////
arangodb::Transaction::IndexHandle _indexId;
//////////////////////////////////////////////////////////////////////////////
/// @brief Temporary builder for index search values
/// NOTE: Single search builder is NOT thread-save
//////////////////////////////////////////////////////////////////////////////
VPackBuilder _searchBuilder;
WeightCalculatorFunction _weighter;
public:
EdgeCollectionInfo(arangodb::Transaction* trx,
std::string const& collectionName,
WeightCalculatorFunction weighter);
////////////////////////////////////////////////////////////////////////////////
/// @brief Get edges for the given direction and start vertex.
////////////////////////////////////////////////////////////////////////////////
std::shared_ptr<arangodb::OperationCursor> getEdges(
TRI_edge_direction_e direction, std::string const&);
std::shared_ptr<arangodb::OperationCursor> getEdges(
TRI_edge_direction_e direction, VPackSlice const&);
double weightEdge(arangodb::velocypack::Slice const);
arangodb::Transaction* trx() const { return _trx; }
////////////////////////////////////////////////////////////////////////////////
/// @brief Return name of the wrapped collection
////////////////////////////////////////////////////////////////////////////////
std::string const& getName();
};
////////////////////////////////////////////////////////////////////////////////
/// @brief Wrapper for the shortest path computation
////////////////////////////////////////////////////////////////////////////////
std::unique_ptr<ArangoDBPathFinder::Path> TRI_RunShortestPathSearch(
std::vector<EdgeCollectionInfo*> const& collectionInfos,
arangodb::traverser::ShortestPathOptions& opts);
std::unique_ptr<ArangoDBConstDistancePathFinder::Path>
TRI_RunSimpleShortestPathSearch(
std::vector<EdgeCollectionInfo*> const& collectionInfos,
arangodb::Transaction*,
arangodb::traverser::ShortestPathOptions& opts);
////////////////////////////////////////////////////////////////////////////////
/// @brief Wrapper for the neighbors computation
////////////////////////////////////////////////////////////////////////////////
void TRI_RunNeighborsSearch(
std::vector<EdgeCollectionInfo*> const& collectionInfos,
arangodb::traverser::NeighborsOptions const& opts,
std::unordered_set<arangodb::velocypack::Slice,
arangodb::basics::VelocyPackHelper::VPackStringHash,
arangodb::basics::VelocyPackHelper::VPackStringEqual>& visited,
std::vector<arangodb::velocypack::Slice>& distinct);
#endif