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Support \u and \x escapes in pref files (bug 307438). r=cbiesinger, sr=darin

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dveditz%cruzio.com 2005-09-29 18:09:06 +00:00
parent 2fa023ccc5
commit 9e0319346f
2 changed files with 118 additions and 5 deletions
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119
modules/libpref/src/prefread.cpp
View File

@ -38,6 +38,8 @@
#include <string.h>
#include <ctype.h>
#include "prefread.h"
#include "nsString.h"
#include "nsUTF8Utils.h"
#ifdef TEST_PREFREAD
#include <stdio.h>
@ -60,12 +62,18 @@ enum {
PREF_PARSE_COMMENT_BLOCK,
PREF_PARSE_COMMENT_BLOCK_MAYBE_END,
PREF_PARSE_ESC_SEQUENCE,
PREF_PARSE_HEX_ESCAPE,
PREF_PARSE_UTF16_LOW_SURROGATE,
PREF_PARSE_UNTIL_OPEN_PAREN,
PREF_PARSE_UNTIL_CLOSE_PAREN,
PREF_PARSE_UNTIL_SEMICOLON,
PREF_PARSE_UNTIL_EOL
};
#define UTF16_ESC_NUM_DIGITS 4
#define HEX_ESC_NUM_DIGITS 2
#define BITS_PER_HEX_DIGIT 4
static const char kUserPref[] = "user_pref";
static const char kPref[] = "pref";
static const char kTrue[] = "true";
@ -75,9 +83,10 @@ static const char kFalse[] = "false";
* pref_GrowBuf
*
* this function will increase the size of the buffer owned
* by the given pref parse state. the only requirement is
* that it increase the buffer by at least one byte, but we
* use a simple doubling algorithm.
* by the given pref parse state. We currently use a simple
* doubling algorithm, but the only hard requirement is that
* it increase the buffer by at least the size of the ps->esctmp
* buffer used for escape processing (currently 6 bytes).
*
* this buffer is used to store partial pref lines. it is
* freed when the parse state is destroyed.
@ -197,6 +206,7 @@ PREF_ParseBuf(PrefParseState *ps, const char *buf, int bufLen)
{
const char *end;
char c;
char udigit;
int state;
state = ps->state;
@ -392,6 +402,7 @@ PREF_ParseBuf(PrefParseState *ps, const char *buf, int bufLen)
* for us in the previous state */
switch (c) {
case '\"':
case '\'':
case '\\':
break;
case 'r':
@ -400,10 +411,21 @@ PREF_ParseBuf(PrefParseState *ps, const char *buf, int bufLen)
case 'n':
c = '\n';
break;
case 'x': /* hex escape -- always interpreted as Latin-1 */
case 'u': /* UTF16 escape */
ps->esctmp[0] = c;
ps->esclen = 1;
ps->utf16[0] = ps->utf16[1] = 0;
ps->sindex = (c == 'x' ) ?
HEX_ESC_NUM_DIGITS :
UTF16_ESC_NUM_DIGITS;
state = PREF_PARSE_HEX_ESCAPE;
continue;
default:
NS_WARNING("preserving unexpected JS escape sequence");
/* grow line buffer if necessary... */
if (ps->lbcur == ps->lbend && !pref_GrowBuf(ps))
/* Invalid escape sequence so we do have to write more than
* one character. Grow line buffer if necessary... */
if ((ps->lbcur+1) == ps->lbend && !pref_GrowBuf(ps))
return PR_FALSE; /* out of memory */
*ps->lbcur++ = '\\'; /* preserve the escape sequence */
break;
@ -412,6 +434,93 @@ PREF_ParseBuf(PrefParseState *ps, const char *buf, int bufLen)
state = PREF_PARSE_QUOTED_STRING;
break;
/* parsing a hex (\xHH) or utf16 escape (\uHHHH) */
case PREF_PARSE_HEX_ESCAPE:
if ( c >= '0' && c <= '9' )
udigit = (c - '0');
else if ( c >= 'A' && c <= 'F' )
udigit = (c - 'A') + 10;
else if ( c >= 'a' && c <= 'f' )
udigit = (c - 'a') + 10;
else {
/* bad escape sequence found, write out broken escape as-is */
NS_WARNING("preserving invalid or incomplete hex escape");
*ps->lbcur++ = '\\'; /* original escape slash */
if ((ps->lbcur + ps->esclen) >= ps->lbend && !pref_GrowBuf(ps))
return PR_FALSE;
for (int i = 0; i < ps->esclen; ++i)
*ps->lbcur++ = ps->esctmp[i];
/* push the non-hex character back for re-parsing. */
/* (++buf at the top of the loop keeps this safe) */
--buf;
state = PREF_PARSE_QUOTED_STRING;
continue;
}
/* have a digit */
ps->esctmp[ps->esclen++] = c; /* preserve it */
ps->utf16[1] <<= BITS_PER_HEX_DIGIT;
ps->utf16[1] |= udigit;
ps->sindex--;
if (ps->sindex == 0) {
/* have the full escape. Convert to UTF8 */
int utf16len = 0;
if (ps->utf16[0]) {
/* already have a high surrogate, this is a two char seq */
utf16len = 2;
}
else if (0xD800 == (0xFC00 & ps->utf16[1])) {
/* a high surrogate, can't convert until we have the low */
ps->utf16[0] = ps->utf16[1];
ps->utf16[1] = 0;
state = PREF_PARSE_UTF16_LOW_SURROGATE;
break;
}
else {
/* a single utf16 character */
ps->utf16[0] = ps->utf16[1];
utf16len = 1;
}
/* actual conversion */
/* make sure there's room, 6 bytes is max utf8 len (in */
/* theory; 4 bytes covers the actual utf16 range) */
if (ps->lbcur+6 >= ps->lbend && !pref_GrowBuf(ps))
return PR_FALSE;
ConvertUTF16toUTF8 converter(ps->lbcur);
converter.write(ps->utf16, utf16len);
ps->lbcur += converter.Size();
state = PREF_PARSE_QUOTED_STRING;
}
break;
/* looking for beginning of utf16 low surrogate */
case PREF_PARSE_UTF16_LOW_SURROGATE:
if (ps->sindex == 0 && c == '\\') {
++ps->sindex;
}
else if (ps->sindex == 1 && c == 'u') {
/* escape sequence is correct, now parse hex */
ps->sindex = UTF16_ESC_NUM_DIGITS;
ps->esctmp[0] = 'u';
ps->esclen = 1;
state = PREF_PARSE_HEX_ESCAPE;
}
else {
/* didn't find expected low surrogate. Ignore high surrogate
* (it would just get converted to nothing anyway) and start
* over with this character */
--buf;
if (ps->sindex == 1)
state = PREF_PARSE_ESC_SEQUENCE;
else
state = PREF_PARSE_QUOTED_STRING;
continue;
}
break;
/* function open and close parsing */
case PREF_PARSE_UNTIL_OPEN_PAREN:
/* tolerate only whitespace and embedded comments */

4
modules/libpref/src/prefread.h
View File

@ -72,6 +72,10 @@ typedef struct PrefParseState {
int nextstate; /* sometimes used... */
const char *smatch; /* string to match */
int sindex; /* next char of smatch to check */
/* also, counter in \u parsing */
PRUnichar utf16[2]; /* parsing UTF16 (\u) escape */
int esclen; /* length in esctmp */
char esctmp[6]; /* raw escape to put back if err */
char quotechar; /* char delimiter for quotations */
char *lb; /* line buffer (only allocation) */
char *lbcur; /* line buffer cursor */