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Commit f0a1e9ec authored by Paul Eggert's avatar Paul Eggert
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Make read1 more reentrant 

This is needed if ‘read’ is called soon after startup, before the
Unicode tables have been set up, and it reads a \N escape and
needs to look up a value the Unicode tables, a lookup that in turn
calls read1 recursively.  Although this change doesn’t make ‘read’
fully reentrant, it’s good enough to handle this case.
* src/lread.c (read_buffer_size, read_buffer): Remove static vars.
(grow_read_buffer): Revamp to use locals, not statics, and to
record memory allocation un the specpdl.  All callers changed.
(read1): Start with a stack-based buffer, and use the heap
only if the stack buffer is too small.  Use unbind_to to
free any heap buffer allocated.  Use bool for boolean.
Redo symbol loop so that only one call to grow_read_buffer
is needed.
(init_obarray): Remove no-longer-needed initialization.
parent 162ba405
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Showing with 106 additions and 97 deletions
src/lread.c
View file @ f0a1e9ec
......@@ -2144,16 +2144,28 @@ read0 (Lisp_Object readcharfun)
Fmake_string (make_number (1), make_number (c)));
}
static ptrdiff_t read_buffer_size;
static char *read_buffer;
/* Grow the read buffer by at least MAX_MULTIBYTE_LENGTH bytes. */
static void
grow_read_buffer (void)
/* Grow a read buffer BUF that contains OFFSET useful bytes of data,
by at least MAX_MULTIBYTE_LENGTH bytes. Update *BUF_ADDR and
*BUF_SIZE accordingly; 0 <= OFFSET <= *BUF_SIZE. If *BUF_ADDR is
initially null, BUF is on the stack: copy its data to the new heap
buffer. Otherwise, BUF must equal *BUF_ADDR and can simply be
reallocated. Either way, remember the heap allocation (which is at
pdl slot COUNT) so that it can be freed when unwinding the stack.*/
static char *
grow_read_buffer (char *buf, ptrdiff_t offset,
char **buf_addr, ptrdiff_t *buf_size, ptrdiff_t count)
{
read_buffer = xpalloc (read_buffer, &read_buffer_size,
MAX_MULTIBYTE_LENGTH, -1, 1);
char *p = xpalloc (*buf_addr, buf_size, MAX_MULTIBYTE_LENGTH, -1, 1);
if (!*buf_addr)
{
memcpy (p, buf, offset);
record_unwind_protect_ptr (xfree, p);
}
else
set_unwind_protect_ptr (count, xfree, p);
*buf_addr = p;
return p;
}
/* Return the scalar value that has the Unicode character name NAME.
......@@ -2432,6 +2444,9 @@ read_escape (Lisp_Object readcharfun, bool stringp)
if (length == 0)
invalid_syntax ("Empty character name");
name[length] = '\0';
/* character_name_to_code can invoke read1, recursively.
This is why read1's buffer is not static. */
return character_name_to_code (name, length);
}
......@@ -2541,8 +2556,9 @@ static Lisp_Object
read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
{
int c;
bool uninterned_symbol = 0;
bool uninterned_symbol = false;
bool multibyte;
char stackbuf[MAX_ALLOCA];
*pch = 0;
......@@ -2873,7 +2889,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
/* #:foo is the uninterned symbol named foo. */
if (c == ':')
{
uninterned_symbol = 1;
uninterned_symbol = true;
c = READCHAR;
if (!(c > 040
&& c != NO_BREAK_SPACE
......@@ -3084,16 +3100,20 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
case '"':
{
ptrdiff_t count = SPECPDL_INDEX ();
char *read_buffer = stackbuf;
ptrdiff_t read_buffer_size = sizeof stackbuf;
char *heapbuf = NULL;
char *p = read_buffer;
char *end = read_buffer + read_buffer_size;
int ch;
/* True if we saw an escape sequence specifying
a multibyte character. */
bool force_multibyte = 0;
bool force_multibyte = false;
/* True if we saw an escape sequence specifying
a single-byte character. */
bool force_singlebyte = 0;
bool cancel = 0;
bool force_singlebyte = false;
bool cancel = false;
ptrdiff_t nchars = 0;
while ((ch = READCHAR) >= 0
......@@ -3102,7 +3122,9 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
if (end - p < MAX_MULTIBYTE_LENGTH)
{
ptrdiff_t offset = p - read_buffer;
grow_read_buffer ();
read_buffer = grow_read_buffer (read_buffer, offset,
&heapbuf, &read_buffer_size,
count);
p = read_buffer + offset;
end = read_buffer + read_buffer_size;
}
......@@ -3117,7 +3139,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
if (ch == -1)
{
if (p == read_buffer)
cancel = 1;
cancel = true;
continue;
}
......@@ -3125,9 +3147,9 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
ch = ch & ~CHAR_MODIFIER_MASK;
if (CHAR_BYTE8_P (ch))
force_singlebyte = 1;
force_singlebyte = true;
else if (! ASCII_CHAR_P (ch))
force_multibyte = 1;
force_multibyte = true;
else /* I.e. ASCII_CHAR_P (ch). */
{
/* Allow `\C- ' and `\C-?'. */
......@@ -3153,7 +3175,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
string. */
modifiers &= ~CHAR_META;
ch = BYTE8_TO_CHAR (ch | 0x80);
force_singlebyte = 1;
force_singlebyte = true;
}
}
......@@ -3166,9 +3188,9 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
{
p += CHAR_STRING (ch, (unsigned char *) p);
if (CHAR_BYTE8_P (ch))
force_singlebyte = 1;
force_singlebyte = true;
else if (! ASCII_CHAR_P (ch))
force_multibyte = 1;
force_multibyte = true;
}
nchars++;
}
......@@ -3180,7 +3202,7 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
return zero instead. This is for doc strings
that we are really going to find in etc/DOC.nn.nn. */
if (!NILP (Vpurify_flag) && NILP (Vdoc_file_name) && cancel)
return make_number (0);
return unbind_to (count, make_number (0));
if (! force_multibyte && force_singlebyte)
{
......@@ -3191,9 +3213,11 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
p = read_buffer + nchars;
}
return make_specified_string (read_buffer, nchars, p - read_buffer,
(force_multibyte
|| (p - read_buffer != nchars)));
Lisp_Object result
= make_specified_string (read_buffer, nchars, p - read_buffer,
(force_multibyte
|| (p - read_buffer != nchars)));
return unbind_to (count, result);
}
case '.':
......@@ -3221,81 +3245,74 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
read_symbol:
{
ptrdiff_t count = SPECPDL_INDEX ();
char *read_buffer = stackbuf;
ptrdiff_t read_buffer_size = sizeof stackbuf;
char *heapbuf = NULL;
char *p = read_buffer;
bool quoted = 0;
char *end = read_buffer + read_buffer_size;
bool quoted = false;
EMACS_INT start_position = readchar_count - 1;
{
char *end = read_buffer + read_buffer_size;
do
{
if (end - p < MAX_MULTIBYTE_LENGTH)
{
ptrdiff_t offset = p - read_buffer;
grow_read_buffer ();
p = read_buffer + offset;
end = read_buffer + read_buffer_size;
}
do
{
if (end - p < MAX_MULTIBYTE_LENGTH + 1)
{
ptrdiff_t offset = p - read_buffer;
read_buffer = grow_read_buffer (read_buffer, offset,
&heapbuf, &read_buffer_size,
count);
p = read_buffer + offset;
end = read_buffer + read_buffer_size;
}
if (c == '\\')
{
c = READCHAR;
if (c == -1)
end_of_file_error ();
quoted = 1;
}
if (c == '\\')
{
c = READCHAR;
if (c == -1)
end_of_file_error ();
quoted = true;
}
if (multibyte)
p += CHAR_STRING (c, (unsigned char *) p);
else
*p++ = c;
c = READCHAR;
}
while (c > 040
&& c != NO_BREAK_SPACE
&& (c >= 0200
|| strchr ("\"';()[]#`,", c) == NULL));
if (multibyte)
p += CHAR_STRING (c, (unsigned char *) p);
else
*p++ = c;
c = READCHAR;
}
while (c > 040
&& c != NO_BREAK_SPACE
&& (c >= 0200
|| strchr ("\"';()[]#`,", c) == NULL));
if (p == end)
{
ptrdiff_t offset = p - read_buffer;
grow_read_buffer ();
p = read_buffer + offset;
end = read_buffer + read_buffer_size;
}
*p = 0;
UNREAD (c);
}
*p = 0;
UNREAD (c);
if (!quoted && !uninterned_symbol)
{
Lisp_Object result = string_to_number (read_buffer, 10, 0);
if (! NILP (result))
return result;
return unbind_to (count, result);
}
{
Lisp_Object name, result;
ptrdiff_t nbytes = p - read_buffer;
ptrdiff_t nchars
= (multibyte
? multibyte_chars_in_text ((unsigned char *) read_buffer,
nbytes)
: nbytes);
name = ((uninterned_symbol && ! NILP (Vpurify_flag)
? make_pure_string : make_specified_string)
(read_buffer, nchars, nbytes, multibyte));
result = (uninterned_symbol ? Fmake_symbol (name)
: Fintern (name, Qnil));
if (EQ (Vread_with_symbol_positions, Qt)
|| EQ (Vread_with_symbol_positions, readcharfun))
Vread_symbol_positions_list
= Fcons (Fcons (result, make_number (start_position)),
Vread_symbol_positions_list);
return result;
}
ptrdiff_t nbytes = p - read_buffer;
ptrdiff_t nchars
= (multibyte
? multibyte_chars_in_text ((unsigned char *) read_buffer,
nbytes)
: nbytes);
Lisp_Object name = ((uninterned_symbol && ! NILP (Vpurify_flag)
? make_pure_string : make_specified_string)
(read_buffer, nchars, nbytes, multibyte));
Lisp_Object result = (uninterned_symbol ? Fmake_symbol (name)
: Fintern (name, Qnil));
if (EQ (Vread_with_symbol_positions, Qt)
|| EQ (Vread_with_symbol_positions, readcharfun))
Vread_symbol_positions_list
= Fcons (Fcons (result, make_number (start_position)),
Vread_symbol_positions_list);
return unbind_to (count, result);
}
}
}
......@@ -4104,12 +4121,7 @@ OBARRAY defaults to the value of `obarray'. */)
void
init_obarray (void)
{
Lisp_Object oblength;
ptrdiff_t size = 100 + MAX_MULTIBYTE_LENGTH;
XSETFASTINT (oblength, OBARRAY_SIZE);
Vobarray = Fmake_vector (oblength, make_number (0));
Vobarray = Fmake_vector (make_number (OBARRAY_SIZE), make_number (0));
initial_obarray = Vobarray;
staticpro (&initial_obarray);
......@@ -4132,9 +4144,6 @@ init_obarray (void)
Vpurify_flag = Qt;
DEFSYM (Qvariable_documentation, "variable-documentation");
read_buffer = xmalloc (size);
read_buffer_size = size;
}
void
......
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