Move list support into a separate convenience library.

* configure.ac: Build libmailutils/list/Makefile
* include/mailutils/sys/list.h (DESTROY_ITEM): New define.
(_mu_list_insert_item): New proto.
* libmailutils/Makefile.am (SUBDIRS): Add list.
(libmailutils_la_LIBADD): Add list/liblist.la
* libmailutils/base/Makefile.am (libbase_la_SOURCES): Remove list sources.
* libmailutils/base/list.c: Split into smaller files (see below).
* libmailutils/base/listlist.c: Move to libmailutils/list/listlist.c
* libmailutils/list/Makefile.am: New file.
* libmailutils/list/append.c: New file.
* libmailutils/list/array.c: New file.
* libmailutils/list/clear.c: New file.
* libmailutils/list/count.c: New file.
* libmailutils/list/create.c: New file.
* libmailutils/list/destroy.c: New file.
* libmailutils/list/do.c: New file.
* libmailutils/list/empty.c: New file.
* libmailutils/list/get.c: New file.
* libmailutils/list/getcomp.c: New file.
* libmailutils/list/insert.c: New file.
* libmailutils/list/intersect.c: New file.
* libmailutils/list/iterator.c: New file.
* libmailutils/list/locate.c: New file.
* libmailutils/list/prepend.c: New file.
* libmailutils/list/remove.c: New file.
* libmailutils/list/replace.c: New file.
* libmailutils/list/setcomp.c: New file.
* libmailutils/list/setdestr.c: New file.

@@ -1473,6 +1473,7 @@ AC_CONFIG_FILES([
  libmailutils/diag/Makefile
  libmailutils/filter/Makefile
  libmailutils/imapio/Makefile
+ libmailutils/list/Makefile
  libmailutils/mailbox/Makefile
  libmailutils/mailer/Makefile
  libmailutils/mime/Makefile

@@ -46,6 +46,14 @@ struct _mu_list
   struct _mu_iterator *itr;
 };
 
+#define DESTROY_ITEM(list, elt)			\
+  do						\
+    {						\
+       if ((list)->destroy_item)		\
+	 (list)->destroy_item ((elt)->item);	\
+    }						\
+  while (0)
+
 extern void _mu_list_clear (mu_list_t list);
 extern void _mu_list_insert_sublist (mu_list_t list,
 				     struct list_data *current,
@@ -53,6 +61,9 @@ extern void _mu_list_insert_sublist (mu_list_t list,
 				     struct list_data *tail,
 				     size_t count,
 				     int insert_before);
+extern int _mu_list_insert_item (mu_list_t list, struct list_data *current,
+				 void *new_item,
+				 int insert_before);
 
 # ifdef __cplusplus
 }

@@ -16,8 +16,10 @@
 # Public License along with this library.  If not, see
 # <http://www.gnu.org/licenses/>.
 
-SUBDIRS = auth base address sockaddr cidr cfg diag filter mailbox mailer mime\
- server string stream stdstream property url imapio . tests 
+SUBDIRS = \
+ auth base address list sockaddr cidr cfg diag\
+ filter mailbox mailer mime server string stream stdstream\
+ property url imapio . tests 
 
 lib_LTLIBRARIES = libmailutils.la
 
@@ -34,6 +36,7 @@ libmailutils_la_LIBADD = \
  diag/libdiag.la\
  filter/libfilter.la\
  imapio/libimapio.la\
+ list/liblist.la\
  mailbox/libmailbox.la\
  mailer/libmailer.la\
  mime/libmime.la\

@@ -39,8 +39,6 @@ libbase_la_SOURCES = \
  iterator.c\
  kwd.c\
  lcall.c\
- list.c\
- listlist.c\
  locale.c\
  locker.c\
  mailcap.c\

+# GNU Mailutils -- a suite of utilities for electronic mail
+# Copyright (C) 2011 Free Software Foundation, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 3 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General
+# Public License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+noinst_LTLIBRARIES = liblist.la
+
+liblist_la_SOURCES = \
+ append.c\
+ array.c\
+ clear.c\
+ count.c\
+ create.c\
+ destroy.c\
+ do.c\
+ empty.c\
+ get.c\
+ getcomp.c\
+ insert.c\
+ intersect.c\
+ iterator.c\
+ listlist.c\
+ locate.c\
+ prepend.c\
+ remove.c\
+ replace.c\
+ setcomp.c\
+ setdestr.c
+
+INCLUDES = @MU_LIB_COMMON_INCLUDES@ -I/libmailutils
+

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_append (mu_list_t list, void *item)
+{
+  struct list_data *ldata;
+  struct list_data *last;
+
+  if (list == NULL)
+    return EINVAL;
+  last = list->head.prev;
+  ldata = calloc (sizeof (*ldata), 1);
+  if (ldata == NULL)
+    return ENOMEM;
+  ldata->item = item;
+  mu_monitor_wrlock (list->monitor);
+  ldata->next = &list->head;
+  ldata->prev = list->head.prev;
+  last->next = ldata;
+  list->head.prev = ldata;
+  list->count++;
+  mu_monitor_unlock (list->monitor);
+  return 0;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_to_array (mu_list_t list, void **array, size_t count, size_t *pcount)
+{
+  size_t total = 0;
+
+  if (!list)
+    return EINVAL;
+
+  total = (count < list->count) ? count : list->count;
+
+  if (array)
+    {
+      size_t i;
+      struct list_data *current;
+
+      for (i = 0, current = list->head.next;
+	   i < total && current != &list->head; current = current->next)
+	array[i++] = current->item;
+    }
+  if (pcount)
+    *pcount = total;
+  return 0;
+}
+

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+
+void
+mu_list_clear (mu_list_t list)
+{
+  struct list_data *current;
+  struct list_data *previous;
+
+  if (!list)
+    return;
+  mu_monitor_wrlock (list->monitor);
+  for (current = list->head.next; current != &list->head;)
+    {
+      previous = current;
+      current = current->next;
+      DESTROY_ITEM (list, previous);
+      free (previous);
+    }
+  list->head.next = list->head.prev = &list->head;
+  mu_monitor_unlock (list->monitor);
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_count (mu_list_t list, size_t *pcount)
+{
+  if (list == NULL)
+    return EINVAL;
+  if (pcount == NULL)
+    return MU_ERR_OUT_PTR_NULL;
+  *pcount = list->count;
+  return 0;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_create (mu_list_t *plist)
+{
+  mu_list_t list;
+  int status;
+
+  if (plist == NULL)
+    return MU_ERR_OUT_PTR_NULL;
+  list = calloc (sizeof (*list), 1);
+  if (list == NULL)
+    return ENOMEM;
+  status = mu_monitor_create (&list->monitor, 0,  list);
+  if (status != 0)
+    {
+      free (list);
+      return status;
+    }
+  list->head.next = &list->head;
+  list->head.prev = &list->head;
+  *plist = list;
+  return 0;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+
+void
+mu_list_destroy (mu_list_t *plist)
+{
+  if (plist && *plist)
+    {
+      mu_list_t list = *plist;
+      mu_list_clear (list);
+      mu_monitor_destroy (&list->monitor, list);
+      free (list);
+      *plist = NULL;
+    }
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_do (mu_list_t list, mu_list_action_t *action, void *cbdata)
+{
+  mu_iterator_t itr;
+  int status = 0;
+
+  if (list == NULL || action == NULL)
+    return EINVAL;
+  status = mu_list_get_iterator (list, &itr);
+  if (status)
+    return status;
+  for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
+       mu_iterator_next (itr))
+    {
+      void *item;
+      mu_iterator_current (itr, &item);
+      if ((status = action (item, cbdata)))
+	break;
+    }
+  mu_iterator_destroy (&itr);
+  return status;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <mailutils/sys/list.h>
+
+int
+mu_list_is_empty (mu_list_t list)
+{
+  size_t n = 0;
+
+  mu_list_count (list, &n);
+  return (n == 0);
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_get (mu_list_t list, size_t indx, void **pitem)
+{
+  struct list_data *current;
+  size_t count;
+  int status = MU_ERR_NOENT;
+
+  if (list == NULL)
+    return EINVAL;
+  if (pitem == NULL)
+    return MU_ERR_OUT_PTR_NULL;
+  mu_monitor_rdlock (list->monitor);
+  for (current = list->head.next, count = 0; current != &list->head;
+       current = current->next, count++)
+    {
+      if (count == indx)
+        {
+          *pitem = current->item;
+	  status = 0;
+	  break;
+        }
+    }
+  mu_monitor_unlock (list->monitor);
+  return status;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_get_comparator (mu_list_t list, mu_list_comparator_t *comp)
+{
+  if (!list)
+    return EINVAL;
+  *comp = list->comp;
+  return 0;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+_mu_list_insert_item (mu_list_t list, struct list_data *current,
+		      void *new_item,
+		      int insert_before)
+{
+  int status;
+  struct list_data *ldata = calloc (sizeof (*ldata), 1);
+  if (ldata == NULL)
+    status = ENOMEM;
+  else
+    {
+      ldata->item = new_item;
+      _mu_list_insert_sublist (list, current,
+			       ldata, ldata,
+			       1,
+			       insert_before);
+      status = 0;
+    }
+  return status;
+}
+
+int
+mu_list_insert (mu_list_t list, void *item, void *new_item, int insert_before)
+{
+  struct list_data *current;
+  mu_list_comparator_t comp;
+  int status = MU_ERR_NOENT;
+
+  if (list == NULL)
+    return EINVAL;
+  comp = list->comp ? list->comp : _mu_list_ptr_comparator;
+
+  mu_monitor_wrlock (list->monitor);
+  for (current = list->head.next;
+       current != &list->head;
+       current = current->next)
+    {
+      if (comp (current->item, item) == 0)
+	{
+	  status = _mu_list_insert_item (list, current, new_item,
+					 insert_before);
+	  break;
+	}
+    }
+  mu_monitor_unlock (list->monitor);
+  return status;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+/* Computes an intersection of two lists and returns it in PDEST.
+   The resulting list contains elements from A that are
+   also encountered in B (as per comparison function of
+   the latter).
+
+   If DUP_ITEM is not NULL, it is used to create copies of
+   items to be stored in PDEST.  In this case, the destroy_item
+   function of B is also attached to PDEST.  Otherwise, if
+   DUP_ITEM is NULL, pointers to elements are stored and
+   no destroy_item function is assigned. */
+int
+mu_list_intersect_dup (mu_list_t *pdest, mu_list_t a, mu_list_t b,
+		       int (*dup_item) (void **, void *, void *),
+		       void *dup_closure)
+{
+  mu_list_t dest;
+  int rc;
+  mu_iterator_t itr;
+  
+  rc = mu_list_create (&dest);
+  if (rc)
+    return rc;
+
+  mu_list_set_comparator (dest, b->comp);
+  if (dup_item)
+    mu_list_set_destroy_item (dest, b->destroy_item);
+  
+  rc = mu_list_get_iterator (a, &itr);
+  if (rc)
+    {
+      mu_list_destroy (&dest);
+      return rc;
+    }
+
+  rc = 0;
+  for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
+       mu_iterator_next (itr))
+    {
+      void *data;
+      mu_iterator_current (itr, &data);
+      if (mu_list_locate (b, data, NULL) == 0)
+	{
+	  void *new_data;
+	  if (dup_item && data)
+	    {
+	      rc = dup_item (&new_data, data, dup_closure);
+	      if (rc)
+		break;
+	    }
+	  else
+	    new_data = data;
+	
+	  mu_list_append (dest, new_data); /* FIXME: Check return, and? */
+	}
+    }
+  mu_iterator_destroy (&itr);
+  *pdest = dest;
+  return rc;
+}
+
+int
+mu_list_intersect (mu_list_t *pdest, mu_list_t a, mu_list_t b)
+{
+  return mu_list_intersect_dup (pdest, a, b, NULL, NULL);
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/sys/iterator.h>
+#include <mailutils/errno.h>
+
+/* Iterator interface */
+
+struct list_iterator
+{
+  mu_list_t list;
+  struct list_data *cur;
+  int backwards; /* true if iterating backwards */
+};
+
+static int
+first (void *owner)
+{
+  struct list_iterator *itr = owner;
+  if (itr->backwards)
+    itr->cur = itr->list->head.prev;
+  else
+    itr->cur = itr->list->head.next;
+  return 0;
+}
+
+static int
+next (void *owner)
+{
+  struct list_iterator *itr = owner;
+  if (itr->backwards)
+    itr->cur = itr->cur->prev;
+  else
+    itr->cur = itr->cur->next;
+  return 0;
+}
+
+static int
+getitem (void *owner, void **pret, const void **pkey)
+{
+  struct list_iterator *itr = owner;
+  *pret = itr->cur->item;
+  if (pkey)
+    *pkey = NULL;
+  return 0;
+}
+
+static int
+finished_p (void *owner)
+{
+  struct list_iterator *itr = owner;
+  return itr->cur == &itr->list->head;
+}
+
+static int
+destroy (mu_iterator_t iterator, void *data)
+{
+  struct list_iterator *itr = data;
+  mu_iterator_detach (&itr->list->itr, iterator);
+  free (data);
+  return 0;
+}
+
+static int
+curitem_p (void *owner, void *item)
+{
+  struct list_iterator *itr = owner;
+  return itr->cur == item;
+}
+
+static int
+list_data_dup (void **ptr, void *owner)
+{
+  *ptr = malloc (sizeof (struct list_iterator));
+  if (*ptr == NULL)
+    return ENOMEM;
+  memcpy (*ptr, owner, sizeof (struct list_iterator));
+  return 0;
+}
+
+static int
+list_itrctl (void *owner, enum mu_itrctl_req req, void *arg)
+{
+  struct list_iterator *itr = owner;
+  mu_list_t list = itr->list;
+  struct list_data *ptr;
+  
+  switch (req)
+    {
+    case mu_itrctl_tell:
+      /* Return current position in the object */
+      if (itr->cur == NULL)
+	return MU_ERR_NOENT;
+      else
+	{
+	  size_t count;
+
+	  for (count = 0, ptr = list->head.next; ptr != &list->head;
+	       ptr = ptr->next, count++)
+	    {
+	      if (ptr == itr->cur)
+		{
+		  *(size_t*)arg = count;
+		  return 0;
+		}
+	    }
+	  return MU_ERR_NOENT;
+	}
+      break;
+      
+    case mu_itrctl_delete:
+    case mu_itrctl_delete_nd:
+      /* Delete current element */
+      if (itr->cur == NULL)
+	return MU_ERR_NOENT;
+      else
+	{
+	  struct list_data *prev;
+	
+	  ptr = itr->cur;
+	  prev = ptr->prev;
+	
+	  mu_iterator_advance (list->itr, ptr);
+	  prev->next = ptr->next;
+	  ptr->next->prev = prev;
+	  if (req == mu_itrctl_delete)
+	    DESTROY_ITEM (list, ptr);
+	  free (ptr);
+	  list->count--;
+	}
+      break;
+      
+    case mu_itrctl_replace:
+    case mu_itrctl_replace_nd:
+      /* Replace current element */
+      if (itr->cur == NULL)
+	return MU_ERR_NOENT;
+      if (!arg)
+	return EINVAL;
+      ptr = itr->cur;
+      if (req == mu_itrctl_replace)
+	  DESTROY_ITEM (list, ptr);
+      ptr = itr->cur;
+      ptr->item = arg;
+      break;
+      
+    case mu_itrctl_insert:
+      /* Insert new element in the current position */
+      if (itr->cur == NULL)
+	return MU_ERR_NOENT;
+      if (!arg)
+	return EINVAL;
+      return _mu_list_insert_item (list, itr->cur, arg, 0);
+
+    case mu_itrctl_insert_list:
+      /* Insert a list of elements */
+      if (itr->cur == NULL)
+	return MU_ERR_NOENT;
+      if (!arg)
+	return EINVAL;
+      else
+	{
+	  mu_list_t new_list = arg;
+	  _mu_list_insert_sublist (list, itr->cur,
+				   new_list->head.next, new_list->head.prev,
+				   new_list->count,
+				   0);
+	  _mu_list_clear (new_list);
+	}
+      break;
+
+    case mu_itrctl_qry_direction:
+      if (!arg)
+	return EINVAL;
+      else
+	*(int*)arg = itr->backwards;
+      break;
+
+    case mu_itrctl_set_direction:
+      if (!arg)
+	return EINVAL;
+      else
+	itr->backwards = !!*(int*)arg;
+      break;
+      
+    default:
+      return ENOSYS;
+    }
+  return 0;
+}
+
+int
+mu_list_get_iterator (mu_list_t list, mu_iterator_t *piterator)
+{
+  mu_iterator_t iterator;
+  int status;
+  struct list_iterator *itr;
+
+  if (!list)
+    return EINVAL;
+
+  itr = calloc (1, sizeof *itr);
+  if (!itr)
+    return ENOMEM;
+  itr->list = list;
+  itr->cur = NULL;
+
+  status = mu_iterator_create (&iterator, itr);
+  if (status)
+    {
+      free (itr);
+      return status;
+    }
+
+  mu_iterator_set_first (iterator, first);
+  mu_iterator_set_next (iterator, next);
+  mu_iterator_set_getitem (iterator, getitem);
+  mu_iterator_set_finished_p (iterator, finished_p);
+  mu_iterator_set_curitem_p (iterator, curitem_p);
+  mu_iterator_set_destroy (iterator, destroy);
+  mu_iterator_set_dup (iterator, list_data_dup);
+  mu_iterator_set_itrctl (iterator, list_itrctl);
+  
+  mu_iterator_attach (&list->itr, iterator);
+
+  *piterator = iterator;
+  return 0;
+}

@@ -19,11 +19,7 @@
 #ifdef HAVE_CONFIG_H
 # include <config.h>
 #endif
-
-#include <errno.h>
 #include <stdlib.h>
-#include <string.h>
-
 #include <mailutils/sys/list.h>
 #include <mailutils/sys/iterator.h>
 #include <mailutils/errno.h>

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+_mu_list_ptr_comparator (const void *item, const void *value)
+{
+  return item != value;
+}
+
+int
+mu_list_locate (mu_list_t list, void *item, void **ret_item)
+{
+  struct list_data *current, *previous;
+  mu_list_comparator_t comp;
+  int status = MU_ERR_NOENT;
+
+  if (list == NULL)
+    return EINVAL;
+  comp = list->comp ? list->comp : _mu_list_ptr_comparator;
+  mu_monitor_wrlock (list->monitor);
+  for (previous = &list->head, current = list->head.next;
+       current != &list->head; previous = current, current = current->next)
+    {
+      if (comp (current->item, item) == 0)
+	{
+	  if (ret_item)
+	    *ret_item = current->item;
+	  status = 0;
+	  break;
+	}
+    }
+  mu_monitor_unlock (list->monitor);
+  return status;
+}
+

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_prepend (mu_list_t list, void *item)
+{
+  struct list_data *ldata;
+  struct list_data *first;
+
+  if (list == NULL)
+    return EINVAL;
+  first = list->head.next;
+  ldata = calloc (sizeof (*ldata), 1);
+  if (ldata == NULL)
+    return ENOMEM;
+  ldata->item = item;
+  mu_monitor_wrlock (list->monitor);
+  ldata->prev = &list->head;
+  ldata->next = list->head.next;
+  first->prev = ldata;
+  list->head.next = ldata;
+  list->count++;
+  mu_monitor_unlock (list->monitor);
+  return 0;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_remove (mu_list_t list, void *item)
+{
+  struct list_data *current;
+  mu_list_comparator_t comp;
+  int status = MU_ERR_NOENT;
+
+  if (list == NULL)
+    return EINVAL;
+  comp = list->comp ? list->comp : _mu_list_ptr_comparator;
+  mu_monitor_wrlock (list->monitor);
+  for (current = list->head.next;
+       current != &list->head; current = current->next)
+    {
+      if (comp (current->item, item) == 0)
+	{
+	  struct list_data *previous = current->prev;
+	  
+	  mu_iterator_advance (list->itr, current);
+	  previous->next = current->next;
+	  current->next->prev = previous;
+	  DESTROY_ITEM (list, current);
+	  free (current);
+	  list->count--;
+	  status = 0;
+	  break;
+	}
+    }
+  mu_monitor_unlock (list->monitor);
+  return status;
+}
+
+int
+mu_list_remove_nd (mu_list_t list, void *item)
+{
+  mu_list_destroy_item_t dptr = mu_list_set_destroy_item (list, NULL);
+  int rc = mu_list_remove (list, item);
+  mu_list_set_destroy_item (list, dptr);
+  return rc;
+}
+

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+#include <mailutils/errno.h>
+
+int
+mu_list_replace (mu_list_t list, void *old_item, void *new_item)
+{
+  struct list_data *current, *previous;
+  mu_list_comparator_t comp;
+  int status = MU_ERR_NOENT;
+
+  if (list == NULL)
+    return EINVAL;
+  comp = list->comp ? list->comp : _mu_list_ptr_comparator;
+  mu_monitor_wrlock (list->monitor);
+  for (previous = &list->head, current = list->head.next;
+       current != &list->head; previous = current, current = current->next)
+    {
+      if (comp (current->item, old_item) == 0)
+	{
+	  DESTROY_ITEM (list, current);
+	  current->item = new_item;
+	  status = 0;
+	  break;
+	}
+    }
+  mu_monitor_unlock (list->monitor);
+  return status;
+}
+
+int
+mu_list_replace_nd (mu_list_t list, void *item, void *new_item)
+{
+  mu_list_destroy_item_t dptr = mu_list_set_destroy_item (list, NULL);
+  int rc = mu_list_replace (list, item, new_item);
+  mu_list_set_destroy_item (list, dptr);
+  return rc;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+
+mu_list_comparator_t
+mu_list_set_comparator (mu_list_t list, mu_list_comparator_t comp)
+{
+  mu_list_comparator_t old_comp;
+
+  if (list == NULL)
+    return NULL;
+  old_comp = list->comp;
+  list->comp = comp;
+  return old_comp;
+}

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001, 2004, 2005, 2007, 2008, 2010, 2011
+   Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see 
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/sys/list.h>
+
+mu_list_destroy_item_t
+mu_list_set_destroy_item (mu_list_t list, void (*destroy_item)(void *item))
+{
+  mu_list_destroy_item_t ret = list->destroy_item;
+  list->destroy_item = destroy_item;
+  return ret;
+}