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/**
* Copyright (C) 2016 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kDefault
#include "mongo/platform/basic.h"
#include "mongo/db/views/view_catalog.h"
#include <string>
#include "mongo/base/status_with.h"
#include "mongo/base/string_data.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/server_parameters.h"
#include "mongo/db/storage/recovery_unit.h"
#include "mongo/db/views/view.h"
#include "mongo/util/log.h"
namespace {
bool enableViews = false;
} // namespace
namespace mongo {
ExportedServerParameter<bool, ServerParameterType::kStartupOnly> enableViewsParameter(
ServerParameterSet::getGlobal(), "enableViews", &enableViews);
const std::uint32_t ViewCatalog::kMaxViewDepth = 20;
Status ViewCatalog::reloadIfNeeded(OperationContext* txn) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _reloadIfNeeded_inlock(txn);
}
Status ViewCatalog::_reloadIfNeeded_inlock(OperationContext* txn) {
if (_valid.load())
return Status::OK();
LOG(1) << "reloading view catalog for database " << _durable->getName();
// Need to reload, first clear our cache.
_viewMap.clear();
Status status = _durable->iterate(txn, [&](const BSONObj& view) {
NamespaceString viewName(view["_id"].str());
ViewDefinition def(
viewName.db(), viewName.coll(), view["viewOn"].str(), view["pipeline"].Obj());
_viewMap[viewName.ns()] = std::make_shared<ViewDefinition>(def);
});
_valid.store(status.isOK());
return status;
}
void ViewCatalog::_createOrUpdateView_inlock(OperationContext* txn,
const NamespaceString& viewName,
const NamespaceString& viewOn,
const BSONArray& pipeline) {
invariant(_valid.load());
BSONObj viewDef =
BSON("_id" << viewName.ns() << "viewOn" << viewOn.coll() << "pipeline" << pipeline);
_durable->upsert(txn, viewName, viewDef);
BSONObj ownedPipeline = pipeline.getOwned();
_viewMap[viewName.ns()] = std::make_shared<ViewDefinition>(
viewName.db(), viewName.coll(), viewOn.coll(), ownedPipeline);
txn->recoveryUnit()->onRollback([this, viewName]() { this->_viewMap.erase(viewName.ns()); });
// We may get invalidated, but we're exclusively locked, so the change must be ours.
txn->recoveryUnit()->onCommit([this]() { this->_valid.store(true); });
}
Status ViewCatalog::createView(OperationContext* txn,
const NamespaceString& viewName,
const NamespaceString& viewOn,
const BSONArray& pipeline) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (!enableViews)
return Status(ErrorCodes::CommandNotSupported, "View support not enabled");
if (viewName.db() != viewOn.db())
return Status(ErrorCodes::BadValue,
"View must be created on a view or collection in the same database");
if (_lookup_inlock(txn, StringData(viewName.ns())))
return Status(ErrorCodes::NamespaceExists, "Namespace already exists");
if (!NamespaceString::validCollectionName(viewOn.coll()))
return Status(ErrorCodes::InvalidNamespace,
str::stream() << "invalid name for 'viewOn': " << viewOn.coll());
// TODO(SERVER-24768): Need to ensure view is correct and doesn't introduce a cycle.
_createOrUpdateView_inlock(txn, viewName, viewOn, pipeline);
return Status::OK();
}
Status ViewCatalog::modifyView(OperationContext* txn,
const NamespaceString& viewName,
const NamespaceString& viewOn,
const BSONArray& pipeline) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
if (viewName.db() != viewOn.db())
return Status(ErrorCodes::BadValue,
"View must be created on a view or collection in the same database");
if (!_lookup_inlock(txn, StringData(viewName.ns())))
return Status(ErrorCodes::NamespaceNotFound,
str::stream() << "cannot modify missing view " << viewName.ns());
if (!NamespaceString::validCollectionName(viewOn.coll()))
return Status(ErrorCodes::InvalidNamespace,
str::stream() << "invalid name for 'viewOn': " << viewOn.coll());
_createOrUpdateView_inlock(txn, viewName, viewOn, pipeline);
return Status::OK();
}
Status ViewCatalog::dropView(OperationContext* txn, const NamespaceString& viewName) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
// Save a copy of the view definition in case we need to roll back.
ViewDefinition* viewPtr = _lookup_inlock(txn, viewName.ns());
if (!viewPtr) {
return {ErrorCodes::NamespaceNotFound,
str::stream() << "cannot drop missing view: " << viewName.ns()};
}
ViewDefinition savedDefinition = *viewPtr;
invariant(_valid.load());
_durable->remove(txn, viewName);
_viewMap.erase(viewName.ns());
txn->recoveryUnit()->onRollback([this, viewName, savedDefinition]() {
this->_viewMap[viewName.ns()] = std::make_shared<ViewDefinition>(savedDefinition);
});
// We may get invalidated, but we're exclusively locked, so the change must be ours.
txn->recoveryUnit()->onCommit([this]() { this->_valid.store(true); });
return Status::OK();
}
ViewDefinition* ViewCatalog::_lookup_inlock(OperationContext* txn, StringData ns) {
uassertStatusOK(_reloadIfNeeded_inlock(txn));
ViewMap::const_iterator it = _viewMap.find(ns);
if (it != _viewMap.end()) {
return it->second.get();
}
return nullptr;
}
ViewDefinition* ViewCatalog::lookup(OperationContext* txn, StringData ns) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
return _lookup_inlock(txn, ns);
}
StatusWith<ResolvedView> ViewCatalog::resolveView(OperationContext* txn,
const NamespaceString& nss) {
stdx::lock_guard<stdx::mutex> lk(_mutex);
const NamespaceString* resolvedNss = &nss;
std::vector<BSONObj> resolvedPipeline;
for (std::uint32_t i = 0; i < ViewCatalog::kMaxViewDepth; i++) {
ViewDefinition* view = _lookup_inlock(txn, resolvedNss->ns());
if (!view)
return StatusWith<ResolvedView>({*resolvedNss, resolvedPipeline});
resolvedNss = &(view->viewOn());
// Prepend the underlying view's pipeline to the current working pipeline.
const std::vector<BSONObj>& toPrepend = view->pipeline();
resolvedPipeline.insert(resolvedPipeline.begin(), toPrepend.begin(), toPrepend.end());
}
return {ErrorCodes::ViewDepthLimitExceeded,
str::stream() << "View depth too deep or view cycle detected; maximum depth is "
<< kMaxViewDepth};
}
} // namespace mongo
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