news.c

广泛使用的邮件服务器！同时

    mail_exists (stream,nmsgs);	/* notify upper level that messages exist */
    stream->local = fs_get (sizeof (NEWSLOCAL));
    LOCAL->dirty = NIL;		/* no update to .newsrc needed yet */
    LOCAL->dir = cpystr (tmp);	/* copy directory name for later */
    LOCAL->name = cpystr (stream->mailbox + 6);
    for (i = 0; i < nmsgs; ++i) {
      stream->uid_last = mail_elt (stream,i+1)->private.uid =
	atoi (names[i]->d_name);
      fs_give ((void **) &names[i]);
    }
    s = (void *) names;		/* stupid language */
    fs_give ((void **) &s);	/* free directory */
    LOCAL->cachedtexts = 0;	/* no cached texts */
    stream->sequence++;		/* bump sequence number */
    stream->rdonly = stream->perm_deleted = T;
				/* UIDs are always valid */
    stream->uid_validity = 0xbeefface;
				/* read .newsrc entries */
    mail_recent (stream,newsrc_read (LOCAL->name,stream));
				/* notify if empty newsgroup */
    if (!(stream->nmsgs || stream->silent)) {
      sprintf (tmp,"Newsgroup %s is empty",LOCAL->name);
      mm_log (tmp,WARN);
    }
  }
  else mm_log ("Unable to scan newsgroup spool directory",ERROR);
  return LOCAL ? stream : NIL;	/* if stream is alive, return to caller */
}

/* News file name selection test
 * Accepts: candidate directory entry
 * Returns: T to use file name, NIL to skip it
 */

int news_select (struct direct *name)
{
  char c;
  char *s = name->d_name;
  while (c = *s++) if (!isdigit (c)) return NIL;
  return T;
}


/* News file name comparision
 * Accepts: first candidate directory entry
 *	    second candidate directory entry
 * Returns: negative if d1 < d2, 0 if d1 == d2, postive if d1 > d2
 */

int news_numsort (const void *d1,const void *d2)
{
  return atoi ((*(struct direct **) d1)->d_name) -
    atoi ((*(struct direct **) d2)->d_name);
}


/* News close
 * Accepts: MAIL stream
 *	    option flags
 */

void news_close (MAILSTREAM *stream,long options)
{
  if (LOCAL) {			/* only if a file is open */
    news_check (stream);	/* dump final checkpoint */
    if (LOCAL->dir) fs_give ((void **) &LOCAL->dir);
    if (LOCAL->name) fs_give ((void **) &LOCAL->name);
				/* nuke the local data */
    fs_give ((void **) &stream->local);
    stream->dtb = NIL;		/* log out the DTB */
  }
}

/* News fetch fast information
 * Accepts: MAIL stream
 *	    sequence
 *	    option flags
 */

void news_fast (MAILSTREAM *stream,char *sequence,long flags)
{
  MESSAGECACHE *elt;
  unsigned long i;
				/* set up metadata for all messages */
  if (stream && LOCAL && ((flags & FT_UID) ?
			  mail_uid_sequence (stream,sequence) :
			  mail_sequence (stream,sequence)))
    for (i = 1; i <= stream->nmsgs; i++)
      if ((elt = mail_elt (stream,i))->sequence &&
	  !(elt->day && elt->rfc822_size)) news_load_message (stream,i,NIL);
}


/* News fetch flags
 * Accepts: MAIL stream
 *	    sequence
 *	    option flags
 */

void news_flags (MAILSTREAM *stream,char *sequence,long flags)
{
  unsigned long i;
  if ((flags & FT_UID) ?	/* validate all elts */
      mail_uid_sequence (stream,sequence) : mail_sequence (stream,sequence))
    for (i = 1; i <= stream->nmsgs; i++) mail_elt (stream,i)->valid = T;
}

/* News load message into cache
 * Accepts: MAIL stream
 *	    message #
 *	    option flags
 */

void news_load_message (MAILSTREAM *stream,unsigned long msgno,long flags)
{
  unsigned long i,j,nlseen;
  int fd;
  unsigned char c,*t;
  struct stat sbuf;
  MESSAGECACHE *elt;
  FDDATA d;
  STRING bs;
  elt = mail_elt (stream,msgno);/* get elt */
				/* build message file name */
  sprintf (LOCAL->buf,"%s/%lu",LOCAL->dir,elt->private.uid);
				/* anything we need not currently cached? */
  if ((!elt->day || !elt->rfc822_size ||
       ((flags & NLM_HEADER) && !elt->private.msg.header.text.data) ||
       ((flags & NLM_TEXT) && !elt->private.msg.text.text.data)) &&
      ((fd = open (LOCAL->buf,O_RDONLY,NIL)) >= 0)) {
    fstat (fd,&sbuf);		/* get file metadata */
    d.fd = fd;			/* set up file descriptor */
    d.pos = 0;			/* start of file */
    d.chunk = LOCAL->buf;
    d.chunksize = CHUNKSIZE;
    INIT (&bs,fd_string,&d,sbuf.st_size);
    if (!elt->day) {		/* set internaldate to file date */
      struct tm *tm = gmtime (&sbuf.st_mtime);
      elt->day = tm->tm_mday; elt->month = tm->tm_mon + 1;
      elt->year = tm->tm_year + 1900 - BASEYEAR;
      elt->hours = tm->tm_hour; elt->minutes = tm->tm_min;
      elt->seconds = tm->tm_sec;
      elt->zhours = 0; elt->zminutes = 0;
    }

    if (!elt->rfc822_size) {	/* know message size yet? */
      for (i = 0, j = SIZE (&bs), nlseen = 0; j--; ) switch (SNX (&bs)) {
      case '\015':		/* unlikely carriage return */
	if (!j || (CHR (&bs) != '\012')) {
	  i++;			/* ugh, raw CR */
	  nlseen = NIL;
	  break;
	}
	SNX (&bs);		/* eat the line feed, drop in */
      case '\012':		/* line feed? */
	i += 2;			/* count a CRLF */
				/* header size known yet? */
	if (!elt->private.msg.header.text.size && nlseen) {
				/* note position in file */
	  elt->private.special.text.size = GETPOS (&bs);
				/* and CRLF-adjusted size */
	  elt->private.msg.header.text.size = i;
	}
	nlseen = T;		/* note newline seen */
	break;
      default:			/* ordinary chararacter */
	i++;
	nlseen = NIL;
	break;
      }
      SETPOS (&bs,0);		/* restore old position */
      elt->rfc822_size = i;	/* note that we have size now */
				/* header is entire message if no delimiter */
      if (!elt->private.msg.header.text.size)
	elt->private.msg.header.text.size = elt->rfc822_size;
				/* text is remainder of message */
      elt->private.msg.text.text.size =
	elt->rfc822_size - elt->private.msg.header.text.size;
    }

				/* need to load cache with message data? */
    if (((flags & NLM_HEADER) && !elt->private.msg.header.text.data) ||
	((flags & NLM_TEXT) && !elt->private.msg.text.text.data)) {
				/* purge cache if too big */
      if (LOCAL->cachedtexts > max (stream->nmsgs * 4096,2097152)) {
				/* just can't keep that much */
	mail_gc (stream,GC_TEXTS);
	LOCAL->cachedtexts = 0;
      }
      if ((flags & NLM_HEADER) && !elt->private.msg.header.text.data) {
	t = elt->private.msg.header.text.data =
	  (unsigned char *) fs_get (elt->private.msg.header.text.size + 1);
	LOCAL->cachedtexts += elt->private.msg.header.text.size;
				/* read in message header */
	for (i = 0; i <= elt->private.msg.header.text.size; i++)
	  switch (c = SNX (&bs)) {
	  case '\015':		/* unlikely carriage return */
	    *t++ = c;
	    if ((CHR (&bs) == '\012')) *t++ = SNX (&bs);
	    break;
	  case '\012':		/* line feed? */
	    *t++ = '\015';
	  default:
	    *t++ = c;
	    break;
	  }
	*t = '\0';		/* tie off string */
      }
      if ((flags & NLM_TEXT) && !elt->private.msg.text.text.data) {
	t = elt->private.msg.text.text.data =
	  (unsigned char *) fs_get (elt->private.msg.text.text.size + 1);
	SETPOS (&bs,elt->private.msg.header.text.size);
	LOCAL->cachedtexts += elt->private.msg.text.text.size;
				/* read in message text */
	for (i = 0; i <= elt->private.msg.text.text.size; i++)
	  switch (c = SNX (&bs)) {
	  case '\015':		/* unlikely carriage return */
	    *t++ = c;
	    if ((CHR (&bs) == '\012')) *t++ = SNX (&bs);
	    break;
	  case '\012':		/* line feed? */
	    *t++ = '\015';
	  default:
	    *t++ = c;
	    break;
	  }
	*t = '\0';		/* tie off string */
      }
    }
    close (fd);			/* flush message file */
  }
}

/* News fetch message header
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned header text length
 *	    option flags
 * Returns: message header in RFC822 format
 */

char *news_header (MAILSTREAM *stream,unsigned long msgno,
		   unsigned long *length,long flags)
{
  MESSAGECACHE *elt;
  *length = 0;			/* default to empty */
  if (flags & FT_UID) return "";/* UID call "impossible" */
  elt = mail_elt (stream,msgno);/* get elt */
  if (!elt->private.msg.header.text.data)
    news_load_message (stream,msgno,NLM_HEADER);
  *length = elt->private.msg.header.text.size;
  return (char *) elt->private.msg.header.text.data;
}


/* News fetch message text (body only)
 * Accepts: MAIL stream
 *	    message # to fetch
 *	    pointer to returned stringstruct
 *	    option flags
 * Returns: T on success, NIL on failure
 */

long news_text (MAILSTREAM *stream,unsigned long msgno,STRING *bs,long flags)
{
  MESSAGECACHE *elt;
				/* UID call "impossible" */
  if (flags & FT_UID) return NIL;
  elt = mail_elt (stream,msgno);/* get elt */
				/* snarf message if don't have it yet */
  if (!elt->private.msg.text.text.data) {
    news_load_message (stream,msgno,NLM_TEXT);
    if (!elt->private.msg.text.text.data) return NIL;
  }
  if (!(flags & FT_PEEK)) {	/* mark as seen */
    mail_elt (stream,msgno)->seen = T;
    mm_flags (stream,msgno);
  }
  INIT (bs,mail_string,elt->private.msg.text.text.data,
	elt->private.msg.text.text.size);
  return T;
}

/* News per-message modify flag
 * Accepts: MAIL stream
 *	    message cache element
 */

void news_flagmsg (MAILSTREAM *stream,MESSAGECACHE *elt)
{
  if (!LOCAL->dirty) {		/* only bother checking if not dirty yet */
    if (elt->valid) {		/* if done, see if deleted changed */
      if (elt->sequence != elt->deleted) LOCAL->dirty = T;
      elt->sequence = T;	/* leave the sequence set */
    }
				/* note current setting of deleted flag */
    else elt->sequence = elt->deleted;
  }
}


/* News ping mailbox
 * Accepts: MAIL stream
 * Returns: T if stream alive, else NIL
 */

long news_ping (MAILSTREAM *stream)
{
  return T;			/* always alive */
}


/* News check mailbox
 * Accepts: MAIL stream
 */

void news_check (MAILSTREAM *stream)
{
				/* never do if no updates */
  if (LOCAL->dirty) newsrc_write (LOCAL->name,stream);
  LOCAL->dirty = NIL;
}


/* News expunge mailbox
 * Accepts: MAIL stream
 *	    sequence to expunge if non-NIL
 *	    expunge options
 * Returns: T if success, NIL if failure
 */

long news_expunge (MAILSTREAM *stream,char *sequence,long options)
{
  if (!stream->silent) mm_log ("Expunge ignored on readonly mailbox",NIL);
  return LONGT;
}

/* News copy message(s)
 * Accepts: MAIL stream
 *	    sequence
 *	    destination mailbox
 *	    option flags
 * Returns: T if copy successful, else NIL
 */

long news_copy (MAILSTREAM *stream,char *sequence,char *mailbox,long options)
{
  mailproxycopy_t pc =
    (mailproxycopy_t) mail_parameters (stream,GET_MAILPROXYCOPY,NIL);
  if (pc) return (*pc) (stream,sequence,mailbox,options);
  mm_log ("Copy not valid for News",ERROR);
  return NIL;
}


/* News append message from stringstruct
 * Accepts: MAIL stream
 *	    destination mailbox
 *	    append callback function
 *	    data for callback
 * Returns: T if append successful, else NIL
 */

long news_append (MAILSTREAM *stream,char *mailbox,append_t af,void *data)
{
  mm_log ("Append not valid for news",ERROR);
  return NIL;
}