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arangodb/arangod/Cluster/TraverserEngineRegistry.cpp

134 lines
4.0 KiB
C++

////////////////////////////////////////////////////////////////////////////////
/// 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
////////////////////////////////////////////////////////////////////////////////
#include "TraverserEngineRegistry.h"
#include "Basics/Exceptions.h"
#include "Basics/ReadLocker.h"
#include "Basics/WriteLocker.h"
#include "Cluster/TraverserEngine.h"
#include "VocBase/ticks.h"
using namespace arangodb::traverser;
#ifndef USE_ENTERPRISE
TraverserEngineRegistry::EngineInfo::EngineInfo(TRI_vocbase_t* vocbase,
VPackSlice info)
: _isInUse(false),
_toBeDeleted(false),
_engine(new TraverserEngine(vocbase, info)),
_timeToLive(0),
_expires(0) {}
TraverserEngineRegistry::EngineInfo::~EngineInfo() {
}
#endif
TraverserEngineRegistry::~TraverserEngineRegistry() {
WRITE_LOCKER(writeLocker, _lock);
for (auto const& it : _engines) {
destroy(it.first, false);
}
}
/// @brief Create a new Engine and return it's id
TraverserEngineID TraverserEngineRegistry::createNew(TRI_vocbase_t* vocbase,
VPackSlice engineInfo) {
TraverserEngineID id = TRI_NewTickServer();
TRI_ASSERT(id != 0);
auto info = std::make_unique<EngineInfo>(vocbase, engineInfo);
WRITE_LOCKER(writeLocker, _lock);
TRI_ASSERT(_engines.find(id) == _engines.end());
_engines.emplace(id, info.get());
info.release();
return id;
}
/// @brief Destroy the engine with the given id
void TraverserEngineRegistry::destroy(TraverserEngineID id) {
destroy(id, true);
}
/// @brief Get the engine with the given id
BaseTraverserEngine* TraverserEngineRegistry::get(TraverserEngineID id) {
WRITE_LOCKER(writeLocker, _lock);
auto e = _engines.find(id);
if (e == _engines.end()) {
// Nothing to hand out
// TODO: Should we throw an error instead?
return nullptr;
}
if (e->second->_isInUse) {
// Someone is still working with this engine.
// TODO can we just delete it? Or throw an error?
THROW_ARANGO_EXCEPTION(TRI_ERROR_DEADLOCK);
}
e->second->_isInUse = true;
return e->second->_engine.get();
}
/// @brief Returns the engine to the registry. Someone else can now use it.
void TraverserEngineRegistry::returnEngine(TraverserEngineID id) {
WRITE_LOCKER(writeLocker, _lock);
auto e = _engines.find(id);
if (e == _engines.end()) {
// Nothing to return
return;
}
if (e->second->_isInUse) {
e->second->_isInUse = false;
if (e->second->_toBeDeleted) {
auto engine = e->second;
_engines.erase(e);
delete engine;
}
}
}
/// @brief Destroy the engine with the given id, worker function
void TraverserEngineRegistry::destroy(TraverserEngineID id, bool doLock) {
EngineInfo* engine = nullptr;
{
CONDITIONAL_WRITE_LOCKER(writeLocker, _lock, doLock);
auto e = _engines.find(id);
if (e == _engines.end()) {
// Nothing to destroy
return;
}
// TODO what about shard locking?
// TODO what about multiple dbs?
if (e->second->_isInUse) {
// Someone is still working with this engine. Mark it as to be deleted
e->second->_toBeDeleted = true;
return;
}
engine = e->second;
_engines.erase(id);
}
delete engine;
}