1 2 /** 3 * Copyright (C) 2018-present MongoDB, Inc. 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the Server Side Public License, version 1, 7 * as published by MongoDB, Inc. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * Server Side Public License for more details. 13 * 14 * You should have received a copy of the Server Side Public License 15 * along with this program. If not, see 16 * <http://www.mongodb.com/licensing/server-side-public-license>. 17 * 18 * As a special exception, the copyright holders give permission to link the 19 * code of portions of this program with the OpenSSL library under certain 20 * conditions as described in each individual source file and distribute 21 * linked combinations including the program with the OpenSSL library. You 22 * must comply with the Server Side Public License in all respects for 23 * all of the code used other than as permitted herein. If you modify file(s) 24 * with this exception, you may extend this exception to your version of the 25 * file(s), but you are not obligated to do so. If you do not wish to do so, 26 * delete this exception statement from your version. If you delete this 27 * exception statement from all source files in the program, then also delete 28 * it in the license file. 29 */ 30 31 #pragma once 32 33 #include "mongo/db/namespace_string.h" 34 #include "mongo/stdx/functional.h" 35 36 namespace mongo { 37 38 class OperationContext; 39 class RecordFetcher; 40 41 /** 42 * See the documentation for yieldAllLocks(...). 43 */ 44 class QueryYield { 45 QueryYield(); 46 47 public: 48 /** 49 * If not in a nested context, unlocks all locks, suggests to the operating system to 50 * switch to another thread, and then reacquires all locks. 51 * 52 * If in a nested context (eg DBDirectClient), does nothing. 53 * 54 * The whileYieldingFn will be executed after unlocking the locks and before re-acquiring them. 55 */ 56 static void yieldAllLocks(OperationContext* opCtx, 57 stdx::function<void()> whileYieldingFn, 58 const NamespaceString& planExecNS); 59 }; 60 61 } // namespace mongo 62