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arangodb/arangod/VocBase/edge-collection.cpp

220 lines
8.1 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// @brief edge collection functionality
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2004-2013 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 triAGENS GmbH, Cologne, Germany
///
/// @author Dr. Frank Celler
/// @author Jan Steemann
/// @author Copyright 2011-2013, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "edge-collection.h"
#include "BasicsC/associative-multi.h"
#include "BasicsC/logging.h"
#include "VocBase/document-collection.h"
#include "VocBase/index.h"
// -----------------------------------------------------------------------------
// --SECTION-- EDGES INDEX
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief find the edges index of a document collection
////////////////////////////////////////////////////////////////////////////////
static TRI_edge_index_t* FindEdgesIndex (
TRI_document_collection_t* const document) {
if (document->base._info._type == TRI_COL_TYPE_EDGE) {
size_t const n = document->_allIndexes._length;
for (size_t i = 0; i < n; ++i) {
TRI_index_t* idx = static_cast<TRI_index_t*>(TRI_AtVectorPointer(&document->_allIndexes, i));
if (idx->_type == TRI_IDX_TYPE_EDGE_INDEX) {
TRI_edge_index_t* edgesIndex = (TRI_edge_index_t*) idx;
return edgesIndex;
}
}
}
// collection does not have an edges index... caller must handle that
return nullptr;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief check whether the _from and _to end of an edge are identical
////////////////////////////////////////////////////////////////////////////////
static bool IsReflexive (TRI_doc_mptr_t const* mptr) {
TRI_df_marker_t const* marker = static_cast<TRI_df_marker_t const*>(mptr->getDataPtr()); // ONLY IN INDEX
if (marker->_type == TRI_DOC_MARKER_KEY_EDGE) {
TRI_doc_edge_key_marker_t const* edge = static_cast<TRI_doc_edge_key_marker_t const*>(mptr->getDataPtr()); // ONLY IN INDEX
if (edge->_toCid == edge->_fromCid) {
char const* fromKey = reinterpret_cast<char const*>(edge) + edge->_offsetFromKey;
char const* toKey = reinterpret_cast<char const*>(edge) + edge->_offsetToKey;
return strcmp(fromKey, toKey) == 0;
}
}
else if (marker->_type == TRI_WAL_MARKER_EDGE) {
triagens::wal::edge_marker_t const* edge = static_cast<triagens::wal::edge_marker_t const*>(mptr->getDataPtr()); // ONLY IN INDEX
if (edge->_toCid == edge->_fromCid) {
char const* fromKey = reinterpret_cast<char const*>(edge) + edge->_offsetFromKey;
char const* toKey = reinterpret_cast<char const*>(edge) + edge->_offsetToKey;
return strcmp(fromKey, toKey) == 0;
}
}
return false;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief find edges matching search criteria and add them to the result
/// this function is called two times for each edge query:
/// the first call (with matchType 1) will query the index with the originally
/// requested direction, whereas the second call will query the index with the
/// opposite direction (with matchType 2 or 3) to find all counterparts
////////////////////////////////////////////////////////////////////////////////
static bool FindEdges (TRI_edge_direction_e direction,
TRI_edge_index_t* idx,
std::vector<TRI_doc_mptr_copy_t>& result,
TRI_edge_header_t* entry,
int matchType) {
TRI_vector_pointer_t found;
if (direction == TRI_EDGE_OUT) {
found = TRI_LookupByKeyMultiPointer(TRI_UNKNOWN_MEM_ZONE,
&idx->_edges_from,
entry);
}
else if (direction == TRI_EDGE_IN) {
found = TRI_LookupByKeyMultiPointer(TRI_UNKNOWN_MEM_ZONE,
&idx->_edges_to,
entry);
}
else {
TRI_ASSERT(false); // TRI_EDGE_ANY not supported here
}
size_t const n = found._length;
if (n > 0) {
if (result.capacity() == 0) {
// if result vector is still empty and we have results, re-init the
// result vector to a "good" size. this will save later reallocations
result.reserve(n);
}
// add all results found
for (size_t i = 0; i < n; ++i) {
TRI_doc_mptr_t* edge = (TRI_doc_mptr_t*) found._buffer[i];
// the following queries will use the following sequences of matchTypes:
// inEdges(): 1, outEdges(): 1, edges(): 1, 3
// if matchType is 1, we'll return all found edges without filtering
// We'll exclude all loop edges now (we already got them in iteration 1),
// and alsoexclude all unidirectional edges
//
// if matchType is 3, the direction is also reversed. We'll exclude all
// loop edges now (we already got them in iteration 1)
if (matchType > 1) {
// if the edge is a loop, we have already found it in iteration 1
// we must skip it here, otherwise we would produce duplicates
if (IsReflexive(edge)) {
continue;
}
}
result.push_back(*edge);
}
}
TRI_DestroyVectorPointer(&found);
return true;
}
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief looks up edges
////////////////////////////////////////////////////////////////////////////////
std::vector<TRI_doc_mptr_copy_t> TRI_LookupEdgesDocumentCollection (
TRI_document_collection_t* document,
TRI_edge_direction_e direction,
TRI_voc_cid_t cid,
TRI_voc_key_t key) {
// search criteria
TRI_edge_header_t entry;
entry._cid = cid;
entry._key = key;
// initialise the result vector
std::vector<TRI_doc_mptr_copy_t> result;
TRI_edge_index_t* edgesIndex = FindEdgesIndex(document);
if (edgesIndex == nullptr) {
LOG_ERROR("collection does not have an edges index");
return result;
}
if (direction == TRI_EDGE_IN) {
// get all edges with a matching IN vertex
FindEdges(TRI_EDGE_IN, edgesIndex, result, &entry, 1);
}
else if (direction == TRI_EDGE_OUT) {
// get all edges with a matching OUT vertex
FindEdges(TRI_EDGE_OUT, edgesIndex, result, &entry, 1);
}
else if (direction == TRI_EDGE_ANY) {
// get all edges with a matching IN vertex
FindEdges(TRI_EDGE_IN, edgesIndex, result, &entry, 1);
// add all non-reflexive edges with a matching OUT vertex
FindEdges(TRI_EDGE_OUT, edgesIndex, result, &entry, 3);
}
return result;
}
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