r22775: For the cluster code I've developed a wrapper around tdb to put different

database backends in place dynamically.

The main abstractions are db_context and db_record, it should be mainly
self-describing, see include/dbwrap.h.  You open the db just as you would open
a tdb, this time with db_open(). If you want to fetch a record, just do the
db->fetch() call, if you want to do operations on it, you need to get it with
fetch_locked().

I added dbwrap_file.c (not heavily tested lately) as an example for what can
be done with that abstraction, uses a file per key. So if anybody is willing
to shape that up, we might have a chance on reiserfs again.... :-)

This abstraction works fine for brlock.tdb, locking.tdb, connections.tdb and
sessionid.tdb. It should work fine for the others as well, I just did not yet
get around to convert them.

If nobody loudly screams NO, then I will import the code that uses this soon.

Volker
(This used to be commit e9d7484ca246cfca4a1fd23be35edc2783136ebe)

1 files changed, 51 insertions, 0 deletions

diff --git a/source3/include/dbwrap.h b/source3/include/dbwrap.h
new file mode 100644
index 0000000000..17d36b8f42
--- /dev/null
+++ b/source3/include/dbwrap.h
@@ -0,0 +1,51 @@
+/* 
+   Unix SMB/CIFS implementation.
+   Database interface wrapper around tdb
+   Copyright (C) Volker Lendecke 2005-2007
+   
+   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 2 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, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#ifndef __FILEDB_H__
+#define __FILEDB_H__
+
+struct db_record {
+	TDB_DATA key, value;
+	NTSTATUS (*store)(struct db_record *rec, TDB_DATA data, int flag);
+	NTSTATUS (*delete_rec)(struct db_record *rec);
+	void *private_data;
+};
+
+struct db_context {
+	struct db_record *(*fetch_locked)(struct db_context *db,
+					  TALLOC_CTX *mem_ctx,
+					  TDB_DATA key);
+	int (*fetch)(struct db_context *db, TALLOC_CTX *mem_ctx,
+		     TDB_DATA key, TDB_DATA *data);
+	int (*traverse)(struct db_context *db,
+			int (*f)(struct db_record *db,
+				 void *private_data),
+			void *private_data);
+	int (*get_seqnum)(struct db_context *db);
+	void *private_data;
+};
+
+struct db_context *db_open(TALLOC_CTX *mem_ctx,
+			   const char *name,
+			   int hash_size, int tdb_flags,
+			   int open_flags, mode_t mode);
+
+
+#endif /* __FILEDB_H__ */