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));
}
}
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));
}
}