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