mail: provide mechanism for listing and editing attachments from the shell

* NEWS: Update.
* mail/escape.c (escape_check_args): Take two additional arguments
specifying minimum and maximum number of parameters to expect.
All uses updated. Remove static qualifier.
* mail/mail.h (send_attach_file): Rename to send_attach_file_default
(escape_check_args,escape_list_attachments)
(escape_attach,escape_remove_attachment): New protos.
* mail/send.c (send_attach_file): Take encoding and content type
as arguments.
(send_attach_file_default): New function.
(escape_list_attachments)
(escape_attach,escape_remove_attachment): New functions.
* mail/table.c: New escapes: l, +, ^

* include/mailutils/list.h (mu_list_remove_nth)
(mu_list_remove_nth_nd): New protos.
* libmailutils/list/Makefile.am (liblist_la_SOURCES): Add removenth.c
* libmailutils/list/removenth.c: New file.

-GNU mailutils NEWS -- history of user-visible changes. 2012-07-18
+GNU mailutils NEWS -- history of user-visible changes. 2012-07-19
 Copyright (C) 2002-2012 Free Software Foundation, Inc.
 See the end of file for copying conditions.
 
@@ -135,6 +135,20 @@ Here, the file "prog" will be attached witg the content type
 "main.c" and "ext.h" will be marked with content type "text/c" and
 encoded using "quoted-printable" algorithm.
 
+The mail shell provides the following new escapes to handle attachments:
+
+ ~l
+    Lists all attachments.  The output is a numbered list of
+    attachments with their corresponding content types and
+    encodings.
+    
+ ~+ filename [content-type [encoding]]
+    Attach the file `filename'.  Optional arguments supply the content
+    type and encoding to use instead of the defaults.
+
+ ~^ N
+    Delete Nth attachment.
+
 ** MH: improved compatibility with other implementations
 
 ** MH inc: new option --moveto

-Subproject commit f32ef1983968e755cd580b06e369476d7e7f88b6
+Subproject commit 04255b6d5551952b4e0c94da15988f573e3e9fc4

@@ -118,6 +118,10 @@ int mu_list_remove   (mu_list_t _list, void *_item);
   /* A non-destructive version of mu_list_remove: removes the _item but does
      not deallocate it. */
 int mu_list_remove_nd  (mu_list_t _list, void *_item);
+  /* Remove Nth element from the list. */
+int mu_list_remove_nth (mu_list_t list, size_t n);
+  /* Remove Nth element from the list, non-destructive. */
+int mu_list_remove_nth_nd (mu_list_t list, size_t n);
   /* Find _old_item in _list and if found, replace it with _new_item,
      deallocating the removed item via the `destroy_item' method. */
 int mu_list_replace  (mu_list_t _list, void *_old_item, void *_new_item);

@@ -42,6 +42,7 @@ liblist_la_SOURCES = \
  prepend.c\
  push.c\
  remove.c\
+ removenth.c\
  replace.c\
  rfold.c\
  setcomp.c\

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2012 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_nth (mu_list_t list, size_t n)
+{
+  struct list_data *current;
+  mu_list_comparator_t comp;
+  int status = MU_ERR_NOENT;
+  size_t i;
+    
+  if (list == NULL)
+    return EINVAL;
+  if (n >= list->count)
+    return ERANGE;
+  mu_monitor_wrlock (list->monitor);
+  for (current = list->head.next, i = 0; current != &list->head;
+       current = current->next, i++)
+    {
+      if (i == n)
+	{
+	  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_nth_nd (mu_list_t list, size_t n)
+{
+  mu_list_destroy_item_t dptr = mu_list_set_destroy_item (list, NULL);
+  int rc = mu_list_remove_nth (list, n);
+  mu_list_set_destroy_item (list, dptr);
+  return rc;
+}
+

@@ -156,16 +156,29 @@ escape_continue (void)
   mu_printf (_("(continue)\n"));
 }
 
-static int 
-escape_check_args (int argc, char **argv)
+int 
+escape_check_args (int argc, char **argv, int minargs, int maxargs)
 {
-  if (argc == 1)
+  char *escape = "~";
+  if (argc < minargs)
     {
-      char *escape = "~";
+      minargs--;
       mailvar_get (&escape, "escape", mailvar_type_string, 0);
-      mu_error (_("%c%s requires an argument"), escape[0], argv[0]);
+      mu_error (ngettext ("%c%s requires at least %d argument",
+			  "%c%s requires at least %d arguments",
+			  minargs), escape[0], argv[0], minargs);
       return 1;
     }
+  if (maxargs > 1 && argc > maxargs)
+    {
+      maxargs--;
+      mailvar_get (&escape, "escape", mailvar_type_string, 0);
+      mu_error (ngettext ("%c%s accepts at most %d argument",
+			  "%c%s accepts at most %d arguments",
+			  maxargs), escape[0], argv[0], maxargs);
+      return 1;
+    }
+    
   return 0;
 }
 
@@ -184,7 +197,7 @@ escape_command (int argc, char **argv, compose_env_t *env)
   const struct mail_command_entry *entry;
   int status;
   
-  if (escape_check_args (argc, argv))
+  if (escape_check_args (argc, argv, 2, 2))
     return 1;
   if (argv[1][0] == '#')
     return 0;
@@ -416,6 +429,8 @@ escape_editor (int argc, char **argv, compose_env_t *env)
   return escape_run_editor (getenv ("EDITOR"), argc, argv, env);
 }
 
+/* ~l -- escape_list_attachments (send.c) */
+
 /* ~v */
 int
 escape_visual (int argc, char **argv, compose_env_t *env)
@@ -457,7 +472,7 @@ escape_headers (int argc, char **argv, compose_env_t *env)
 int
 escape_insert (int argc, char **argv, compose_env_t *env)
 {
-  if (escape_check_args (argc, argv))
+  if (escape_check_args (argc, argv, 2, 2))
     return 1;
   mailvar_variable_format (env->compstr, mailvar_find_variable (argv[1], 0),
 			   NULL);
@@ -574,7 +589,7 @@ escape_read (int argc, char **argv, compose_env_t *env MU_ARG_UNUSED)
   mu_stream_t instr;
   int rc;
   
-  if (escape_check_args (argc, argv))
+  if (escape_check_args (argc, argv, 2, 2))
     return 1;
   filename = util_fullpath (argv[1]);
 
@@ -597,7 +612,7 @@ int
 escape_subj (int argc, char **argv, compose_env_t *env)
 {
   char *buf;
-  if (escape_check_args (argc, argv))
+  if (escape_check_args (argc, argv, 2, 2))
     return 1;
   mu_argcv_string (argc - 1, argv + 1, &buf);
   compose_header_set (env, MU_HEADER_SUBJECT, buf, COMPOSE_REPLACE);
@@ -623,7 +638,7 @@ escape_write (int argc, char **argv, compose_env_t *env)
   int rc;
   mu_off_t size;
   
-  if (escape_check_args (argc, argv))
+  if (escape_check_args (argc, argv, 2, 2))
     return 1;
   filename = util_fullpath (argv[1]);
   /* FIXME: check for existence first */

@@ -95,7 +95,7 @@ parse_opt (int key, char *arg, struct argp_state *state)
 
     case 'A':
       args->hint |= HINT_SEND_MODE;
-      if (send_attach_file (arg))
+      if (send_attach_file_default (arg))
 	exit (1);
       break;
       

@@ -258,7 +258,9 @@ extern char *mail_expand_name (const char *name);
 
 extern void send_append_header (char *text);
 extern void send_append_header2 (char *name, char *value, int mode);
-extern int send_attach_file (const char *name);
+extern int send_attach_file_default (const char *name);
+
+extern int escape_check_args (int argc, char **argv, int minargs, int maxargs);
 
 extern int escape_shell (int argc, char **argv, compose_env_t *env);
 extern int escape_command (int argc, char **argv, compose_env_t *env);
@@ -280,6 +282,11 @@ extern int escape_visual (int argc, char **argv, compose_env_t *env);
 extern int escape_write (int argc, char **argv, compose_env_t *env);
 extern int escape_exit (int argc, char **argv, compose_env_t *env);
 extern int escape_pipe (int argc, char **argv, compose_env_t *env);
+extern int escape_list_attachments  (int argc, char **argv,
+				     compose_env_t *env);
+extern int escape_attach (int argc, char **argv, compose_env_t *env);
+extern int escape_remove_attachment (int argc, char **argv,
+				     compose_env_t *env);
 
 /* Cursor */
 extern void set_cursor (unsigned value);

@@ -154,11 +154,13 @@ atchinfo_free (void *p)
 }
 
 int
-send_attach_file (const char *name)
+send_attach_file (const char *name,
+		  const char *content_type, const char *encoding)
 {
   int rc;
   struct stat st;
   struct atchinfo *aptr;
+  mu_list_t list;
   
   if (stat (name, &st))
     {
@@ -180,6 +182,16 @@ send_attach_file (const char *name)
       return 1;
     }
 
+  if (!encoding)
+    encoding = "base64";
+  mu_filter_get_list (&list);
+  rc = mu_list_locate (list, encoding, NULL);
+  if (rc)
+    {
+      mu_error (_("unsupported encoding: %s"), encoding);
+      return 1;
+    }
+  
   if (!attlist)
     {
       rc = mu_list_create (&attlist);
@@ -191,10 +203,10 @@ send_attach_file (const char *name)
       mu_list_set_destroy_item (attlist, atchinfo_free);
     }
   aptr = mu_alloc (sizeof (*aptr));
-  aptr->encoding = mu_strdup (default_encoding ?
-			      default_encoding : "base64");
-  aptr->content_type = mu_strdup (default_content_type ?
-				  default_content_type :
+
+  aptr->encoding = mu_strdup (encoding);  
+  aptr->content_type = mu_strdup (content_type ?
+				  content_type :
 				    "application/octet-stream");
   aptr->filename = mu_strdup (name);
   rc = mu_list_append (attlist, aptr);
@@ -206,6 +218,86 @@ send_attach_file (const char *name)
   return 0;
 }
 
+int
+send_attach_file_default (const char *name)
+{
+  return send_attach_file (name, default_content_type, default_encoding);
+}
+
+int
+escape_list_attachments (int argc, char **argv, compose_env_t *env)
+{
+  mu_iterator_t itr;
+  int i;
+  
+  if (mu_list_is_empty (attlist) ||
+      mu_list_get_iterator (attlist, &itr))
+    {
+      mu_printf ("%s\n", _("No attachments"));
+      return 0;
+    }
+  
+  for (mu_iterator_first (itr), i = 1; !mu_iterator_is_done (itr);
+       mu_iterator_next (itr), i++)
+    {
+      struct atchinfo *aptr;
+      if (mu_iterator_current (itr, (void**)&aptr))
+	continue;
+	  
+      mu_printf ("%3d %-12s %-30s %-s\n",
+		 i, aptr->filename, aptr->content_type, aptr->encoding);
+    }
+  mu_iterator_destroy (&itr);
+
+  return 0;
+}
+
+int
+escape_attach (int argc, char **argv, compose_env_t *env)
+{
+  const char *encoding = default_encoding;
+  const char *content_type = default_content_type;
+  
+  switch (argc)
+    {
+    case 4:
+      encoding = argv[3];
+    case 3:
+      content_type = argv[2];
+    case 2:
+      return send_attach_file (argv[1], content_type, encoding);
+    default:
+      return escape_check_args (argc, argv, 2, 4);
+    }
+  return 1;
+}
+
+int
+escape_remove_attachment (int argc, char **argv, compose_env_t *env)
+{
+  size_t count;
+  unsigned long n;
+  char *p;
+  
+  if (escape_check_args (argc, argv, 2, 2))
+    return 1;
+  n = strtoul (argv[1], &p, 10);
+  if (*p)
+    {
+      mu_error (_("not a valid number: %s"), argv[1]);
+      return 1;
+    }
+  
+  mu_list_count (attlist, &count);
+  if (n == 0 || n > count)
+    {
+      mu_error (_("index out of range"));
+      return 1;
+    }
+
+  return mu_list_remove_nth (attlist, n - 1);
+}
+
 static int
 saveatt (void *item, void *data)
 {

@@ -226,6 +226,8 @@ static const struct mail_escape_entry mail_escape_table[] = {
   {"!",	"!",	"![shell-command]", escape_shell },
   {":",	":",	":[mail-command]",  escape_command },
   {"-",	"-",	"-[mail-command]",  escape_command },
+  {"+",	"+",	"+[name [content-type [encoding]]]", escape_attach },
+  {"^",	"^",	"^[N]",             escape_remove_attachment },
   {"?",	"?",	"?",		    escape_help },
   {"A",	"A",	"A",		    escape_sign },
   {"a",	"a",	"a",		    escape_sign },
@@ -237,6 +239,7 @@ static const struct mail_escape_entry mail_escape_table[] = {
   {"F",	"F",	"F[mesg-list]",	    escape_print },
   {"h",	"h",	"h",		    escape_headers },
   {"i",	"i",	"i[var-name]",	    escape_insert },
+  {"l",	"l",	"l",                escape_list_attachments },
   {"m",	"m",	"m[mesg-list]",	    escape_quote },
   {"M",	"M",	"M[mesg-list]",	    escape_quote },
   {"p",	"p",	"p",		    escape_type_input },