1/*
2 *  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
3 *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
4 *  Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
5 *  Copyright (C) 2007 Cameron Zwarich (cwzwarich@uwaterloo.ca)
6 *  Copyright (C) 2007 Maks Orlovich
7 *
8 *  This library is free software; you can redistribute it and/or
9 *  modify it under the terms of the GNU Library General Public
10 *  License as published by the Free Software Foundation; either
11 *  version 2 of the License, or (at your option) any later version.
12 *
13 *  This library is distributed in the hope that it will be useful,
14 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 *  Library General Public License for more details.
17 *
18 *  You should have received a copy of the GNU Library General Public License
19 *  along with this library; see the file COPYING.LIB.  If not, write to
20 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 *  Boston, MA 02110-1301, USA.
22 *
23 */
24
25#include "config.h"
26#include "JSGlobalObjectFunctions.h"
27
28#include "CallFrame.h"
29#include "Interpreter.h"
30#include "JSFunction.h"
31#include "JSGlobalObject.h"
32#include "JSString.h"
33#include "JSStringBuilder.h"
34#include "Lexer.h"
35#include "LiteralParser.h"
36#include "Nodes.h"
37#include "JSCInlines.h"
38#include "Parser.h"
39#include "StackVisitor.h"
40#include <wtf/dtoa.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <wtf/ASCIICType.h>
44#include <wtf/Assertions.h>
45#include <wtf/MathExtras.h>
46#include <wtf/StringExtras.h>
47#include <wtf/text/StringBuilder.h>
48#include <wtf/unicode/UTF8.h>
49
50using namespace WTF;
51using namespace Unicode;
52
53namespace JSC {
54
55static JSValue encode(ExecState* exec, const char* doNotEscape)
56{
57    CString cstr = exec->argument(0).toString(exec)->value(exec).utf8(StrictConversion);
58    if (!cstr.data())
59        return exec->vm().throwException(exec, createURIError(exec, ASCIILiteral("String contained an illegal UTF-16 sequence.")));
60
61    JSStringBuilder builder;
62    const char* p = cstr.data();
63    for (size_t k = 0; k < cstr.length(); k++, p++) {
64        char c = *p;
65        if (c && strchr(doNotEscape, c))
66            builder.append(static_cast<LChar>(c));
67        else {
68            char tmp[4];
69            snprintf(tmp, sizeof(tmp), "%%%02X", static_cast<unsigned char>(c));
70            builder.append(tmp);
71        }
72    }
73    return builder.build(exec);
74}
75
76template <typename CharType>
77ALWAYS_INLINE
78static JSValue decode(ExecState* exec, const CharType* characters, int length, const char* doNotUnescape, bool strict)
79{
80    JSStringBuilder builder;
81    int k = 0;
82    UChar u = 0;
83    while (k < length) {
84        const CharType* p = characters + k;
85        CharType c = *p;
86        if (c == '%') {
87            int charLen = 0;
88            if (k <= length - 3 && isASCIIHexDigit(p[1]) && isASCIIHexDigit(p[2])) {
89                const char b0 = Lexer<CharType>::convertHex(p[1], p[2]);
90                const int sequenceLen = UTF8SequenceLength(b0);
91                if (sequenceLen && k <= length - sequenceLen * 3) {
92                    charLen = sequenceLen * 3;
93                    char sequence[5];
94                    sequence[0] = b0;
95                    for (int i = 1; i < sequenceLen; ++i) {
96                        const CharType* q = p + i * 3;
97                        if (q[0] == '%' && isASCIIHexDigit(q[1]) && isASCIIHexDigit(q[2]))
98                            sequence[i] = Lexer<CharType>::convertHex(q[1], q[2]);
99                        else {
100                            charLen = 0;
101                            break;
102                        }
103                    }
104                    if (charLen != 0) {
105                        sequence[sequenceLen] = 0;
106                        const int character = decodeUTF8Sequence(sequence);
107                        if (character < 0 || character >= 0x110000)
108                            charLen = 0;
109                        else if (character >= 0x10000) {
110                            // Convert to surrogate pair.
111                            builder.append(static_cast<UChar>(0xD800 | ((character - 0x10000) >> 10)));
112                            u = static_cast<UChar>(0xDC00 | ((character - 0x10000) & 0x3FF));
113                        } else
114                            u = static_cast<UChar>(character);
115                    }
116                }
117            }
118            if (charLen == 0) {
119                if (strict)
120                    return exec->vm().throwException(exec, createURIError(exec, ASCIILiteral("URI error")));
121                // The only case where we don't use "strict" mode is the "unescape" function.
122                // For that, it's good to support the wonky "%u" syntax for compatibility with WinIE.
123                if (k <= length - 6 && p[1] == 'u'
124                        && isASCIIHexDigit(p[2]) && isASCIIHexDigit(p[3])
125                        && isASCIIHexDigit(p[4]) && isASCIIHexDigit(p[5])) {
126                    charLen = 6;
127                    u = Lexer<UChar>::convertUnicode(p[2], p[3], p[4], p[5]);
128                }
129            }
130            if (charLen && (u == 0 || u >= 128 || !strchr(doNotUnescape, u))) {
131                builder.append(u);
132                k += charLen;
133                continue;
134            }
135        }
136        k++;
137        builder.append(c);
138    }
139    return builder.build(exec);
140}
141
142static JSValue decode(ExecState* exec, const char* doNotUnescape, bool strict)
143{
144    String str = exec->argument(0).toString(exec)->value(exec);
145
146    if (str.is8Bit())
147        return decode(exec, str.characters8(), str.length(), doNotUnescape, strict);
148    return decode(exec, str.characters16(), str.length(), doNotUnescape, strict);
149}
150
151bool isStrWhiteSpace(UChar c)
152{
153    switch (c) {
154        // ECMA-262-5th 7.2 & 7.3
155        case 0x0009:
156        case 0x000A:
157        case 0x000B:
158        case 0x000C:
159        case 0x000D:
160        case 0x0020:
161        case 0x00A0:
162        case 0x180E: // This character used to be in Zs category before Unicode 6.3, and EcmaScript says that we should keep treating it as such.
163        case 0x2028:
164        case 0x2029:
165        case 0xFEFF:
166            return true;
167        default:
168            return c > 0xFF && u_charType(c) == U_SPACE_SEPARATOR;
169    }
170}
171
172static int parseDigit(unsigned short c, int radix)
173{
174    int digit = -1;
175
176    if (c >= '0' && c <= '9')
177        digit = c - '0';
178    else if (c >= 'A' && c <= 'Z')
179        digit = c - 'A' + 10;
180    else if (c >= 'a' && c <= 'z')
181        digit = c - 'a' + 10;
182
183    if (digit >= radix)
184        return -1;
185    return digit;
186}
187
188double parseIntOverflow(const LChar* s, unsigned length, int radix)
189{
190    double number = 0.0;
191    double radixMultiplier = 1.0;
192
193    for (const LChar* p = s + length - 1; p >= s; p--) {
194        if (radixMultiplier == std::numeric_limits<double>::infinity()) {
195            if (*p != '0') {
196                number = std::numeric_limits<double>::infinity();
197                break;
198            }
199        } else {
200            int digit = parseDigit(*p, radix);
201            number += digit * radixMultiplier;
202        }
203
204        radixMultiplier *= radix;
205    }
206
207    return number;
208}
209
210static double parseIntOverflow(const UChar* s, unsigned length, int radix)
211{
212    double number = 0.0;
213    double radixMultiplier = 1.0;
214
215    for (const UChar* p = s + length - 1; p >= s; p--) {
216        if (radixMultiplier == std::numeric_limits<double>::infinity()) {
217            if (*p != '0') {
218                number = std::numeric_limits<double>::infinity();
219                break;
220            }
221        } else {
222            int digit = parseDigit(*p, radix);
223            number += digit * radixMultiplier;
224        }
225
226        radixMultiplier *= radix;
227    }
228
229    return number;
230}
231
232static double parseIntOverflow(StringView string, int radix)
233{
234    if (string.is8Bit())
235        return parseIntOverflow(string.characters8(), string.length(), radix);
236    return parseIntOverflow(string.characters16(), string.length(), radix);
237}
238
239// ES5.1 15.1.2.2
240template <typename CharType>
241ALWAYS_INLINE
242static double parseInt(const String& s, const CharType* data, int radix)
243{
244    // 1. Let inputString be ToString(string).
245    // 2. Let S be a newly created substring of inputString consisting of the first character that is not a
246    //    StrWhiteSpaceChar and all characters following that character. (In other words, remove leading white
247    //    space.) If inputString does not contain any such characters, let S be the empty string.
248    int length = s.length();
249    int p = 0;
250    while (p < length && isStrWhiteSpace(data[p]))
251        ++p;
252
253    // 3. Let sign be 1.
254    // 4. If S is not empty and the first character of S is a minus sign -, let sign be -1.
255    // 5. If S is not empty and the first character of S is a plus sign + or a minus sign -, then remove the first character from S.
256    double sign = 1;
257    if (p < length) {
258        if (data[p] == '+')
259            ++p;
260        else if (data[p] == '-') {
261            sign = -1;
262            ++p;
263        }
264    }
265
266    // 6. Let R = ToInt32(radix).
267    // 7. Let stripPrefix be true.
268    // 8. If R != 0,then
269    //   b. If R != 16, let stripPrefix be false.
270    // 9. Else, R == 0
271    //   a. LetR = 10.
272    // 10. If stripPrefix is true, then
273    //   a. If the length of S is at least 2 and the first two characters of S are either ―0x or ―0X,
274    //      then remove the first two characters from S and let R = 16.
275    // 11. If S contains any character that is not a radix-R digit, then let Z be the substring of S
276    //     consisting of all characters before the first such character; otherwise, let Z be S.
277    if ((radix == 0 || radix == 16) && length - p >= 2 && data[p] == '0' && (data[p + 1] == 'x' || data[p + 1] == 'X')) {
278        radix = 16;
279        p += 2;
280    } else if (radix == 0)
281        radix = 10;
282
283    // 8.a If R < 2 or R > 36, then return NaN.
284    if (radix < 2 || radix > 36)
285        return PNaN;
286
287    // 13. Let mathInt be the mathematical integer value that is represented by Z in radix-R notation, using the letters
288    //     A-Z and a-z for digits with values 10 through 35. (However, if R is 10 and Z contains more than 20 significant
289    //     digits, every significant digit after the 20th may be replaced by a 0 digit, at the option of the implementation;
290    //     and if R is not 2, 4, 8, 10, 16, or 32, then mathInt may be an implementation-dependent approximation to the
291    //     mathematical integer value that is represented by Z in radix-R notation.)
292    // 14. Let number be the Number value for mathInt.
293    int firstDigitPosition = p;
294    bool sawDigit = false;
295    double number = 0;
296    while (p < length) {
297        int digit = parseDigit(data[p], radix);
298        if (digit == -1)
299            break;
300        sawDigit = true;
301        number *= radix;
302        number += digit;
303        ++p;
304    }
305
306    // 12. If Z is empty, return NaN.
307    if (!sawDigit)
308        return PNaN;
309
310    // Alternate code path for certain large numbers.
311    if (number >= mantissaOverflowLowerBound) {
312        if (radix == 10) {
313            size_t parsedLength;
314            number = parseDouble(StringView(s).substring(firstDigitPosition, p - firstDigitPosition), parsedLength);
315        } else if (radix == 2 || radix == 4 || radix == 8 || radix == 16 || radix == 32)
316            number = parseIntOverflow(StringView(s).substring(firstDigitPosition, p - firstDigitPosition), radix);
317    }
318
319    // 15. Return sign x number.
320    return sign * number;
321}
322
323static double parseInt(const String& s, int radix)
324{
325    if (s.is8Bit())
326        return parseInt(s, s.characters8(), radix);
327    return parseInt(s, s.characters16(), radix);
328}
329
330static const int SizeOfInfinity = 8;
331
332template <typename CharType>
333static bool isInfinity(const CharType* data, const CharType* end)
334{
335    return (end - data) >= SizeOfInfinity
336        && data[0] == 'I'
337        && data[1] == 'n'
338        && data[2] == 'f'
339        && data[3] == 'i'
340        && data[4] == 'n'
341        && data[5] == 'i'
342        && data[6] == 't'
343        && data[7] == 'y';
344}
345
346// See ecma-262 9.3.1
347template <typename CharType>
348static double jsHexIntegerLiteral(const CharType*& data, const CharType* end)
349{
350    // Hex number.
351    data += 2;
352    const CharType* firstDigitPosition = data;
353    double number = 0;
354    while (true) {
355        number = number * 16 + toASCIIHexValue(*data);
356        ++data;
357        if (data == end)
358            break;
359        if (!isASCIIHexDigit(*data))
360            break;
361    }
362    if (number >= mantissaOverflowLowerBound)
363        number = parseIntOverflow(firstDigitPosition, data - firstDigitPosition, 16);
364
365    return number;
366}
367
368// See ecma-262 9.3.1
369template <typename CharType>
370static double jsStrDecimalLiteral(const CharType*& data, const CharType* end)
371{
372    RELEASE_ASSERT(data < end);
373
374    size_t parsedLength;
375    double number = parseDouble(data, end - data, parsedLength);
376    if (parsedLength) {
377        data += parsedLength;
378        return number;
379    }
380
381    // Check for [+-]?Infinity
382    switch (*data) {
383    case 'I':
384        if (isInfinity(data, end)) {
385            data += SizeOfInfinity;
386            return std::numeric_limits<double>::infinity();
387        }
388        break;
389
390    case '+':
391        if (isInfinity(data + 1, end)) {
392            data += SizeOfInfinity + 1;
393            return std::numeric_limits<double>::infinity();
394        }
395        break;
396
397    case '-':
398        if (isInfinity(data + 1, end)) {
399            data += SizeOfInfinity + 1;
400            return -std::numeric_limits<double>::infinity();
401        }
402        break;
403    }
404
405    // Not a number.
406    return PNaN;
407}
408
409template <typename CharType>
410static double toDouble(const CharType* characters, unsigned size)
411{
412    const CharType* endCharacters = characters + size;
413
414    // Skip leading white space.
415    for (; characters < endCharacters; ++characters) {
416        if (!isStrWhiteSpace(*characters))
417            break;
418    }
419
420    // Empty string.
421    if (characters == endCharacters)
422        return 0.0;
423
424    double number;
425    if (characters[0] == '0' && characters + 2 < endCharacters && (characters[1] | 0x20) == 'x' && isASCIIHexDigit(characters[2]))
426        number = jsHexIntegerLiteral(characters, endCharacters);
427    else
428        number = jsStrDecimalLiteral(characters, endCharacters);
429
430    // Allow trailing white space.
431    for (; characters < endCharacters; ++characters) {
432        if (!isStrWhiteSpace(*characters))
433            break;
434    }
435    if (characters != endCharacters)
436        return PNaN;
437
438    return number;
439}
440
441// See ecma-262 9.3.1
442double jsToNumber(const String& s)
443{
444    unsigned size = s.length();
445
446    if (size == 1) {
447        UChar c = s[0];
448        if (isASCIIDigit(c))
449            return c - '0';
450        if (isStrWhiteSpace(c))
451            return 0;
452        return PNaN;
453    }
454
455    if (s.is8Bit())
456        return toDouble(s.characters8(), size);
457    return toDouble(s.characters16(), size);
458}
459
460static double parseFloat(const String& s)
461{
462    unsigned size = s.length();
463
464    if (size == 1) {
465        UChar c = s[0];
466        if (isASCIIDigit(c))
467            return c - '0';
468        return PNaN;
469    }
470
471    if (s.is8Bit()) {
472        const LChar* data = s.characters8();
473        const LChar* end = data + size;
474
475        // Skip leading white space.
476        for (; data < end; ++data) {
477            if (!isStrWhiteSpace(*data))
478                break;
479        }
480
481        // Empty string.
482        if (data == end)
483            return PNaN;
484
485        return jsStrDecimalLiteral(data, end);
486    }
487
488    const UChar* data = s.characters16();
489    const UChar* end = data + size;
490
491    // Skip leading white space.
492    for (; data < end; ++data) {
493        if (!isStrWhiteSpace(*data))
494            break;
495    }
496
497    // Empty string.
498    if (data == end)
499        return PNaN;
500
501    return jsStrDecimalLiteral(data, end);
502}
503
504EncodedJSValue JSC_HOST_CALL globalFuncEval(ExecState* exec)
505{
506    JSValue x = exec->argument(0);
507    if (!x.isString())
508        return JSValue::encode(x);
509
510    String s = x.toString(exec)->value(exec);
511
512    if (s.is8Bit()) {
513        LiteralParser<LChar> preparser(exec, s.characters8(), s.length(), NonStrictJSON);
514        if (JSValue parsedObject = preparser.tryLiteralParse())
515            return JSValue::encode(parsedObject);
516    } else {
517        LiteralParser<UChar> preparser(exec, s.characters16(), s.length(), NonStrictJSON);
518        if (JSValue parsedObject = preparser.tryLiteralParse())
519            return JSValue::encode(parsedObject);
520    }
521
522    JSGlobalObject* calleeGlobalObject = exec->callee()->globalObject();
523    EvalExecutable* eval = EvalExecutable::create(exec, makeSource(s), false);
524    if (!eval)
525        return JSValue::encode(jsUndefined());
526
527    return JSValue::encode(exec->interpreter()->execute(eval, exec, calleeGlobalObject->globalThis(), calleeGlobalObject));
528}
529
530EncodedJSValue JSC_HOST_CALL globalFuncParseInt(ExecState* exec)
531{
532    JSValue value = exec->argument(0);
533    JSValue radixValue = exec->argument(1);
534
535    // Optimized handling for numbers:
536    // If the argument is 0 or a number in range 10^-6 <= n < INT_MAX+1, then parseInt
537    // results in a truncation to integer. In the case of -0, this is converted to 0.
538    //
539    // This is also a truncation for values in the range INT_MAX+1 <= n < 10^21,
540    // however these values cannot be trivially truncated to int since 10^21 exceeds
541    // even the int64_t range. Negative numbers are a little trickier, the case for
542    // values in the range -10^21 < n <= -1 are similar to those for integer, but
543    // values in the range -1 < n <= -10^-6 need to truncate to -0, not 0.
544    static const double tenToTheMinus6 = 0.000001;
545    static const double intMaxPlusOne = 2147483648.0;
546    if (value.isNumber()) {
547        double n = value.asNumber();
548        if (((n < intMaxPlusOne && n >= tenToTheMinus6) || !n) && radixValue.isUndefinedOrNull())
549            return JSValue::encode(jsNumber(static_cast<int32_t>(n)));
550    }
551
552    // If ToString throws, we shouldn't call ToInt32.
553    String s = value.toString(exec)->value(exec);
554    if (exec->hadException())
555        return JSValue::encode(jsUndefined());
556
557    return JSValue::encode(jsNumber(parseInt(s, radixValue.toInt32(exec))));
558}
559
560EncodedJSValue JSC_HOST_CALL globalFuncParseFloat(ExecState* exec)
561{
562    return JSValue::encode(jsNumber(parseFloat(exec->argument(0).toString(exec)->value(exec))));
563}
564
565EncodedJSValue JSC_HOST_CALL globalFuncIsNaN(ExecState* exec)
566{
567    return JSValue::encode(jsBoolean(std::isnan(exec->argument(0).toNumber(exec))));
568}
569
570EncodedJSValue JSC_HOST_CALL globalFuncIsFinite(ExecState* exec)
571{
572    double n = exec->argument(0).toNumber(exec);
573    return JSValue::encode(jsBoolean(std::isfinite(n)));
574}
575
576EncodedJSValue JSC_HOST_CALL globalFuncDecodeURI(ExecState* exec)
577{
578    static const char do_not_unescape_when_decoding_URI[] =
579        "#$&+,/:;=?@";
580
581    return JSValue::encode(decode(exec, do_not_unescape_when_decoding_URI, true));
582}
583
584EncodedJSValue JSC_HOST_CALL globalFuncDecodeURIComponent(ExecState* exec)
585{
586    return JSValue::encode(decode(exec, "", true));
587}
588
589EncodedJSValue JSC_HOST_CALL globalFuncEncodeURI(ExecState* exec)
590{
591    static const char do_not_escape_when_encoding_URI[] =
592        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
593        "abcdefghijklmnopqrstuvwxyz"
594        "0123456789"
595        "!#$&'()*+,-./:;=?@_~";
596
597    return JSValue::encode(encode(exec, do_not_escape_when_encoding_URI));
598}
599
600EncodedJSValue JSC_HOST_CALL globalFuncEncodeURIComponent(ExecState* exec)
601{
602    static const char do_not_escape_when_encoding_URI_component[] =
603        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
604        "abcdefghijklmnopqrstuvwxyz"
605        "0123456789"
606        "!'()*-._~";
607
608    return JSValue::encode(encode(exec, do_not_escape_when_encoding_URI_component));
609}
610
611EncodedJSValue JSC_HOST_CALL globalFuncEscape(ExecState* exec)
612{
613    static const char do_not_escape[] =
614        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
615        "abcdefghijklmnopqrstuvwxyz"
616        "0123456789"
617        "*+-./@_";
618
619    JSStringBuilder builder;
620    String str = exec->argument(0).toString(exec)->value(exec);
621    if (str.is8Bit()) {
622        const LChar* c = str.characters8();
623        for (unsigned k = 0; k < str.length(); k++, c++) {
624            int u = c[0];
625            if (u && strchr(do_not_escape, static_cast<char>(u)))
626                builder.append(*c);
627            else {
628                char tmp[4];
629                snprintf(tmp, sizeof(tmp), "%%%02X", u);
630                builder.append(tmp);
631            }
632        }
633
634        return JSValue::encode(builder.build(exec));
635    }
636
637    const UChar* c = str.characters16();
638    for (unsigned k = 0; k < str.length(); k++, c++) {
639        int u = c[0];
640        if (u > 255) {
641            char tmp[7];
642            snprintf(tmp, sizeof(tmp), "%%u%04X", u);
643            builder.append(tmp);
644        } else if (u != 0 && strchr(do_not_escape, static_cast<char>(u)))
645            builder.append(*c);
646        else {
647            char tmp[4];
648            snprintf(tmp, sizeof(tmp), "%%%02X", u);
649            builder.append(tmp);
650        }
651    }
652
653    return JSValue::encode(builder.build(exec));
654}
655
656EncodedJSValue JSC_HOST_CALL globalFuncUnescape(ExecState* exec)
657{
658    StringBuilder builder;
659    String str = exec->argument(0).toString(exec)->value(exec);
660    int k = 0;
661    int len = str.length();
662
663    if (str.is8Bit()) {
664        const LChar* characters = str.characters8();
665        LChar convertedLChar;
666        while (k < len) {
667            const LChar* c = characters + k;
668            if (c[0] == '%' && k <= len - 6 && c[1] == 'u') {
669                if (isASCIIHexDigit(c[2]) && isASCIIHexDigit(c[3]) && isASCIIHexDigit(c[4]) && isASCIIHexDigit(c[5])) {
670                    builder.append(Lexer<UChar>::convertUnicode(c[2], c[3], c[4], c[5]));
671                    k += 6;
672                    continue;
673                }
674            } else if (c[0] == '%' && k <= len - 3 && isASCIIHexDigit(c[1]) && isASCIIHexDigit(c[2])) {
675                convertedLChar = LChar(Lexer<LChar>::convertHex(c[1], c[2]));
676                c = &convertedLChar;
677                k += 2;
678            }
679            builder.append(*c);
680            k++;
681        }
682    } else {
683        const UChar* characters = str.characters16();
684
685        while (k < len) {
686            const UChar* c = characters + k;
687            UChar convertedUChar;
688            if (c[0] == '%' && k <= len - 6 && c[1] == 'u') {
689                if (isASCIIHexDigit(c[2]) && isASCIIHexDigit(c[3]) && isASCIIHexDigit(c[4]) && isASCIIHexDigit(c[5])) {
690                    convertedUChar = Lexer<UChar>::convertUnicode(c[2], c[3], c[4], c[5]);
691                    c = &convertedUChar;
692                    k += 5;
693                }
694            } else if (c[0] == '%' && k <= len - 3 && isASCIIHexDigit(c[1]) && isASCIIHexDigit(c[2])) {
695                convertedUChar = UChar(Lexer<UChar>::convertHex(c[1], c[2]));
696                c = &convertedUChar;
697                k += 2;
698            }
699            k++;
700            builder.append(*c);
701        }
702    }
703
704    return JSValue::encode(jsString(exec, builder.toString()));
705}
706
707EncodedJSValue JSC_HOST_CALL globalFuncThrowTypeError(ExecState* exec)
708{
709    return throwVMTypeError(exec);
710}
711
712class GlobalFuncProtoGetterFunctor {
713public:
714    GlobalFuncProtoGetterFunctor(JSObject* thisObject)
715        : m_hasSkippedFirstFrame(false)
716        , m_thisObject(thisObject)
717        , m_result(JSValue::encode(jsUndefined()))
718    {
719    }
720
721    EncodedJSValue result() { return m_result; }
722
723    StackVisitor::Status operator()(StackVisitor& visitor)
724    {
725        if (!m_hasSkippedFirstFrame) {
726            m_hasSkippedFirstFrame = true;
727            return StackVisitor::Continue;
728        }
729
730        if (m_thisObject->allowsAccessFrom(visitor->callFrame()))
731            m_result = JSValue::encode(m_thisObject->prototype());
732
733        return StackVisitor::Done;
734    }
735
736private:
737    bool m_hasSkippedFirstFrame;
738    JSObject* m_thisObject;
739    EncodedJSValue m_result;
740};
741
742EncodedJSValue JSC_HOST_CALL globalFuncProtoGetter(ExecState* exec)
743{
744    JSObject* thisObject = jsDynamicCast<JSObject*>(exec->thisValue().toThis(exec, NotStrictMode));
745
746    if (!thisObject)
747        return JSValue::encode(exec->thisValue().synthesizePrototype(exec));
748
749    GlobalFuncProtoGetterFunctor functor(thisObject);
750    exec->iterate(functor);
751    return functor.result();
752}
753
754class GlobalFuncProtoSetterFunctor {
755public:
756    GlobalFuncProtoSetterFunctor(JSObject* thisObject)
757        : m_hasSkippedFirstFrame(false)
758        , m_allowsAccess(false)
759        , m_thisObject(thisObject)
760    {
761    }
762
763    bool allowsAccess() const { return m_allowsAccess; }
764
765    StackVisitor::Status operator()(StackVisitor& visitor)
766    {
767        if (!m_hasSkippedFirstFrame) {
768            m_hasSkippedFirstFrame = true;
769            return StackVisitor::Continue;
770        }
771
772        m_allowsAccess = m_thisObject->allowsAccessFrom(visitor->callFrame());
773        return StackVisitor::Done;
774    }
775
776private:
777    bool m_hasSkippedFirstFrame;
778    bool m_allowsAccess;
779    JSObject* m_thisObject;
780};
781
782EncodedJSValue JSC_HOST_CALL globalFuncProtoSetter(ExecState* exec)
783{
784    JSValue value = exec->argument(0);
785
786    JSObject* thisObject = jsDynamicCast<JSObject*>(exec->thisValue().toThis(exec, NotStrictMode));
787
788    // Setting __proto__ of a primitive should have no effect.
789    if (!thisObject)
790        return JSValue::encode(jsUndefined());
791
792    GlobalFuncProtoSetterFunctor functor(thisObject);
793    exec->iterate(functor);
794    if (!functor.allowsAccess())
795        return JSValue::encode(jsUndefined());
796
797    // Setting __proto__ to a non-object, non-null value is silently ignored to match Mozilla.
798    if (!value.isObject() && !value.isNull())
799        return JSValue::encode(jsUndefined());
800
801    if (!thisObject->isExtensible())
802        return throwVMError(exec, createTypeError(exec, StrictModeReadonlyPropertyWriteError));
803
804    if (!thisObject->setPrototypeWithCycleCheck(exec, value))
805        exec->vm().throwException(exec, createError(exec, "cyclic __proto__ value"));
806    return JSValue::encode(jsUndefined());
807}
808
809EncodedJSValue JSC_HOST_CALL globalFuncBuiltinLog(ExecState* exec)
810{
811    dataLog(exec->argument(0).toWTFString(exec), "\n");
812    return JSValue::encode(jsUndefined());
813}
814
815} // namespace JSC
816