Make sure modifications to a message or its parts become visible in the message stream.

* include/mailutils/sys/body.h (_mu_body)<rawstream>: New member.
* include/mailutils/sys/message.h (_mu_message)<rawstream>: New member.
* libmailutils/mailbox/body.c: Rewrite. Return the specially crafted
"body-stream" for user I/O operations. Writes to that stream trigger
creation of a temporary stream (write-through mode) which will be used
for subsequent I/O.
* libmailutils/mailbox/msgbody.c (mu_message_get_body): Use msg->rawstream.
* libmailutils/mailbox/msgheader.c (message_header_fill): Do not
call mu_message_get_streamref, as that can result in endless recursion.
Use msg->rawstream instead.
* libmailutils/mailbox/msgref.c (_mu_message_free): Destroy both
rawstream and outstream.
* libmailutils/mailbox/msgstream.c (mu_message_set_stream): Set
rawstream.
(mu_message_get_stream): Create outstream as needed.
(mu_message_get_streamref): If the message has been modified,
create the outstream and return it to the caller. This way, the
modifications become visible via the stream interface.
* libmailutils/tests/Makefile.am: Add new testcases.
* libmailutils/tests/testsuite.at: Likewise.
* libmailutils/tests/modmesg.c: New file.
* libmailutils/tests/modmesg00.at: New file.
* libmailutils/tests/modmesg01.at: New file.
* libmailutils/tests/modmesg02.at: New file.
* libmailutils/tests/modmesg03.at: New file.
* mh/mhn.c: Fix message reference counting.

@@ -33,6 +33,7 @@ struct _mu_body
 {
   void *owner;
   mu_stream_t stream;
+  mu_stream_t rawstream;
   mu_stream_t fstream;
   int flags;
 

@@ -47,7 +47,8 @@ struct _mu_message
   mu_body_t body;
 
   int flags;
-  mu_stream_t stream;
+  mu_stream_t rawstream;
+  mu_stream_t outstream;
   mu_attribute_t attribute;
   mu_monitor_t monitor;
   mu_mime_t mime;

@@ -43,8 +43,7 @@ mu_message_get_body (mu_message_t msg, mu_body_t *pbody)
       if (status != 0)
 	return status;
       /* If a stream is already set, use it to create the body stream.  */
-      /* FIXME: I'm not sure if the second condition is really needed */
-      if (msg->stream/* && (msg->flags & MESSAGE_INTERNAL_STREAM)*/)
+      if (msg->rawstream)
 	{
 	  mu_stream_t stream;
 	  int flags = 0;
@@ -52,8 +51,8 @@ mu_message_get_body (mu_message_t msg, mu_body_t *pbody)
 	  /* FIXME: The actual mu_header_size cannot be used as offset,
 	     because the headers might have been modified in between. */
 	  
-	  mu_stream_get_flags (msg->stream, &flags);
-	  status = mu_streamref_create_abridged (&stream, msg->stream,
+	  mu_stream_get_flags (msg->rawstream, &flags);
+	  status = mu_streamref_create_abridged (&stream, msg->rawstream,
 						 msg->orig_header_size, 0);
 	  if (status)
 	    {

@@ -109,17 +109,9 @@ _header_fill (mu_stream_t stream, char **pbuf, size_t *plen)
 static int
 message_header_fill (void *data, char **pbuf, size_t *plen)
 {
-  int status = 0;
   mu_message_t msg = data;
-  mu_stream_t stream;
 
-  status = mu_message_get_streamref (msg, &stream);
-  if (status == 0)
-    {
-      status = _header_fill (stream, pbuf, plen);
-      mu_stream_destroy (&stream);
-    }
-  return status;
+  return _header_fill (msg->rawstream, pbuf, plen);
 }
 
 int
@@ -136,7 +128,7 @@ mu_message_get_header (mu_message_t msg, mu_header_t *phdr)
       int status = mu_header_create (&header, NULL, 0);
       if (status != 0)
 	return status;
-      if (msg->stream)
+      if (msg->rawstream)
 	mu_header_set_fill (header, message_header_fill, msg);
       status = mu_header_size (header, &msg->orig_header_size);
       if (status)

@@ -54,29 +54,13 @@ _mu_message_free (mu_message_t msg)
       mu_observable_destroy (&msg->observable, msg);
     }
       
-  /* Envelope.  */
-  if (msg->envelope)
-    mu_envelope_destroy (&msg->envelope, msg);
-      
-  /* Header.  */
-  if (msg->header)
-    mu_header_destroy (&msg->header);
-      
-  /* Body.  */
-  if (msg->body)
-    mu_body_destroy (&msg->body, msg);
-      
-  /* Attribute.  */
-  if (msg->attribute)
-    mu_attribute_destroy (&msg->attribute, msg);
-      
-  /* Stream.  */
-  if (msg->stream)
-    mu_stream_destroy (&msg->stream);
-      
-  /*  Mime.  */
-  if (msg->flags & MESSAGE_MIME_OWNER)
-    mu_mime_destroy (&msg->mime);
+  mu_envelope_destroy (&msg->envelope, msg);
+  mu_header_destroy (&msg->header);
+  mu_body_destroy (&msg->body, msg);
+  mu_attribute_destroy (&msg->attribute, msg);
+  mu_stream_destroy (&msg->rawstream);
+  mu_stream_destroy (&msg->outstream);
+  mu_mime_destroy (&msg->mime);
       
   /* Loose the owner.  */
   msg->owner = NULL;

@@ -283,16 +283,41 @@ mu_message_set_stream (mu_message_t msg, mu_stream_t stream, void *owner)
     return EINVAL;
   if (msg->owner != owner)
     return EACCES;
-  if (msg->stream)
-    mu_stream_destroy (&msg->stream);
-  msg->stream = stream;
+  mu_stream_destroy (&msg->rawstream);
+  mu_stream_destroy (&msg->outstream);
+  msg->rawstream = stream;
   msg->flags |= MESSAGE_MODIFIED;
   msg->flags &= ~MESSAGE_INTERNAL_STREAM;
   return 0;
 }
 
 static int
-_message_get_stream (mu_message_t msg, mu_stream_t *pstream, int ref)
+mkoutstream (mu_message_t msg)
+{
+  int status;
+  mu_header_t hdr;
+  mu_body_t body;
+
+  if (msg->outstream)
+    return 0;
+  /* FIXME: Kind of a kludge: make sure the message has header
+     and body initialized. */
+  status = mu_message_get_header (msg, &hdr);
+  if (status)
+    return status;
+  status = mu_message_get_body (msg, &body);
+  if (status)
+    return status;
+	  
+  status = _message_stream_create (&msg->outstream, msg, MU_STREAM_RDWR);
+  if (status == 0)
+    msg->flags |= MESSAGE_INTERNAL_STREAM;
+  return status;
+}
+
+
+int
+mu_message_get_stream (mu_message_t msg, mu_stream_t *pstream)
 {
   int status;
 
@@ -301,54 +326,67 @@ _message_get_stream (mu_message_t msg, mu_stream_t *pstream, int ref)
   if (pstream == NULL)
     return MU_ERR_OUT_PTR_NULL;
 
-  if (msg->stream == NULL)
+  /* FIXME: Deprecation warning */
+
+  if (msg->rawstream == NULL)
     {
       if (msg->_get_stream)
 	{
-	  status = msg->_get_stream (msg, &msg->stream);
+	  status = msg->_get_stream (msg, &msg->rawstream);
 	  if (status)
 	    return status;
 	}
       else
 	{
-	  mu_header_t hdr;
-	  mu_body_t body;
-
-	  /* FIXME: Kind of a kludge: make sure the message has header
-	     and body initialized. */
-	  status = mu_message_get_header (msg, &hdr);
+	  status = mkoutstream (msg);
 	  if (status)
 	    return status;
-	  status = mu_message_get_body (msg, &body);
+	  status = mu_streamref_create (&msg->rawstream, msg->outstream);
+	}
+    }
+  *pstream = msg->rawstream;
+  return 0;
+}
+
+int
+mu_message_get_streamref (mu_message_t msg, mu_stream_t *pstream)
+{
+  int status = 0;
+
+  if (msg == NULL)
+    return EINVAL;
+  if (pstream == NULL)
+    return MU_ERR_OUT_PTR_NULL;
+  
+  if (!msg->rawstream)
+    {
+      if (msg->_get_stream)
+	{
+	  status = msg->_get_stream (msg, &msg->rawstream);
 	  if (status)
 	    return status;
-	  
-	  status = _message_stream_create (&msg->stream, msg, MU_STREAM_RDWR);
+	  status = mu_streamref_create (&msg->outstream, msg->rawstream);
+	}
+      else
+	{
+	  status = mkoutstream (msg);
 	  if (status)
 	    return status;
-	  msg->flags |= MESSAGE_INTERNAL_STREAM;
+	  status = mu_streamref_create (&msg->rawstream, msg->outstream);
 	}
     }
   
-  if (!ref)
+  if (status)
+    return status;
+
+  if (!msg->outstream ||
+      (!(msg->flags & MESSAGE_INTERNAL_STREAM) &&
+       mu_message_is_modified (msg)))
     {
-      *pstream = msg->stream;
-      return 0;
+      mu_stream_destroy (&msg->outstream);
+      status = mkoutstream (msg);
     }
-  return mu_streamref_create (pstream, msg->stream);
-}
-
-int
-mu_message_get_stream (mu_message_t msg, mu_stream_t *pstream)
-{
-  /* FIXME: Deprecation warning */
-  return _message_get_stream (msg, pstream, 0);
-}
-
-int
-mu_message_get_streamref (mu_message_t msg, mu_stream_t *pstream)
-{
-  return _message_get_stream (msg, pstream, 1);
+  return mu_streamref_create (pstream, msg->outstream);
 }
 
 int

@@ -38,7 +38,7 @@ $(srcdir)/package.m4: $(top_srcdir)/configure.ac
 ## Non-installable programs
 ## -------------------------- ##
 
-INCLUDES = @MU_LIB_COMMON_INCLUDES@ 
+AM_CPPFLAGS = @MU_LIB_COMMON_INCLUDES@ 
 noinst_PROGRAMS = \
  addr\
  cidr\
@@ -55,6 +55,7 @@ noinst_PROGRAMS = \
  mimehdr\
  modtofsaf\
  msgset\
+ modmesg\
  prop\
  scantime\
  strftime\
@@ -94,6 +95,10 @@ TESTSUITE_AT = \
  list.at\
  mailcap.at\
  mimehdr.at\
+ modmesg00.at\
+ modmesg01.at\
+ modmesg02.at\
+ modmesg03.at\
  modtofsaf.at\
  msgset.at\
  prop.at\

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2013 Free Software Foundation, Inc.
+
+   GNU Mailutils 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 3, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+#include <mailutils/mailutils.h>
+
+char *text = "From: root\n\
+\n\
+This is a test message.\n\
+oo\n\
+";
+
+int
+main (int argc, char **argv)
+{
+  int i;
+  char *p;
+  mu_message_t msg;
+  mu_stream_t stream = NULL;
+  mu_header_t hdr;
+  mu_body_t body;
+  char *buf = NULL;
+  
+  mu_set_program_name (argv[0]);
+
+  mu_static_memory_stream_create (&stream, text, strlen (text));
+  assert (mu_stream_to_message (stream, &msg) == 0);
+  mu_stream_unref (stream);
+  assert (mu_message_get_header (msg, &hdr) == 0);
+  assert (mu_message_get_body (msg, &body) == 0);
+  assert (mu_body_get_streamref (body, &stream) == 0);
+  assert (mu_stream_seek (stream, 0, MU_SEEK_END, NULL) == 0);
+  
+  for (i = 1; i < argc; i++)
+    {
+      if (strcmp (argv[i], "-h") == 0)
+	{
+	  mu_printf ("usage: %s [-a HDR:VAL] [-t TEXT]\n", mu_program_name);
+	  return 0;
+	}
+      
+      if (strcmp (argv[i], "-a") == 0)
+	{
+	  i++;
+	  assert (argv[i] != NULL);
+	  p = strchr (argv[i], ':');
+	  assert (p != NULL);
+	  *p++ = 0;
+	  while (*p && mu_isspace (*p))
+	    p++;
+	  assert (mu_header_set_value (hdr, argv[i], p, 1) == 0);
+	}
+      else if (strcmp (argv[i], "-l") == 0)
+	{
+	  mu_off_t off;
+	  int whence = MU_SEEK_SET;
+	  
+	  i++;
+	  assert (argv[i] != NULL);
+	  off = strtol (argv[i], &p, 10);
+	  assert (*p == 0);
+	  if (off < 0)
+	    whence = MU_SEEK_END;
+	  assert (mu_stream_seek (stream, off, whence, NULL) == 0);
+	}
+      else if (strcmp (argv[i], "-t") == 0)
+	{
+	  size_t len;
+	  i++;
+	  assert (argv[i] != NULL);
+	  len = strlen (argv[i]);
+	  buf = realloc (buf, len + 1);
+	  mu_wordsplit_c_unquote_copy (buf, argv[i], len);
+	  assert (buf != NULL);
+	  assert (mu_stream_write (stream, buf,
+				   strlen (buf), NULL) == 0);
+	}
+      else
+	mu_error ("ignoring unknown argument %s", argv[i]);
+    }
+  mu_stream_unref (stream);
+
+  assert (mu_message_get_streamref (msg, &stream) == 0);
+  assert (mu_stream_copy (mu_strout, stream, 0, NULL) == 0);
+  mu_stream_unref (stream);
+
+  return 0;
+}
+
+  

+# This file is part of GNU Mailutils. -*- Autotest -*-
+# Copyright (C) 2011-2012 Free Software Foundation, Inc.
+#
+# GNU Mailutils 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 3, or (at
+# your option) any later version.
+#
+# GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([unmodified message])
+AT_KEYWORDS([modmesg00])
+
+AT_CHECK([modmesg],
+[0],
+[From: root
+
+This is a test message.
+oo
+])
+
+AT_CLEANUP
+

+# This file is part of GNU Mailutils. -*- Autotest -*-
+# Copyright (C) 2011-2012 Free Software Foundation, Inc.
+#
+# GNU Mailutils 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 3, or (at
+# your option) any later version.
+#
+# GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([add headers])
+AT_KEYWORDS([modmesg01])
+
+AT_CHECK([modmesg -a To:gray@localhost -a Subject:test],
+[0],
+[Subject: test
+To: gray@localhost
+From: root
+
+This is a test message.
+oo
+])
+
+AT_CLEANUP
+

+# This file is part of GNU Mailutils. -*- Autotest -*-
+# Copyright (C) 2011-2012 Free Software Foundation, Inc.
+#
+# GNU Mailutils 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 3, or (at
+# your option) any later version.
+#
+# GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([modify body])
+AT_KEYWORDS([modmesg02])
+
+AT_CHECK([modmesg -t "word\n"],
+[0],
+[From: root
+
+This is a test message.
+oo
+word
+])
+
+AT_CHECK([modmesg -l 0 -t "That"],
+[0],
+[From: root
+
+That is a test message.
+oo
+])
+
+AT_CLEANUP
+

+# This file is part of GNU Mailutils. -*- Autotest -*-
+# Copyright (C) 2011-2012 Free Software Foundation, Inc.
+#
+# GNU Mailutils 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 3, or (at
+# your option) any later version.
+#
+# GNU Mailutils 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 GNU Mailutils.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_SETUP([modify headers and body])
+AT_KEYWORDS([modmesg02])
+
+AT_CHECK([modmesg -a To:gray@localhost -a Subject:test -l 0 -t "That"],
+[0],
+[Subject: test
+To: gray@localhost
+From: root
+
+That is a test message.
+oo
+])
+
+AT_CLEANUP
+

@@ -92,6 +92,12 @@ m4_include([debugspec.at])
 AT_BANNER([IMAP IO])
 m4_include([imapio.at])
 
+AT_BANNER(Message modification)
+m4_include([modmesg00.at])
+m4_include([modmesg01.at])
+m4_include([modmesg02.at])
+m4_include([modmesg03.at])
+
 m4_include([scantime.at])
 m4_include([strftime.at])
 

@@ -2159,7 +2159,6 @@ finish_msg (struct compose_env *env, mu_message_t *msg)
       free (p);
     }
   mu_mime_add_part (env->mime, *msg);
-  mu_message_unref (*msg);
   *msg = NULL;
 }
 
@@ -2598,6 +2597,7 @@ mhn_edit (struct compose_env *env, int level)
 
 	  mu_message_get_body (msg, &body);
 	  mu_body_get_streamref (body, &output);
+	  mu_message_ref (msg);
 	  line_count = 0;
 	  ascii_buf = 1; /* Suppose it is ascii */
 	  env->subpart++;
@@ -2640,6 +2640,7 @@ mhn_edit (struct compose_env *env, int level)
 		  /* Close and append the previous part */
 		  mu_stream_close (output);
 		  mu_stream_destroy (&output);
+		  mu_message_unref (msg);
 		  finish_text_msg (env, &msg, ascii_buf);
 		}