lib/tevent: add tevent_req.c as copy of lib/async_req/async_req.c

metze

diff --git a/lib/tevent/tevent_req.c b/lib/tevent/tevent_req.c
new file mode 100644 (file)
index 0000000..db47bd9
--- /dev/null
+++ b/lib/tevent/tevent_req.c
@@ -0,0 +1,338 @@
+/*
+   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/>.
+*/
+
+#include "includes.h"
+#include "lib/tevent/tevent.h"
+#include "lib/talloc/talloc.h"
+#include "lib/util/dlinklist.h"
+#include "lib/async_req/async_req.h"
+
+#ifndef TALLOC_FREE
+#define TALLOC_FREE(ctx) do { talloc_free(ctx); ctx=NULL; } while(0)
+#endif
+
+/**
+ * @brief Print an async_req structure
+ * @param[in] mem_ctx  The memory context for the result
+ * @param[in] req      The request to be printed
+ * @retval             Text representation of req
+ *
+ * This is a default print function for async requests. Implementations should
+ * override this with more specific information.
+ *
+ * This function should not be used by async API users, this is non-static
+ * only to allow implementations to easily provide default information in
+ * their specific functions.
+ */
+
+char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req)
+{
+       return talloc_asprintf(mem_ctx, "async_req: state=%d, error=%d, "
+                              "priv=%s", req->state, (int)req->error,
+                              talloc_get_name(req->private_data));
+}
+
+/**
+ * @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 async_req *async_req_new(TALLOC_CTX *mem_ctx)
+{
+       struct async_req *result;
+
+       result = talloc_zero(mem_ctx, struct async_req);
+       if (result == NULL) {
+               return NULL;
+       }
+       result->state = ASYNC_REQ_IN_PROGRESS;
+       result->print = async_req_print;
+       return result;
+}
+
+static void async_req_finish(struct async_req *req, enum async_req_state state)
+{
+       req->state = state;
+       if (req->async.fn != NULL) {
+               req->async.fn(req);
+       }
+}
+
+/**
+ * @brief An async request has successfully finished
+ * @param[in] req      The finished request
+ *
+ * async_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 async_req_done(struct async_req *req)
+{
+       async_req_finish(req, ASYNC_REQ_DONE);
+}
+
+/**
+ * @brief An async request has seen an error
+ * @param[in] req      The request with an error
+ * @param[in] error    The error code
+ *
+ * async_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.
+ */
+
+void async_req_error(struct async_req *req, uint64_t error)
+{
+       req->error = error;
+       async_req_finish(req, ASYNC_REQ_USER_ERROR);
+}
+
+/**
+ * @brief Timed event callback
+ * @param[in] ev       Event context
+ * @param[in] te       The timed event
+ * @param[in] now      zero time
+ * @param[in] priv     The async request to be finished
+ */
+
+static void async_trigger(struct tevent_context *ev, struct tevent_timer *te,
+                         struct timeval now, void *priv)
+{
+       struct async_req *req = talloc_get_type_abort(priv, struct async_req);
+
+       TALLOC_FREE(te);
+       if (req->error == 0) {
+               async_req_done(req);
+       }
+       else {
+               async_req_error(req, req->error);
+       }
+}
+
+/**
+ * @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 (async_req_ntnomem(p, req)) {
+ *     return;
+ * }
+ * \endcode
+ */
+
+bool async_req_nomem(const void *p, struct async_req *req)
+{
+       if (p != NULL) {
+               return false;
+       }
+       async_req_finish(req, ASYNC_REQ_NO_MEMORY);
+       return true;
+}
+
+/**
+ * @brief Finish a request before it started processing
+ * @param[in] req      The finished request
+ * @param[in] status   The success code
+ *
+ * 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.
+ */
+
+bool async_post_error(struct async_req *req, struct tevent_context *ev,
+                     uint64_t error)
+{
+       req->error = error;
+
+       if (tevent_add_timer(ev, req, timeval_zero(),
+                           async_trigger, req) == NULL) {
+               return false;
+       }
+       return true;
+}
+
+bool async_req_is_error(struct async_req *req, enum async_req_state *state,
+                       uint64_t *error)
+{
+       if (req->state == ASYNC_REQ_DONE) {
+               return false;
+       }
+       if (req->state == ASYNC_REQ_USER_ERROR) {
+               *error = req->error;
+       }
+       *state = req->state;
+       return true;
+}
+
+static void async_req_timedout(struct tevent_context *ev,
+                              struct tevent_timer *te,
+                              struct timeval now,
+                              void *priv)
+{
+       struct async_req *req = talloc_get_type_abort(priv, struct async_req);
+       TALLOC_FREE(te);
+       async_req_finish(req, ASYNC_REQ_TIMED_OUT);
+}
+
+bool async_req_set_timeout(struct async_req *req, struct tevent_context *ev,
+                          struct timeval to)
+{
+       return (tevent_add_timer(
+                       ev, req, timeval_current_ofs(to.tv_sec, to.tv_usec),
+                       async_req_timedout, req)
+               != NULL);
+}
+
+struct async_req *async_wait_send(TALLOC_CTX *mem_ctx,
+                                 struct tevent_context *ev,
+                                 struct timeval to)
+{
+       struct async_req *result;
+
+       result = async_req_new(mem_ctx);
+       if (result == NULL) {
+               return result;
+       }
+       if (!async_req_set_timeout(result, ev, to)) {
+               TALLOC_FREE(result);
+               return NULL;
+       }
+       return result;
+}
+
+bool async_wait_recv(struct async_req *req)
+{
+       return true;
+}
+
+struct async_queue_entry {
+       struct async_queue_entry *prev, *next;
+       struct async_req_queue *queue;
+       struct async_req *req;
+       void (*trigger)(struct async_req *req);
+};
+
+struct async_req_queue {
+       struct async_queue_entry *queue;
+};
+
+struct async_req_queue *async_req_queue_init(TALLOC_CTX *mem_ctx)
+{
+       return talloc_zero(mem_ctx, struct async_req_queue);
+}
+
+static int async_queue_entry_destructor(struct async_queue_entry *e)
+{
+       struct async_req_queue *queue = e->queue;
+
+       DLIST_REMOVE(queue->queue, e);
+
+       if (queue->queue != NULL) {
+               queue->queue->trigger(queue->queue->req);
+       }
+
+       return 0;
+}
+
+static void async_req_immediate_trigger(struct tevent_context *ev,
+                                       struct tevent_timer *te,
+                                       struct timeval now,
+                                       void *priv)
+{
+       struct async_queue_entry *e = talloc_get_type_abort(
+               priv, struct async_queue_entry);
+
+       TALLOC_FREE(te);
+       e->trigger(e->req);
+}
+
+bool async_req_enqueue(struct async_req_queue *queue, struct tevent_context *ev,
+                      struct async_req *req,
+                      void (*trigger)(struct async_req *req))
+{
+       struct async_queue_entry *e;
+       bool busy;
+
+       busy = (queue->queue != NULL);
+
+       e = talloc(req, struct async_queue_entry);
+       if (e == NULL) {
+               return false;
+       }
+
+       e->req = req;
+       e->trigger = trigger;
+       e->queue = queue;
+
+       DLIST_ADD_END(queue->queue, e, struct async_queue_entry *);
+       talloc_set_destructor(e, async_queue_entry_destructor);
+
+       if (!busy) {
+               struct tevent_timer *te;
+
+               te = tevent_add_timer(ev, e, timeval_zero(),
+                                    async_req_immediate_trigger,
+                                    e);
+               if (te == NULL) {
+                       TALLOC_FREE(e);
+                       return false;
+               }
+       }
+
+       return true;
+}
+
+bool _async_req_setup(TALLOC_CTX *mem_ctx, struct async_req **preq,
+                     void *pstate, size_t state_size, const char *typename)
+{
+       struct async_req *req;
+       void **ppstate = (void **)pstate;
+       void *state;
+
+       req = async_req_new(mem_ctx);
+       if (req == NULL) {
+               return false;
+       }
+       state = talloc_size(req, state_size);
+       if (state == NULL) {
+               TALLOC_FREE(req);
+               return false;
+       }
+       talloc_set_name_const(state, typename);
+       req->private_data = state;
+
+       *preq = req;
+       *ppstate = state;
+
+       return true;
+}