/* GNU mailutils - a suite of utilities for electronic mail
   Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Library Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program 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 Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* First draft by Alain Magloire */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <time.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <time.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>
#include <errno.h>
#ifdef HAVE_PTHREAD_H
#  define _XOPEN_SOURCE  500
#  include <pthread.h>
#endif

#include <mailutils/message.h>
#include <mailutils/stream.h>
#include <mailutils/body.h>
#include <mailutils/header.h>
#include <mailutils/attribute.h>
#include <registrar0.h>
#include <mailbox0.h>


#define ATTRIBUTE_IS_DELETED(flag)        (flag & MU_ATTRIBUTE_DELETED)
#define ATTRIBUTE_IS_EQUAL(flag1, flag2)  (flag1 == flag2)

static void mbox_destroy (mailbox_t);

struct _mbox_message;
struct _mbox_data;

typedef struct _mbox_data* mbox_data_t;
typedef struct _mbox_message* mbox_message_t;

#define HDRSIZE      8
const char *fhdr_table[] =
{
#define HFROM         0
  "From",
#define HTO           1
  "To",
#define HCC           2
  "Cc",
#define HSUBJECT      3
  "Subject",
#define HDATE         4
  "Date",
#define HX_UIDL       5
  "X-UIDL",
#define HX_UID        6
  "X-UID",
#define HCONTENT_TYPE 7
  "Content-Type",
};
/* Keep the position of where the header and body starts and ends.
   old_flags is the "Status:" message.  */
struct _mbox_message
{
  /* Offset of the parts of the messages in the mailbox.  */
  off_t header_from;
  off_t header_from_end;
  /* Little hack to make things easier when updating the attribute.  */
  off_t header_status;
  off_t header_status_end;
  off_t body;
  off_t body_end;

  /* Fast header retrieve, we save here the most common header. Reasons this
     will speed the header search.  The header are copied on write or if we
     the fast status failed.  */
  char *fhdr[HDRSIZE];

  /* The old_flags contains the definition of Header.  */
  int old_flags;
  /* The new_flags holds the attributes changes for the current session. We
     use this so when expunging we can tell when an attribute been modified.
     This is a big help so we can jump to the first modify email for speed
     in expunging (see mark dirty).  */
  int new_flags;

  size_t header_lines;
  size_t body_lines;
  stream_t stream;

  /* A message attach to it.  */
  message_t message;
  mbox_data_t mud; /* Back pointer.  */
};

/* The umessages is an array of pointers that contains umessages_count of
   mbox_message_t*; umessages[umessages_count].  We do it this way because
   realloc() can move everything to a new memory region and invalidate all
   the pointers.  Thanks to <Dave Inglis> for pointing this out.  The
   messages_count is the count number of messages parsed so far.  */
struct _mbox_data
{
  mbox_message_t *umessages; /* Array.  */
  size_t umessages_count; /* How big is the umessages[].  */
  size_t messages_count; /* How many valid entry in umessages[].  */
  stream_t stream;
  off_t size;
  char *name;

  /* The variables below are use to hold the state when appending messages.  */
  enum mbox_state
  {
    MBOX_NO_STATE = 0,
    MBOX_STATE_APPEND_SENDER, MBOX_STATE_APPEND_DATE, MBOX_STATE_APPEND_HEADER,
    MBOX_STATE_APPEND_ATTRIBUTE, MBOX_STATE_APPEND_BODY,
    MBOX_STATE_APPEND_MESSAGE
  } state ;
  char *sender;
  char *date;
  off_t off;
  mailbox_t mailbox; /* Back pointer. */
};

/* Mailbox concrete implementation.  */
static int mbox_open                  __P ((mailbox_t, int));
static int mbox_close                 __P ((mailbox_t));
static int mbox_get_message           __P ((mailbox_t, size_t, message_t *));
static int mbox_append_message        __P ((mailbox_t, message_t));
static int mbox_messages_count        __P ((mailbox_t, size_t *));
static int mbox_unseen_count          __P ((mailbox_t, size_t *));
static int mbox_expunge               __P ((mailbox_t));
static int mbox_scan                  __P ((mailbox_t, size_t, size_t *));
static int mbox_is_updated            __P ((mailbox_t));
static int mbox_size                  __P ((mailbox_t, off_t *));

/* private stuff */
static int mbox_scan0                 __P ((mailbox_t, size_t, size_t *, int));
static int mbox_append_message0       __P ((mailbox_t, message_t, off_t *,
					    int));
static int mbox_header_fill           __P ((header_t, char *, size_t, off_t,
					    size_t *));
static int mbox_get_header_readstream __P ((message_t, char *, size_t, off_t,
					    size_t *, int));
static int mbox_get_body_fd           __P ((stream_t, int *));
static int mbox_get_fd                __P ((mbox_message_t, int *));
static int mbox_get_attr_flags        __P ((attribute_t, int *));
static int mbox_set_attr_flags        __P ((attribute_t, int));
static int mbox_unset_attr_flags      __P ((attribute_t, int));
static int mbox_body_read             __P ((stream_t, char *, size_t, off_t,
					    size_t *));
static int mbox_body_readline         __P ((stream_t, char *, size_t, off_t,
					    size_t *));
static int mbox_body_readstream       __P ((stream_t, char *, size_t, off_t,
					    size_t *, int));
static int mbox_header_size           __P ((header_t, size_t *));
static int mbox_header_lines          __P ((header_t, size_t *));
static int mbox_body_size             __P ((body_t, size_t *));
static int mbox_body_lines            __P ((body_t, size_t *));
static int mbox_envelope_sender       __P ((envelope_t, char *, size_t,
					    size_t *));
static int mbox_envelope_date         __P ((envelope_t, char *, size_t,
					    size_t *));
static int mbox_tmpfile               __P ((mailbox_t, char **pbox));
#ifdef WITH_PTHREAD
static void mbox_cleanup              __P ((void *));
#endif

/* We allocate the mbox_data_t struct, but don't do any parsing on the name or
   even test for existence.  However we do strip any leading "mbox:" part of
   the name, this is suppose to be the protocol/scheme name.  */
int
_mailbox_mbox_init (mailbox_t mailbox)
{
  mbox_data_t mud;
  size_t name_len;

  if (mailbox == NULL)
    return EINVAL;

  /* Allocate specific mbox data.  */
  mud = mailbox->data = calloc (1, sizeof (*mud));
  if (mailbox->data == NULL)
    return ENOMEM;

  /* Back pointer.  */
  mud->mailbox = mailbox;

  /* Copy the name.
     We do not do any further interpretation after the scheme "mbox:"
     Because for example on distributed system like QnX4 a file name is
     //390/etc/passwd.  So the best approach is to let the OS handle it
     for example if we receive: "mbox:///var/mail/alain" the mailbox name
     will be "///var/mail/alain", we let open() do the right thing.
     So it will let things like this "mbox://390/var/mail/alain" where
     "//390/var/mail/alain" _is_ the filename, pass correctely.  */
  url_get_path (mailbox->url, NULL, 0, &name_len);
  mud->name = calloc (name_len + 1, sizeof (char));
  if (mud->name == NULL)
    {
      free (mud);
      mailbox->data = NULL;
      return ENOMEM;
    }
  url_get_path (mailbox->url, mud->name, name_len + 1, NULL);

  mud->state = MBOX_NO_STATE;

  /* Overloading the default.  */
  mailbox->_destroy = mbox_destroy;

  mailbox->_open = mbox_open;
  mailbox->_close = mbox_close;

  /* Messages.  */
  mailbox->_get_message = mbox_get_message;
  mailbox->_append_message = mbox_append_message;
  mailbox->_messages_count = mbox_messages_count;
  mailbox->_unseen_count = mbox_unseen_count;
  mailbox->_expunge = mbox_expunge;

  mailbox->_scan = mbox_scan;
  mailbox->_is_updated = mbox_is_updated;

  mailbox->_size = mbox_size;

  MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE, "mbox_init(%s)\n", mud->name);
  return 0; /* okdoke */
}

/* Free all ressources associated with Unix mailbox.  */
static void
mbox_destroy (mailbox_t mailbox)
{
  if (mailbox->data)
    {
      size_t i;
      mbox_data_t mud = mailbox->data;
      MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE,
		      "mbox_destroy (%s)\n", mud->name);
      monitor_wrlock (mailbox->monitor);
      for (i = 0; i < mud->umessages_count; i++)
	{
	  mbox_message_t mum = mud->umessages[i];
	  if (mum)
	    {
	      size_t j;
	      message_destroy (&(mum->message), mum);
	      for (j = 0; j < HDRSIZE; j++)
		if (mum->fhdr[j])
		  free (mum->fhdr[j]);
	      free (mum);
	    }
	}
      if (mud->umessages)
	free (mud->umessages);
      if (mud->name)
	free (mud->name);
      free (mud);
      mailbox->data = NULL;
      monitor_unlock (mailbox->monitor);
    }
}

/* Open the file.  */
static int
mbox_open (mailbox_t mailbox, int flags)
{
  mbox_data_t mud = mailbox->data;
  int status = 0;

  if (mud == NULL)
    return EINVAL;

  mailbox->flags = flags | MU_STREAM_FILE;

  /* Get a stream.  */
  if (mailbox->stream == NULL)
    {
      /* FIXME: for small mbox we should try to mmap ().  */

      /* We do not try to mmap for CREAT or APPEND, it is not supported.  */
      status = (flags & MU_STREAM_CREAT)
	|| (mailbox->flags & MU_STREAM_APPEND);

      /* Try to mmap() the file first.  */
      if (status == 0)
	{
	  status = mapfile_stream_create (&(mailbox->stream));
	  if (status == 0)
	    {
	      status = stream_open (mailbox->stream, mud->name, 0,
				    mailbox->flags);
	      if (status != 0)
		stream_destroy (&mailbox->stream, NULL);
	    }
	}

      /* Fall back to normal file if mmap() failed.  */
      if (status != 0)
	{
	  status = file_stream_create (&(mailbox->stream));
	  if (status != 0)
	    return status;
	  status = stream_open (mailbox->stream, mud->name, 0, mailbox->flags);
	}
      /* All failed, bail out.  */
      if (status != 0)
	return status;
      stream_setbufsiz (mailbox->stream, BUFSIZ);
    }
  else
    {
      status = stream_open (mailbox->stream, mud->name, 0, mailbox->flags);
      if (status != 0)
	return status;
    }

  MAILBOX_DEBUG2 (mailbox, MU_DEBUG_TRACE, "mbox_open(%s, 0x%x)\n",
		  mud->name, mailbox->flags);

  if (mailbox->authority)
    {
      status = authority_authenticate (mailbox->authority);
      if (status != 0)
	return status;
    }

  /* Give an appropriate way to file lock.  */
  if (mailbox->locker == NULL)
    locker_create (&(mailbox->locker), mud->name, strlen (mud->name),
		   MU_LOCKER_PID | MU_LOCKER_FCNTL);
  return 0;
}

static int
mbox_close (mailbox_t mailbox)
{
  mbox_data_t mud = mailbox->data;
  size_t i;

  if (mud == NULL)
    return EINVAL;

  MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE,  "mbox_close(%s)\n", mud->name);

  /* Make sure that we do hold any file locking.  */
  locker_unlock (mailbox->locker);

  monitor_wrlock (mailbox->monitor);
  /* Before closing we need to remove all the messages
     - to reclaim the memory
     - to prepare for another scan.  */
  for (i = 0; i < mud->umessages_count; i++)
    {
      mbox_message_t mum = mud->umessages[i];
      /* Destroy the attach messages.  */
      if (mum)
	{
	  size_t j;
	  message_destroy (&(mum->message), mum);
	  for (j = 0; j < HDRSIZE; j++)
	    if (mum->fhdr[j])
	      free (mum->fhdr[j]);
	  free (mum);
	}
    }
  if (mud->umessages)
    free (mud->umessages);
  mud->umessages = NULL;
  mud->messages_count = mud->umessages_count = 0;
  mud->size = 0;
  monitor_unlock (mailbox->monitor);
  return stream_close (mailbox->stream);
}

/* Mailbox Parsing.  */
#include "mbx_mboxscan.c"

static int
mbox_scan (mailbox_t mailbox, size_t msgno, size_t *pcount)
{
  mbox_data_t mud = mailbox->data;
  MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE, "mbox_scan(%s)\n", mud->name);
  return mbox_scan0 (mailbox, msgno, pcount, 1);
}


/* FIXME:  How to handle a shrink ? meaning, the &^$^@%#@^& user start two
   browsers and deleted emails in one.  My views is that we should scream
   bloody murder and hunt them with a machette. But for now just play dumb,
   but maybe the best approach is to pack our things and leave .i.e exit().  */
static int
mbox_is_updated (mailbox_t mailbox)
{
  off_t size = 0;
  mbox_data_t mud = mailbox->data;
  if (stream_size (mailbox->stream, &size) != 0)
    return 0;
  if (size < mud->size)
    {
      observable_notify (mailbox->observable, MU_EVT_MAILBOX_CORRUPT);
      /* And be verbose.  */
      fprintf (stderr, "Mailbox corrupted, shrink size\n");
    }
  return (mud->size == size);
}

/* Try to create an uniq file.  */
static int
mbox_tmpfile (mailbox_t mailbox, char **pbox)
{
  const char *tmpdir;
  int fd;
  const char *basename;
  mbox_data_t mud = mailbox->data;

  /*  P_tmpdir should be define in <stdio.h>.  */
#ifndef P_tmpdir
#  define P_tmpdir "/tmp"
#endif

  /* FIXME: Use a macro for the separator to be portable.  */
  basename = strrchr (mud->name, '/');
  if (basename)
    basename++;
  else
    basename = mud->name;

  tmpdir =  getenv ("TMPDIR") ? getenv ("TMPDIR") : P_tmpdir;
  /* (separator + null) == 2 + XXXXXX == 6 + ... */
  *pbox = calloc (strlen (tmpdir) + /* '/' */ 1 + /*strlen ("MU_")*/ 3 +
		  strlen (basename) + /*strlen ("_XXXXXX")*/ 7 + /*null*/1,
		  sizeof (**pbox));
  if (*pbox == NULL)
    return -1;
  sprintf (*pbox, "%s/MU_%s_XXXXXX", tmpdir, basename);
#ifdef HAVE_MKSTEMP
  fd = mkstemp (*pbox);
#else
  /* Create the file.  It must not exist.  If it does exist, fail.  */
  if (mktemp (*pbox))
    {
      fd = open (*pbox, O_RDWR|O_CREAT|O_EXCL, 0600);
    }
  else
    {
      free (*pbox);
      fd = -1;
    }
#endif
  return fd;
}

/* For the expunge bits  we took a very cautionnary approach, meaning
   we create a temporary mailbox in the tmpdir copy all the message not mark
   deleted(Actually we copy all the message that may have been modified, we
   do not have(yet) an api call to tell whether a message was modified)
   and skip the deleted ones, truncate the real mailbox to the desired size
   and overwrite with the tmp mailbox.  The approach to do everyting
   in core is tempting but require
   - to much memory, it is not rare now a day to have 30 Megs mailbox,
   - also there is danger for filesystems with quotas,
   - if we run out of disk space everything is lost.
   - or some program may not respect the advisory lock and decide to append
   a new message while your expunging etc ...
   The real downside to the approach we take is that when things go wrong
   the temporary file may be left in /tmp, which is not all that bad
   because at least, we have something to recuparate when failure.  */
static int
mbox_expunge (mailbox_t mailbox)
{
  mbox_data_t mud = mailbox->data;
  mbox_message_t mum;
  int status = 0;
  sigset_t signalset;
  int tempfile;
  size_t i, j, dirty;
  off_t marker = 0;
  off_t total = 0;
  char *tmpmboxname = NULL;
  mailbox_t tmpmailbox = NULL;
#ifdef WITH_PTHREAD
  int state;
#endif

  if (mud == NULL)
    return EINVAL;

  MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE, "mbox_expunge (%s)\n", mud->name);

  /* Noop.  */
  if (mud->messages_count == 0)
    return 0;

  /* Mark dirty the first mum(concrete message) with a message pointer.  */
  /* FIXME: This is not right, the way to really know if a message is modified
     is by changing the API, we should have an message_is_modified ().  */
  for (dirty = 0; dirty < mud->messages_count; dirty++)
    {
      mum = mud->umessages[dirty];
#if 0
      /* No, cheking if the attribute was changed is not enough, for example
	 They may have modified a header, say adding the X-UIDL field.  Those
	 changes are not save yet but still in memory part of the header blurb.
	 So unless we have a message_is_modified() call we should assume that
	 the message was modified.  */
      if (mum->new_flags &&
	  ! ATTRIBUTE_IS_EQUAL (mum->old_flags, mum->new_flags))
	break;
#else
      /* Message may have been tampered, break here.  */
      if (mum->message && message_is_modified (mum->message))
	break;
#endif
    }

  /* Did something change ?  */
  if (dirty == mud->messages_count)
    return 0; /* Nothing change, bail out.  */

  /* This is redundant, we go to the loop again.  But it's more secure here
     since we don't want to be disturb when expunging.  Destroy all the
     messages mark for deletion.  */
  for (j = 0; j < mud->messages_count; j++)
    {
      mum = mud->umessages[j];
      if (mum && mum->message &&  mum->new_flags &&
	  ATTRIBUTE_IS_DELETED (mum->new_flags))
	message_destroy (&(mum->message), mum);
    }

  /* Create a temporary file.  */
  tempfile = mbox_tmpfile (mailbox, &tmpmboxname);
  if (tempfile == -1)
    {
      free (tmpmboxname);
      fprintf (stderr, "Failed to create temporary file when expunging.\n");
      return errno;
    }
  else
    {
      char *m = alloca (5 + strlen (tmpmboxname) + 1);
      /* Try via the mbox: protocol.  */
      sprintf (m, "mbox:%s", tmpmboxname);
      status = mailbox_create (&tmpmailbox, m);
      if (status != 0)
	{
	  /* Do not give up just yet, maybe they register the path_record.  */
	  sprintf (m, "%s", tmpmboxname);
	  status = mailbox_create (&tmpmailbox, m);
	  if (status != 0)
	    {
	      /* Ok give up.  */
	      close (tempfile);
	      remove (tmpmboxname);
	      free (tmpmboxname);
	      return status;
	    }
	}

      /* Must be flag create if not the open will try to mmap() the file.  */
      status = mailbox_open (tmpmailbox, MU_STREAM_CREAT | MU_STREAM_RDWR);
      if (status != 0)
	{
	  close (tempfile);
	  remove (tmpmboxname);
	  free (tmpmboxname);
	  return status;
	}
      close (tempfile); /* This one is useless the mailbox have its own.  */
    }

  /* Get the File lock.  */
  if (locker_lock (mailbox->locker, MU_LOCKER_WRLOCK) < 0)
    {
      mailbox_close (tmpmailbox);
      mailbox_destroy (&tmpmailbox);
      remove (tmpmboxname);
      free (tmpmboxname);
      fprintf (stderr, "Failed to grab the lock\n");
      return ENOLCK;
    }

  /* Critical section, we can not allowed signal here.  */
#ifdef WITH_PTHREAD
  pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
#endif
  sigemptyset (&signalset);
  sigaddset (&signalset, SIGTERM);
  sigaddset (&signalset, SIGHUP);
  sigaddset (&signalset, SIGTSTP);
  sigaddset (&signalset, SIGINT);
  sigaddset (&signalset, SIGWINCH);
  sigprocmask (SIG_BLOCK, &signalset, 0);

  /* Set the marker position.  */
  marker = mud->umessages[dirty]->header_from;
  total = 0;

  /* Copy to tempfile emails not mark deleted.  */
  for (i = dirty; i < mud->messages_count; i++)
    {
      mum = mud->umessages[i];

      /* Skip it, if mark for deletion.  */
      if (ATTRIBUTE_IS_DELETED (mum->new_flags))
	continue;

      if (mum->message)
	{
	  status = mbox_append_message0 (tmpmailbox, mum->message, &total, 1);
	  if (status != 0)
	    {
	      fprintf (stderr, "Error expunge:%d: %s", __LINE__,
		       strerror (status));
	      goto bailout0;
	    }
	}
      else
	{
	  /* Nothing changed copy the message straight.  */
	  char buffer [1024];
	  size_t n;
	  off_t offset = mum->header_from;
	  size_t len = mum->body_end - mum->header_from;
	  while (len > 0)
	    {
	      n = (len < sizeof (buffer)) ? len : sizeof (buffer);
	      if ((status = stream_read (mailbox->stream, buffer, n, offset,
					 &n) != 0)
		  || (status = stream_write (tmpmailbox->stream, buffer, n,
					     total, &n) != 0))
		{
		  fprintf (stderr, "Error expunge:%d: %s", __LINE__,
			   strerror (status));
		  goto bailout0;
		}
	      len -= n;
	      total += n;
	      offset += n;
	    }
	  /* Add the newline separator.  */
	  status = stream_write (tmpmailbox->stream, "\n", 1, total, &n);
	  if (status != 0)
	    {
	      fprintf (stderr, "Error expunge:%d: %s", __LINE__,
		       strerror (status));
	      goto bailout0;
	    }
	  total++;
	}
    } /* for (;;) */

  /* Caution: before ftruncate()ing the file see
     - if we've receive new mails.
     Some programs may not respect the lock, or the lock was held for too
     long.
     - The mailbox may not have been properly updated before expunging.  */
  {
    off_t size = 0;
    if (stream_size (mailbox->stream, &size) == 0)
      {
	off_t len = size - mud->size;
	off_t offset = mud->size;
	char buffer [1024];
	size_t n = 0;
	if (len > 0 )
	  {
	    while ((status = stream_read (mailbox->stream, buffer,
					  sizeof (buffer), offset, &n)) == 0
		   && n > 0)
	      {
		status = stream_write (tmpmailbox->stream, buffer, n,
				       total, &n);
		if (status != 0)
		  {
		    fprintf (stderr, "Error expunge:%d: %s", __LINE__,
			     strerror (status));
		    goto bailout0;
		  }
		total += n;
		offset += n;
	      }
	  }
	else if (len < 0)
	  {
	    /* Corrupted mailbox.  */
	    fprintf (stderr, "Error expunge:%d: %s", __LINE__,
		     strerror (status));
	    goto bailout0;
	  }
      }
  } /* End of precaution.  */

  /* Seek and rewrite it.  */
  if (total > 0)
    {
      char buffer [1024];
      size_t n = 0;
      off_t off = 0;
      off_t offset = marker;
      while ((status = stream_read (tmpmailbox->stream, buffer,
				    sizeof (buffer), off, &n)) == 0
	     && n > 0)
	{
	  status = stream_write (mailbox->stream, buffer, n, offset, &n);
	  if (status != 0)
	    {
	      fprintf (stderr, "Error expunge:%d: %s\n", __LINE__,
		       strerror (status));
	      goto bailout;
	    }
	  off += n;
	  offset += n;
	}
    }

  /* Flush/truncation. Need to flush before truncate.  */
  stream_flush (mailbox->stream);
  status = stream_truncate (mailbox->stream, total + marker);
  if (status != 0)
    {
      fprintf (stderr, "Error expunging:%d: %s\n", __LINE__, strerror (status));
      goto bailout;
    }

  /* Don't remove the tmp mbox in case of errors, when writing back.  */
 bailout0:
  remove (tmpmboxname);

 bailout:

  free (tmpmboxname);
  /* Release the File lock.  */
  locker_unlock (mailbox->locker);
  mailbox_close (tmpmailbox);
  mailbox_destroy (&tmpmailbox);
#ifdef WITH_PTHREAD
  pthread_setcancelstate (state, &state);
#endif
  sigprocmask (SIG_UNBLOCK, &signalset, 0);

  /* We need to readjust the pointers.  */
  if (status == 0)
    {
      size_t dlast;
      monitor_wrlock (mailbox->monitor);
      for (j = dirty, dlast = mud->messages_count - 1;
	   j <= dlast; j++)
	{
	  /* Clear all the references, any attach messages been already
	     destroy above.  */
	  mum = mud->umessages[j];
	  if (mum->new_flags && ATTRIBUTE_IS_DELETED (mum->new_flags))
	    {
	      if ((j + 1) <= dlast)
		{
		  /* Move all the pointers up.  So the message pointer
		     part of mum will be at the right position.  */
		  memmove (mud->umessages + j, mud->umessages + j + 1,
			   (dlast - j) * sizeof (mum));
		  //mum->header_from = mum->header_from_end = 0;
		  //mum->header_status = mum->header_status_end = 0;
		  //mum->body = mum->body_end = 0;
		  //mum->header_lines = mum->body_lines = 0;
		  for (i = 0; i < HDRSIZE; i++)
		    if (mum->fhdr[i])
		      {
			free (mum->fhdr[i]);
		      }
		  memset (mum, 0, sizeof (*mum));
		  /* We are not free()ing the useless mum, but instead
		     we put it back in the pool, to be reuse.  */
		  mud->umessages[dlast] = mum;
		  dlast--;
		  /* Set mum to the new value after the memmove so it
		     gets cleared to.  */
		  mum = mud->umessages[j];
		}
	      else
		{
		  memset (mum, 0, sizeof (*mum));
		}
	    }
	  mum->header_from = mum->header_from_end = 0;
	  mum->header_status = mum->header_status_end = 0;
	  mum->body = mum->body_end = 0;
	  mum->header_lines = mum->body_lines = 0;
	}
      monitor_unlock (mailbox->monitor);
      /* This is should reset the messages_count, the last argument 0 means
	 not to send event notification.  */
      mbox_scan0 (mailbox, dirty, NULL, 0);
    }
  return status;
}

static int
mbox_get_body_fd (stream_t is, int *pfd)
{
  body_t body = stream_get_owner (is);
  message_t msg = body_get_owner (body);
  mbox_message_t mum = message_get_owner (msg);
  return mbox_get_fd (mum, pfd);
}

static int
mbox_get_fd (mbox_message_t mum, int *pfd)
{
  int status;
  if (mum == NULL)
    return EINVAL;
  status = stream_get_fd (mum->stream, pfd);
  return status;
}

static int
mbox_get_attr_flags (attribute_t attr, int *pflags)
{
  message_t msg = attribute_get_owner (attr);
  mbox_message_t mum = message_get_owner (msg);

  if (mum == NULL)
    return EINVAL;
  if (pflags)
    *pflags = mum->new_flags;
  return 0;
}

static int
mbox_set_attr_flags (attribute_t attr, int flags)
{
  message_t msg = attribute_get_owner (attr);
  mbox_message_t mum = message_get_owner (msg);

  if (mum == NULL)
    return EINVAL;
  mum->new_flags |= flags;
  return 0;
}

static int
mbox_unset_attr_flags (attribute_t attr, int flags)
{
  message_t msg = attribute_get_owner (attr);
  mbox_message_t mum = message_get_owner (msg);

  if (mum == NULL)
    return EINVAL;
  mum->new_flags &= ~flags;
  return 0;
}

static int
mbox_body_readline (stream_t is, char *buffer, size_t buflen,
		    off_t off, size_t *pnread)
{
  return mbox_body_readstream (is, buffer, buflen, off, pnread, 1);
}

static int
mbox_body_read (stream_t is, char *buffer, size_t buflen,
		off_t off, size_t *pnread)
{
  return mbox_body_readstream (is, buffer, buflen, off, pnread, 0);
}

static int
mbox_body_readstream (stream_t is, char *buffer, size_t buflen,
		off_t off, size_t *pnread, int isreadline)
{
  body_t body = stream_get_owner (is);
  message_t msg = body_get_owner (body);
  mbox_message_t mum = message_get_owner (msg);
  size_t nread = 0;
  int status = 0;

  if (mum == NULL)
    return EINVAL;

  if (buffer == NULL || buflen == 0)
    {
      if (pnread)
	*pnread = nread;
      return 0;
    }

  monitor_rdlock (mum->mud->mailbox->monitor);
#ifdef WITH_PTHREAD
  /* read() is cancellation point since we're doing a potentially
     long operation.  Lets make sure we clean the state.  */
  pthread_cleanup_push (mbox_cleanup, (void *)mum->mud->mailbox);
#endif
  {
    off_t ln = mum->body_end - (mum->body + off);
    if (ln > 0)
      {
	/* Position the file pointer and the buffer.  */
	if (isreadline)
	  {
	    status = stream_readline (mum->stream, buffer, buflen,
				      mum->body + off, &nread);
	    /* This mean we went pass the message boundary, thechnically it
	       should not be sine we are reading by line, but just in case
	       truncate the string.  */
	    if (nread > (size_t)ln)
	      {
		buffer[ln] = '\0';
		nread = ln;
	      }
	  }
	else
	  {
	    nread = ((size_t)ln < buflen) ? ln : buflen;
	    status = stream_read (mum->stream, buffer, nread,
				  mum->body + off, &nread);
	  }
      }
  }
  monitor_unlock (mum->mud->mailbox->monitor);
#ifdef WITH_PTHREAD
  pthread_cleanup_pop (0);
#endif

  if (pnread)
    *pnread = nread;
  return status;
}

static int
mbox_header_fill (header_t header, char *buffer, size_t len,
		  off_t off, size_t *pnread)
{
  message_t msg = header_get_owner (header);
  return mbox_get_header_readstream (msg, buffer, len, off, pnread, 0);
}

static int
mbox_header_get_fvalue (header_t header, const char *name, char *buffer,
		       size_t buflen, size_t *pnread)
{
  size_t i, fv_value = 0;
  message_t msg = header_get_owner (header);
  mbox_message_t mum = message_get_owner (msg);
  int err = ENOENT;
  for (i = 0; i < HDRSIZE; i++)
    if (*name == *(fhdr_table[i]) && strcasecmp (fhdr_table[i], name) == 0)
      {
	fv_value = (mum->fhdr[i]) ? strlen (mum->fhdr[i]) : 0;
	if (buffer && buflen > 0)
	  {
	    buflen--;
	    fv_value = (fv_value < buflen) ? fv_value : buflen;
	    memcpy (buffer, mum->fhdr[i], fv_value);
	    buffer[fv_value] = '\0';
	  }
	err = 0;
	break;
      }

  if (pnread)
    *pnread = fv_value;
  return err;
}

static int
mbox_get_header_readstream (message_t msg, char *buffer, size_t len,
			    off_t off, size_t *pnread, int isreadline)
{
  mbox_message_t mum = message_get_owner (msg);
  size_t nread = 0;
  int status = 0;
  off_t ln;

  if (mum == NULL)
    return EINVAL;

  monitor_rdlock (mum->mud->mailbox->monitor);
#ifdef WITH_PTHREAD
  /* read() is cancellation point since we're doing a potentially
     long operation.  Lets make sure we clean the state.  */
  pthread_cleanup_push (mbox_cleanup, (void *)mum->mud->mailbox);
#endif
  ln = mum->body - (mum->header_from_end + off);
  if (ln > 0)
    {
      nread = ((size_t)ln < len) ? ln : len;
      /* Position the file pointer and the buffer.  */
      status = (isreadline) ?
	stream_readline (mum->stream, buffer, nread,
			 mum->header_from_end + off, &nread) :
	stream_read (mum->stream, buffer, nread,
		     mum->header_from_end + off, &nread);
    }
  monitor_unlock (mum->mud->mailbox->monitor);
#ifdef WITH_PTHREAD
  pthread_cleanup_pop (0);
#endif
  if (pnread)
    *pnread = nread;
  return status;
}

static int
mbox_header_size (header_t header, size_t *psize)
{
  message_t msg = header_get_owner (header);
  mbox_message_t mum = message_get_owner (msg);
  if (mum == NULL)
    return EINVAL;
  if (psize)
    *psize = mum->body - mum->header_from_end;
  return 0;
}

static int
mbox_header_lines (header_t header, size_t *plines)
{
  message_t msg = header_get_owner (header);
  mbox_message_t mum = message_get_owner (msg);
  if (mum == NULL)
    return EINVAL;
  if (plines)
    *plines = mum->header_lines;
  return 0;
}

static int
mbox_body_size (body_t body, size_t *psize)
{
  message_t msg = body_get_owner (body);
  mbox_message_t mum = message_get_owner (msg);
  if (mum == NULL)
    return EINVAL;
  if (psize)
    *psize = mum->body_end - mum->body + 1;
  return 0;
}

static int
mbox_body_lines (body_t body, size_t *plines)
{
  message_t msg = body_get_owner (body);
  mbox_message_t mum = message_get_owner (msg);
  if (mum == NULL)
    return EINVAL;
  if (plines)
    *plines = mum->body_lines;
  return 0;
}

static int
mbox_envelope_date (envelope_t envelope, char *buf, size_t len,
		    size_t *pnwrite)
{
  message_t msg = envelope_get_owner (envelope);
  mbox_message_t mum = message_get_owner (msg);
  size_t n = 0;
  int status;
  char buffer[512];
  char *s;

  if (mum == NULL)
    return EINVAL;

  status = stream_readline (mum->stream, buffer, sizeof(buffer),
			    mum->header_from, &n);
  if (status != 0)
    {
      if (pnwrite)
	*pnwrite = 0;
      return status;
    }

  /* Format:  "From [sender] [date]" */
  /* strlen ("From ") == 5 */
  if (n > 5 && (s = strchr (buffer + 5, ' ')) != NULL)
    {
      if (buf && len > 0)
	{
	  len--; /* Leave space for the null.  */
	  strncpy (buf, s + 1, len)[len] = '\0';
	  len = strlen (buf);
	}
      else
	len = strlen (s + 1);
    }
  else
    len = 0;

  if (pnwrite)
    *pnwrite = len;
  return 0;
}

static int
mbox_envelope_sender (envelope_t envelope, char *buf, size_t len,
		    size_t *pnwrite)
{
  message_t msg = envelope_get_owner (envelope);
  mbox_message_t mum = message_get_owner (msg);
  size_t n = 0;
  int status;
  char buffer[512];
  char *s;

  if (mum == NULL)
    return EINVAL;

  status = stream_readline (mum->stream, buffer, sizeof(buffer),
			    mum->header_from, &n);
  if (status != 0)
    {
      if (pnwrite)
	*pnwrite = 0;
      return status;
    }

  /* Format:  "From [sender] [date]" */
  /* strlen ("From ") == 5 */
  if (n > 5 && (s = strchr (buffer + 5, ' ')) != NULL)
    {
      /* Put a NULL to isolate the sender string, make a C string.  */
      *s = '\0';
      if (buf && len > 0)
	{
	  len--; /* leave space for the null */
	  strncpy (buf, buffer + 5, len)[len] = '\0';
	  len = strlen (buf);
	}
      else
	len = strlen (buffer + 5);
    }
  else
    len = 0;

  if (pnwrite)
    *pnwrite = len;
  return 0;
}

static int
mbox_get_message (mailbox_t mailbox, size_t msgno, message_t *pmsg)
{
  int status;
  mbox_data_t mud = mailbox->data;
  mbox_message_t mum;
  message_t msg = NULL;

  /* Sanity checks.  */
  if (pmsg == NULL || mud == NULL)
    return EINVAL;

  /* We did not start a scanning yet do it now.  */
  if (mud->messages_count == 0)
    {
      status = mbox_scan0 (mailbox, 1, NULL, 0);
      if (status != 0)
	return status;
    }

  /* Second sanity: check the message number.  */
  if (!(mud->messages_count > 0
	&& msgno > 0
	&& msgno <= mud->messages_count))
    return EINVAL;

  mum = mud->umessages[msgno - 1];

  /* Check if we already have it.  */
  if (mum->message)
    {
      if (pmsg)
	*pmsg = mum->message;
      return 0;
    }

  MAILBOX_DEBUG2 (mailbox, MU_DEBUG_TRACE, "mbox_get_message(%s, %d)\n",
		  mud->name, msgno);

  /* Get an empty message struct.  */
  status = message_create (&msg, mum);
  if (status != 0)
    return status;

  /* Set the header.  */
  {
    header_t header = NULL;
    status = header_create (&header, NULL, 0, msg);
    if (status != 0)
      {
	message_destroy (&msg, mum);
	return status;
      }
    header_set_fill (header, mbox_header_fill, msg);
    header_set_get_fvalue (header, mbox_header_get_fvalue, msg);
    header_set_size (header, mbox_header_size, msg);
    header_set_lines (header, mbox_header_lines, msg);
    message_set_header (msg, header, mum);
  }

  /* Set the attribute.  */
  {
    attribute_t attribute;
    status = attribute_create (&attribute, msg);
    if (status != 0)
      {
	message_destroy (&msg, mum);
	return status;
      }
    mum->new_flags = mum->old_flags;
    attribute_set_get_flags (attribute, mbox_get_attr_flags, msg);
    attribute_set_set_flags (attribute, mbox_set_attr_flags, msg);
    attribute_set_unset_flags (attribute, mbox_unset_attr_flags, msg);
    message_set_attribute (msg, attribute, mum);
  }

  /* Prepare the body.  */
  {
    body_t body = NULL;
    stream_t stream = NULL;
    if ((status = body_create (&body, msg)) != 0
	|| (status = stream_create (&stream, mailbox->flags, body)) != 0)
      {
	body_destroy (&body, msg);
	stream_destroy (&stream, body);
	message_destroy (&msg, mum);
	return status;
      }
    stream_set_read (stream, mbox_body_read, body);
    stream_set_readline (stream, mbox_body_readline, body);
    stream_set_fd (stream, mbox_get_body_fd, body);
    body_set_stream (body, stream, msg);
    body_set_size (body, mbox_body_size, msg);
    body_set_lines (body, mbox_body_lines, msg);
    message_set_body (msg, body, mum);
  }

  /* Set the envelope.  */
  {
    envelope_t envelope= NULL;
    status = envelope_create (&envelope, msg);
    if (status != 0)
      {
	message_destroy (&msg, mum);
	return status;
      }
    envelope_set_sender (envelope, mbox_envelope_sender, msg);
    envelope_set_date (envelope, mbox_envelope_date, msg);
    message_set_envelope (msg, envelope, mum);
  }

  /* Attach the message to the mailbox mbox data.  */
  mum->message = msg;
  message_set_mailbox (msg, mailbox);

  *pmsg = msg;
  return 0;
}

static int
mbox_append_message (mailbox_t mailbox, message_t msg)
{
  mbox_data_t mud = mailbox->data;
  if (msg == NULL || mud == NULL)
    return EINVAL;

  MAILBOX_DEBUG1 (mailbox, MU_DEBUG_TRACE, "mbox_append_message (%s)\n",
		  mud->name);

  switch (mud->state)
    {
    case MBOX_NO_STATE:
      locker_lock (mailbox->locker, MU_LOCKER_WRLOCK);

    default:
      {
	off_t size;
	int status;
	/* Move to the end of the file, not necesary if _APPEND mode.  */
	if ((status = stream_size (mailbox->stream, &size)) != 0
	    || (status = mbox_append_message0 (mailbox, msg, &size, 0)) != 0)
	  {
	    if (status != EAGAIN)
	      locker_unlock (mailbox->locker);
	    return status;
	  }
      }
    }
  locker_unlock (mailbox->locker);
  return 0;
}

static int
mbox_append_message0 (mailbox_t mailbox, message_t msg, off_t *psize,
		      int is_expunging)
{
  mbox_data_t mud = mailbox->data;
  int status = 0;
  size_t n = 0;
  char nl = '\n';

  switch (mud->state)
    {
    case MBOX_NO_STATE:
      /* Allocate memory for the sender/date buffers.  */
      mud->sender = calloc (128, sizeof (char));
      if (mud->sender == NULL)
	return ENOMEM;
      mud->date = calloc (128, sizeof (char));
      if (mud->date == NULL)
	{
	  free (mud->sender);
	  mud->sender = NULL;
	  return ENOMEM;
	}
      mud->off = 0;
      mud->state = MBOX_STATE_APPEND_SENDER;

    case MBOX_STATE_APPEND_SENDER:
      /* Generate the sender for the "From " separator.  */
      {
	char *s;
	size_t len = 0;
	envelope_t envelope;
	message_get_envelope (msg, &envelope);
	status = envelope_sender (envelope, mud->sender, 128, &len);
	if (status != 0)
	  {
	    if (status != EAGAIN)
	      {
		free (mud->sender);
		free (mud->date);
		mud->date = mud->sender = NULL;
		mud->state = MBOX_NO_STATE;
	      }
	    return status;
	  }

	/* Nuke trailing newline.  */
	s = memchr (mud->sender, nl, len);
	if (s)
	  *s = '\0';
	mud->state = MBOX_STATE_APPEND_DATE;
      }

    case MBOX_STATE_APPEND_DATE:
      /* Generate a date for the "From "  separator.  */
      {
	char *s;
	size_t len = 0;
	envelope_t envelope;
	message_get_envelope (msg, &envelope);
	status = envelope_date (envelope, mud->date, 128, &len);
	if (status != 0)
	  {
	    if (status != EAGAIN)
	      {
		free (mud->sender);
		free (mud->date);
		mud->date = mud->sender = NULL;
		mud->state = MBOX_NO_STATE;
	      }
	    return status;
	  }

	/* Nuke trailing newline.  */
	s = memchr (mud->date, nl, len);
	if (s)
	  *s = '\0';

	/* Write the separator to the mailbox.  */
	status = stream_write (mailbox->stream, "From ", 5, *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	/* Write sender.  */
	status = stream_write (mailbox->stream, mud->sender,
			       strlen (mud->sender), *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	status = stream_write (mailbox->stream, " ", 1, *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	/* Write date.  */
	status = stream_write (mailbox->stream, mud->date, strlen(mud->date),
			       *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	status = stream_write (mailbox->stream, &nl , 1, *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	free (mud->sender);
	free (mud->date);
	mud->sender = mud->date = NULL;
	/* If we are not expunging get the message in one block via the stream
	   message instead of the header/body.  This is good for example for
	   POP where there is no separtation between header and body.  */
	if (! is_expunging)
	  {
	    mud->state = MBOX_STATE_APPEND_MESSAGE;
	    break;
	  }
	mud->state = MBOX_STATE_APPEND_HEADER;
      }

    case MBOX_STATE_APPEND_HEADER:
      /* Append the Header.  */
      {
	char buffer[1024];
	size_t nread = 0;
	stream_t is;
	header_t header;
	message_get_header (msg, &header);
	header_get_stream (header, &is);
	do
	  {
	    status = stream_readline (is, buffer, sizeof (buffer), mud->off,
				      &nread);
	    if (status != 0)
	      {
		if (status != EAGAIN)
		  {
		    mud->state = MBOX_NO_STATE;
		    mud->off = 0;
		  }
		return status;
	      }
	    mud->off += nread;
	    if (*buffer == '\n')
	      break;

	    /* We do not copy the Status since it is rewritten by the
	       attribute code below.  */
	    /* FIXME:  - We have a problem here the header field may not fit
	       the buffer.
	       - Should  we skip the IMAP "X-Status"?
	       strncasecmp (buffer, "X-Status", 8) == 0)  */
	    if (strncasecmp (buffer, "Status", 6) == 0)
	      continue;

	    status = stream_write (mailbox->stream, buffer, nread,
				    *psize, &n);
	    if (status != 0)
	      break;
	    *psize += n;
	  }
	while (nread > 0);
	mud->off = 0;
	mud->state = MBOX_STATE_APPEND_ATTRIBUTE;
      }

      case MBOX_STATE_APPEND_ATTRIBUTE:
      /* Put the new attributes.  */
      {
	char abuf[64];
	size_t na = 0;
	attribute_t attr = NULL;
	abuf[0] = '\0';
	message_get_attribute (msg, &attr);
	attribute_to_string (attr, abuf, sizeof(abuf), &na);

	status = stream_write (mailbox->stream, abuf, na, *psize, &n);
	if (status != 0)
	  break;
	*psize += n;

	status = stream_write (mailbox->stream, &nl , 1, *psize, &n);
	if (status != 0)
	  break;
	*psize += n;
	mud->state = MBOX_STATE_APPEND_BODY;
      }

    case MBOX_STATE_APPEND_BODY:
      /* Append the Body.  */
      {
	char buffer[1024];
	size_t nread = 0;
	stream_t is;
	body_t body;
	message_get_body (msg, &body);
	body_get_stream (body, &is);
	do
	  {
	    status = stream_read (is, buffer, sizeof (buffer), mud->off,
				  &nread);
	    if (status != 0)
	      {
		if (status != EAGAIN)
		  {
		    mud->state = MBOX_NO_STATE;
		    mud->off = 0;
		  }
		return status;
	      }
	    mud->off += nread;
	    status = stream_write (mailbox->stream, buffer, nread, *psize, &n);
	    if (status != 0)
	      break;
	    *psize += n;
	  }
	while (nread > 0);
	mud->off = 0;
	n = 0;
	stream_write (mailbox->stream, &nl, 1, *psize, &n);
	*psize += n;
      }

    default:
      break;
    }

  /* If not expunging we are taking the stream message.  */
  if (!is_expunging)
    {
      switch (mud->state)
        {
	case MBOX_STATE_APPEND_MESSAGE:
	  {
	    /* Append the Message.  */
	    char buffer[1024];
	    size_t nread = 0;
	    stream_t is;
	    message_get_stream (msg, &is);
	    do
	      {
		status = stream_read (is, buffer, sizeof (buffer), mud->off,
				      &nread);
		if (status != 0)
		  {
		    if (status != EAGAIN)
		      {
			mud->state = MBOX_NO_STATE;
			mud->off = 0;
		      }
		    stream_flush (mailbox->stream);
		    return status;
		  }
		stream_write (mailbox->stream, buffer, nread, *psize, &n);
		mud->off += nread;
		*psize += n;
	      }
	    while (nread > 0);
	    n = 0;
	    stream_write (mailbox->stream, &nl, 1, *psize, &n);
	    *psize += n;
	  }

	default:
	  break;
	}
    } /* is_expunging */
  mud->state = MBOX_NO_STATE;
  stream_flush (mailbox->stream);
  return status;
}

static int
mbox_size (mailbox_t mailbox, off_t *psize)
{
  off_t size;
  int status;

  /* Maybe was not open yet ??  */
  status  = stream_size (mailbox->stream, &size);
  if (status != 0)
    return status;
  if (psize)
    *psize = size;
  return 0;
}

static int
mbox_messages_count (mailbox_t mailbox, size_t *pcount)
{
  mbox_data_t mud = mailbox->data;
  if (mud == NULL)
    return EINVAL;

  if (! mbox_is_updated (mailbox))
    return mbox_scan0 (mailbox,  1, pcount, 1);

  if (pcount)
    *pcount = mud->messages_count;

  return 0;
}

static int
mbox_unseen_count (mailbox_t mailbox, size_t *pcount)
{
  mbox_data_t mud = mailbox->data;
  mbox_message_t mum;
  size_t j, total;

  if (pcount)
    return EINVAL;
  for (total = j = 0; j < mud->messages_count; j++)
    {
      mum = mud->umessages[j];
      if (mum && mum->new_flags == 0)
	total++;
    }
  *pcount = total;
  return 0;
}

#ifdef WITH_PTHREAD
static void
mbox_cleanup (void *arg)
{
  mailbox_t mailbox = arg;
  monitor_unlock (mailbox->monitor);
  locker_unlock (mailbox->locker);
}
#endif