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arangodb/VocBase/shadow-data.c

241 lines
7.9 KiB
C

////////////////////////////////////////////////////////////////////////////////
/// @brief shadow data storage
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2011-2012 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 Copyright 2012, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "shadow-data.h"
// -----------------------------------------------------------------------------
// --SECTION-- SHADOW DATA
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- private functions
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief hashs an element
////////////////////////////////////////////////////////////////////////////////
static uint64_t HashElement (TRI_associative_pointer_t* array, void const* e) {
TRI_shadow_t const* element = e;
return element->_did;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief tests if two elements are equal
////////////////////////////////////////////////////////////////////////////////
static bool EqualElement (TRI_associative_pointer_t* array, void const* l, void const* r) {
TRI_shadow_t const* left = l;
TRI_shadow_t const* right = r;
return left->_cid == right->_cid && left->_did == right->_did;
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- constructors and destructors
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief initialisases a shadow data storage
////////////////////////////////////////////////////////////////////////////////
void TRI_InitShadowDataStore (TRI_shadow_store_t* store,
void* (*create) (TRI_shadow_store_t*, TRI_doc_collection_t*, TRI_doc_mptr_t const*),
bool (*verify) (TRI_shadow_store_t*, TRI_doc_collection_t*, TRI_doc_mptr_t const*, void*),
void (*destroy) (TRI_shadow_store_t*, TRI_shadow_t*)) {
TRI_InitAssociativePointer(&store->_index,
NULL,
HashElement,
NULL,
EqualElement);
store->createShadow = create;
store->verifyShadow = verify;
store->destroyShadow = destroy;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a shadow data storage, but does not free the pointer
////////////////////////////////////////////////////////////////////////////////
void TRI_DestroyShadowDataStore (TRI_shadow_store_t* store) {
TRI_DestroyAssociativePointer(&store->_index);
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @addtogroup VocBase
/// @{
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
/// @brief looks up or create shadow data
////////////////////////////////////////////////////////////////////////////////
TRI_shadow_t* TRI_FindShadowData (TRI_shadow_store_t* store, TRI_vocbase_t* vocbase, TRI_voc_cid_t cid, TRI_voc_did_t did) {
union { TRI_shadow_t* s; TRI_shadow_t const* c; } cnv;
TRI_vocbase_col_t const* col;
TRI_doc_collection_t* collection;
TRI_doc_mptr_t const* mptr;
TRI_shadow_t search;
TRI_shadow_t* shadow;
void* element;
bool ok;
// extract the collection
col = TRI_LookupCollectionByIdVocBase(vocbase, cid);
if (col == NULL) {
return NULL;
}
collection = col->_collection;
// lock the collection
collection->beginRead(collection);
// find the document
mptr = collection->read(collection, did);
if (mptr == NULL) {
collection->endRead(collection);
return NULL;
}
// check if we already know a parsed version
TRI_LockMutex(&store->_lock);
search._cid = cid;
search._did = did;
cnv.c = TRI_LookupByElementAssociativePointer(&store->_index, &search);
shadow = cnv.s;
if (shadow != NULL) {
ok = store->verifyShadow(store, collection, mptr, shadow->_data);
if (ok) {
++shadow->_rc;
TRI_UnlockMutex(&store->_lock);
collection->endRead(collection);
return shadow;
}
else {
TRI_ReleaseShadowData(store, shadow);
}
}
// parse the document
element = store->createShadow(store, collection, mptr);
if (element == NULL) {
TRI_UnlockMutex(&store->_lock);
collection->endRead(collection);
return NULL;
}
// enter the element into the store
shadow = TRI_Allocate(sizeof(TRI_shadow_t));
if (shadow == NULL) {
TRI_UnlockMutex(&store->_lock);
collection->endRead(collection);
return NULL;
}
shadow->_rc = 1;
shadow->_cid = cid;
shadow->_did = did;
shadow->_rid = mptr->_rid;
shadow->_data = element;
TRI_InsertElementAssociativePointer(&store->_index, shadow, true);
// use element, unlock the store and the collection
++shadow->_rc;
TRI_UnlockMutex(&store->_lock);
collection->endRead(collection);
// and return the element
return shadow;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief releases shadow data
////////////////////////////////////////////////////////////////////////////////
void TRI_ReleaseShadowData (TRI_shadow_store_t* store, TRI_shadow_t* shadow) {
TRI_LockMutex(&store->_lock);
// release the element
--shadow->_rc;
// need to destroy the element
if (shadow->_rc < 1) {
TRI_RemoveElementAssociativePointer(&store->_index, shadow);
store->destroyShadow(store, shadow);
TRI_Free(shadow);
}
TRI_UnlockMutex(&store->_lock);
}
////////////////////////////////////////////////////////////////////////////////
/// @}
////////////////////////////////////////////////////////////////////////////////
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// outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
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