Add dm_list_splice() to join two lists.

WHATS_NEW

@@ -1,6 +1,8 @@
 Version 2.02.65 - 
 =================================
   Suppress duplicate error messages about read failures and missing devices.
+  Install plugins to $(libdir)/device-mapper and $(libdir)/lvm2.
+  Add dm_list_splice() function to join two lists together.
 
 Version 2.02.64 - 30th April 2010
 =================================

libdm/.exported_symbols

@@ -155,6 +155,7 @@ dm_list_add
 dm_list_add_h
 dm_list_del
 dm_list_move
+dm_list_splice
 dm_list_empty
 dm_list_start
 dm_list_end

libdm/datastruct/list.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2010 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -144,3 +144,25 @@ unsigned int dm_list_size(const struct dm_list *head)
 
 	return s;
 }
+
+/*
+ * Join two lists together.
+ * This moves all the elements of the list 'head1' to the end of the list
+ * 'head', leaving 'head1' empty.
+ */
+void dm_list_splice(struct dm_list *head, struct dm_list *head1)
+{
+	assert(head->n);
+	assert(head1->n);
+
+	if (dm_list_empty(head1))
+	    return;
+
+	head1->p->n = head;
+	head1->n->p = head->p;
+
+	head->p->n = head1->n;
+	head->p = head1->p;
+
+	dm_list_init(head1);
+}

libdm/libdevmapper.h

@@ -717,6 +717,11 @@ void dm_list_del(struct dm_list *elem);
  */
 void dm_list_move(struct dm_list *head, struct dm_list *elem);
 
+/*
+ * Join 'head1' to the of 'head'.
+ */
+void dm_list_splice(struct dm_list *head, struct dm_list *head1);
+
 /*
  * Is the list empty?
  */