Add basic infrastructure for general async requests

(This used to be commit 9f8b2a87ee8bba930b776dcfda608a5639f6d55a)

4 files changed, 159 insertions, 1 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index acd39d79b9..134f4c1b46 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -327,7 +327,7 @@ LIB_WITHOUT_PROTO_OBJ = $(LIBSAMBAUTIL_OBJ) \
 	lib/messages.o librpc/gen_ndr/ndr_messaging.o lib/messages_local.o \
 	lib/messages_ctdbd.o lib/packet.o lib/ctdbd_conn.o lib/talloc_stack.o \
 	lib/interfaces.o lib/rbtree.o lib/memcache.o \
-	lib/util_transfer_file.o
+	lib/util_transfer_file.o lib/async_req.o
 
 LIB_WITH_PROTO_OBJ = $(VERSION_OBJ) lib/charcnv.o lib/debug.o lib/fault.o \
 	  lib/interface.o lib/md4.o \
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 c54afd8933..8d4bfc0f8e 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 {
diff --git a/source3/lib/async_req.c b/source3/lib/async_req.c
new file mode 100644
index 0000000000..01154ca436
--- /dev/null
+++ b/source3/lib/async_req.c
@@ -0,0 +1,68 @@
+/*
+   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"
+
+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));
+}
+
+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;
+}
+
+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);
+	}
+}
+
+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);
+	}
+}
+
+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;
+}