1 /* 2 * Simple transactions API 3 * 4 * Copyright (c) 2021 Virtuozzo International GmbH. 5 * 6 * Author: 7 * Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program. If not, see <http://www.gnu.org/licenses/>. 21 * 22 * 23 * = Generic transaction API = 24 * 25 * The intended usage is the following: you create "prepare" functions, which 26 * represents the actions. They will usually have Transaction* argument, and 27 * call tran_add() to register finalization callbacks. For finalization 28 * callbacks, prepare corresponding TransactionActionDrv structures. 29 * 30 * Then, when you need to make a transaction, create an empty Transaction by 31 * tran_create(), call your "prepare" functions on it, and finally call 32 * tran_abort() or tran_commit() to finalize the transaction by corresponding 33 * finalization actions in reverse order. 34 * 35 * The clean() functions registered by the drivers in a transaction are called 36 * last, after all abort() or commit() functions have been called. 37 */ 38 39 #ifndef QEMU_TRANSACTIONS_H 40 #define QEMU_TRANSACTIONS_H 41 42 #include <gmodule.h> 43 44 typedef struct TransactionActionDrv { 45 void (*abort)(void *opaque); 46 void (*commit)(void *opaque); 47 void (*clean)(void *opaque); 48 } TransactionActionDrv; 49 50 typedef struct Transaction Transaction; 51 52 Transaction *tran_new(void); 53 void tran_add(Transaction *tran, TransactionActionDrv *drv, void *opaque); 54 void tran_abort(Transaction *tran); 55 void tran_commit(Transaction *tran); 56 57 static inline void tran_finalize(Transaction *tran, int ret) 58 { 59 if (ret < 0) { 60 tran_abort(tran); 61 } else { 62 tran_commit(tran); 63 } 64 } 65 66 #endif /* QEMU_TRANSACTIONS_H */ 67