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ruby--ruby/ext/cgi/escape/escape.c
Takashi Kokubun 0a29dc87e6
Optimize CGI.escapeHTML by reducing buffer extension
and switch-case branches.

Buffer allocation optimization using `ALLOCA_N` would be the main
benefit of patch. It eliminates the O(N) buffer extensions.

It also reduces the number of branches using escape table like
https://mattn.kaoriya.net/software/lang/c/20160817011915.htm.

Closes: https://github.com/ruby/ruby/pull/2226

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Yasuhiro MATSUMOTO <mattn.jp@gmail.com>
2019-06-05 21:07:04 +09:00

409 lines
9.1 KiB
C

#include "ruby.h"
#include "ruby/encoding.h"
RUBY_EXTERN unsigned long ruby_scan_digits(const char *str, ssize_t len, int base, size_t *retlen, int *overflow);
RUBY_EXTERN const char ruby_hexdigits[];
RUBY_EXTERN const signed char ruby_digit36_to_number_table[];
#define lower_hexdigits (ruby_hexdigits+0)
#define upper_hexdigits (ruby_hexdigits+16)
#define char_to_number(c) ruby_digit36_to_number_table[(unsigned char)(c)]
static VALUE rb_cCGI, rb_mUtil, rb_mEscape;
static ID id_accept_charset;
#define HTML_ESCAPE_MAX_LEN 6
static const struct {
uint8_t len;
char str[HTML_ESCAPE_MAX_LEN+1];
} html_escape_table[UCHAR_MAX+1] = {
#define HTML_ESCAPE(c, str) [c] = {rb_strlen_lit(str), str}
HTML_ESCAPE('\'', "&#39;"),
HTML_ESCAPE('&', "&amp;"),
HTML_ESCAPE('"', "&quot;"),
HTML_ESCAPE('<', "&lt;"),
HTML_ESCAPE('>', "&gt;"),
#undef HTML_ESCAPE
};
static inline void
preserve_original_state(VALUE orig, VALUE dest)
{
rb_enc_associate(dest, rb_enc_get(orig));
RB_OBJ_INFECT_RAW(dest, orig);
}
static VALUE
optimized_escape_html(VALUE str)
{
VALUE vbuf;
char *buf = ALLOCV_N(char, vbuf, RSTRING_LEN(str) * HTML_ESCAPE_MAX_LEN);
const char *cstr = RSTRING_PTR(str);
const char *end = cstr + RSTRING_LEN(str);
char *dest = buf;
while (cstr < end) {
const unsigned char c = *cstr++;
uint8_t len = html_escape_table[c].len;
if (len) {
memcpy(dest, html_escape_table[c].str, len);
dest += len;
}
else {
*dest++ = c;
}
}
VALUE escaped;
if (RSTRING_LEN(str) < (dest - buf)) {
escaped = rb_str_new(buf, dest - buf);
preserve_original_state(str, escaped);
}
else {
escaped = rb_str_dup(str);
}
ALLOCV_END(vbuf);
return escaped;
}
static VALUE
optimized_unescape_html(VALUE str)
{
enum {UNICODE_MAX = 0x10ffff};
rb_encoding *enc = rb_enc_get(str);
unsigned long charlimit = (strcasecmp(rb_enc_name(enc), "UTF-8") == 0 ? UNICODE_MAX :
strcasecmp(rb_enc_name(enc), "ISO-8859-1") == 0 ? 256 :
128);
long i, len, beg = 0;
size_t clen, plen;
int overflow;
const char *cstr;
char buf[6];
VALUE dest = 0;
len = RSTRING_LEN(str);
cstr = RSTRING_PTR(str);
for (i = 0; i < len; i++) {
unsigned long cc;
char c = cstr[i];
if (c != '&') continue;
plen = i - beg;
if (++i >= len) break;
c = (unsigned char)cstr[i];
#define MATCH(s) (len - i >= (int)rb_strlen_lit(s) && \
memcmp(&cstr[i], s, rb_strlen_lit(s)) == 0 && \
(i += rb_strlen_lit(s) - 1, 1))
switch (c) {
case 'a':
++i;
if (MATCH("pos;")) {
c = '\'';
}
else if (MATCH("mp;")) {
c = '&';
}
else continue;
break;
case 'q':
++i;
if (MATCH("uot;")) {
c = '"';
}
else continue;
break;
case 'g':
++i;
if (MATCH("t;")) {
c = '>';
}
else continue;
break;
case 'l':
++i;
if (MATCH("t;")) {
c = '<';
}
else continue;
break;
case '#':
if (len - ++i >= 2 && ISDIGIT(cstr[i])) {
cc = ruby_scan_digits(&cstr[i], len-i, 10, &clen, &overflow);
}
else if ((cstr[i] == 'x' || cstr[i] == 'X') && len - ++i >= 2 && ISXDIGIT(cstr[i])) {
cc = ruby_scan_digits(&cstr[i], len-i, 16, &clen, &overflow);
}
else continue;
i += clen;
if (overflow || cc >= charlimit || cstr[i] != ';') continue;
if (!dest) {
dest = rb_str_buf_new(len);
}
rb_str_cat(dest, cstr + beg, plen);
if (charlimit > 256) {
rb_str_cat(dest, buf, rb_enc_mbcput((OnigCodePoint)cc, buf, enc));
}
else {
c = (unsigned char)cc;
rb_str_cat(dest, &c, 1);
}
beg = i + 1;
continue;
default:
--i;
continue;
}
if (!dest) {
dest = rb_str_buf_new(len);
}
rb_str_cat(dest, cstr + beg, plen);
rb_str_cat(dest, &c, 1);
beg = i + 1;
}
if (dest) {
rb_str_cat(dest, cstr + beg, len - beg);
preserve_original_state(str, dest);
return dest;
}
else {
return rb_str_dup(str);
}
}
static unsigned char
url_unreserved_char(unsigned char c)
{
switch (c) {
case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g': case 'h': case 'i': case 'j':
case 'k': case 'l': case 'm': case 'n': case 'o': case 'p': case 'q': case 'r': case 's': case 't':
case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G': case 'H': case 'I': case 'J':
case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T':
case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':
case '-': case '.': case '_': case '~':
return 1;
default:
break;
}
return 0;
}
static VALUE
optimized_escape(VALUE str)
{
long i, len, beg = 0;
VALUE dest = 0;
const char *cstr;
char buf[4] = {'%'};
len = RSTRING_LEN(str);
cstr = RSTRING_PTR(str);
for (i = 0; i < len; ++i) {
const unsigned char c = (unsigned char)cstr[i];
if (!url_unreserved_char(c)) {
if (!dest) {
dest = rb_str_buf_new(len);
}
rb_str_cat(dest, cstr + beg, i - beg);
beg = i + 1;
if (c == ' ') {
rb_str_cat_cstr(dest, "+");
}
else {
buf[1] = upper_hexdigits[(c >> 4) & 0xf];
buf[2] = upper_hexdigits[c & 0xf];
rb_str_cat(dest, buf, 3);
}
}
}
if (dest) {
rb_str_cat(dest, cstr + beg, len - beg);
preserve_original_state(str, dest);
return dest;
}
else {
return rb_str_dup(str);
}
}
static VALUE
optimized_unescape(VALUE str, VALUE encoding)
{
long i, len, beg = 0;
VALUE dest = 0;
const char *cstr;
rb_encoding *enc = rb_to_encoding(encoding);
int cr, origenc, encidx = rb_enc_to_index(enc);
len = RSTRING_LEN(str);
cstr = RSTRING_PTR(str);
for (i = 0; i < len; ++i) {
char buf[1];
const char c = cstr[i];
int clen = 0;
if (c == '%') {
if (i + 3 > len) break;
if (!ISXDIGIT(cstr[i+1])) continue;
if (!ISXDIGIT(cstr[i+2])) continue;
buf[0] = ((char_to_number(cstr[i+1]) << 4)
| char_to_number(cstr[i+2]));
clen = 2;
}
else if (c == '+') {
buf[0] = ' ';
}
else {
continue;
}
if (!dest) {
dest = rb_str_buf_new(len);
}
rb_str_cat(dest, cstr + beg, i - beg);
i += clen;
beg = i + 1;
rb_str_cat(dest, buf, 1);
}
if (dest) {
rb_str_cat(dest, cstr + beg, len - beg);
preserve_original_state(str, dest);
cr = ENC_CODERANGE_UNKNOWN;
}
else {
dest = rb_str_dup(str);
cr = ENC_CODERANGE(str);
}
origenc = rb_enc_get_index(str);
if (origenc != encidx) {
rb_enc_associate_index(dest, encidx);
if (!ENC_CODERANGE_CLEAN_P(rb_enc_str_coderange(dest))) {
rb_enc_associate_index(dest, origenc);
if (cr != ENC_CODERANGE_UNKNOWN)
ENC_CODERANGE_SET(dest, cr);
}
}
return dest;
}
/*
* call-seq:
* CGI.escapeHTML(string) -> string
*
* Returns HTML-escaped string.
*
*/
static VALUE
cgiesc_escape_html(VALUE self, VALUE str)
{
StringValue(str);
if (rb_enc_str_asciicompat_p(str)) {
return optimized_escape_html(str);
}
else {
return rb_call_super(1, &str);
}
}
/*
* call-seq:
* CGI.unescapeHTML(string) -> string
*
* Returns HTML-unescaped string.
*
*/
static VALUE
cgiesc_unescape_html(VALUE self, VALUE str)
{
StringValue(str);
if (rb_enc_str_asciicompat_p(str)) {
return optimized_unescape_html(str);
}
else {
return rb_call_super(1, &str);
}
}
/*
* call-seq:
* CGI.escape(string) -> string
*
* Returns URL-escaped string.
*
*/
static VALUE
cgiesc_escape(VALUE self, VALUE str)
{
StringValue(str);
if (rb_enc_str_asciicompat_p(str)) {
return optimized_escape(str);
}
else {
return rb_call_super(1, &str);
}
}
static VALUE
accept_charset(int argc, VALUE *argv, VALUE self)
{
if (argc > 0)
return argv[0];
return rb_cvar_get(CLASS_OF(self), id_accept_charset);
}
/*
* call-seq:
* CGI.unescape(string, encoding=@@accept_charset) -> string
*
* Returns URL-unescaped string.
*
*/
static VALUE
cgiesc_unescape(int argc, VALUE *argv, VALUE self)
{
VALUE str = (rb_check_arity(argc, 1, 2), argv[0]);
StringValue(str);
if (rb_enc_str_asciicompat_p(str)) {
VALUE enc = accept_charset(argc-1, argv+1, self);
return optimized_unescape(str, enc);
}
else {
return rb_call_super(argc, argv);
}
}
void
Init_escape(void)
{
id_accept_charset = rb_intern_const("@@accept_charset");
InitVM(escape);
}
void
InitVM_escape(void)
{
rb_cCGI = rb_define_class("CGI", rb_cObject);
rb_mEscape = rb_define_module_under(rb_cCGI, "Escape");
rb_mUtil = rb_define_module_under(rb_cCGI, "Util");
rb_define_method(rb_mEscape, "escapeHTML", cgiesc_escape_html, 1);
rb_define_method(rb_mEscape, "unescapeHTML", cgiesc_unescape_html, 1);
rb_define_method(rb_mEscape, "escape", cgiesc_escape, 1);
rb_define_method(rb_mEscape, "unescape", cgiesc_unescape, -1);
rb_prepend_module(rb_mUtil, rb_mEscape);
rb_extend_object(rb_cCGI, rb_mEscape);
}