Commit b8ead34f authored by Paul Eggert's avatar Paul Eggert

Fix more ungetc bugs with encoding errors

* src/lread.c (infile): New variable, replacing ...
(instream): ... this.  All uses changed.
(readbyte_from_stdio): New function, which deals with lookahead.
(readbyte_from_file, Fget_file_char): Use it.
(Fget_file_char): When misused, signal an error instead of
relying on undefined behavior.
(close_infile_unwind): New function.
(Fload): Use it.
(readevalloop): 2nd arg is now struct infile *, not FILE *.
All callers changed.
(read1): Handle lookahead when copying doc strings with
encoding errors.
parent 16283058
......@@ -103,8 +103,20 @@ static Lisp_Object read_objects_map;
(to reduce allocations), or nil. */
static Lisp_Object read_objects_completed;
/* File for get_file_char to read from. Use by load. */
static FILE *instream;
/* File and lookahead for get-file-char and get-emacs-mule-file-char
to read from. Used by Fload. */
static struct infile
{
/* The input stream. */
FILE *stream;
/* Lookahead byte count. */
signed char lookahead;
/* Lookahead bytes, in reverse order. Keep these here because it is
not portable to ungetc more than one byte at a time. */
unsigned char buf[MAX_MULTIBYTE_LENGTH - 1];
} *infile;
/* For use within read-from-string (this reader is non-reentrant!!) */
static ptrdiff_t read_from_string_index;
......@@ -149,7 +161,7 @@ static Lisp_Object Vloads_in_progress;
static int read_emacs_mule_char (int, int (*) (int, Lisp_Object),
Lisp_Object);
static void readevalloop (Lisp_Object, FILE *, Lisp_Object, bool,
static void readevalloop (Lisp_Object, struct infile *, Lisp_Object, bool,
Lisp_Object, Lisp_Object,
Lisp_Object, Lisp_Object);
......@@ -361,8 +373,9 @@ skip_dyn_bytes (Lisp_Object readcharfun, ptrdiff_t n)
if (FROM_FILE_P (readcharfun))
{
block_input (); /* FIXME: Not sure if it's needed. */
fseek (instream, n, SEEK_CUR);
fseek (infile->stream, n - infile->lookahead, SEEK_CUR);
unblock_input ();
infile->lookahead = 0;
}
else
{ /* We're not reading directly from a file. In that case, it's difficult
......@@ -384,8 +397,9 @@ skip_dyn_eof (Lisp_Object readcharfun)
if (FROM_FILE_P (readcharfun))
{
block_input (); /* FIXME: Not sure if it's needed. */
fseek (instream, 0, SEEK_END);
fseek (infile->stream, 0, SEEK_END);
unblock_input ();
infile->lookahead = 0;
}
else
while (READCHAR >= 0);
......@@ -458,15 +472,13 @@ readbyte_for_lambda (int c, Lisp_Object readcharfun)
static int
readbyte_from_file (int c, Lisp_Object readcharfun)
readbyte_from_stdio (void)
{
if (c >= 0)
{
block_input ();
ungetc (c, instream);
unblock_input ();
return 0;
}
if (infile->lookahead)
return infile->buf[--infile->lookahead];
int c;
FILE *instream = infile->stream;
block_input ();
......@@ -485,6 +497,19 @@ readbyte_from_file (int c, Lisp_Object readcharfun)
return (c == EOF ? -1 : c);
}
static int
readbyte_from_file (int c, Lisp_Object readcharfun)
{
if (c >= 0)
{
eassert (infile->lookahead < sizeof infile->buf);
infile->buf[infile->lookahead++] = c;
return 0;
}
return readbyte_from_stdio ();
}
static int
readbyte_from_string (int c, Lisp_Object readcharfun)
{
......@@ -507,7 +532,7 @@ readbyte_from_string (int c, Lisp_Object readcharfun)
}
/* Read one non-ASCII character from INSTREAM. The character is
/* Read one non-ASCII character from INFILE. The character is
encoded in `emacs-mule' and the first byte is already read in
C. */
......@@ -777,11 +802,9 @@ DEFUN ("get-file-char", Fget_file_char, Sget_file_char, 0, 0, 0,
doc: /* Don't use this yourself. */)
(void)
{
register Lisp_Object val;
block_input ();
XSETINT (val, getc_unlocked (instream));
unblock_input ();
return val;
if (!infile)
error ("get-file-char misused");
return make_number (readbyte_from_stdio ());
}
......@@ -1026,6 +1049,15 @@ suffix_p (Lisp_Object string, const char *suffix)
return string_len >= suffix_len && !strcmp (SSDATA (string) + string_len - suffix_len, suffix);
}
static void
close_infile_unwind (void *arg)
{
FILE *stream = arg;
eassert (infile->stream == stream);
infile = NULL;
fclose (stream);
}
DEFUN ("load", Fload, Sload, 1, 5, 0,
doc: /* Execute a file of Lisp code named FILE.
First try FILE with `.elc' appended, then try with `.el', then try
......@@ -1345,7 +1377,7 @@ Return t if the file exists and loads successfully. */)
}
if (! stream)
report_file_error ("Opening stdio stream", file);
set_unwind_protect_ptr (fd_index, fclose_unwind, stream);
set_unwind_protect_ptr (fd_index, close_infile_unwind, stream);
if (! NILP (Vpurify_flag))
Vpreloaded_file_list = Fcons (Fpurecopy (file), Vpreloaded_file_list);
......@@ -1368,19 +1400,23 @@ Return t if the file exists and loads successfully. */)
specbind (Qinhibit_file_name_operation, Qnil);
specbind (Qload_in_progress, Qt);
instream = stream;
struct infile input;
input.stream = stream;
input.lookahead = 0;
infile = &input;
if (lisp_file_lexically_bound_p (Qget_file_char))
Fset (Qlexical_binding, Qt);
if (! version || version >= 22)
readevalloop (Qget_file_char, stream, hist_file_name,
readevalloop (Qget_file_char, &input, hist_file_name,
0, Qnil, Qnil, Qnil, Qnil);
else
{
/* We can't handle a file which was compiled with
byte-compile-dynamic by older version of Emacs. */
specbind (Qload_force_doc_strings, Qt);
readevalloop (Qget_emacs_mule_file_char, stream, hist_file_name,
readevalloop (Qget_emacs_mule_file_char, &input, hist_file_name,
0, Qnil, Qnil, Qnil, Qnil);
}
unbind_to (count, Qnil);
......@@ -1811,7 +1847,7 @@ readevalloop_eager_expand_eval (Lisp_Object val, Lisp_Object macroexpand)
static void
readevalloop (Lisp_Object readcharfun,
FILE *stream,
struct infile *infile0,
Lisp_Object sourcename,
bool printflag,
Lisp_Object unibyte, Lisp_Object readfun,
......@@ -1911,7 +1947,7 @@ readevalloop (Lisp_Object readcharfun,
if (b && first_sexp)
whole_buffer = (BUF_PT (b) == BUF_BEG (b) && BUF_ZV (b) == BUF_Z (b));
instream = stream;
infile = infile0;
read_next:
c = READCHAR;
if (c == ';')
......@@ -2001,7 +2037,7 @@ readevalloop (Lisp_Object readcharfun,
}
build_load_history (sourcename,
stream || whole_buffer);
infile0 || whole_buffer);
unbind_to (count, Qnil);
}
......@@ -2941,11 +2977,17 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
saved_doc_string_size = nskip + extra;
}
saved_doc_string_position = file_tell (instream);
FILE *instream = infile->stream;
saved_doc_string_position = (file_tell (instream)
- infile->lookahead);
/* Copy that many characters into saved_doc_string. */
/* Copy that many bytes into saved_doc_string. */
i = 0;
for (int n = min (nskip, infile->lookahead); 0 < n; n--)
saved_doc_string[i++]
= c = infile->buf[--infile->lookahead];
block_input ();
for (i = 0; i < nskip && c >= 0; i++)
for (; i < nskip && 0 <= c; i++)
saved_doc_string[i] = c = getc_unlocked (instream);
unblock_input ();
......
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