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lib/tevent: add tevent_req.c as copy of lib/async_req/async_req.c
metze
This commit is contained in:
Stefan Metzmacher
parent
fa2461ae73
commit
f337974ed5
338
lib/tevent/tevent_req.c
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338
lib/tevent/tevent_req.c
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@ -0,0 +1,338 @@
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/*
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Unix SMB/CIFS implementation.
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Infrastructure for async requests
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Copyright (C) Volker Lendecke 2008
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "lib/tevent/tevent.h"
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#include "lib/talloc/talloc.h"
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#include "lib/util/dlinklist.h"
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#include "lib/async_req/async_req.h"
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#ifndef TALLOC_FREE
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#define TALLOC_FREE(ctx) do { talloc_free(ctx); ctx=NULL; } while(0)
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#endif
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/**
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* @brief Print an async_req structure
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* @param[in] mem_ctx The memory context for the result
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* @param[in] req The request to be printed
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* @retval Text representation of req
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*
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* This is a default print function for async requests. Implementations should
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* override this with more specific information.
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*
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* This function should not be used by async API users, this is non-static
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* only to allow implementations to easily provide default information in
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* their specific functions.
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*/
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char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req)
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{
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return talloc_asprintf(mem_ctx, "async_req: state=%d, error=%d, "
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"priv=%s", req->state, (int)req->error,
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talloc_get_name(req->private_data));
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}
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/**
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* @brief Create an async request
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* @param[in] mem_ctx The memory context for the result
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* @param[in] ev The event context this async request will be driven by
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* @retval A new async request
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*
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* The new async request will be initialized in state ASYNC_REQ_IN_PROGRESS
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*/
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struct async_req *async_req_new(TALLOC_CTX *mem_ctx)
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{
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struct async_req *result;
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result = talloc_zero(mem_ctx, struct async_req);
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if (result == NULL) {
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return NULL;
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}
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result->state = ASYNC_REQ_IN_PROGRESS;
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result->print = async_req_print;
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return result;
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}
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static void async_req_finish(struct async_req *req, enum async_req_state state)
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{
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req->state = state;
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if (req->async.fn != NULL) {
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req->async.fn(req);
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}
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}
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/**
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* @brief An async request has successfully finished
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* @param[in] req The finished request
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*
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* async_req_done is to be used by implementors of async requests. When a
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* request is successfully finished, this function calls the user's completion
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* function.
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*/
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void async_req_done(struct async_req *req)
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{
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async_req_finish(req, ASYNC_REQ_DONE);
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}
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/**
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* @brief An async request has seen an error
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* @param[in] req The request with an error
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* @param[in] error The error code
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*
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* async_req_done is to be used by implementors of async requests. When a
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* request can not successfully completed, the implementation should call this
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* function with the appropriate status code.
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*/
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void async_req_error(struct async_req *req, uint64_t error)
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{
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req->error = error;
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async_req_finish(req, ASYNC_REQ_USER_ERROR);
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}
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/**
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* @brief Timed event callback
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* @param[in] ev Event context
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* @param[in] te The timed event
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* @param[in] now zero time
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* @param[in] priv The async request to be finished
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*/
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static void async_trigger(struct tevent_context *ev, struct tevent_timer *te,
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struct timeval now, void *priv)
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{
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struct async_req *req = talloc_get_type_abort(priv, struct async_req);
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TALLOC_FREE(te);
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if (req->error == 0) {
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async_req_done(req);
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}
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else {
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async_req_error(req, req->error);
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}
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}
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/**
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* @brief Helper function for nomem check
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* @param[in] p The pointer to be checked
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* @param[in] req The request being processed
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*
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* Convenience helper to easily check alloc failure within a callback
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* implementing the next step of an async request.
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*
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* Call pattern would be
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* \code
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* p = talloc(mem_ctx, bla);
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* if (async_req_ntnomem(p, req)) {
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* return;
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* }
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* \endcode
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*/
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bool async_req_nomem(const void *p, struct async_req *req)
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{
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if (p != NULL) {
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return false;
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}
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async_req_finish(req, ASYNC_REQ_NO_MEMORY);
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return true;
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}
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/**
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* @brief Finish a request before it started processing
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* @param[in] req The finished request
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* @param[in] status The success code
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*
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* An implementation of an async request might find that it can either finish
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* the request without waiting for an external event, or it can't even start
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* the engine. To present the illusion of a callback to the user of the API,
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* the implementation can call this helper function which triggers an
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* immediate timed event. This way the caller can use the same calling
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* conventions, independent of whether the request was actually deferred.
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*/
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bool async_post_error(struct async_req *req, struct tevent_context *ev,
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uint64_t error)
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{
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req->error = error;
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if (tevent_add_timer(ev, req, timeval_zero(),
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async_trigger, req) == NULL) {
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return false;
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}
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return true;
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}
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bool async_req_is_error(struct async_req *req, enum async_req_state *state,
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uint64_t *error)
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{
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if (req->state == ASYNC_REQ_DONE) {
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return false;
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}
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if (req->state == ASYNC_REQ_USER_ERROR) {
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*error = req->error;
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}
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*state = req->state;
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return true;
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}
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static void async_req_timedout(struct tevent_context *ev,
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struct tevent_timer *te,
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struct timeval now,
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void *priv)
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{
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struct async_req *req = talloc_get_type_abort(priv, struct async_req);
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TALLOC_FREE(te);
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async_req_finish(req, ASYNC_REQ_TIMED_OUT);
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}
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bool async_req_set_timeout(struct async_req *req, struct tevent_context *ev,
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struct timeval to)
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{
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return (tevent_add_timer(
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ev, req, timeval_current_ofs(to.tv_sec, to.tv_usec),
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async_req_timedout, req)
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!= NULL);
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}
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struct async_req *async_wait_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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struct timeval to)
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{
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struct async_req *result;
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result = async_req_new(mem_ctx);
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if (result == NULL) {
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return result;
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}
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if (!async_req_set_timeout(result, ev, to)) {
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TALLOC_FREE(result);
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return NULL;
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}
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return result;
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}
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bool async_wait_recv(struct async_req *req)
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{
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return true;
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}
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struct async_queue_entry {
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struct async_queue_entry *prev, *next;
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struct async_req_queue *queue;
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struct async_req *req;
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void (*trigger)(struct async_req *req);
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};
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struct async_req_queue {
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struct async_queue_entry *queue;
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};
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struct async_req_queue *async_req_queue_init(TALLOC_CTX *mem_ctx)
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{
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return talloc_zero(mem_ctx, struct async_req_queue);
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}
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static int async_queue_entry_destructor(struct async_queue_entry *e)
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{
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struct async_req_queue *queue = e->queue;
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DLIST_REMOVE(queue->queue, e);
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if (queue->queue != NULL) {
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queue->queue->trigger(queue->queue->req);
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}
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return 0;
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}
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static void async_req_immediate_trigger(struct tevent_context *ev,
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struct tevent_timer *te,
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struct timeval now,
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void *priv)
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{
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struct async_queue_entry *e = talloc_get_type_abort(
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priv, struct async_queue_entry);
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TALLOC_FREE(te);
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e->trigger(e->req);
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}
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bool async_req_enqueue(struct async_req_queue *queue, struct tevent_context *ev,
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struct async_req *req,
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void (*trigger)(struct async_req *req))
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{
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struct async_queue_entry *e;
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bool busy;
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busy = (queue->queue != NULL);
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e = talloc(req, struct async_queue_entry);
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if (e == NULL) {
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return false;
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}
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e->req = req;
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e->trigger = trigger;
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e->queue = queue;
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DLIST_ADD_END(queue->queue, e, struct async_queue_entry *);
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talloc_set_destructor(e, async_queue_entry_destructor);
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if (!busy) {
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struct tevent_timer *te;
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te = tevent_add_timer(ev, e, timeval_zero(),
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async_req_immediate_trigger,
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e);
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if (te == NULL) {
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TALLOC_FREE(e);
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return false;
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}
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}
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return true;
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}
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bool _async_req_setup(TALLOC_CTX *mem_ctx, struct async_req **preq,
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void *pstate, size_t state_size, const char *typename)
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{
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struct async_req *req;
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void **ppstate = (void **)pstate;
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void *state;
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req = async_req_new(mem_ctx);
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if (req == NULL) {
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return false;
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}
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state = talloc_size(req, state_size);
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if (state == NULL) {
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TALLOC_FREE(req);
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return false;
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}
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talloc_set_name_const(state, typename);
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req->private_data = state;
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*preq = req;
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*ppstate = state;
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return true;
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}
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