ctdb/common/reqid.h

   1 /*
   2    Request id database
   3
   4    Copyright (C) Amitay Isaacs  2015
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #ifndef __CTDB_REQID_H__
  21 #define __CTDB_REQID_H__
  22
  23 #include <talloc.h>
  24
  25 /**
  26  * @file reqid.h
  27  *
  28  * @brief Request id database
  29  *
  30  * CTDB tracks messages using request id. CTDB stores client state for each
  31  * request id to process the replies correctly.
  32  */
  33
  34 /**
  35  * @brief Abstract struct to store request id database
  36  */
  37 struct reqid_context;
  38
  39 #define REQID_INVALID   0xffffffff
  40
  41 /**
  42  * @brief Initialize request id database
  43  *
  44  * This returns a new request id context. Freeing this context will free
  45  * all the memory associated with request id database.
  46  *
  47  * @param[in] mem_ctx Talloc memory context
  48  * @param[in] start_id The initial id
  49  * @param[out] result The new talloc_context structure
  50  * @return 0 on success, errno on failure
  51  */
  52 int reqid_init(TALLOC_CTX *mem_ctx, int start_id,
  53                struct reqid_context **result);
  54
  55 /**
  56  * @brief Generate new request id and associate given data with the request id
  57  *
  58  * @param[in] reqid_ctx The request id context
  59  * @param[in] private_data The state to associate with new request id
  60  * @return new request id, REQID_INVALID on failure
  61  */
  62 uint32_t reqid_new(struct reqid_context *reqid_ctx, void *private_data);
  63
  64 #ifdef DOXYGEN
  65 /**
  66  * @brief Fetch the data associated with the request id
  67  *
  68  * @param[in] reqid_ctx The request id context
  69  * @param[in] reqid The request id
  70  * @param[in] type The data type of the stored data
  71  * @return the data stored for the reqid, NULL on failure
  72  */
  73 type *reqid_find(struct reqid_context *reqid_ctx, uint32_t reqid, #type);
  74 #else
  75 void *_reqid_find(struct reqid_context *reqid_ctx, uint32_t reqid);
  76 #define reqid_find(ctx, reqid, type) \
  77         (type *)talloc_check_name(_reqid_find(ctx, reqid), #type)
  78 #endif
  79
  80 /**
  81  * @brief Remove the data associated with the request id
  82  *
  83  * @param[in] reqid_ctx The request id context
  84  * @param[in] reqid The request id
  85  * @return 0 on success, errno on failure
  86  */
  87 int reqid_remove(struct reqid_context *reqid_ctx, uint32_t reqid);
  88
  89 #endif /* __CTDB_REQID_H__ */