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cpython/Parser/tokenizer/helpers.c

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#include "Python.h"
#include "errcode.h"
#include "pycore_token.h"
#include "../lexer/state.h"
/* ############## ERRORS ############## */
static int
_syntaxerror_range(struct tok_state *tok, const char *format,
int col_offset, int end_col_offset,
va_list vargs)
{
// In release builds, we don't want to overwrite a previous error, but in debug builds we
// want to fail if we are not doing it so we can fix it.
assert(tok->done != E_ERROR);
if (tok->done == E_ERROR) {
return ERRORTOKEN;
}
PyObject *errmsg, *errtext, *args;
errmsg = PyUnicode_FromFormatV(format, vargs);
if (!errmsg) {
goto error;
}
errtext = PyUnicode_DecodeUTF8(tok->line_start, tok->cur - tok->line_start,
"replace");
if (!errtext) {
goto error;
}
if (col_offset == -1) {
col_offset = (int)PyUnicode_GET_LENGTH(errtext);
}
if (end_col_offset == -1) {
end_col_offset = col_offset;
}
Py_ssize_t line_len = strcspn(tok->line_start, "\n");
if (line_len != tok->cur - tok->line_start) {
Py_DECREF(errtext);
errtext = PyUnicode_DecodeUTF8(tok->line_start, line_len,
"replace");
}
if (!errtext) {
goto error;
}
args = Py_BuildValue("(O(OiiNii))", errmsg, tok->filename, tok->lineno,
col_offset, errtext, tok->lineno, end_col_offset);
if (args) {
PyErr_SetObject(PyExc_SyntaxError, args);
Py_DECREF(args);
}
error:
Py_XDECREF(errmsg);
tok->done = E_ERROR;
return ERRORTOKEN;
}
int
_PyTokenizer_syntaxerror(struct tok_state *tok, const char *format, ...)
{
// This errors are cleaned on startup. Todo: Fix it.
va_list vargs;
va_start(vargs, format);
int ret = _syntaxerror_range(tok, format, -1, -1, vargs);
va_end(vargs);
return ret;
}
int
_PyTokenizer_syntaxerror_known_range(struct tok_state *tok,
int col_offset, int end_col_offset,
const char *format, ...)
{
va_list vargs;
va_start(vargs, format);
int ret = _syntaxerror_range(tok, format, col_offset, end_col_offset, vargs);
va_end(vargs);
return ret;
}
int
_PyTokenizer_indenterror(struct tok_state *tok)
{
tok->done = E_TABSPACE;
tok->cur = tok->inp;
return ERRORTOKEN;
}
char *
_PyTokenizer_error_ret(struct tok_state *tok) /* XXX */
{
tok->decoding_erred = 1;
if ((tok->fp != NULL || tok->readline != NULL) && tok->buf != NULL) {/* see _PyTokenizer_Free */
PyMem_Free(tok->buf);
}
tok->buf = tok->cur = tok->inp = NULL;
tok->start = NULL;
tok->end = NULL;
tok->done = E_DECODE;
return NULL; /* as if it were EOF */
}
int
_PyTokenizer_warn_invalid_escape_sequence(struct tok_state *tok, int first_invalid_escape_char)
{
if (!tok->report_warnings) {
return 0;
}
PyObject *msg = PyUnicode_FromFormat(
"invalid escape sequence '\\%c'",
(char) first_invalid_escape_char
);
if (msg == NULL) {
return -1;
}
if (PyErr_WarnExplicitObject(PyExc_SyntaxWarning, msg, tok->filename,
tok->lineno, NULL, NULL) < 0) {
Py_DECREF(msg);
if (PyErr_ExceptionMatches(PyExc_SyntaxWarning)) {
/* Replace the SyntaxWarning exception with a SyntaxError
to get a more accurate error report */
PyErr_Clear();
return _PyTokenizer_syntaxerror(tok, "invalid escape sequence '\\%c'", (char) first_invalid_escape_char);
}
return -1;
}
Py_DECREF(msg);
return 0;
}
int
_PyTokenizer_parser_warn(struct tok_state *tok, PyObject *category, const char *format, ...)
{
if (!tok->report_warnings) {
return 0;
}
PyObject *errmsg;
va_list vargs;
va_start(vargs, format);
errmsg = PyUnicode_FromFormatV(format, vargs);
va_end(vargs);
if (!errmsg) {
goto error;
}
if (PyErr_WarnExplicitObject(category, errmsg, tok->filename,
tok->lineno, NULL, NULL) < 0) {
if (PyErr_ExceptionMatches(category)) {
/* Replace the DeprecationWarning exception with a SyntaxError
to get a more accurate error report */
PyErr_Clear();
_PyTokenizer_syntaxerror(tok, "%U", errmsg);
}
goto error;
}
Py_DECREF(errmsg);
return 0;
error:
Py_XDECREF(errmsg);
tok->done = E_ERROR;
return -1;
}
/* ############## STRING MANIPULATION ############## */
char *
_PyTokenizer_new_string(const char *s, Py_ssize_t len, struct tok_state *tok)
{
char* result = (char *)PyMem_Malloc(len + 1);
if (!result) {
tok->done = E_NOMEM;
return NULL;
}
memcpy(result, s, len);
result[len] = '\0';
return result;
}
PyObject *
_PyTokenizer_translate_into_utf8(const char* str, const char* enc) {
PyObject *utf8;
PyObject* buf = PyUnicode_Decode(str, strlen(str), enc, NULL);
if (buf == NULL)
return NULL;
utf8 = PyUnicode_AsUTF8String(buf);
Py_DECREF(buf);
return utf8;
}
char *
_PyTokenizer_translate_newlines(const char *s, int exec_input, int preserve_crlf,
struct tok_state *tok) {
int skip_next_lf = 0;
size_t needed_length = strlen(s) + 2, final_length;
char *buf, *current;
char c = '\0';
buf = PyMem_Malloc(needed_length);
if (buf == NULL) {
tok->done = E_NOMEM;
return NULL;
}
for (current = buf; *s; s++, current++) {
c = *s;
if (skip_next_lf) {
skip_next_lf = 0;
if (c == '\n') {
c = *++s;
if (!c)
break;
}
}
if (!preserve_crlf && c == '\r') {
skip_next_lf = 1;
c = '\n';
}
*current = c;
}
/* If this is exec input, add a newline to the end of the string if
there isn't one already. */
if (exec_input && c != '\n' && c != '\0') {
*current = '\n';
current++;
}
*current = '\0';
final_length = current - buf + 1;
if (final_length < needed_length && final_length) {
/* should never fail */
char* result = PyMem_Realloc(buf, final_length);
if (result == NULL) {
PyMem_Free(buf);
}
buf = result;
}
return buf;
}
/* ############## ENCODING STUFF ############## */
/* See whether the file starts with a BOM. If it does,
invoke the set_readline function with the new encoding.
Return 1 on success, 0 on failure. */
int
_PyTokenizer_check_bom(int get_char(struct tok_state *),
void unget_char(int, struct tok_state *),
int set_readline(struct tok_state *, const char *),
struct tok_state *tok)
{
int ch1, ch2, ch3;
ch1 = get_char(tok);
tok->decoding_state = STATE_SEEK_CODING;
if (ch1 == EOF) {
return 1;
} else if (ch1 == 0xEF) {
ch2 = get_char(tok);
if (ch2 != 0xBB) {
unget_char(ch2, tok);
unget_char(ch1, tok);
return 1;
}
ch3 = get_char(tok);
if (ch3 != 0xBF) {
unget_char(ch3, tok);
unget_char(ch2, tok);
unget_char(ch1, tok);
return 1;
}
} else {
unget_char(ch1, tok);
return 1;
}
if (tok->encoding != NULL)
PyMem_Free(tok->encoding);
tok->encoding = _PyTokenizer_new_string("utf-8", 5, tok);
if (!tok->encoding)
return 0;
/* No need to set_readline: input is already utf-8 */
return 1;
}
static const char *
get_normal_name(const char *s) /* for utf-8 and latin-1 */
{
char buf[13];
int i;
for (i = 0; i < 12; i++) {
int c = s[i];
if (c == '\0')
break;
else if (c == '_')
buf[i] = '-';
else
buf[i] = Py_TOLOWER(c);
}
buf[i] = '\0';
if (strcmp(buf, "utf-8") == 0 ||
strncmp(buf, "utf-8-", 6) == 0)
return "utf-8";
else if (strcmp(buf, "latin-1") == 0 ||
strcmp(buf, "iso-8859-1") == 0 ||
strcmp(buf, "iso-latin-1") == 0 ||
strncmp(buf, "latin-1-", 8) == 0 ||
strncmp(buf, "iso-8859-1-", 11) == 0 ||
strncmp(buf, "iso-latin-1-", 12) == 0)
return "iso-8859-1";
else
return s;
}
/* Return the coding spec in S, or NULL if none is found. */
static int
get_coding_spec(const char *s, char **spec, Py_ssize_t size, struct tok_state *tok)
{
Py_ssize_t i;
*spec = NULL;
/* Coding spec must be in a comment, and that comment must be
* the only statement on the source code line. */
for (i = 0; i < size - 6; i++) {
if (s[i] == '#')
break;
if (s[i] != ' ' && s[i] != '\t' && s[i] != '\014')
return 1;
}
for (; i < size - 6; i++) { /* XXX inefficient search */
const char* t = s + i;
if (memcmp(t, "coding", 6) == 0) {
const char* begin = NULL;
t += 6;
if (t[0] != ':' && t[0] != '=')
continue;
do {
t++;
} while (t[0] == ' ' || t[0] == '\t');
begin = t;
while (Py_ISALNUM(t[0]) ||
t[0] == '-' || t[0] == '_' || t[0] == '.')
t++;
if (begin < t) {
char* r = _PyTokenizer_new_string(begin, t - begin, tok);
const char* q;
if (!r)
return 0;
q = get_normal_name(r);
if (r != q) {
PyMem_Free(r);
r = _PyTokenizer_new_string(q, strlen(q), tok);
if (!r)
return 0;
}
*spec = r;
break;
}
}
}
return 1;
}
/* Check whether the line contains a coding spec. If it does,
invoke the set_readline function for the new encoding.
This function receives the tok_state and the new encoding.
Return 1 on success, 0 on failure. */
int
_PyTokenizer_check_coding_spec(const char* line, Py_ssize_t size, struct tok_state *tok,
int set_readline(struct tok_state *, const char *))
{
char *cs;
if (tok->cont_line) {
/* It's a continuation line, so it can't be a coding spec. */
tok->decoding_state = STATE_NORMAL;
return 1;
}
if (!get_coding_spec(line, &cs, size, tok)) {
return 0;
}
if (!cs) {
Py_ssize_t i;
for (i = 0; i < size; i++) {
if (line[i] == '#' || line[i] == '\n' || line[i] == '\r')
break;
if (line[i] != ' ' && line[i] != '\t' && line[i] != '\014') {
/* Stop checking coding spec after a line containing
* anything except a comment. */
tok->decoding_state = STATE_NORMAL;
break;
}
}
return 1;
}
tok->decoding_state = STATE_NORMAL;
if (tok->encoding == NULL) {
assert(tok->decoding_readline == NULL);
if (strcmp(cs, "utf-8") != 0 && !set_readline(tok, cs)) {
_PyTokenizer_error_ret(tok);
PyErr_Format(PyExc_SyntaxError, "encoding problem: %s", cs);
PyMem_Free(cs);
return 0;
}
tok->encoding = cs;
} else { /* then, compare cs with BOM */
if (strcmp(tok->encoding, cs) != 0) {
_PyTokenizer_error_ret(tok);
PyErr_Format(PyExc_SyntaxError,
"encoding problem: %s with BOM", cs);
PyMem_Free(cs);
return 0;
}
PyMem_Free(cs);
}
return 1;
}
/* Check whether the characters at s start a valid
UTF-8 sequence. Return the number of characters forming
the sequence if yes, 0 if not. The special cases match
those in stringlib/codecs.h:utf8_decode.
*/
static int
valid_utf8(const unsigned char* s)
{
int expected = 0;
int length;
if (*s < 0x80) {
/* single-byte code */
return 1;
}
else if (*s < 0xE0) {
/* \xC2\x80-\xDF\xBF -- 0080-07FF */
if (*s < 0xC2) {
/* invalid sequence
\x80-\xBF -- continuation byte
\xC0-\xC1 -- fake 0000-007F */
return 0;
}
expected = 1;
}
else if (*s < 0xF0) {
/* \xE0\xA0\x80-\xEF\xBF\xBF -- 0800-FFFF */
if (*s == 0xE0 && *(s + 1) < 0xA0) {
/* invalid sequence
\xE0\x80\x80-\xE0\x9F\xBF -- fake 0000-0800 */
return 0;
}
else if (*s == 0xED && *(s + 1) >= 0xA0) {
/* Decoding UTF-8 sequences in range \xED\xA0\x80-\xED\xBF\xBF
will result in surrogates in range D800-DFFF. Surrogates are
not valid UTF-8 so they are rejected.
See https://www.unicode.org/versions/Unicode5.2.0/ch03.pdf
(table 3-7) and http://www.rfc-editor.org/rfc/rfc3629.txt */
return 0;
}
expected = 2;
}
else if (*s < 0xF5) {
/* \xF0\x90\x80\x80-\xF4\x8F\xBF\xBF -- 10000-10FFFF */
if (*(s + 1) < 0x90 ? *s == 0xF0 : *s == 0xF4) {
/* invalid sequence -- one of:
\xF0\x80\x80\x80-\xF0\x8F\xBF\xBF -- fake 0000-FFFF
\xF4\x90\x80\x80- -- 110000- overflow */
return 0;
}
expected = 3;
}
else {
/* invalid start byte */
return 0;
}
length = expected + 1;
for (; expected; expected--)
if (s[expected] < 0x80 || s[expected] >= 0xC0)
return 0;
return length;
}
int
_PyTokenizer_ensure_utf8(char *line, struct tok_state *tok)
{
int badchar = 0;
unsigned char *c;
int length;
for (c = (unsigned char *)line; *c; c += length) {
if (!(length = valid_utf8(c))) {
badchar = *c;
break;
}
}
if (badchar) {
PyErr_Format(PyExc_SyntaxError,
"Non-UTF-8 code starting with '\\x%.2x' "
"in file %U on line %i, "
"but no encoding declared; "
"see https://peps.python.org/pep-0263/ for details",
badchar, tok->filename, tok->lineno);
return 0;
}
return 1;
}
/* ############## DEBUGGING STUFF ############## */
#ifdef Py_DEBUG
void
_PyTokenizer_print_escape(FILE *f, const char *s, Py_ssize_t size)
{
if (s == NULL) {
fputs("NULL", f);
return;
}
putc('"', f);
while (size-- > 0) {
unsigned char c = *s++;
switch (c) {
case '\n': fputs("\\n", f); break;
case '\r': fputs("\\r", f); break;
case '\t': fputs("\\t", f); break;
case '\f': fputs("\\f", f); break;
case '\'': fputs("\\'", f); break;
case '"': fputs("\\\"", f); break;
default:
if (0x20 <= c && c <= 0x7f)
putc(c, f);
else
fprintf(f, "\\x%02x", c);
}
}
putc('"', f);
}
void
_PyTokenizer_tok_dump(int type, char *start, char *end)
{
fprintf(stderr, "%s", _PyParser_TokenNames[type]);
if (type == NAME || type == NUMBER || type == STRING || type == OP)
fprintf(stderr, "(%.*s)", (int)(end - start), start);
}
#endif
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