Add basic infrastructure for general async requests

(This used to be commit ae254cb61f4b9331755848c47ebc34e90dd80390)

2 files changed, 90 insertions, 0 deletions

diff --git a/source3/include/async_req.h b/source3/include/async_req.h
new file mode 100644
index 0000000000..6df53602b2
--- /dev/null
+++ b/source3/include/async_req.h
@@ -0,0 +1,89 @@
+/*
+   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 "includes.h"
+
+/*
+ * An async request moves between the following 4 states.
+ */
+enum async_req_state {
+	ASYNC_REQ_INIT,		/* we are creating the request */
+	ASYNC_REQ_IN_PROGRESS,	/* we are waiting the request to complete */
+	ASYNC_REQ_DONE,		/* the request is finished */
+	ASYNC_REQ_ERROR };	/* an error has occured */
+
+struct async_req {
+	/* the external state - will be queried by the caller */
+	enum async_req_state state;
+
+	/* a private pointer for use by the async function implementation */
+	void *private_data;
+
+	/* print yourself, for debugging purposes */
+	char *(*print)(TALLOC_CTX *mem_ctx, struct async_req *);
+
+	/* status code when finished */
+	NTSTATUS status;
+
+	/* the event context we are using */
+	struct event_context *event_ctx;
+
+	/* information on what to do on completion */
+	struct {
+		void (*fn)(struct async_req *);
+		void *priv;
+	} async;
+};
+
+/*
+ * Print an async_req structure for debugging purposes
+ */
+char *async_req_print(TALLOC_CTX *mem_ctx, struct async_req *req);
+
+/*
+ * Create an async request
+ */
+struct async_req *async_req_new(TALLOC_CTX *mem_ctx, struct event_context *ev);
+
+/*
+ * An async request has successfully finished, invoke the callback
+ */
+void async_req_done(struct async_req *req);
+
+/*
+ * An async request has seen an error, invoke the callback
+ */
+void async_req_error(struct async_req *req, NTSTATUS status);
+
+/*
+ * Convenience helper to easily check alloc failure within a callback.
+ *
+ * Call pattern would be
+ * p = talloc(mem_ctx, bla);
+ * if (async_req_nomem(p, req)) {
+ *	return;
+ * }
+ *
+ */
+bool async_req_nomem(const void *p, struct async_req *req);
+
+#endif
diff --git a/source3/include/includes.h b/source3/include/includes.h
index a2c3a0c466..8b94d7aed2 100644
--- a/source3/include/includes.h
+++ b/source3/include/includes.h
@@ -723,6 +723,7 @@ typedef char fstring[FSTRING_LEN];
 #include "ctdbd_conn.h"
 #include "talloc_stack.h"
 #include "memcache.h"
+#include "async_req.h"
 
 /* used in net.c */
 struct functable {