New option --mime

* mail/mail.c (mime_option): New variable.
(main): assume --mime if either or both of --content-type and
--content-encoding are set.  Set the mime variable if so.
* mail/mail.h (mailvar_is_true): New prototype.
* mail/send.c (add_attachments): Continue if the mime variable
is set.
(add_body): Rewrite, treating the text read from the stdin as
MIME part in itself.
* mailvar.c (mailvar_tab): New variable "mime"
(mailvar_is_true): New function.

* NEWS: Document --mime
* doc/texinfo/programs.texi: Rewrite the Attachments subsection.

-GNU mailutils NEWS -- history of user-visible changes. 2017-04-13
+GNU mailutils NEWS -- history of user-visible changes. 2017-04-19
 Copyright (C) 2002-2017 Free Software Foundation, Inc.
 See the end of file for copying conditions.
 
@@ -90,6 +90,20 @@ defined.  Instead, the following constants are defined in config.h:
 
 * mail: sending multipart messages
 
+** New option --mime
+
+This option instructs mail to compose output messages in MIME format.
+The options --content-type and --encoding turn this option on.  As a
+side effect, both --content-type and --encoding now affect the message
+body read from the standard input as well.
+
+** New variable 'mime'
+
+The 'mime' variable, if set instructs mail to compose output messages
+in MIME format.  In fact, the '--mime' option is equivalent to
+'-E set mime', except that it takes effect after all options are
+processed.
+
 ** New option --alternative
 
 When used with --attach or --attach-fd options, this option sets the

@@ -2987,7 +2987,7 @@ Configuration Files}, for a detailed description of their format.
 * Invoking Mail::            Command Line Options.
 * Specifying Messages::      How to Specify Message Sets.
 * Composing Mail::           Composing Mail.
-* Attachments::              Attaching Files.
+* MIME::                     How to Attach Files.
 * Reading Mail::             Reading Mail.
 * Scripting::                Scripting.
 * Mail Variables::           How to Alter the Behavior of @command{mail}.
@@ -3084,6 +3084,14 @@ Print header summary to stdout and exit.
 @itemx --ignore
 Ignore interrupts when composing the message.
 
+@item -M
+@itemx --mime
+@itemx --no-mime
+The @option{--mime} option instructs @command{mail} to compose MIME
+messages.  It is equivalent for @option{-E 'set mime'}, except that it
+is processed after all other options.  The @option{--no-mime} disables
+the MIME compose mode, and is a shortcut for @option{-E 'set nomime'},
+
 @item -N
 @itemx --nosum
 Do not display initial header summary.
@@ -3522,8 +3530,53 @@ the old contents of your message.
 
 @c *********************************************************************
 
-@node Attachments
-@subsection Sending Attachments
+@node MIME
+@subsection Composing Multipart Messages
+
+Multipart messages (or MIME, for short) can be used to send text in
+character set other than ASCII, attach non-text files, send multiple
+parts in alternative formats, etc.
+
+Technically speaking, the boolean variable @code{mime}
+controls this feature.  If it is set (@pxref{Setting and Unsetting
+the Variables}), @command{MIME} will create MIME messages by default.
+The variable can be set in the global or user configuration file
+(@pxref{Mail Configuration Files}), using the following command:
+
+@example
+set mime
+@end example
+
+It can also be set from the command line, using the @option{--mime}
+option.
+
+GNU @command{mail} automatically turns on the MIME mode, when it is
+requested to send a non-plaintext message, or a message in character
+set other than ASCII, when the encoding is specified, or when
+attachments are given.
+
+To send a message in another character set, specify it with the
+@option{--content-type} option:
+
+@example
+mail --content-type 'text/plain; charset=utf-8'
+@end example
+
+The @option{--encoding} specifies the encoding to use:
+
+@example
+mail --content-type 'text/plain; charset=utf-8' --encoding=base64
+@end example
+
+Its argument is any encoding supported by GNU mailutils.  The two most
+often used encodings are @samp{base64} and @samp{quoted-printable}.
+
+To specify the charset from @command{mail} interactive section, enable
+the ``edit headers'' mode (@code{set editheaders}) and add the
+needed @code{Content-Type} header manually.
+
+GNU @command{mail} also gives you a possibility to attach files to the
+message being sent.
 
 The simplest way to attach a file from command line is by using the
 @option{--attach} (@option{-A}) option.  Its argument specifies the
@@ -3545,9 +3598,9 @@ $ mail --content-type=text/html --attach=in.html
 @end example
 
 The @option{--content-type} option affects all @option{--attach}
-options that follow it.  To change the content type, simply add
-another @option{--content-type} option.  For example, to send both
-the HTML file and the archive:
+options that follow it, and the message body (if any).  To change the
+content type, simply add another @option{--content-type} option.  For
+example, to send both the HTML file and the archive:
 
 @example
 $ mail --content-type=text/html --attach=in.html \
@@ -3556,8 +3609,9 @@ $ mail --content-type=text/html --attach=in.html \
 
 Similarly, the encoding to use is set up by the @option{--encoding}
 option.  As well as @option{--content-type}, this option affects all
-attachments supplied after it in the command line, until changed by
-the eventual next appearance of the same option.  Extending the above
+attachments supplied after it in the command line as well as the
+message body read from the standard input, until changed by
+the eventual next instance of the same option.  Extending the above
 example:
 
 @example
@@ -5066,6 +5120,17 @@ set metamail
 set metamail="metamail -m mail -p"
 @end example
 
+@kwindex mime
+@item mime
+@*Type: String
+@*Default: Unset (false)
+@vrindex mime, mail variable
+
+If set, this variable instructs @command{mail} to compose MIME
+messages.
+
+It can be set from the command line using @option{--mime} option.
+
 @kwindex mimenoask
 @item mimenoask
 @*Type: String

@@ -36,6 +36,7 @@ int hint;
 char *file;
 char *user;
 
+int mime_option;
 int skip_empty_attachments;
 char *default_encoding;
 char *default_content_type;
@@ -274,6 +275,10 @@ static struct mu_option mail_options[] = {
     N_("attach from file descriptor FD"),
     mu_c_string, NULL, cli_attach_fd },
 
+  { "mime",    'M',  NULL, MU_OPTION_DEFAULT,
+    N_("compose MIME messages"),
+    mu_c_bool, &mime_option },
+
   MU_OPTION_END
 }, *options[] = { mail_options, NULL };
 
@@ -483,6 +488,11 @@ main (int argc, char **argv)
   /* argument parsing */
   mu_cli (argc, argv, &cli, mail_capa, NULL, &argc, &argv);
 
+  if (default_content_type || default_encoding)
+    mime_option = 1;
+  if (mime_option)
+    util_cache_command (&command_list, "set mime");
+      
   if (read_recipients)
     {
       argv += argc;

@@ -380,6 +380,7 @@ extern int util_get_crt (void);
 extern struct mailvar_variable *mailvar_find_variable (const char *var, int create);
 extern int mailvar_get (void *ptr, const char *variable,
 			enum mailvar_type type, int warn);
+int mailvar_is_true (char const *name);
 
 extern void mailvar_print (int set);
 extern void mailvar_variable_format (mu_stream_t,

@@ -276,6 +276,10 @@ struct mailvar_symbol mailvar_tab[] =
     { { "xmailer", },
       MAILVAR_TYPEMASK (mailvar_type_boolean),
       N_("add the `X-Mailer' header to the outgoing messages") },
+    
+    { { "mime" },
+      MAILVAR_TYPEMASK (mailvar_type_boolean),
+      N_("always compose MIME messages") },
 
     /* These will be implemented later */
     { { "onehop", }, MAILVAR_HIDDEN, NULL },
@@ -450,6 +454,12 @@ mailvar_get (void *ptr, const char *variable, enum mailvar_type type, int warn)
   return 0;
 }
 
+int
+mailvar_is_true (char const *name)
+{
+  return mailvar_get (NULL, name, mailvar_type_boolean, 0) == 0;
+}
+
 /* Initialize mailvar_list entry: clear set indicator and free any memory
    associated with the data */
 void

@@ -499,98 +499,51 @@ saveatt (void *item, void *data)
 }
 
 static int
-add_body (mu_message_t inmsg, mu_iterator_t itr, mu_mime_t mime)
+add_body (mu_message_t inmsg, compose_env_t *env)
 {
-  mu_body_t body;
-  mu_message_t part;
-  mu_stream_t str, output;
-  mu_header_t outhdr;
-  char *p;
   int rc;
-  
+  mu_body_t body;
+  mu_stream_t str;
+  struct atchinfo *aptr;
+
   mu_message_get_body (inmsg, &body);
-  if (skip_empty_attachments || multipart_alternative)
-    {
-      size_t size;
-      rc = mu_body_size (body, &size);
-      if (rc)
-	{
-	  mu_diag_funcall (MU_DIAG_ERROR, "mu_body_size", NULL, rc);
-	  return -1;
-	}
-      if (size == 0)
-	return 0;
-    }
-    
-  /* Add original message as the first part */
-  
-  /* 1. Create the part and obtain a reference to its stream */
-  if ((rc = mu_message_create (&part, NULL)) == 0)
-    {
-      mu_body_t pbody;
-      
-      mu_message_get_body (part, &pbody);
-      mu_body_get_streamref (pbody, &output);
-    }
-  else
-    {
-      mu_diag_funcall (MU_DIAG_ERROR, "mu_message_create", NULL, rc);
-      return -1;
-    }
-  
-  /* 2. Get original body stream and copy it out to the part's body */
   mu_body_get_streamref (body, &str);
-  mu_stream_copy (output, str, 0, NULL);
 
-  mu_stream_close (output);
-  mu_stream_destroy (&output);
-
-  /* 3. Copy "Content-*" headers from the original message */
-  mu_message_get_header (part, &outhdr);
-  for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
-       mu_iterator_next (itr))
-    {
-      const char *name, *value;
-      
-      if (mu_iterator_current_kv (itr, (const void **)&name,
-				  (void**)&value) == 0)
-	{
-	  if (mu_c_strncasecmp (name, "Content-", 8) == 0)
-	    mu_header_set_value (outhdr, name, value, 0);
-	}
-    }
+  aptr = mu_alloc (sizeof (*aptr));
+  aptr->id = NULL;
+  aptr->encoding = default_encoding ? mu_strdup (default_encoding) : NULL;  
+  aptr->content_type = mu_strdup (default_content_type ?
+				  default_content_type : "text/plain");
+  aptr->name = NULL;
+  aptr->filename = NULL;
+  aptr->source = str;
+  aptr->skip_empty = skip_empty_attachments || multipart_alternative;
+  if (!env->attlist)
+    env->attlist = attlist_new ();
+  rc = mu_list_prepend (env->attlist, aptr);
+  if (rc)
+    mu_diag_funcall (MU_DIAG_ERROR, "mu_list_prepend", NULL, rc);
+  return rc;
+}
   
-  /* 4. Add the content type and content ID headers. */
-  mu_header_set_value (outhdr, MU_HEADER_CONTENT_TYPE,
-		       default_content_type ? default_content_type : "text/plain",
-		       0);
-  mu_rfc2822_msg_id (0, &p);
-  mu_header_set_value (outhdr, MU_HEADER_CONTENT_ID, p, 1);
-  free (p);
-
-  /* 5. Add part to the mime object */
-  mu_mime_add_part (mime, part);
-  mu_message_unref (part);
-
-  return 0;
-}  
-
 static int
 add_attachments (compose_env_t *env, mu_message_t *pmsg)
 {
   mu_message_t inmsg, outmsg;
   mu_header_t inhdr, outhdr;
   mu_iterator_t itr;
-  mu_mime_t mime;  
   int rc;
   
+  inmsg = *pmsg;
+
+  if (mailvar_is_true ("mime") && add_body (inmsg, env))
+    return 1;
+  
   if (mu_list_is_empty (env->attlist))
     return 0;
   
-  inmsg = *pmsg;
-
   /* Create a mime object */
-  rc = mu_mime_create (&mime, NULL,
+  rc = mu_mime_create (&env->mime, NULL,
 		       env->alt ?
 		         MU_MIME_MULTIPART_ALT : MU_MIME_MULTIPART_MIXED);
   if (rc)
@@ -600,39 +553,35 @@ add_attachments (compose_env_t *env, mu_message_t *pmsg)
     }
 
   mu_message_get_header (inmsg, &inhdr);
-  mu_header_get_iterator (inhdr, &itr);
-
-  if (add_body (inmsg, itr, mime))
-    {
-      mu_mime_destroy (&mime);
-      mu_iterator_destroy (&itr);
-      return 1;
-    }
-
-  env->mime = mime;
 
   /* Add the respective attachments */
   rc = mu_list_foreach (env->attlist, saveatt, env);
   if (rc)
-    {
-      mu_mime_destroy (&mime);
-      mu_iterator_destroy (&itr);
-      return 1;
-    }
+    return 1;
 
   /* Get the resulting message */
-  rc = mu_mime_get_message (mime, &outmsg);
+  rc = mu_mime_get_message (env->mime, &outmsg);
 
   if (rc)
     {
       mu_diag_funcall (MU_DIAG_ERROR, "mu_mime_get_message", NULL, rc);
-      mu_mime_destroy (&mime);
-      mu_iterator_destroy (&itr);
       return 1;
     }
 
   /* Copy rest of headers from the original message */
-  mu_message_get_header (outmsg, &outhdr);
+  rc = mu_message_get_header (outmsg, &outhdr);
+  if (rc)
+    {
+      mu_diag_funcall (MU_DIAG_ERROR, "mu_message_get_header", NULL, rc);
+      return 1;
+    }
+
+  rc = mu_header_get_iterator (inhdr, &itr);
+  if (rc)
+    {
+      mu_diag_funcall (MU_DIAG_ERROR, "mu_header_get_iterator", NULL, rc);
+      return 1;
+    }
   for (mu_iterator_first (itr); !mu_iterator_is_done (itr);
        mu_iterator_next (itr))
     {
@@ -1356,7 +1305,7 @@ mail_send0 (compose_env_t *env, int save_to)
 	  
 	  mu_message_set_header (msg, env->header, NULL);
 	  env->header = NULL;
-	  
+
 	  status = add_attachments (env, &msg);
 	  if (status)
 	    break;