[Python-checkins] closes bpo-39721: Fix constness of members of tok_state struct. (GH-18600)
Andy Lester
webhook-mailer at python.org
Thu Feb 27 21:45:16 EST 2020
https://github.com/python/cpython/commit/384f3c536dd15ba33ea7e8afb4087ae359d4c12e
commit: 384f3c536dd15ba33ea7e8afb4087ae359d4c12e
branch: master
author: Andy Lester <andy at petdance.com>
committer: GitHub <noreply at github.com>
date: 2020-02-27T18:44:52-08:00
summary:
closes bpo-39721: Fix constness of members of tok_state struct. (GH-18600)
The function PyTokenizer_FromUTF8 from Parser/tokenizer.c had a comment:
/* XXX: constify members. */
This patch addresses that.
In the tok_state struct:
* end and start were non-const but could be made const
* str and input were const but should have been non-const
Changes to support this include:
* decode_str() now returns a char * since it is allocated.
* PyTokenizer_FromString() and PyTokenizer_FromUTF8() each creates a
new char * for an allocate string instead of reusing the input
const char *.
* PyTokenizer_Get() and tok_get() now take const char ** arguments.
* Various local vars are const or non-const accordingly.
I was able to remove five casts that cast away constness.
files:
M Parser/parsetok.c
M Parser/tokenizer.c
M Parser/tokenizer.h
diff --git a/Parser/parsetok.c b/Parser/parsetok.c
index b0b1bd38a7bba..554455dbc2bad 100644
--- a/Parser/parsetok.c
+++ b/Parser/parsetok.c
@@ -240,7 +240,7 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
#endif
for (;;) {
- char *a, *b;
+ const char *a, *b;
int type;
size_t len;
char *str;
@@ -371,7 +371,7 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
buffer after parsing. Trailing whitespace and comments
are OK. */
if (err_ret->error == E_DONE && start == single_input) {
- char *cur = tok->cur;
+ const char *cur = tok->cur;
char c = *tok->cur;
for (;;) {
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index 630b0aaab03f9..f82b102998171 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -59,7 +59,9 @@ tok_new(void)
sizeof(struct tok_state));
if (tok == NULL)
return NULL;
- tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
+ tok->buf = tok->cur = tok->inp = NULL;
+ tok->start = NULL;
+ tok->end = NULL;
tok->done = E_OK;
tok->fp = NULL;
tok->input = NULL;
@@ -111,7 +113,9 @@ error_ret(struct tok_state *tok) /* XXX */
tok->decoding_erred = 1;
if (tok->fp != NULL && tok->buf != NULL) /* see PyTokenizer_Free */
PyMem_FREE(tok->buf);
- tok->buf = tok->cur = tok->end = tok->inp = tok->start = NULL;
+ tok->buf = tok->cur = tok->inp = NULL;
+ tok->start = NULL;
+ tok->end = NULL;
tok->done = E_DECODE;
return NULL; /* as if it were EOF */
}
@@ -664,11 +668,11 @@ translate_newlines(const char *s, int exec_input, struct tok_state *tok) {
Look for encoding declarations inside STR, and record them
inside TOK. */
-static const char *
+static char *
decode_str(const char *input, int single, struct tok_state *tok)
{
PyObject* utf8 = NULL;
- const char *str;
+ char *str;
const char *s;
const char *newl[2] = {NULL, NULL};
int lineno = 0;
@@ -726,16 +730,18 @@ struct tok_state *
PyTokenizer_FromString(const char *str, int exec_input)
{
struct tok_state *tok = tok_new();
+ char *decoded;
+
if (tok == NULL)
return NULL;
- str = decode_str(str, exec_input, tok);
- if (str == NULL) {
+ decoded = decode_str(str, exec_input, tok);
+ if (decoded == NULL) {
PyTokenizer_Free(tok);
return NULL;
}
- /* XXX: constify members. */
- tok->buf = tok->cur = tok->end = tok->inp = (char*)str;
+ tok->buf = tok->cur = tok->inp = decoded;
+ tok->end = decoded;
return tok;
}
@@ -743,17 +749,18 @@ struct tok_state *
PyTokenizer_FromUTF8(const char *str, int exec_input)
{
struct tok_state *tok = tok_new();
+ char *translated;
if (tok == NULL)
return NULL;
- tok->input = str = translate_newlines(str, exec_input, tok);
- if (str == NULL) {
+ tok->input = translated = translate_newlines(str, exec_input, tok);
+ if (translated == NULL) {
PyTokenizer_Free(tok);
return NULL;
}
tok->decoding_state = STATE_RAW;
tok->read_coding_spec = 1;
tok->enc = NULL;
- tok->str = str;
+ tok->str = translated;
tok->encoding = (char *)PyMem_MALLOC(6);
if (!tok->encoding) {
PyTokenizer_Free(tok);
@@ -761,8 +768,8 @@ PyTokenizer_FromUTF8(const char *str, int exec_input)
}
strcpy(tok->encoding, "utf-8");
- /* XXX: constify members. */
- tok->buf = tok->cur = tok->end = tok->inp = (char*)str;
+ tok->buf = tok->cur = tok->inp = translated;
+ tok->end = translated;
return tok;
}
@@ -812,7 +819,7 @@ PyTokenizer_Free(struct tok_state *tok)
if (tok->fp != NULL && tok->buf != NULL)
PyMem_FREE(tok->buf);
if (tok->input)
- PyMem_FREE((char *)tok->input);
+ PyMem_FREE(tok->input);
PyMem_FREE(tok);
}
@@ -1138,7 +1145,7 @@ tok_decimal_tail(struct tok_state *tok)
/* Get next token, after space stripping etc. */
static int
-tok_get(struct tok_state *tok, char **p_start, char **p_end)
+tok_get(struct tok_state *tok, const char **p_start, const char **p_end)
{
int c;
int blankline, nonascii;
@@ -1321,7 +1328,7 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
&& ((unsigned char)ignore_end[0] >= 128 || Py_ISALNUM(ignore_end[0]))));
if (is_type_ignore) {
- *p_start = (char *) ignore_end;
+ *p_start = ignore_end;
*p_end = tok->cur;
/* If this type ignore is the only thing on the line, consume the newline also. */
@@ -1331,7 +1338,7 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
}
return TYPE_IGNORE;
} else {
- *p_start = (char *) type_start; /* after type_comment_prefix */
+ *p_start = type_start; /* after type_comment_prefix */
*p_end = tok->cur;
return TYPE_COMMENT;
}
@@ -1410,7 +1417,8 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
Look ahead one token to see if that is 'def'. */
struct tok_state ahead_tok;
- char *ahead_tok_start = NULL, *ahead_tok_end = NULL;
+ const char *ahead_tok_start = NULL;
+ const char *ahead_tok_end = NULL;
int ahead_tok_kind;
memcpy(&ahead_tok, tok, sizeof(ahead_tok));
@@ -1798,7 +1806,7 @@ tok_get(struct tok_state *tok, char **p_start, char **p_end)
}
int
-PyTokenizer_Get(struct tok_state *tok, char **p_start, char **p_end)
+PyTokenizer_Get(struct tok_state *tok, const char **p_start, const char **p_end)
{
int result = tok_get(tok, p_start, p_end);
if (tok->decoding_erred) {
@@ -1823,7 +1831,9 @@ PyTokenizer_FindEncodingFilename(int fd, PyObject *filename)
{
struct tok_state *tok;
FILE *fp;
- char *p_start =NULL , *p_end =NULL , *encoding = NULL;
+ const char *p_start = NULL;
+ const char *p_end = NULL;
+ char *encoding = NULL;
fd = _Py_dup(fd);
if (fd < 0) {
diff --git a/Parser/tokenizer.h b/Parser/tokenizer.h
index 92669bfd8a160..5660ea38e9443 100644
--- a/Parser/tokenizer.h
+++ b/Parser/tokenizer.h
@@ -26,8 +26,8 @@ struct tok_state {
char *buf; /* Input buffer, or NULL; malloc'ed if fp != NULL */
char *cur; /* Next character in buffer */
char *inp; /* End of data in buffer */
- char *end; /* End of input buffer if buf != NULL */
- char *start; /* Start of current token if not NULL */
+ const char *end; /* End of input buffer if buf != NULL */
+ const char *start; /* Start of current token if not NULL */
int done; /* E_OK normally, E_EOF at EOF, otherwise error code */
/* NB If done != E_OK, cur must be == inp!!! */
FILE *fp; /* Rest of input; NULL if tokenizing a string */
@@ -60,8 +60,8 @@ struct tok_state {
PyObject *decoding_readline; /* open(...).readline */
PyObject *decoding_buffer;
const char* enc; /* Encoding for the current str. */
- const char* str;
- const char* input; /* Tokenizer's newline translated copy of the string. */
+ char* str;
+ char* input; /* Tokenizer's newline translated copy of the string. */
int type_comments; /* Whether to look for type comments */
@@ -78,7 +78,7 @@ extern struct tok_state *PyTokenizer_FromUTF8(const char *, int);
extern struct tok_state *PyTokenizer_FromFile(FILE *, const char*,
const char *, const char *);
extern void PyTokenizer_Free(struct tok_state *);
-extern int PyTokenizer_Get(struct tok_state *, char **, char **);
+extern int PyTokenizer_Get(struct tok_state *, const char **, const char **);
#define tok_dump _Py_tok_dump
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