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/*
Unix SMB/CIFS implementation.
Infrastructure for async requests
Copyright (C) Volker Lendecke 2008
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASYNC_REQ_H__
#define __ASYNC_REQ_H__
#include "lib/talloc/talloc.h"
/**
* An async request moves between the following 4 states:
*/
enum async_req_state {
/**
* we are creating the request
*/
ASYNC_REQ_INIT,
/**
* we are waiting the request to complete
*/
ASYNC_REQ_IN_PROGRESS,
/**
* the request is finished
*/
ASYNC_REQ_DONE,
/**
* A user error has occured
*/
ASYNC_REQ_USER_ERROR,
/**
* Request timed out
*/
ASYNC_REQ_TIMED_OUT,
/**
* No memory in between
*/
ASYNC_REQ_NO_MEMORY
};
/**
* @brief An async request
*
* This represents an async request being processed by callbacks via an event
* context. A user can issue for example a write request to a socket, giving
* an implementation function the fd, the buffer and the number of bytes to
* transfer. The function issuing the request will immediately return without
* blocking most likely without having sent anything. The API user then fills
* in req->async.fn and req->async.priv, functions that are called when the
* request is finished.
*
* It is up to the user of the async request to talloc_free it after it has
* finished. This can happen while the completion function is called.
*/
struct async_req {
/**
* @brief The external state - will be queried by the caller
*
* While the async request is being processed, state will remain in
* ASYNC_REQ_IN_PROGRESS. A request is finished if
* req->state>=ASYNC_REQ_DONE.
*/
enum async_req_state state;
/**
* @brief Private pointer for the actual implementation
*
* The implementation doing the work for the async request needs a
* current state like for example a fd event. The user of an async
* request should not touch this.
*/
void *private_data;
/**
* @brief Print yourself, for debugging purposes
*
* Async requests are opaque data structures. The implementation of an
* async request can define a custom function to print more debug
* info.
*/
char *(*print)(TALLOC_CTX *mem_ctx, struct async_req *);
/**
* @brief status code when finished
*
* This status can be queried in the async completion function. It
* will be set to 0 when everything went fine.
**/
uint64_t error;
/**
* @brief What to do on completion
*
* This is used for the user of an async request, fn is called when
* the request completes, either successfully or with an error.
*/
struct {
/**
* @brief Completion function
* Completion function, to be filled by the API user
*/
void (*fn)(struct async_req *);
/**
* @brief Private data for the completion function
*/
void *priv;
} async;
};
struct async_req *async_req_new(TALLOC_CTX *mem_ctx);
char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req);
void async_req_done(struct async_req *req);
void async_req_error(struct async_req *req, uint64_t error);
bool async_req_nomem(const void *p, struct async_req *req);
bool async_post_error(struct async_req *req, struct tevent_context *ev,
uint64_t error);
bool async_req_is_error(struct async_req *req, enum async_req_state *state,
uint64_t *error);
struct async_req_queue;
struct async_req_queue *async_req_queue_init(TALLOC_CTX *mem_ctx);
bool async_req_enqueue(struct async_req_queue *queue,
struct tevent_context *ev,
struct async_req *req,
void (*trigger)(struct async_req *req));
bool _async_req_setup(TALLOC_CTX *mem_ctx, struct async_req **preq,
void *pstate, size_t state_size, const char *typename);
#define async_req_setup(_mem_ctx, _preq, _pstate, type) \
_async_req_setup((_mem_ctx), (_preq), (_pstate), sizeof(type), #type)
#endif
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