Ejemplo n.º 1
0
Lisp_Object
get_doc_string (Lisp_Object filepos, bool unibyte, bool definition)
{
  char *from, *to, *name, *p, *p1;
  int fd;
  int offset;
  EMACS_INT position;
  Lisp_Object file, tem, pos;
  ptrdiff_t count;
  USE_SAFE_ALLOCA;

  if (INTEGERP (filepos))
    {
      file = Vdoc_file_name;
      pos = filepos;
    }
  else if (CONSP (filepos))
    {
      file = XCAR (filepos);
      pos = XCDR (filepos);
    }
  else
    return Qnil;

  position = eabs (XINT (pos));

  if (!STRINGP (Vdoc_directory))
    return Qnil;

  if (!STRINGP (file))
    return Qnil;

  /* Put the file name in NAME as a C string.
     If it is relative, combine it with Vdoc_directory.  */

  tem = Ffile_name_absolute_p (file);
  file = ENCODE_FILE (file);
  Lisp_Object docdir
    = NILP (tem) ? ENCODE_FILE (Vdoc_directory) : empty_unibyte_string;
  ptrdiff_t docdir_sizemax = SBYTES (docdir) + 1;
#ifndef CANNOT_DUMP
  docdir_sizemax = max (docdir_sizemax, sizeof sibling_etc);
#endif
  name = SAFE_ALLOCA (docdir_sizemax + SBYTES (file));
  lispstpcpy (lispstpcpy (name, docdir), file);

  fd = emacs_open (name, O_RDONLY, 0);
  if (fd < 0)
    {
#ifndef CANNOT_DUMP
      if (!NILP (Vpurify_flag))
	{
	  /* Preparing to dump; DOC file is probably not installed.
	     So check in ../etc.  */
	  lispstpcpy (stpcpy (name, sibling_etc), file);

	  fd = emacs_open (name, O_RDONLY, 0);
	}
#endif
      if (fd < 0)
	{
	  if (errno == EMFILE || errno == ENFILE)
	    report_file_error ("Read error on documentation file", file);

	  SAFE_FREE ();
	  AUTO_STRING (cannot_open, "Cannot open doc string file \"");
	  AUTO_STRING (quote_nl, "\"\n");
	  return concat3 (cannot_open, file, quote_nl);
	}
    }
  count = SPECPDL_INDEX ();
  record_unwind_protect_int (close_file_unwind, fd);

  /* Seek only to beginning of disk block.  */
  /* Make sure we read at least 1024 bytes before `position'
     so we can check the leading text for consistency.  */
  offset = min (position, max (1024, position % (8 * 1024)));
  if (TYPE_MAXIMUM (off_t) < position
      || lseek (fd, position - offset, 0) < 0)
    error ("Position %"pI"d out of range in doc string file \"%s\"",
	   position, name);

  /* Read the doc string into get_doc_string_buffer.
     P points beyond the data just read.  */

  p = get_doc_string_buffer;
  while (1)
    {
      ptrdiff_t space_left = (get_doc_string_buffer_size - 1
			      - (p - get_doc_string_buffer));
      int nread;

      /* Allocate or grow the buffer if we need to.  */
      if (space_left <= 0)
	{
	  ptrdiff_t in_buffer = p - get_doc_string_buffer;
	  get_doc_string_buffer
	    = xpalloc (get_doc_string_buffer, &get_doc_string_buffer_size,
		       16 * 1024, -1, 1);
	  p = get_doc_string_buffer + in_buffer;
	  space_left = (get_doc_string_buffer_size - 1
			- (p - get_doc_string_buffer));
	}

      /* Read a disk block at a time.
         If we read the same block last time, maybe skip this?  */
      if (space_left > 1024 * 8)
	space_left = 1024 * 8;
      nread = emacs_read (fd, p, space_left);
      if (nread < 0)
	report_file_error ("Read error on documentation file", file);
      p[nread] = 0;
      if (!nread)
	break;
      if (p == get_doc_string_buffer)
	p1 = strchr (p + offset, '\037');
      else
	p1 = strchr (p, '\037');
      if (p1)
	{
	  *p1 = 0;
	  p = p1;
	  break;
	}
      p += nread;
    }
  unbind_to (count, Qnil);
  SAFE_FREE ();

  /* Sanity checking.  */
  if (CONSP (filepos))
    {
      int test = 1;
      /* A dynamic docstring should be either at the very beginning of a "#@
	 comment" or right after a dynamic docstring delimiter (in case we
	 pack several such docstrings within the same comment).  */
      if (get_doc_string_buffer[offset - test] != '\037')
	{
	  if (get_doc_string_buffer[offset - test++] != ' ')
	    return Qnil;
	  while (get_doc_string_buffer[offset - test] >= '0'
		 && get_doc_string_buffer[offset - test] <= '9')
	    test++;
	  if (get_doc_string_buffer[offset - test++] != '@'
	      || get_doc_string_buffer[offset - test] != '#')
	    return Qnil;
	}
    }
  else
    {
      int test = 1;
      if (get_doc_string_buffer[offset - test++] != '\n')
	return Qnil;
      while (get_doc_string_buffer[offset - test] > ' ')
	test++;
      if (get_doc_string_buffer[offset - test] != '\037')
	return Qnil;
    }

  /* Scan the text and perform quoting with ^A (char code 1).
     ^A^A becomes ^A, ^A0 becomes a null char, and ^A_ becomes a ^_.  */
  from = get_doc_string_buffer + offset;
  to = get_doc_string_buffer + offset;
  while (from != p)
    {
      if (*from == 1)
	{
	  int c;

	  from++;
	  c = *from++;
	  if (c == 1)
	    *to++ = c;
	  else if (c == '0')
	    *to++ = 0;
	  else if (c == '_')
	    *to++ = 037;
	  else
	    {
	      unsigned char uc = c;
	      error ("\
Invalid data in documentation file -- %c followed by code %03o",
		     1, uc);
	    }
	}
      else
	*to++ = *from++;
    }

  /* If DEFINITION, read from this buffer
     the same way we would read bytes from a file.  */
  if (definition)
    {
      read_bytecode_pointer = (unsigned char *) get_doc_string_buffer + offset;
      return Fread (Qlambda);
    }

  if (unibyte)
    return make_unibyte_string (get_doc_string_buffer + offset,
				to - (get_doc_string_buffer + offset));
  else
    {
      /* The data determines whether the string is multibyte.  */
      ptrdiff_t nchars
	= multibyte_chars_in_text (((unsigned char *) get_doc_string_buffer
				    + offset),
				   to - (get_doc_string_buffer + offset));
      return make_string_from_bytes (get_doc_string_buffer + offset,
				     nchars,
				     to - (get_doc_string_buffer + offset));
    }
}
Ejemplo n.º 2
0
Archivo: doc.c Proyecto: T-force/emacs
Lisp_Object
get_doc_string (Lisp_Object filepos, int unibyte, int definition)
{
  char *from, *to;
  register int fd;
  register char *name;
  register char *p, *p1;
  EMACS_INT minsize;
  EMACS_INT offset, position;
  Lisp_Object file, tem;

  if (INTEGERP (filepos))
    {
      file = Vdoc_file_name;
      position = XINT (filepos);
    }
  else if (CONSP (filepos))
    {
      file = XCAR (filepos);
      position = XINT (XCDR (filepos));
    }
  else
    return Qnil;

  if (position < 0)
    position = - position;

  if (!STRINGP (Vdoc_directory))
    return Qnil;

  if (!STRINGP (file))
    return Qnil;

  /* Put the file name in NAME as a C string.
     If it is relative, combine it with Vdoc_directory.  */

  tem = Ffile_name_absolute_p (file);
  if (NILP (tem))
    {
      minsize = SCHARS (Vdoc_directory);
      /* sizeof ("../etc/") == 8 */
      if (minsize < 8)
	minsize = 8;
      name = (char *) alloca (minsize + SCHARS (file) + 8);
      strcpy (name, SSDATA (Vdoc_directory));
      strcat (name, SSDATA (file));
    }
  else
    {
      name = SSDATA (file);
    }

  fd = emacs_open (name, O_RDONLY, 0);
  if (fd < 0)
    {
#ifndef CANNOT_DUMP
      if (!NILP (Vpurify_flag))
	{
	  /* Preparing to dump; DOC file is probably not installed.
	     So check in ../etc. */
	  strcpy (name, "../etc/");
	  strcat (name, SSDATA (file));

	  fd = emacs_open (name, O_RDONLY, 0);
	}
#endif
      if (fd < 0)
	error ("Cannot open doc string file \"%s\"", name);
    }

  /* Seek only to beginning of disk block.  */
  /* Make sure we read at least 1024 bytes before `position'
     so we can check the leading text for consistency.  */
  offset = min (position, max (1024, position % (8 * 1024)));
  if (0 > lseek (fd, position - offset, 0))
    {
      emacs_close (fd);
      error ("Position %"pI"d out of range in doc string file \"%s\"",
	     position, name);
    }

  /* Read the doc string into get_doc_string_buffer.
     P points beyond the data just read.  */

  p = get_doc_string_buffer;
  while (1)
    {
      EMACS_INT space_left = (get_doc_string_buffer_size
			      - (p - get_doc_string_buffer));
      int nread;

      /* Allocate or grow the buffer if we need to.  */
      if (space_left == 0)
	{
	  EMACS_INT in_buffer = p - get_doc_string_buffer;
	  get_doc_string_buffer_size += 16 * 1024;
	  get_doc_string_buffer
	    = (char *) xrealloc (get_doc_string_buffer,
				 get_doc_string_buffer_size + 1);
	  p = get_doc_string_buffer + in_buffer;
	  space_left = (get_doc_string_buffer_size
			- (p - get_doc_string_buffer));
	}

      /* Read a disk block at a time.
         If we read the same block last time, maybe skip this?  */
      if (space_left > 1024 * 8)
	space_left = 1024 * 8;
      nread = emacs_read (fd, p, space_left);
      if (nread < 0)
	{
	  emacs_close (fd);
	  error ("Read error on documentation file");
	}
      p[nread] = 0;
      if (!nread)
	break;
      if (p == get_doc_string_buffer)
	p1 = strchr (p + offset, '\037');
      else
	p1 = strchr (p, '\037');
      if (p1)
	{
	  *p1 = 0;
	  p = p1;
	  break;
	}
      p += nread;
    }
  emacs_close (fd);

  /* Sanity checking.  */
  if (CONSP (filepos))
    {
      int test = 1;
      if (get_doc_string_buffer[offset - test++] != ' ')
	return Qnil;
      while (get_doc_string_buffer[offset - test] >= '0'
	     && get_doc_string_buffer[offset - test] <= '9')
	test++;
      if (get_doc_string_buffer[offset - test++] != '@'
	  || get_doc_string_buffer[offset - test] != '#')
	return Qnil;
    }
  else
    {
      int test = 1;
      if (get_doc_string_buffer[offset - test++] != '\n')
	return Qnil;
      while (get_doc_string_buffer[offset - test] > ' ')
	test++;
      if (get_doc_string_buffer[offset - test] != '\037')
	return Qnil;
    }

  /* Scan the text and perform quoting with ^A (char code 1).
     ^A^A becomes ^A, ^A0 becomes a null char, and ^A_ becomes a ^_.  */
  from = get_doc_string_buffer + offset;
  to = get_doc_string_buffer + offset;
  while (from != p)
    {
      if (*from == 1)
	{
	  int c;

	  from++;
	  c = *from++;
	  if (c == 1)
	    *to++ = c;
	  else if (c == '0')
	    *to++ = 0;
	  else if (c == '_')
	    *to++ = 037;
	  else
	    {
	      unsigned char uc = c;
	      error ("\
Invalid data in documentation file -- %c followed by code %03o",
		     1, uc);
	    }
	}
      else
	*to++ = *from++;
    }

  /* If DEFINITION, read from this buffer
     the same way we would read bytes from a file.  */
  if (definition)
    {
      read_bytecode_pointer = (unsigned char *) get_doc_string_buffer + offset;
      return Fread (Qlambda);
    }

  if (unibyte)
    return make_unibyte_string (get_doc_string_buffer + offset,
				to - (get_doc_string_buffer + offset));
  else
    {
      /* The data determines whether the string is multibyte.  */
      EMACS_INT nchars =
	multibyte_chars_in_text (((unsigned char *) get_doc_string_buffer
				  + offset),
				 to - (get_doc_string_buffer + offset));
      return make_string_from_bytes (get_doc_string_buffer + offset,
				     nchars,
				     to - (get_doc_string_buffer + offset));
    }
}