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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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.
*/
#pragma once
#include "mongo/db/catalog/collection.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/query/canonical_query.h"
#include "mongo/db/query/plan_yield_policy.h"
namespace mongo::insert_listener {
/**
* A helper wrapper struct around CappedInsertNotifier which also holds the last version returned
* by the 'notifier'.
*/
struct CappedInsertNotifierData {
std::shared_ptr<CappedInsertNotifier> notifier;
uint64_t lastEOFVersion = ~0;
};
/**
* Returns true if the PlanExecutor should listen for inserts, which is when a getMore is called
* on a tailable and awaitData cursor that still has time left and hasn't been interrupted.
*/
bool shouldListenForInserts(OperationContext* opCtx, CanonicalQuery* cq);
/**
* Returns true if the PlanExecutor should wait for data to be inserted, which is when a getMore
* is called on a tailable and awaitData cursor on a capped collection. Returns false if an EOF
* should be returned immediately.
*/
bool shouldWaitForInserts(OperationContext* opCtx,
CanonicalQuery* cq,
PlanYieldPolicy* yieldPolicy);
/**
* Gets the CappedInsertNotifier for a capped collection. Returns nullptr if this plan executor
* is not capable of yielding based on a notifier.
*/
std::shared_ptr<CappedInsertNotifier> getCappedInsertNotifier(OperationContext* opCtx,
const NamespaceString& nss,
PlanYieldPolicy* yieldPolicy);
/**
* Called for tailable and awaitData cursors in order to yield locks and waits for inserts to
* the collection being tailed. Returns control to the caller once there has been an insertion
* and there may be new results. If the PlanExecutor was killed during a yield, throws an
* exception.
*/
void waitForInserts(OperationContext* opCtx,
PlanYieldPolicy* yieldPolicy,
CappedInsertNotifierData* notifierData);
} // namespace mongo::insert_listener
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