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arangodb/arangod/VocBase/edge-collection.c

449 lines
16 KiB
C

////////////////////////////////////////////////////////////////////////////////
/// @brief edge collection functionality
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2010-2011 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, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "edge-collection.h"
// -----------------------------------------------------------------------------
// --SECTION-- EDGES INDEX
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private defines
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief special bit that can be set within edge flags
/// this bit will be set if the edge is an in-marker
////////////////////////////////////////////////////////////////////////////////
#define BIT_DIRECTION_IN ((TRI_edge_flags_t) (1 << 1))
////////////////////////////////////////////////////////////////////////////////
/// @brief special bit that can be set within edge flags
/// this bit will be set if the edge is an out-marker
////////////////////////////////////////////////////////////////////////////////
#define BIT_DIRECTION_OUT ((TRI_edge_flags_t) (1 << 2))
////////////////////////////////////////////////////////////////////////////////
/// @brief special bit that can be set within edge flags
/// this bit will be set if the edge is self-reflexive (i.e. _from and _to are
/// the same)
////////////////////////////////////////////////////////////////////////////////
#define BIT_REFLEXIVE ((TRI_edge_flags_t) (1 << 3))
////////////////////////////////////////////////////////////////////////////////
/// @brief special bit that can be set within edge flags
/// this bit will be set if the edge is bidirectional
////////////////////////////////////////////////////////////////////////////////
#define BIT_BIDIRECTIONAL ((TRI_edge_flags_t) (1 << 4))
////////////////////////////////////////////////////////////////////////////////
/// @brief combination of the two directional bits
////////////////////////////////////////////////////////////////////////////////
#define BITS_DIRECTION (BIT_DIRECTION_IN | BIT_DIRECTION_OUT)
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief return whether an edge is bi-directional
////////////////////////////////////////////////////////////////////////////////
static bool IsBidirectional (const TRI_edge_header_t* const edge) {
return ((edge->_flags & BIT_BIDIRECTIONAL) > 0);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief return whether an edge is self-reflexive
////////////////////////////////////////////////////////////////////////////////
static bool IsReflexive (const TRI_edge_header_t* const edge) {
return ((edge->_flags & BIT_REFLEXIVE) > 0);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compose edge flags aggregate out of only the direction
////////////////////////////////////////////////////////////////////////////////
static TRI_edge_flags_t MakeLookupFlags (const TRI_edge_direction_e direction) {
if (direction == TRI_EDGE_IN) {
return BIT_DIRECTION_IN;
}
if (direction == TRI_EDGE_OUT) {
return BIT_DIRECTION_OUT;
}
// invalid direction type
assert(false);
return 0;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief compose edge flags aggregate out of multiple individual parameters
////////////////////////////////////////////////////////////////////////////////
static TRI_edge_flags_t MakeFlags (const TRI_edge_direction_e direction,
const bool isReflexive,
const bool isBidirectional) {
TRI_edge_flags_t result = MakeLookupFlags(direction);
if (isReflexive) {
result |= BIT_REFLEXIVE;
}
if (isBidirectional) {
result |= BIT_BIDIRECTIONAL;
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief hashes an edge header
////////////////////////////////////////////////////////////////////////////////
static uint64_t HashElementEdge (TRI_multi_pointer_t* array, void const* data) {
TRI_edge_header_t const* h;
uint64_t hash[3];
h = data;
// only include directional bits for hashing, exclude special bits
hash[0] = (uint64_t) (h->_flags & BITS_DIRECTION);
hash[1] = h->_cid;
hash[2] = TRI_FnvHashString((char const*) h->_key);
return TRI_FnvHashPointer(hash, sizeof(hash));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief checks if key and element match
////////////////////////////////////////////////////////////////////////////////
static bool IsEqualKeyEdge (TRI_multi_pointer_t* array, void const* left, void const* right) {
TRI_edge_header_t const* l;
TRI_edge_header_t const* r;
l = left;
r = right;
// only include directional flags, exclude special bits
return ((l->_flags & BITS_DIRECTION) == (r->_flags & BITS_DIRECTION)) &&
(l->_cid == r->_cid) &&
(strcmp(l->_key, r->_key) == 0);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief checks for elements are equal
////////////////////////////////////////////////////////////////////////////////
static bool IsEqualElementEdge (TRI_multi_pointer_t* array, void const* left, void const* right) {
TRI_edge_header_t const* l;
TRI_edge_header_t const* r;
l = left;
r = right;
// only include directional flags, exclude special bits
return (l->_mptr == r->_mptr) &&
((l->_flags & BITS_DIRECTION) == (r->_flags & BITS_DIRECTION)) &&
(l->_cid == r->_cid) &&
(strcmp(l->_key, r->_key) == 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) {
union { TRI_doc_mptr_t* v; TRI_doc_mptr_t const* c; } cnv;
TRI_vector_pointer_t found;
TRI_edge_header_t* edge;
entry->_flags = MakeLookupFlags(direction);
found = TRI_LookupByKeyMultiPointer(TRI_UNKNOWN_MEM_ZONE, idx, entry);
if (found._length > 0) {
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];
cnv.c = edge->_mptr;
// 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;
}
// in type 2 we are only interested in the counterparts of bidirectional edges
if (matchType == 2 && ! IsBidirectional(edge)) {
continue;
}
}
TRI_PushBackVectorPointer(result, cnv.v);
}
}
TRI_DestroyVectorPointer(&found);
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- public functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief initialise the edges index of a collection
////////////////////////////////////////////////////////////////////////////////
void TRI_InitEdgesDocumentCollection (TRI_document_collection_t* collection) {
TRI_InitMultiPointer(&collection->_edgesIndex,
TRI_UNKNOWN_MEM_ZONE,
HashElementEdge,
HashElementEdge,
IsEqualKeyEdge,
IsEqualElementEdge);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief free all edges in the collection's edges index
////////////////////////////////////////////////////////////////////////////////
void TRI_FreeEdgesDocumentCollection (TRI_document_collection_t* collection) {
size_t i, n;
// free all elements in the edges index
n = collection->_edgesIndex._nrAlloc;
for (i = 0; i < n; ++i) {
void* element = collection->_edgesIndex._table[i];
if (element) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, element);
}
}
TRI_DestroyMultiPointer(&collection->_edgesIndex);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief insert an edge into the edges index
////////////////////////////////////////////////////////////////////////////////
int TRI_InsertEdgeDocumentCollection (TRI_document_collection_t* collection,
TRI_doc_mptr_t const* header) {
TRI_edge_header_t* entryIn;
TRI_edge_header_t* entryOut;
TRI_doc_edge_key_marker_t const* edge;
bool isReflexive;
bool isBidirectional;
edge = header->_data;
// is the edge self-reflexive (_from & _to are identical)?
isReflexive = (edge->_toCid == edge->_fromCid && strcmp(((char*) edge) + edge->_offsetToKey, ((char*) edge) + edge->_offsetFromKey) == 0);
isBidirectional = edge->_isBidirectional;
// allocate all edge headers and return early if memory allocation fails
// IN
entryIn = TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, sizeof(TRI_edge_header_t), true);
if (entryIn == NULL) {
return TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
}
// OUT
entryOut = TRI_Allocate(TRI_UNKNOWN_MEM_ZONE, sizeof(TRI_edge_header_t), true);
if (entryOut == NULL) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, entryIn);
return TRI_set_errno(TRI_ERROR_OUT_OF_MEMORY);
}
// we have allocated all necessary memory by here
// IN
assert(entryIn);
entryIn->_mptr = header;
entryIn->_flags = MakeFlags(TRI_EDGE_IN, isReflexive, isBidirectional);
entryIn->_cid = edge->_toCid;
entryIn->_key = ((char*) edge) + edge->_offsetToKey;
TRI_InsertElementMultiPointer(&collection->_edgesIndex, entryIn, true);
// OUT
assert(entryOut);
entryOut->_mptr = header;
entryOut->_flags = MakeFlags(TRI_EDGE_OUT, isReflexive, isBidirectional);
entryOut->_cid = edge->_fromCid;
entryOut->_key = ((char*) edge) + edge->_offsetFromKey;
TRI_InsertElementMultiPointer(&collection->_edgesIndex, entryOut, true);
return TRI_ERROR_NO_ERROR;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief remove an edge from the edges index
////////////////////////////////////////////////////////////////////////////////
void TRI_DeleteEdgeDocumentCollection (TRI_document_collection_t* collection,
TRI_doc_mptr_t const* header) {
TRI_edge_header_t entry;
TRI_edge_header_t* old;
TRI_doc_edge_key_marker_t const* edge;
edge = header->_data;
entry._mptr = header;
// IN
entry._flags = MakeLookupFlags(TRI_EDGE_IN);
entry._cid = edge->_toCid;
entry._key = ((char*) edge) + edge->_offsetToKey;
old = TRI_RemoveElementMultiPointer(&collection->_edgesIndex, &entry);
if (old != NULL) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, old);
}
// OUT
entry._flags = MakeLookupFlags(TRI_EDGE_OUT);
entry._cid = edge->_fromCid;
entry._key = ((char*) edge) + edge->_offsetFromKey;
old = TRI_RemoveElementMultiPointer(&collection->_edgesIndex, &entry);
if (old != NULL) {
TRI_Free(TRI_UNKNOWN_MEM_ZONE, old);
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief looks up edges
////////////////////////////////////////////////////////////////////////////////
TRI_vector_pointer_t TRI_LookupEdgesDocumentCollection (TRI_document_collection_t* collection,
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;
// search criteria
entry._mptr = 0;
entry._cid = cid;
entry._key = key;
// initialise the result vector
TRI_InitVectorPointer(&result, TRI_UNKNOWN_MEM_ZONE);
if (direction == TRI_EDGE_IN) {
// get all edges with a matching IN vertex
FindEdges(TRI_EDGE_IN, &collection->_edgesIndex, &result, &entry, 1);
// add all bidirectional edges with a matching OUT vertex
FindEdges(TRI_EDGE_OUT, &collection->_edgesIndex, &result, &entry, 2);
}
else if (direction == TRI_EDGE_OUT) {
// get all edges with a matching OUT vertex
FindEdges(TRI_EDGE_OUT, &collection->_edgesIndex, &result, &entry, 1);
// add all bidirectional edges with a matching IN vertex
FindEdges(TRI_EDGE_IN, &collection->_edgesIndex, &result, &entry, 2);
}
else if (direction == TRI_EDGE_ANY) {
// get all edges with a matching IN vertex
FindEdges(TRI_EDGE_IN, &collection->_edgesIndex, &result, &entry, 1);
// add all non-reflexive edges with a matching OUT vertex
FindEdges(TRI_EDGE_OUT, &collection->_edgesIndex, &result, &entry, 3);
}
return result;
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
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