/*
 * Copyright notice from original mutt:
 * Copyright (C) 1996-2002 Michael R. Elkins <me@mutt.org>
 *
 * This file is part of mutt-ng, see http://www.muttng.org/.
 * It's licensed under the GNU General Public License,
 * please see the file GPL in the top level source directory.
 */

/* This file contains code to parse ``mbox'' and ``mmdf'' style mailboxes */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include "mutt.h"
#include "mx.h"
#include "buffy.h"
#include "mbox.h"
#include "sort.h"
#include "thread.h"
#include "copy.h"

#ifdef USE_COMPRESSED
#include "compress.h"
#endif

#include "lib/mem.h"
#include "lib/intl.h"
#include "lib/str.h"
#include "lib/debug.h"

#include <sys/stat.h>
#include <dirent.h>
#include <string.h>
#include <utime.h>
#include <sys/file.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

/* struct used by mutt_sync_mailbox() to store new offsets */
struct m_update_t {
  short valid;
  LOFF_T hdr;
  LOFF_T body;
  long lines;
  LOFF_T length;
};


static int mbox_open_new_message (MESSAGE * msg, CONTEXT * dest, HEADER * hdr)
{
  msg->fp = dest->fp;
  return 0;
}

/* prototypes */
static int mbox_reopen_mailbox (CONTEXT*, int*);

/* parameters:
 * ctx - context to lock
 * excl - exclusive lock?
 * retry - should retry if unable to lock?
 */
int mbox_lock_mailbox (CONTEXT * ctx, int excl, int retry)
{
  int r;

  if ((r = mx_lock_file (ctx->path, fileno (ctx->fp), excl, 1, retry)) == 0)
    ctx->locked = 1;
  else if (retry && !excl) {
    ctx->readonly = 1;
    return 0;
  }

  return (r);
}

void mbox_unlock_mailbox (CONTEXT * ctx)
{
  if (ctx->locked) {
    fflush (ctx->fp);

    mx_unlock_file (ctx->path, fileno (ctx->fp), 1);
    ctx->locked = 0;
  }
}

static int mmdf_parse_mailbox (CONTEXT * ctx)
{
  char buf[HUGE_STRING];
  char return_path[LONG_STRING];
  int count = 0, oldmsgcount = ctx->msgcount;
  int lines;
  time_t t, tz;
  LOFF_T loc, tmploc;
  HEADER *hdr;
  struct stat sb;

#ifdef NFS_ATTRIBUTE_HACK
  struct utimbuf newtime;
#endif

  if (stat (ctx->path, &sb) == -1) {
    mutt_perror (ctx->path);
    return (-1);
  }
  ctx->mtime = sb.st_mtime;
  ctx->size = sb.st_size;

#ifdef NFS_ATTRIBUTE_HACK
  if (sb.st_mtime > sb.st_atime) {
    newtime.modtime = sb.st_mtime;
    newtime.actime = time (NULL);
    utime (ctx->path, &newtime);
  }
#endif

  /* precompute the local timezone to speed up calculation of the
     received time */
  tz = mutt_local_tz (0);

  buf[sizeof (buf) - 1] = 0;

  FOREVER {
    if (fgets (buf, sizeof (buf) - 1, ctx->fp) == NULL)
      break;

    if (str_cmp (buf, MMDF_SEP) == 0) {
      loc = ftello (ctx->fp);

      count++;
      if (!ctx->quiet && ReadInc && ((count % ReadInc == 0) || count == 1))
        mutt_message (_("Reading %s... %d (%d%%)"), ctx->path, count,
                      (int) (loc / (ctx->size / 100 + 1)));


      if (ctx->msgcount == ctx->hdrmax)
        mx_alloc_memory (ctx);
      ctx->hdrs[ctx->msgcount] = hdr = mutt_new_header ();
      hdr->offset = loc;
      hdr->index = ctx->msgcount;

      if (fgets (buf, sizeof (buf) - 1, ctx->fp) == NULL) {
        /* TODO: memory leak??? */
        debug_print (1, ("unexpected EOF\n"));
        break;
      }

      return_path[0] = 0;

      if (!is_from (buf, return_path, sizeof (return_path), &t)) {
        if (fseeko (ctx->fp, loc, SEEK_SET) != 0) {
          debug_print (1, ("fseeko() failed\n"));
          mutt_error _("Mailbox is corrupt!");

          return (-1);
        }
      }
      else
        hdr->received = t - tz;

      hdr->env = mutt_read_rfc822_header (ctx->fp, hdr, 0, 0);

      loc = ftello (ctx->fp);

      if (hdr->content->length > 0 && hdr->lines > 0) {
        tmploc = loc + hdr->content->length;

        if (0 < tmploc && tmploc < ctx->size) {
          if (fseeko (ctx->fp, tmploc, SEEK_SET) != 0 ||
              fgets (buf, sizeof (buf) - 1, ctx->fp) == NULL ||
              str_cmp (MMDF_SEP, buf) != 0) {
            if (fseeko (ctx->fp, loc, SEEK_SET) != 0)
              debug_print (1, ("fseeko() failed\n"));
            hdr->content->length = -1;
          }
        }
        else
          hdr->content->length = -1;
      }
      else
        hdr->content->length = -1;

      if (hdr->content->length < 0) {
        lines = -1;
        do {
          loc = ftello (ctx->fp);
          if (fgets (buf, sizeof (buf) - 1, ctx->fp) == NULL)
            break;
          lines++;
        } while (str_cmp (buf, MMDF_SEP) != 0);

        hdr->lines = lines;
        hdr->content->length = loc - hdr->content->offset;
      }

      if (!hdr->env->return_path && return_path[0])
        hdr->env->return_path =
          rfc822_parse_adrlist (hdr->env->return_path, return_path);

      if (!hdr->env->from)
        hdr->env->from = rfc822_cpy_adr (hdr->env->return_path);

      ctx->msgcount++;
    }
    else {
      debug_print (1, ("corrupt mailbox!\n"));
      mutt_error _("Mailbox is corrupt!");

      return (-1);
    }
  }

  if (ctx->msgcount > oldmsgcount)
    mx_update_context (ctx, ctx->msgcount - oldmsgcount);

  return (0);
}

/* Note that this function is also called when new mail is appended to the
 * currently open folder, and NOT just when the mailbox is initially read.
 *
 * NOTE: it is assumed that the mailbox being read has been locked before
 * this routine gets called.  Strange things could happen if it's not!
 */
static int mbox_parse_mailbox (CONTEXT * ctx)
{
  struct stat sb;
  char buf[HUGE_STRING], return_path[STRING];
  HEADER *curhdr;
  time_t t, tz;
  int count = 0, lines = 0;
  LOFF_T loc;

#ifdef NFS_ATTRIBUTE_HACK
  struct utimbuf newtime;
#endif

  /* Save information about the folder at the time we opened it. */
  if (stat (ctx->path, &sb) == -1) {
    mutt_perror (ctx->path);
    return (-1);
  }

  ctx->size = sb.st_size;
  ctx->mtime = sb.st_mtime;

#ifdef NFS_ATTRIBUTE_HACK
  if (sb.st_mtime > sb.st_atime) {
    newtime.modtime = sb.st_mtime;
    newtime.actime = time (NULL);
    utime (ctx->path, &newtime);
  }
#endif

  if (!ctx->readonly)
    ctx->readonly = access (ctx->path, W_OK) ? 1 : 0;

  /* precompute the local timezone to speed up calculation of the
     date received */
  tz = mutt_local_tz (0);

  loc = ftello (ctx->fp);
  while (fgets (buf, sizeof (buf), ctx->fp) != NULL) {
    if (is_from (buf, return_path, sizeof (return_path), &t)) {
      /* Save the Content-Length of the previous message */
      if (count > 0) {
#define PREV ctx->hdrs[ctx->msgcount-1]

        if (PREV->content->length < 0) {
          PREV->content->length = loc - PREV->content->offset - 1;
          if (PREV->content->length < 0)
            PREV->content->length = 0;
        }
        if (!PREV->lines)
          PREV->lines = lines ? lines - 1 : 0;
      }

      count++;

      if (!ctx->quiet && ReadInc && ((count % ReadInc == 0) || count == 1))
        mutt_message (_("Reading %s... %d (%d%%)"), ctx->path, count,
                      (int) (ftello (ctx->fp) / (ctx->size / 100 + 1)));

      if (ctx->msgcount == ctx->hdrmax)
        mx_alloc_memory (ctx);

      curhdr = ctx->hdrs[ctx->msgcount] = mutt_new_header ();
      curhdr->received = t - tz;
      curhdr->offset = loc;
      curhdr->index = ctx->msgcount;

      curhdr->env = mutt_read_rfc822_header (ctx->fp, curhdr, 0, 0);

      /* if we know how long this message is, either just skip over the body,
       * or if we don't know how many lines there are, count them now (this will
       * save time by not having to search for the next message marker).
       */
      if (curhdr->content->length > 0) {
        LOFF_T tmploc;

        loc = ftello (ctx->fp);
        tmploc = loc + curhdr->content->length + 1;

        if (0 < tmploc && tmploc < ctx->size) {
          /*
           * check to see if the content-length looks valid.  we expect to
           * to see a valid message separator at this point in the stream
           */
          if (fseeko (ctx->fp, tmploc, SEEK_SET) != 0 ||
              fgets (buf, sizeof (buf), ctx->fp) == NULL ||
              str_ncmp ("From ", buf, 5) != 0) {
            debug_print (1, ("bad content-length in message %d (cl="
                             OFF_T_FMT ")\n", curhdr->index, curhdr->content->length));
            debug_print (1, ("LINE: %s\n", buf));
            if (fseeko (ctx->fp, loc, SEEK_SET) != 0) {  /* nope, return the previous position */
              debug_print (1, ("fseeko() failed\n"));
            }
            curhdr->content->length = -1;
          }
        }
        else if (tmploc != ctx->size) {
          /* content-length would put us past the end of the file, so it
           * must be wrong
           */
          curhdr->content->length = -1;
        }

        if (curhdr->content->length != -1) {
          /* good content-length.  check to see if we know how many lines
           * are in this message.
           */
          if (curhdr->lines == 0) {
            int cl = curhdr->content->length;

            /* count the number of lines in this message */
            if (fseeko (ctx->fp, loc, SEEK_SET) != 0)
              debug_print (1, ("fseeko() failed\n"));
            while (cl-- > 0) {
              if (fgetc (ctx->fp) == '\n')
                curhdr->lines++;
            }
          }

          /* return to the offset of the next message separator */
          if (fseeko (ctx->fp, tmploc, SEEK_SET) != 0)
            debug_print (1, ("fseeko() failed\n"));
        }
      }

      ctx->msgcount++;

      if (!curhdr->env->return_path && return_path[0])
        curhdr->env->return_path =
          rfc822_parse_adrlist (curhdr->env->return_path, return_path);

      if (!curhdr->env->from)
        curhdr->env->from = rfc822_cpy_adr (curhdr->env->return_path);

      lines = 0;
    }
    else
      lines++;

    loc = ftello (ctx->fp);
  }

  /*
   * Only set the content-length of the previous message if we have read more
   * than one message during _this_ invocation.  If this routine is called
   * when new mail is received, we need to make sure not to clobber what
   * previously was the last message since the headers may be sorted.
   */
  if (count > 0) {
    if (PREV->content->length < 0) {
      PREV->content->length = ftello (ctx->fp) - PREV->content->offset - 1;
      if (PREV->content->length < 0)
        PREV->content->length = 0;
    }

    if (!PREV->lines)
      PREV->lines = lines ? lines - 1 : 0;

    mx_update_context (ctx, count);
  }

  return (0);
}

#undef PREV

/* open a mbox or mmdf style mailbox */
static int mbox_open_mailbox (CONTEXT * ctx)
{
  int rc;

  if ((ctx->fp = fopen (ctx->path, "r")) == NULL) {
    mutt_perror (ctx->path);
    return (-1);
  }
  mutt_block_signals ();
  if (mbox_lock_mailbox (ctx, 0, 1) == -1) {
    mutt_unblock_signals ();
    return (-1);
  }

  if (ctx->magic == M_MBOX)
    rc = mbox_parse_mailbox (ctx);
  else if (ctx->magic == M_MMDF)
    rc = mmdf_parse_mailbox (ctx);
  else
    rc = -1;

  mbox_unlock_mailbox (ctx);
  mutt_unblock_signals ();
  return (rc);
}

/* check to see if the mailbox has changed on disk.
 *
 * return values:
 *	M_REOPENED	mailbox has been reopened
 *	M_NEW_MAIL	new mail has arrived!
 *	M_LOCKED	couldn't lock the file
 *	0		no change
 *	-1		error
 */
static int _mbox_check_mailbox (CONTEXT * ctx, int *index_hint)
{
  struct stat st;
  char buffer[LONG_STRING];
  int unlock = 0;
  int modified = 0;

  if (stat (ctx->path, &st) == 0) {
    if (st.st_mtime == ctx->mtime && st.st_size == ctx->size)
      return (0);

    if (st.st_size == ctx->size) {
      /* the file was touched, but it is still the same length, so just exit */
      ctx->mtime = st.st_mtime;
      return (0);
    }

    if (st.st_size > ctx->size) {
      /* lock the file if it isn't already */
      if (!ctx->locked) {
        mutt_block_signals ();
        if (mbox_lock_mailbox (ctx, 0, 0) == -1) {
          mutt_unblock_signals ();
          /* we couldn't lock the mailbox, but nothing serious happened:
           * probably the new mail arrived: no reason to wait till we can
           * parse it: we'll get it on the next pass
           */
          return (M_LOCKED);
        }
        unlock = 1;
      }

      /*
       * Check to make sure that the only change to the mailbox is that 
       * message(s) were appended to this file.  My heuristic is that we should
       * see the message separator at *exactly* what used to be the end of the
       * folder.
       */
      if (fseeko (ctx->fp, ctx->size, SEEK_SET) != 0)
        debug_print (1, ("fseeko() failed\n"));
      if (fgets (buffer, sizeof (buffer), ctx->fp) != NULL) {
        if ((ctx->magic == M_MBOX && str_ncmp ("From ", buffer, 5) == 0)
            || (ctx->magic == M_MMDF && str_cmp (MMDF_SEP, buffer) == 0)) {
          if (fseeko (ctx->fp, ctx->size, SEEK_SET) != 0)
            debug_print (1, ("fseeko() failed\n"));
          if (ctx->magic == M_MBOX)
            mbox_parse_mailbox (ctx);
          else
            mmdf_parse_mailbox (ctx);

          /* Only unlock the folder if it was locked inside of this routine.
           * It may have been locked elsewhere, like in
           * mutt_checkpoint_mailbox().
           */

          if (unlock) {
            mbox_unlock_mailbox (ctx);
            mutt_unblock_signals ();
          }

          return (M_NEW_MAIL);  /* signal that new mail arrived */
        }
        else
          modified = 1;
      }
      else {
        debug_print (1, ("fgets returned NULL.\n"));
        modified = 1;
      }
    }
    else
      modified = 1;
  }

  if (modified) {
    if (mbox_reopen_mailbox (ctx, index_hint) != -1) {
      if (unlock) {
        mbox_unlock_mailbox (ctx);
        mutt_unblock_signals ();
      }
      return (M_REOPENED);
    }
  }

  /* fatal error */

  mbox_unlock_mailbox (ctx);
  mx_fastclose_mailbox (ctx);
  mutt_unblock_signals ();
  mutt_error _("Mailbox was corrupted!");

  return (-1);
}

static int mbox_check_mailbox (CONTEXT* ctx, int* index_hint, int lock) {
  int rc = 0;

  if (lock) {
    mutt_block_signals ();
    if (mbox_lock_mailbox (ctx, 0, 0) == -1) {
      mutt_unblock_signals ();
      return M_LOCKED;
    }
  }

  rc = _mbox_check_mailbox (ctx, index_hint);

  if (lock) {
    mutt_unblock_signals ();
    mbox_unlock_mailbox (ctx);
  }
  return rc;
}

/* return values:
 *	0	success
 *	-1	failure
 */
static int _mbox_sync_mailbox (CONTEXT * ctx, int unused, int *index_hint)
{
  char tempfile[_POSIX_PATH_MAX];
  char buf[32];
  int i, j, save_sort = SORT_ORDER;
  int rc = -1;
  int need_sort = 0;            /* flag to resort mailbox if new mail arrives */
  int first = -1;               /* first message to be written */
  LOFF_T offset;                /* location in mailbox to write changed messages */
  struct stat statbuf;
  struct utimbuf utimebuf;
  struct m_update_t *newOffset = NULL;
  struct m_update_t *oldOffset = NULL;
  FILE *fp = NULL;

  /* sort message by their position in the mailbox on disk */
  if (Sort != SORT_ORDER) {
    save_sort = Sort;
    Sort = SORT_ORDER;
    mutt_sort_headers (ctx, 0);
    Sort = save_sort;
    need_sort = 1;
  }

  /* need to open the file for writing in such a way that it does not truncate
   * the file, so use read-write mode.
   */
  if ((ctx->fp = freopen (ctx->path, "r+", ctx->fp)) == NULL) {
    mx_fastclose_mailbox (ctx);
    mutt_error _("Fatal error!  Could not reopen mailbox!");

    return (-1);
  }

  mutt_block_signals ();

  if (mbox_lock_mailbox (ctx, 1, 1) == -1) {
    mutt_unblock_signals ();
    mutt_error _("Unable to lock mailbox!");

    goto bail;
  }

  /* Check to make sure that the file hasn't changed on disk */
  if ((i = _mbox_check_mailbox (ctx, index_hint)) == M_NEW_MAIL
      || i == M_REOPENED) {
    /* new mail arrived, or mailbox reopened */
    need_sort = i;
    rc = i;
    goto bail;
  }
  else if (i < 0)
    /* fatal error */
    return (-1);

  /* Create a temporary file to write the new version of the mailbox in. */
  mutt_mktemp (tempfile);
  if ((i = open (tempfile, O_WRONLY | O_EXCL | O_CREAT, 0600)) == -1 ||
      (fp = fdopen (i, "w")) == NULL) {
    if (-1 != i) {
      close (i);
      unlink (tempfile);
    }
    mutt_error _("Could not create temporary file!");

    mutt_sleep (5);
    goto bail;
  }

  /* find the first deleted/changed message.  we save a lot of time by only
   * rewriting the mailbox from the point where it has actually changed.
   */
  for (i = 0; i < ctx->msgcount && !ctx->hdrs[i]->deleted &&
       !ctx->hdrs[i]->changed && !ctx->hdrs[i]->attach_del; i++);
  if (i == ctx->msgcount) {
    /* this means ctx->changed or ctx->deleted was set, but no
     * messages were found to be changed or deleted.  This should
     * never happen, is we presume it is a bug in mutt.
     */
    mutt_error
      _("sync: mbox modified, but no modified messages! (report this bug)");
    mutt_sleep (5);             /* the mutt_error /will/ get cleared! */
    debug_print (1, ("no modified messages.\n"));
    unlink (tempfile);
    goto bail;
  }

  /* save the index of the first changed/deleted message */
  first = i;
  /* where to start overwriting */
  offset = ctx->hdrs[i]->offset;

  /* the offset stored in the header does not include the MMDF_SEP, so make
   * sure we seek to the correct location
   */
  if (ctx->magic == M_MMDF)
    offset -= (sizeof MMDF_SEP - 1);

  /* allocate space for the new offsets */
  newOffset = mem_calloc (ctx->msgcount - first, sizeof (struct m_update_t));
  oldOffset = mem_calloc (ctx->msgcount - first, sizeof (struct m_update_t));

  for (i = first, j = 0; i < ctx->msgcount; i++) {
    /*
     * back up some information which is needed to restore offsets when
     * something fails.
     */

    oldOffset[i - first].valid = 1;
    oldOffset[i - first].hdr = ctx->hdrs[i]->offset;
    oldOffset[i - first].body = ctx->hdrs[i]->content->offset;
    oldOffset[i - first].lines = ctx->hdrs[i]->lines;
    oldOffset[i - first].length = ctx->hdrs[i]->content->length;

    if (!ctx->hdrs[i]->deleted) {
      j++;
      if (!ctx->quiet && WriteInc && ((i % WriteInc) == 0 || j == 1))
        mutt_message (_("Writing messages... %d (%d%%)"), i,
                      (int) (ftello (ctx->fp) / (ctx->size / 100 + 1)));

      if (ctx->magic == M_MMDF) {
        if (fputs (MMDF_SEP, fp) == EOF) {
          mutt_perror (tempfile);
          mutt_sleep (5);
          unlink (tempfile);
          goto bail;
        }

      }

      /* save the new offset for this message.  we add `offset' because the
       * temporary file only contains saved message which are located after
       * `offset' in the real mailbox
       */
      newOffset[i - first].hdr = ftello (fp) + offset;

      if (mutt_copy_message
          (fp, ctx, ctx->hdrs[i], M_CM_UPDATE,
           CH_FROM | CH_UPDATE | CH_UPDATE_LEN) == -1) {
        mutt_perror (tempfile);
        mutt_sleep (5);
        unlink (tempfile);
        goto bail;
      }

      /* Since messages could have been deleted, the offsets stored in memory
       * will be wrong, so update what we can, which is the offset of this
       * message, and the offset of the body.  If this is a multipart message,
       * we just flush the in memory cache so that the message will be reparsed
       * if the user accesses it later.
       */
      newOffset[i - first].body =
        ftello (fp) - ctx->hdrs[i]->content->length + offset;
      mutt_free_body (&ctx->hdrs[i]->content->parts);

      switch (ctx->magic) {
      case M_MMDF:
        if (fputs (MMDF_SEP, fp) == EOF) {
          mutt_perror (tempfile);
          mutt_sleep (5);
          unlink (tempfile);
          goto bail;
        }
        break;
      default:
        if (fputs ("\n", fp) == EOF) {
          mutt_perror (tempfile);
          mutt_sleep (5);
          unlink (tempfile);
          goto bail;
        }
      }
    }
  }

  if (fclose (fp) != 0) {
    fp = NULL;
    debug_print (1, ("fclose() returned non-zero.\n"));
    unlink (tempfile);
    mutt_perror (tempfile);
    mutt_sleep (5);
    goto bail;
  }
  fp = NULL;

  /* Save the state of this folder. */
  if (stat (ctx->path, &statbuf) == -1) {
    mutt_perror (ctx->path);
    mutt_sleep (5);
    unlink (tempfile);
    goto bail;
  }

  if ((fp = fopen (tempfile, "r")) == NULL) {
    mutt_unblock_signals ();
    mx_fastclose_mailbox (ctx);
    debug_print (1, ("unable to reopen temp copy of mailbox!\n"));
    mutt_perror (tempfile);
    mutt_sleep (5);
    return (-1);
  }

  if (fseeko (ctx->fp, offset, SEEK_SET) != 0 || /* seek the append location */
      /* do a sanity check to make sure the mailbox looks ok */
      fgets (buf, sizeof (buf), ctx->fp) == NULL ||
      (ctx->magic == M_MBOX && str_ncmp ("From ", buf, 5) != 0) ||
      (ctx->magic == M_MMDF && str_cmp (MMDF_SEP, buf) != 0)) {
    debug_print (1, ("message not in expected position.\n"));
    debug_print (1, ("LINE: %s\n", buf));
    i = -1;
  }
  else {
    if (fseeko (ctx->fp, offset, SEEK_SET) != 0) {       /* return to proper offset */
      i = -1;
      debug_print (1, ("fseeko() failed\n"));
    }
    else {
      /* copy the temp mailbox back into place starting at the first
       * change/deleted message
       */
      mutt_message _("Committing changes...");

      i = mutt_copy_stream (fp, ctx->fp);

      if (ferror (ctx->fp))
        i = -1;
    }
    if (i == 0) {
      ctx->size = ftello (ctx->fp);      /* update the size of the mailbox */
      ftruncate (fileno (ctx->fp), ctx->size);
    }
  }

  fclose (fp);
  fp = NULL;
  mbox_unlock_mailbox (ctx);

  if (fclose (ctx->fp) != 0 || i == -1) {
    /* error occured while writing the mailbox back, so keep the temp copy
     * around
     */

    char savefile[_POSIX_PATH_MAX];

    snprintf (savefile, sizeof (savefile), "%s/mutt.%s-%s-%u",
              NONULL (Tempdir), NONULL (Username), NONULL (Hostname),
              (unsigned int) getpid ());
    rename (tempfile, savefile);
    mutt_unblock_signals ();
    mx_fastclose_mailbox (ctx);
    mutt_pretty_mailbox (savefile);
    mutt_error (_("Write failed!  Saved partial mailbox to %s"), savefile);
    mutt_sleep (5);
    return (-1);
  }

  /* Restore the previous access/modification times */
  utimebuf.actime = statbuf.st_atime;
  utimebuf.modtime = statbuf.st_mtime;
  utime (ctx->path, &utimebuf);

  /* reopen the mailbox in read-only mode */
  if ((ctx->fp = fopen (ctx->path, "r")) == NULL) {
    unlink (tempfile);
    mutt_unblock_signals ();
    mx_fastclose_mailbox (ctx);
    mutt_error _("Fatal error!  Could not reopen mailbox!");
    return (-1);
  }

  /* update the offsets of the rewritten messages */
  for (i = first, j = first; i < ctx->msgcount; i++) {
    if (!ctx->hdrs[i]->deleted) {
      ctx->hdrs[i]->offset = newOffset[i - first].hdr;
      ctx->hdrs[i]->content->hdr_offset = newOffset[i - first].hdr;
      ctx->hdrs[i]->content->offset = newOffset[i - first].body;
      ctx->hdrs[i]->index = j++;
    }
  }
  mem_free (&newOffset);
  mem_free (&oldOffset);
  unlink (tempfile);            /* remove partial copy of the mailbox */
  mutt_unblock_signals ();

  return (0);                   /* signal success */

bail:                          /* Come here in case of disaster */

  safe_fclose (&fp);

  /* restore offsets, as far as they are valid */
  if (first >= 0 && oldOffset) {
    for (i = first; i < ctx->msgcount && oldOffset[i - first].valid; i++) {
      ctx->hdrs[i]->offset = oldOffset[i - first].hdr;
      ctx->hdrs[i]->content->hdr_offset = oldOffset[i - first].hdr;
      ctx->hdrs[i]->content->offset = oldOffset[i - first].body;
      ctx->hdrs[i]->lines = oldOffset[i - first].lines;
      ctx->hdrs[i]->content->length = oldOffset[i - first].length;
    }
  }

  /* this is ok to call even if we haven't locked anything */
  mbox_unlock_mailbox (ctx);

  mutt_unblock_signals ();
  mem_free (&newOffset);
  mem_free (&oldOffset);

  if ((ctx->fp = freopen (ctx->path, "r", ctx->fp)) == NULL) {
    mutt_error _("Could not reopen mailbox!");

    mx_fastclose_mailbox (ctx);
    return (-1);
  }

  if (need_sort)
    /* if the mailbox was reopened, the thread tree will be invalid so make
     * sure to start threading from scratch.  */
    mutt_sort_headers (ctx, (need_sort == M_REOPENED));

  return rc;
}

static int mbox_sync_mailbox (CONTEXT * ctx, int unused, int *index_hint) {
#ifdef BUFFY_SIZE
  BUFFY* tmp = NULL;
#endif
  int rc = _mbox_sync_mailbox (ctx, unused, index_hint);

#ifdef BUFFY_SIZE
  if ((tmp = buffy_find_mailbox (ctx->path)) && tmp->new == 0)
    buffy_update_mailbox (tmp);
#endif
  return (rc);
}

/* close a mailbox opened in write-mode */
int mbox_close_mailbox (CONTEXT * ctx)
{
  mx_unlock_file (ctx->path, fileno (ctx->fp), 1);

#ifdef USE_COMPRESSED
  if (ctx->compressinfo)
    mutt_slow_close_compressed (ctx);
#endif

  mutt_unblock_signals ();
  mx_fastclose_mailbox (ctx);
  return 0;
}

static int mbox_reopen_mailbox (CONTEXT * ctx, int *index_hint)
{
  int (*cmp_headers) (const HEADER *, const HEADER *) = NULL;
  HEADER **old_hdrs;
  int old_msgcount;
  int msg_mod = 0;
  int index_hint_set;
  int i, j;
  int rc = -1;

  /* silent operations */
  ctx->quiet = 1;

  mutt_message _("Reopening mailbox...");

  /* our heuristics require the old mailbox to be unsorted */
  if (Sort != SORT_ORDER) {
    short old_sort;

    old_sort = Sort;
    Sort = SORT_ORDER;
    mutt_sort_headers (ctx, 1);
    Sort = old_sort;
  }

  old_hdrs = NULL;
  old_msgcount = 0;

  /* simulate a close */
  if (ctx->id_hash)
    hash_destroy (&ctx->id_hash, NULL);
  if (ctx->subj_hash)
    hash_destroy (&ctx->subj_hash, NULL);
  mutt_clear_threads (ctx);
  mem_free (&ctx->v2r);
  if (ctx->readonly) {
    for (i = 0; i < ctx->msgcount; i++)
      mutt_free_header (&(ctx->hdrs[i]));       /* nothing to do! */
    mem_free (&ctx->hdrs);
  }
  else {
    /* save the old headers */
    old_msgcount = ctx->msgcount;
    old_hdrs = ctx->hdrs;
    ctx->hdrs = NULL;
  }

  ctx->hdrmax = 0;              /* force allocation of new headers */
  ctx->msgcount = 0;
  ctx->vcount = 0;
  ctx->tagged = 0;
  ctx->deleted = 0;
  ctx->new = 0;
  ctx->unread = 0;
  ctx->flagged = 0;
  ctx->changed = 0;
  ctx->id_hash = NULL;
  ctx->subj_hash = NULL;

  switch (ctx->magic) {
  case M_MBOX:
  case M_MMDF:
    if (fseeko (ctx->fp, 0, SEEK_SET) != 0) {
      debug_print (1, ("fseeko() failed\n"));
      rc = -1;
    }
    else {
      cmp_headers = mutt_cmp_header;
      if (ctx->magic == M_MBOX)
        rc = mbox_parse_mailbox (ctx);
      else
        rc = mmdf_parse_mailbox (ctx);
    }
    break;

  default:
    rc = -1;
    break;
  }

  if (rc == -1) {
    /* free the old headers */
    for (j = 0; j < old_msgcount; j++)
      mutt_free_header (&(old_hdrs[j]));
    mem_free (&old_hdrs);

    ctx->quiet = 0;
    return (-1);
  }

  /* now try to recover the old flags */

  index_hint_set = (index_hint == NULL);

  if (!ctx->readonly) {
    for (i = 0; i < ctx->msgcount; i++) {
      int found = 0;

      /* some messages have been deleted, and new  messages have been
       * appended at the end; the heuristic is that old messages have then
       * "advanced" towards the beginning of the folder, so we begin the
       * search at index "i"
       */
      for (j = i; j < old_msgcount; j++) {
        if (old_hdrs[j] == NULL)
          continue;
        if (cmp_headers (ctx->hdrs[i], old_hdrs[j])) {
          found = 1;
          break;
        }
      }
      if (!found) {
        for (j = 0; j < i && j < old_msgcount; j++) {
          if (old_hdrs[j] == NULL)
            continue;
          if (cmp_headers (ctx->hdrs[i], old_hdrs[j])) {
            found = 1;
            break;
          }
        }
      }

      if (found) {
        /* this is best done here */
        if (!index_hint_set && *index_hint == j)
          *index_hint = i;

        if (old_hdrs[j]->changed) {
          /* Only update the flags if the old header was changed;
           * otherwise, the header may have been modified externally,
           * and we don't want to lose _those_ changes
           */
          mutt_set_flag (ctx, ctx->hdrs[i], M_FLAG, old_hdrs[j]->flagged);
          mutt_set_flag (ctx, ctx->hdrs[i], M_REPLIED, old_hdrs[j]->replied);
          mutt_set_flag (ctx, ctx->hdrs[i], M_OLD, old_hdrs[j]->old);
          mutt_set_flag (ctx, ctx->hdrs[i], M_READ, old_hdrs[j]->read);
        }
        mutt_set_flag (ctx, ctx->hdrs[i], M_DELETE, old_hdrs[j]->deleted);
        mutt_set_flag (ctx, ctx->hdrs[i], M_TAG, old_hdrs[j]->tagged);

        /* we don't need this header any more */
        mutt_free_header (&(old_hdrs[j]));
      }
    }

    /* free the remaining old headers */
    for (j = 0; j < old_msgcount; j++) {
      if (old_hdrs[j]) {
        mutt_free_header (&(old_hdrs[j]));
        msg_mod = 1;
      }
    }
    mem_free (&old_hdrs);
  }

  ctx->quiet = 0;

  return ((ctx->changed || msg_mod) ? M_REOPENED : M_NEW_MAIL);
}

/*
 * Returns:
 * 1 if the mailbox is not empty
 * 0 if the mailbox is empty
 * -1 on error
 */
int mbox_check_empty (const char *path)
{
  struct stat st;

  if (stat (path, &st) == -1)
    return -1;

  return ((st.st_size == 0));
}

int mbox_is_magic (const char* path, struct stat* st) {
  int magic = -1;
  FILE* f;
  char tmp[_POSIX_PATH_MAX];

  if (S_ISDIR(st->st_mode))
    return (-1);

  if (st->st_size == 0) {
    /* hard to tell what zero-length files are, so assume the default magic */
    if (DefaultMagic == M_MBOX || DefaultMagic == M_MMDF)
      return (DefaultMagic);
    else
      return (M_MBOX);
  }
  else if ((f = fopen (path, "r")) != NULL) {
#ifndef BUFFY_SIZE
    struct utimbuf times;
#endif
    fgets (tmp, sizeof (tmp), f);
    if (str_ncmp ("From ", tmp, 5) == 0)
      magic = M_MBOX;
    else if (str_cmp (MMDF_SEP, tmp) == 0)
      magic = M_MMDF;
    safe_fclose (&f);
#ifndef BUFFY_SIZE
    /* need to restore the times here, the file was not really accessed,
     * only the type was accessed.  This is important, because detection
     * of "new mail" depends on those times set correctly.
     */
    times.actime = st->st_atime;
    times.modtime = st->st_mtime;
    utime (path, &times);
#endif
  } else {
    mutt_perror (path);
    return (-1);         /* fopen failed */
  }

#ifdef USE_COMPRESSED
  if (magic == -1 && mutt_can_read_compressed (path))
    return (M_COMPRESSED);
#endif
  return (magic);
}

static int commit_message (MESSAGE* msg, CONTEXT* ctx, int mbox) {
  if ((mbox && fputc ('\n', msg->fp) == EOF) ||
      (!mbox && fputs (MMDF_SEP, msg->fp) == EOF))
    return (-1);
  if ((fflush (msg->fp) == EOF || fsync (fileno (msg->fp)) == -1)) {
    mutt_perror (_("Can't write message"));
    return (-1);
  }
  return (0);
}

static int mbox_commit_message (MESSAGE* msg, CONTEXT* ctx) {
  return (commit_message (msg, ctx, 1));
}

static int mmdf_commit_message (MESSAGE* msg, CONTEXT* ctx) {
  return (commit_message (msg, ctx, 0));
}

static mx_t* reg_mx (void) {
  mx_t* fmt = mem_calloc (1, sizeof (mx_t));
  fmt->local = 1;
  fmt->mx_check_empty = mbox_check_empty;
  fmt->mx_is_magic = mbox_is_magic;
  fmt->mx_access = access;
  fmt->mx_open_mailbox = mbox_open_mailbox;
  fmt->mx_open_new_message = mbox_open_new_message;
  fmt->mx_sync_mailbox = mbox_sync_mailbox;
  fmt->mx_check_mailbox = mbox_check_mailbox;
  return (fmt);
}

mx_t* mbox_reg_mx (void) {
  mx_t* fmt = reg_mx ();
  fmt->type = M_MBOX;
  fmt->mx_commit_message = mbox_commit_message;
  return (fmt);
}
mx_t* mmdf_reg_mx (void) {
  mx_t* fmt = reg_mx ();
  fmt->type = M_MMDF;
  fmt->mx_commit_message = mmdf_commit_message;
  return (fmt);
}