asterisk/include/asterisk/res_odbc_transaction.h

55 lines
2.5 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 2016, Digium, Inc.
*
* Mark Michelson <mmichelson@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
#ifndef RES_ODBC_TRANSACTION_H
#define RES_ODBC_TRANSACTION_H
/*!
* \brief
*
* Retrieve an ODBC transaction connection with the given ODBC class name.
*
* \note The name passed here is *not* the name of the transaction but the name of the
* ODBC class defined in res_odbc.conf.
*
* \note Do not call ast_odbc_release_obj() on the retrieved connection. Calling this function
* does not make you the owner of the connection.
*
* XXX This function is majorly flawed because it ignores properties of transactions and simply
* finds one that corresponds to the given DSN. The problem here is that transactions have names
* and they maintain which transaction is "active" for operations like transaction creation,
* commit, and rollback. However, when it comes to intermediary operations to be made on the
* transactions, all that is ignored. It means that if a channel has created multiple transactions
* for the same DSN, it's a crapshoot which of those transactions the operation will be performed
* on. This can potentially lead to baffling errors under the right circumstances.
*
* XXX The semantics of this function make for writing some awkward code. If you use func_odbc as
* an example, it has to first try to retrieve a transactional connection, then failing that, create
* a non-transactional connection. The result is that it has to remember which type of connection it's
* using and know whether to release the connection when completed or not. It would be much better
* if callers did not have to jump through such hoops.
*
* \param chan Channel on which the ODBC transaction was created
* \param objname The name of the ODBC class configured in res_odbc.conf
* \retval NULL Transaction connection could not be found.
* \retval non-NULL A transactional connection
*/
struct odbc_obj *ast_odbc_retrieve_transaction_obj(struct ast_channel *chan, const char *objname);
#endif /* RES_ODBC_TRANSACTION_H */