LXR qemu/include/qemu/transactions.h

   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
  44typedef struct TransactionActionDrv {
  45    void (*abort)(void *opaque);
  46    void (*commit)(void *opaque);
  47    void (*clean)(void *opaque);
  48} TransactionActionDrv;
  49
  50typedef struct Transaction Transaction;
  51
  52Transaction *tran_new(void);
  53void tran_add(Transaction *tran, TransactionActionDrv *drv, void *opaque);
  54void tran_abort(Transaction *tran);
  55void tran_commit(Transaction *tran);
  56
  57static 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