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arangodb/arangod/VocBase/edge-collection.c

251 lines
9.0 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
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief find the edges index of a document collection
////////////////////////////////////////////////////////////////////////////////
static TRI_multi_pointer_t* FindEdgesIndex (TRI_document_collection_t* const document) {
size_t i, n;
if (document->base.base._info._type != TRI_COL_TYPE_EDGE) {
// collection is not an edge collection... caller must handle that
return NULL;
}
n = document->_allIndexes._length;
for (i = 0; i < n; ++i) {
TRI_index_t* idx = (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->_edges;
}
}
// collection does not have an edges index... caller must handle that
return NULL;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return whether an edge is self-reflexive
////////////////////////////////////////////////////////////////////////////////
static bool IsReflexive (const TRI_edge_header_t* const edge) {
return ((edge->_flags & TRI_EDGE_BIT_REFLEXIVE) > 0);
}
////////////////////////////////////////////////////////////////////////////////
/// @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 (const TRI_edge_direction_e direction,
TRI_multi_pointer_t* idx,
TRI_vector_pointer_t* result,
TRI_edge_header_t* entry,
const int matchType) {
TRI_vector_pointer_t found;
entry->_flags = TRI_LookupFlagsEdge(direction);
found = TRI_LookupByKeyMultiPointer(TRI_UNKNOWN_MEM_ZONE, idx, entry);
if (found._length > 0) {
TRI_edge_header_t* edge;
size_t i;
if (result->_capacity == 0) {
int res;
// if result vector is still empty and we have results, re-init the
// result vector to a "good" size. this will save later reallocations
res = TRI_InitVectorPointer2(result, TRI_UNKNOWN_MEM_ZONE, found._length);
if (res != TRI_ERROR_NO_ERROR) {
TRI_DestroyVectorPointer(&found);
TRI_set_errno(res);
return false;
}
}
// add all results found
for (i = 0; i < found._length; ++i) {
edge = (TRI_edge_header_t*) found._buffer[i];
// the following queries will use the following sequences of matchTypes:
// inEdges(): 1, 2, outEdges(): 1, 2, edges(): 1, 3
// if matchType is 1, we'll return all found edges without further filtering
//
// if matchType is 2 (inEdges or outEdges query), the direction is reversed.
// We'll exclude all self-reflexive 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
// self-reflexive edges now (we already got them in iteration 1)
if (matchType > 1) {
// if the edge is self-reflexive, we have already found it in iteration 1
// we must skip it here, otherwise we would produce duplicates
if (IsReflexive(edge)) {
continue;
}
}
TRI_PushBackVectorPointer(result, CONST_CAST(edge->_mptr));
}
}
TRI_DestroyVectorPointer(&found);
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief compose edge flags aggregate out of only the direction
////////////////////////////////////////////////////////////////////////////////
TRI_edge_flags_t TRI_LookupFlagsEdge (const TRI_edge_direction_e direction) {
if (direction == TRI_EDGE_IN) {
return TRI_EDGE_BIT_DIRECTION_IN;
}
if (direction == TRI_EDGE_OUT) {
return TRI_EDGE_BIT_DIRECTION_OUT;
}
// invalid direction type
assert(false);
return 0;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compose edge flags aggregate out of multiple individual parameters
////////////////////////////////////////////////////////////////////////////////
TRI_edge_flags_t TRI_FlagsEdge (const TRI_edge_direction_e direction,
const bool isReflexive) {
TRI_edge_flags_t result = TRI_LookupFlagsEdge(direction);
if (isReflexive) {
result |= TRI_EDGE_BIT_REFLEXIVE;
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief looks up edges
////////////////////////////////////////////////////////////////////////////////
TRI_vector_pointer_t TRI_LookupEdgesDocumentCollection (TRI_document_collection_t* document,
TRI_edge_direction_e direction,
TRI_voc_cid_t cid,
TRI_voc_key_t key) {
TRI_vector_pointer_t result;
TRI_edge_header_t entry;
TRI_multi_pointer_t* edgesIndex;
// search criteria
entry._mptr = NULL;
entry._cid = cid;
entry._searchKey._key = key;
// initialise the result vector
TRI_InitVectorPointer(&result, TRI_UNKNOWN_MEM_ZONE);
edgesIndex = FindEdgesIndex(document);
if (edgesIndex == NULL) {
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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