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samba-mirror/lib/tevent/tevent_req.c
Volker Lendecke c6f39b46a7 Add tevent_req_notify_callback
This is necessary for requests that have multiple results. Examples would be
SMBEcho and ldap_search.
2009-06-04 17:29:48 +02:00

363 lines
9.1 KiB
C

/*
Unix SMB/CIFS implementation.
Infrastructure for async requests
Copyright (C) Volker Lendecke 2008
Copyright (C) Stefan Metzmacher 2009
** NOTE! The following LGPL license applies to the tevent
** library. This does NOT imply that all of Samba is released
** under the LGPL
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "replace.h"
#include "tevent.h"
#include "tevent_internal.h"
#include "tevent_util.h"
/**
* @brief The default print function for creating debug messages
* @param[in] req The request to be printed
* @param[in] mem_ctx The memory context for the result
* @retval Text representation of req
*
* The function should not be used by users of the asynx API,
* but custom print function can use it and append custom text
* to the string.
*/
char *tevent_req_default_print(struct tevent_req *req, TALLOC_CTX *mem_ctx)
{
return talloc_asprintf(mem_ctx,
"tevent_req[%p/%s]: state[%d] error[%lld (0x%llX)] "
" state[%s (%p)] timer[%p]",
req, req->internal.create_location,
req->internal.state,
(unsigned long long)req->internal.error,
(unsigned long long)req->internal.error,
talloc_get_name(req->data),
req->data,
req->internal.timer
);
}
/**
* @brief Print an tevent_req structure in debug messages
* @param[in] mem_ctx The memory context for the result
* @param[in] req The request to be printed
* @retval Text representation of req
*
* This function should be used by callers of the async API
*/
char *tevent_req_print(TALLOC_CTX *mem_ctx, struct tevent_req *req)
{
if (!req->private_print) {
return tevent_req_default_print(req, mem_ctx);
}
return req->private_print(req, mem_ctx);
}
/**
* @brief Create an async request
* @param[in] mem_ctx The memory context for the result
* @param[in] ev The event context this async request will be driven by
* @retval A new async request
*
* The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS
*/
struct tevent_req *_tevent_req_create(TALLOC_CTX *mem_ctx,
void *pdata,
size_t data_size,
const char *type,
const char *location)
{
struct tevent_req *req;
void **ppdata = (void **)pdata;
void *data;
req = talloc_zero(mem_ctx, struct tevent_req);
if (req == NULL) {
return NULL;
}
req->internal.private_type = type;
req->internal.create_location = location;
req->internal.finish_location = NULL;
req->internal.state = TEVENT_REQ_IN_PROGRESS;
req->internal.trigger = tevent_create_immediate(req);
if (!req->internal.trigger) {
talloc_free(req);
return NULL;
}
data = talloc_size(req, data_size);
if (data == NULL) {
talloc_free(req);
return NULL;
}
talloc_set_name_const(data, type);
req->data = data;
*ppdata = data;
return req;
}
void _tevent_req_notify_callback(struct tevent_req *req, const char *location)
{
req->internal.finish_location = location;
if (req->async.fn != NULL) {
req->async.fn(req);
}
}
static void tevent_req_finish(struct tevent_req *req,
enum tevent_req_state state,
const char *location)
{
req->internal.state = state;
_tevent_req_notify_callback(req, location);
}
/**
* @brief An async request has successfully finished
* @param[in] req The finished request
*
* tevent_req_done is to be used by implementors of async requests. When a
* request is successfully finished, this function calls the user's completion
* function.
*/
void _tevent_req_done(struct tevent_req *req,
const char *location)
{
tevent_req_finish(req, TEVENT_REQ_DONE, location);
}
/**
* @brief An async request has seen an error
* @param[in] req The request with an error
* @param[in] error The error code
*
* tevent_req_done is to be used by implementors of async requests. When a
* request can not successfully completed, the implementation should call this
* function with the appropriate status code.
*
* If error is 0 the function returns false and does nothing more.
*
* Call pattern would be
* \code
* int error = first_function();
* if (tevent_req_error(req, error)) {
* return;
* }
*
* error = second_function();
* if (tevent_req_error(req, error)) {
* return;
* }
*
* tevent_req_done(req);
* return;
* \endcode
*/
bool _tevent_req_error(struct tevent_req *req,
uint64_t error,
const char *location)
{
if (error == 0) {
return false;
}
req->internal.error = error;
tevent_req_finish(req, TEVENT_REQ_USER_ERROR, location);
return true;
}
/**
* @brief Helper function for nomem check
* @param[in] p The pointer to be checked
* @param[in] req The request being processed
*
* Convenience helper to easily check alloc failure within a callback
* implementing the next step of an async request.
*
* Call pattern would be
* \code
* p = talloc(mem_ctx, bla);
* if (tevent_req_nomem(p, req)) {
* return;
* }
* \endcode
*/
bool _tevent_req_nomem(const void *p,
struct tevent_req *req,
const char *location)
{
if (p != NULL) {
return false;
}
tevent_req_finish(req, TEVENT_REQ_NO_MEMORY, location);
return true;
}
/**
* @brief Immediate event callback
* @param[in] ev Event context
* @param[in] im The immediate event
* @param[in] priv The async request to be finished
*/
static void tevent_req_trigger(struct tevent_context *ev,
struct tevent_immediate *im,
void *private_data)
{
struct tevent_req *req = talloc_get_type(private_data,
struct tevent_req);
tevent_req_finish(req, req->internal.state,
req->internal.finish_location);
}
/**
* @brief Finish a request before the caller had the change to set the callback
* @param[in] req The finished request
* @param[in] ev The tevent_context for the timed event
* @retval req will be returned
*
* An implementation of an async request might find that it can either finish
* the request without waiting for an external event, or it can't even start
* the engine. To present the illusion of a callback to the user of the API,
* the implementation can call this helper function which triggers an
* immediate timed event. This way the caller can use the same calling
* conventions, independent of whether the request was actually deferred.
*/
struct tevent_req *tevent_req_post(struct tevent_req *req,
struct tevent_context *ev)
{
tevent_schedule_immediate(req->internal.trigger,
ev, tevent_req_trigger, req);
return req;
}
bool tevent_req_is_in_progress(struct tevent_req *req)
{
if (req->internal.state == TEVENT_REQ_IN_PROGRESS) {
return true;
}
return false;
}
/**
* @brief This function destroys the attached private data
* @param[in] req The finished request
*
* This function can be called as last action of a _recv()
* function, it destroys the data attached to the tevent_req.
*/
void tevent_req_received(struct tevent_req *req)
{
TALLOC_FREE(req->data);
req->private_print = NULL;
TALLOC_FREE(req->internal.trigger);
TALLOC_FREE(req->internal.timer);
req->internal.state = TEVENT_REQ_RECEIVED;
}
bool tevent_req_poll(struct tevent_req *req,
struct tevent_context *ev)
{
while (tevent_req_is_in_progress(req)) {
int ret;
ret = tevent_loop_once(ev);
if (ret != 0) {
return false;
}
}
return true;
}
bool tevent_req_is_error(struct tevent_req *req, enum tevent_req_state *state,
uint64_t *error)
{
if (req->internal.state == TEVENT_REQ_DONE) {
return false;
}
if (req->internal.state == TEVENT_REQ_USER_ERROR) {
*error = req->internal.error;
}
*state = req->internal.state;
return true;
}
static void tevent_req_timedout(struct tevent_context *ev,
struct tevent_timer *te,
struct timeval now,
void *private_data)
{
struct tevent_req *req = talloc_get_type(private_data,
struct tevent_req);
TALLOC_FREE(req->internal.timer);
tevent_req_finish(req, TEVENT_REQ_TIMED_OUT, __FUNCTION__);
}
bool tevent_req_set_endtime(struct tevent_req *req,
struct tevent_context *ev,
struct timeval endtime)
{
TALLOC_FREE(req->internal.timer);
req->internal.timer = tevent_add_timer(ev, req, endtime,
tevent_req_timedout,
req);
if (tevent_req_nomem(req->internal.timer, req)) {
return false;
}
return true;
}
void tevent_req_set_callback(struct tevent_req *req, tevent_req_fn fn, void *pvt)
{
req->async.fn = fn;
req->async.private_data = pvt;
}
void *_tevent_req_callback_data(struct tevent_req *req)
{
return req->async.private_data;
}
void *_tevent_req_data(struct tevent_req *req)
{
return req->data;
}
void tevent_req_set_print_fn(struct tevent_req *req, tevent_req_print_fn fn)
{
req->private_print = fn;
}