1 files changed, 174 insertions, 0 deletions
diff --git a/source3/lib/async_req.c b/source3/lib/async_req.c
new file mode 100644
index 0000000000..501a6b5524
--- /dev/null
+++ b/source3/lib/async_req.c
@@ -0,0 +1,174 @@
+/*
+   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"
+
+/**
+ * @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, status=%s, "
+			       "priv=%s", req->state, nt_errstr(req->status),
+			       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 event_context *ev)
+{
+	struct async_req *result;
+
+	result = TALLOC_ZERO_P(mem_ctx, struct async_req);
+	if (result == NULL) {
+		return NULL;
+	}
+	result->state = ASYNC_REQ_IN_PROGRESS;
+	result->event_ctx = ev;
+	result->print = async_req_print;
+	return result;
+}
+
+/**
+ * @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)
+{
+	req->status = NT_STATUS_OK;
+	req->state = ASYNC_REQ_DONE;
+	if (req->async.fn != NULL) {
+		req->async.fn(req);
+	}
+}
+
+/**
+ * @brief An async request has seen an error
+ * @param[in] req	The request with an error
+ * @param[in] status	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, NTSTATUS status)
+{
+	req->status = status;
+	req->state = ASYNC_REQ_ERROR;
+	if (req->async.fn != NULL) {
+		req->async.fn(req);
+	}
+}
+
+/**
+ * @brief Timed event callback
+ * @param[in] ev	Event context
+ * @param[in] te	The timed event
+ * @param[in] now	current time
+ * @param[in] priv	The async request to be finished
+ */
+
+static void async_trigger(struct event_context *ev, struct timed_event *te,
+			  const struct timeval *now, void *priv)
+{
+	struct async_req *req = talloc_get_type_abort(priv, struct async_req);
+
+	TALLOC_FREE(te);
+	if (NT_STATUS_IS_OK(req->status)) {
+		async_req_done(req);
+	}
+	else {
+		async_req_error(req, req->status);
+	}
+}
+
+/**
+ * @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_status(struct async_req *req, NTSTATUS status)
+{
+	req->status = status;
+
+	if (event_add_timed(req->event_ctx, req, timeval_zero(),
+			    "async_trigger",
+			    async_trigger, req) == NULL) {
+		return false;
+	}
+	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 (async_req_nomem(p, req)) {
+ *	return;
+ * }
+ * \endcode
+ */
+
+bool async_req_nomem(const void *p, struct async_req *req)
+{
+	if (p != NULL) {
+		return false;
+	}
+	async_req_error(req, NT_STATUS_NO_MEMORY);
+	return true;
+}