json.cpp
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "json.h"
#include "mozilla/FloatingPoint.h"
#include "mozilla/Range.h"
#include "jsarray.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsnum.h"
#include "jsobj.h"
#include "jsonparser.h"
#include "jsstr.h"
#include "jstypes.h"
#include "jsutil.h"
#include "vm/Interpreter.h"
#include "vm/StringBuffer.h"
#include "jsatominlines.h"
#include "jsboolinlines.h"
#include "jsobjinlines.h"
using namespace js;
using namespace js::gc;
using namespace js::types;
using mozilla::IsFinite;
using mozilla::Maybe;
using mozilla::RangedPtr;
const Class js::JSONClass = {
js_JSON_str,
JSCLASS_HAS_CACHED_PROTO(JSProto_JSON),
JS_PropertyStub, /* addProperty */
JS_DeletePropertyStub, /* delProperty */
JS_PropertyStub, /* getProperty */
JS_StrictPropertyStub, /* setProperty */
JS_EnumerateStub,
JS_ResolveStub,
JS_ConvertStub
};
static inline bool IsQuoteSpecialCharacter(jschar c)
{
JS_STATIC_ASSERT('\b' < ' ');
JS_STATIC_ASSERT('\f' < ' ');
JS_STATIC_ASSERT('\n' < ' ');
JS_STATIC_ASSERT('\r' < ' ');
JS_STATIC_ASSERT('\t' < ' ');
return c == '"' || c == '\\' || c < ' ';
}
/* ES5 15.12.3 Quote. */
template <typename CharT>
static bool
Quote(StringBuffer& sb, JSLinearString* str)
{
size_t len = str->length();
/* Step 1. */
if (!sb.append('"'))
return false;
/* Step 2. */
JS::AutoCheckCannotGC nogc;
const RangedPtr<const CharT> buf(str->chars<CharT>(nogc), len);
for (size_t i = 0; i < len; ++i) {
/* Batch-append maximal character sequences containing no escapes. */
size_t mark = i;
do {
if (IsQuoteSpecialCharacter(buf[i]))
break;
} while (++i < len);
if (i > mark) {
if (!sb.appendSubstring(str, mark, i - mark))
return false;
if (i == len)
break;
}
jschar c = buf[i];
if (c == '"' || c == '\\') {
if (!sb.append('\\') || !sb.append(c))
return false;
} else if (c == '\b' || c == '\f' || c == '\n' || c == '\r' || c == '\t') {
jschar abbrev = (c == '\b')
? 'b'
: (c == '\f')
? 'f'
: (c == '\n')
? 'n'
: (c == '\r')
? 'r'
: 't';
if (!sb.append('\\') || !sb.append(abbrev))
return false;
} else {
JS_ASSERT(c < ' ');
if (!sb.append("\\u00"))
return false;
JS_ASSERT((c >> 4) < 10);
uint8_t x = c >> 4, y = c % 16;
if (!sb.append(Latin1Char('0' + x)) ||
!sb.append(Latin1Char(y < 10 ? '0' + y : 'a' + (y - 10))))
{
return false;
}
}
}
/* Steps 3-4. */
return sb.append('"');
}
static bool
Quote(JSContext* cx, StringBuffer& sb, JSString* str)
{
JS::Anchor<JSString*> anchor(str);
JSLinearString* linear = str->ensureLinear(cx);
if (!linear)
return false;
return linear->hasLatin1Chars()
? Quote<Latin1Char>(sb, linear)
: Quote<jschar>(sb, linear);
}
namespace {
class StringifyContext
{
public:
StringifyContext(JSContext* cx, StringBuffer& sb, const StringBuffer& gap,
HandleObject replacer, const AutoIdVector& propertyList)
: sb(sb),
gap(gap),
replacer(cx, replacer),
propertyList(propertyList),
depth(0)
{}
StringBuffer& sb;
const StringBuffer& gap;
RootedObject replacer;
const AutoIdVector& propertyList;
uint32_t depth;
};
} /* anonymous namespace */
static bool Str(JSContext* cx, const Value& v, StringifyContext* scx);
static bool
WriteIndent(JSContext* cx, StringifyContext* scx, uint32_t limit)
{
if (!scx->gap.empty()) {
if (!scx->sb.append('\n'))
return false;
if (scx->gap.isUnderlyingBufferLatin1()) {
for (uint32_t i = 0; i < limit; i++) {
if (!scx->sb.append(scx->gap.rawLatin1Begin(), scx->gap.rawLatin1End()))
return false;
}
} else {
for (uint32_t i = 0; i < limit; i++) {
if (!scx->sb.append(scx->gap.rawTwoByteBegin(), scx->gap.rawTwoByteEnd()))
return false;
}
}
}
return true;
}
namespace {
template<typename KeyType>
class KeyStringifier {
};
template<>
class KeyStringifier<uint32_t> {
public:
static JSString* toString(JSContext* cx, uint32_t index) {
return IndexToString(cx, index);
}
};
template<>
class KeyStringifier<HandleId> {
public:
static JSString* toString(JSContext* cx, HandleId id) {
return IdToString(cx, id);
}
};
} /* anonymous namespace */
/*
* ES5 15.12.3 Str, steps 2-4, extracted to enable preprocessing of property
* values when stringifying objects in JO.
*/
template<typename KeyType>
static bool
PreprocessValue(JSContext* cx, HandleObject holder, KeyType key, MutableHandleValue vp, StringifyContext* scx)
{
RootedString keyStr(cx);
/* Step 2. */
if (vp.isObject()) {
RootedValue toJSON(cx);
RootedObject obj(cx, &vp.toObject());
if (!JSObject::getProperty(cx, obj, obj, cx->names().toJSON, &toJSON))
return false;
if (IsCallable(toJSON)) {
keyStr = KeyStringifier<KeyType>::toString(cx, key);
if (!keyStr)
return false;
InvokeArgs args(cx);
if (!args.init(1))
return false;
args.setCallee(toJSON);
args.setThis(vp);
args[0].setString(keyStr);
if (!Invoke(cx, args))
return false;
vp.set(args.rval());
}
}
/* Step 3. */
if (scx->replacer && scx->replacer->isCallable()) {
if (!keyStr) {
keyStr = KeyStringifier<KeyType>::toString(cx, key);
if (!keyStr)
return false;
}
InvokeArgs args(cx);
if (!args.init(2))
return false;
args.setCallee(ObjectValue(*scx->replacer));
args.setThis(ObjectValue(*holder));
args[0].setString(keyStr);
args[1].set(vp);
if (!Invoke(cx, args))
return false;
vp.set(args.rval());
}
/* Step 4. */
if (vp.get().isObject()) {
RootedObject obj(cx, &vp.get().toObject());
if (ObjectClassIs(obj, ESClass_Number, cx)) {
double d;
if (!ToNumber(cx, vp, &d))
return false;
vp.setNumber(d);
} else if (ObjectClassIs(obj, ESClass_String, cx)) {
JSString* str = ToStringSlow<CanGC>(cx, vp);
if (!str)
return false;
vp.setString(str);
} else if (ObjectClassIs(obj, ESClass_Boolean, cx)) {
if (!Unbox(cx, obj, vp))
return false;
}
}
return true;
}
/*
* Determines whether a value which has passed by ES5 150.2.3 Str steps 1-4's
* gauntlet will result in Str returning |undefined|. This function is used to
* properly omit properties resulting in such values when stringifying objects,
* while properly stringifying such properties as null when they're encountered
* in arrays.
*/
static inline bool
IsFilteredValue(const Value& v)
{
return v.isUndefined() || v.isSymbol() || IsCallable(v);
}
/* ES5 15.12.3 JO. */
static bool
JO(JSContext* cx, HandleObject obj, StringifyContext* scx)
{
/*
* This method implements the JO algorithm in ES5 15.12.3, but:
*
* * The algorithm is somewhat reformulated to allow the final string to
* be streamed into a single buffer, rather than be created and copied
* into place incrementally as the ES5 algorithm specifies it. This
* requires moving portions of the Str call in 8a into this algorithm
* (and in JA as well).
*/
/* Steps 1-2, 11. */
AutoCycleDetector detect(cx, obj);
if (!detect.init())
return false;
if (detect.foundCycle()) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_JSON_CYCLIC_VALUE,
js_object_str);
return false;
}
if (!scx->sb.append('{'))
return false;
/* Steps 5-7. */
Maybe<AutoIdVector> ids;
const AutoIdVector* props;
if (scx->replacer && !scx->replacer->isCallable()) {
JS_ASSERT(IsArray(scx->replacer, cx));
props = &scx->propertyList;
} else {
JS_ASSERT_IF(scx->replacer, scx->propertyList.length() == 0);
ids.emplace(cx);
if (!GetPropertyNames(cx, obj, JSITER_OWNONLY, ids.ptr()))
return false;
props = ids.ptr();
}
/* My kingdom for not-quite-initialized-from-the-start references. */
const AutoIdVector& propertyList = *props;
/* Steps 8-10, 13. */
bool wroteMember = false;
RootedId id(cx);
for (size_t i = 0, len = propertyList.length(); i < len; i++) {
/*
* Steps 8a-8b. Note that the call to Str is broken up into 1) getting
* the property; 2) processing for toJSON, calling the replacer, and
* handling boxed Number/String/Boolean objects; 3) filtering out
* values which process to |undefined|, and 4) stringifying all values
* which pass the filter.
*/
id = propertyList[i];
RootedValue outputValue(cx);
if (!JSObject::getGeneric(cx, obj, obj, id, &outputValue))
return false;
if (!PreprocessValue(cx, obj, HandleId(id), &outputValue, scx))
return false;
if (IsFilteredValue(outputValue))
continue;
/* Output a comma unless this is the first member to write. */
if (wroteMember && !scx->sb.append(','))
return false;
wroteMember = true;
if (!WriteIndent(cx, scx, scx->depth))
return false;
JSString* s = IdToString(cx, id);
if (!s)
return false;
if (!Quote(cx, scx->sb, s) ||
!scx->sb.append(':') ||
!(scx->gap.empty() || scx->sb.append(' ')) ||
!Str(cx, outputValue, scx))
{
return false;
}
}
if (wroteMember && !WriteIndent(cx, scx, scx->depth - 1))
return false;
return scx->sb.append('}');
}
/* ES5 15.12.3 JA. */
static bool
JA(JSContext* cx, HandleObject obj, StringifyContext* scx)
{
/*
* This method implements the JA algorithm in ES5 15.12.3, but:
*
* * The algorithm is somewhat reformulated to allow the final string to
* be streamed into a single buffer, rather than be created and copied
* into place incrementally as the ES5 algorithm specifies it. This
* requires moving portions of the Str call in 8a into this algorithm
* (and in JO as well).
*/
/* Steps 1-2, 11. */
AutoCycleDetector detect(cx, obj);
if (!detect.init())
return false;
if (detect.foundCycle()) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_JSON_CYCLIC_VALUE,
js_object_str);
return false;
}
if (!scx->sb.append('['))
return false;
/* Step 6. */
uint32_t length;
if (!GetLengthProperty(cx, obj, &length))
return false;
/* Steps 7-10. */
if (length != 0) {
/* Steps 4, 10b(i). */
if (!WriteIndent(cx, scx, scx->depth))
return false;
/* Steps 7-10. */
RootedValue outputValue(cx);
for (uint32_t i = 0; i < length; i++) {
/*
* Steps 8a-8c. Again note how the call to the spec's Str method
* is broken up into getting the property, running it past toJSON
* and the replacer and maybe unboxing, and interpreting some
* values as |null| in separate steps.
*/
if (!JSObject::getElement(cx, obj, obj, i, &outputValue))
return false;
if (!PreprocessValue(cx, obj, i, &outputValue, scx))
return false;
if (IsFilteredValue(outputValue)) {
if (!scx->sb.append("null"))
return false;
} else {
if (!Str(cx, outputValue, scx))
return false;
}
/* Steps 3, 4, 10b(i). */
if (i < length - 1) {
if (!scx->sb.append(','))
return false;
if (!WriteIndent(cx, scx, scx->depth))
return false;
}
}
/* Step 10(b)(iii). */
if (!WriteIndent(cx, scx, scx->depth - 1))
return false;
}
return scx->sb.append(']');
}
static bool
Str(JSContext* cx, const Value& v, StringifyContext* scx)
{
/* Step 11 must be handled by the caller. */
JS_ASSERT(!IsFilteredValue(v));
JS_CHECK_RECURSION(cx, return false);
/*
* This method implements the Str algorithm in ES5 15.12.3, but:
*
* * We move property retrieval (step 1) into callers to stream the
* stringification process and avoid constantly copying strings.
* * We move the preprocessing in steps 2-4 into a helper function to
* allow both JO and JA to use this method. While JA could use it
* without this move, JO must omit any |undefined|-valued property per
* so it can't stream out a value using the Str method exactly as
* defined by ES5.
* * We move step 11 into callers, again to ease streaming.
*/
/* Step 8. */
if (v.isString())
return Quote(cx, scx->sb, v.toString());
/* Step 5. */
if (v.isNull())
return scx->sb.append("null");
/* Steps 6-7. */
if (v.isBoolean())
return v.toBoolean() ? scx->sb.append("true") : scx->sb.append("false");
/* Step 9. */
if (v.isNumber()) {
if (v.isDouble()) {
if (!IsFinite(v.toDouble()))
return scx->sb.append("null");
}
return NumberValueToStringBuffer(cx, v, scx->sb);
}
/* Step 10. */
JS_ASSERT(v.isObject());
RootedObject obj(cx, &v.toObject());
scx->depth++;
bool ok;
if (IsArray(obj, cx))
ok = JA(cx, obj, scx);
else
ok = JO(cx, obj, scx);
scx->depth--;
return ok;
}
/* ES5 15.12.3. */
bool
js_Stringify(JSContext* cx, MutableHandleValue vp, JSObject* replacer_, Value space_,
StringBuffer& sb)
{
RootedObject replacer(cx, replacer_);
RootedValue space(cx, space_);
/* Step 4. */
AutoIdVector propertyList(cx);
if (replacer) {
if (replacer->isCallable()) {
/* Step 4a(i): use replacer to transform values. */
} else if (IsArray(replacer, cx)) {
/*
* Step 4b: The spec algorithm is unhelpfully vague about the exact
* steps taken when the replacer is an array, regarding the exact
* sequence of [[Get]] calls for the array's elements, when its
* overall length is calculated, whether own or own plus inherited
* properties are considered, and so on. A rewrite was proposed in
* <https://mail.mozilla.org/pipermail/es5-discuss/2011-April/003976.html>,
* whose steps are copied below, and which are implemented here.
*
* i. Let PropertyList be an empty internal List.
* ii. Let len be the result of calling the [[Get]] internal
* method of replacer with the argument "length".
* iii. Let i be 0.
* iv. While i < len:
* 1. Let item be undefined.
* 2. Let v be the result of calling the [[Get]] internal
* method of replacer with the argument ToString(i).
* 3. If Type(v) is String then let item be v.
* 4. Else if Type(v) is Number then let item be ToString(v).
* 5. Else if Type(v) is Object then
* a. If the [[Class]] internal property of v is "String"
* or "Number" then let item be ToString(v).
* 6. If item is not undefined and item is not currently an
* element of PropertyList then,
* a. Append item to the end of PropertyList.
* 7. Let i be i + 1.
*/
/* Step 4b(ii). */
uint32_t len;
if (!GetLengthProperty(cx, replacer, &len))
return false;
if (replacer->is<ArrayObject>() && !replacer->isIndexed())
len = Min(len, replacer->getDenseInitializedLength());
// Cap the initial size to a moderately small value. This avoids
// ridiculous over-allocation if an array with bogusly-huge length
// is passed in. If we end up having to add elements past this
// size, the set will naturally resize to accommodate them.
const uint32_t MaxInitialSize = 1024;
HashSet<jsid, JsidHasher> idSet(cx);
if (!idSet.init(Min(len, MaxInitialSize)))
return false;
/* Step 4b(iii). */
uint32_t i = 0;
/* Step 4b(iv). */
RootedValue v(cx);
for (; i < len; i++) {
if (!CheckForInterrupt(cx))
return false;
/* Step 4b(iv)(2). */
if (!JSObject::getElement(cx, replacer, replacer, i, &v))
return false;
RootedId id(cx);
if (v.isNumber()) {
/* Step 4b(iv)(4). */
int32_t n;
if (v.isNumber() && ValueFitsInInt32(v, &n) && INT_FITS_IN_JSID(n)) {
id = INT_TO_JSID(n);
} else {
if (!ValueToId<CanGC>(cx, v, &id))
return false;
}
} else if (v.isString() ||
IsObjectWithClass(v, ESClass_String, cx) ||
IsObjectWithClass(v, ESClass_Number, cx))
{
/* Step 4b(iv)(3), 4b(iv)(5). */
if (!ValueToId<CanGC>(cx, v, &id))
return false;
} else {
continue;
}
/* Step 4b(iv)(6). */
HashSet<jsid, JsidHasher>::AddPtr p = idSet.lookupForAdd(id);
if (!p) {
/* Step 4b(iv)(6)(a). */
if (!idSet.add(p, id) || !propertyList.append(id))
return false;
}
}
} else {
replacer = nullptr;
}
}
/* Step 5. */
if (space.isObject()) {
RootedObject spaceObj(cx, &space.toObject());
if (ObjectClassIs(spaceObj, ESClass_Number, cx)) {
double d;
if (!ToNumber(cx, space, &d))
return false;
space = NumberValue(d);
} else if (ObjectClassIs(spaceObj, ESClass_String, cx)) {
JSString* str = ToStringSlow<CanGC>(cx, space);
if (!str)
return false;
space = StringValue(str);
}
}
StringBuffer gap(cx);
if (space.isNumber()) {
/* Step 6. */
double d;
JS_ALWAYS_TRUE(ToInteger(cx, space, &d));
d = Min(10.0, d);
if (d >= 1 && !gap.appendN(' ', uint32_t(d)))
return false;
} else if (space.isString()) {
/* Step 7. */
JSLinearString* str = space.toString()->ensureLinear(cx);
if (!str)
return false;
JS::Anchor<JSString*> anchor(str);
size_t len = Min(size_t(10), str->length());
if (!gap.appendSubstring(str, 0, len))
return false;
} else {
/* Step 8. */
JS_ASSERT(gap.empty());
}
/* Step 9. */
RootedObject wrapper(cx, NewBuiltinClassInstance(cx, &JSObject::class_));
if (!wrapper)
return false;
/* Step 10. */
RootedId emptyId(cx, NameToId(cx->names().empty));
if (!DefineNativeProperty(cx, wrapper, emptyId, vp, JS_PropertyStub, JS_StrictPropertyStub,
JSPROP_ENUMERATE))
{
return false;
}
/* Step 11. */
StringifyContext scx(cx, sb, gap, replacer, propertyList);
if (!PreprocessValue(cx, wrapper, HandleId(emptyId), vp, &scx))
return false;
if (IsFilteredValue(vp))
return true;
return Str(cx, vp, &scx);
}
/* ES5 15.12.2 Walk. */
static bool
Walk(JSContext* cx, HandleObject holder, HandleId name, HandleValue reviver, MutableHandleValue vp)
{
JS_CHECK_RECURSION(cx, return false);
/* Step 1. */
RootedValue val(cx);
if (!JSObject::getGeneric(cx, holder, holder, name, &val))
return false;
/* Step 2. */
if (val.isObject()) {
RootedObject obj(cx, &val.toObject());
if (IsArray(obj, cx)) {
/* Step 2a(ii). */
uint32_t length;
if (!GetLengthProperty(cx, obj, &length))
return false;
/* Step 2a(i), 2a(iii-iv). */
RootedId id(cx);
RootedValue newElement(cx);
for (uint32_t i = 0; i < length; i++) {
if (!IndexToId(cx, i, &id))
return false;
/* Step 2a(iii)(1). */
if (!Walk(cx, obj, id, reviver, &newElement))
return false;
if (newElement.isUndefined()) {
/* Step 2a(iii)(2). */
bool succeeded;
if (!JSObject::deleteGeneric(cx, obj, id, &succeeded))
return false;
} else {
/* Step 2a(iii)(3). */
// XXX This definition should ignore success/failure, when
// our property-definition APIs indicate that.
if (!JSObject::defineGeneric(cx, obj, id, newElement))
return false;
}
}
} else {
/* Step 2b(i). */
AutoIdVector keys(cx);
if (!GetPropertyNames(cx, obj, JSITER_OWNONLY, &keys))
return false;
/* Step 2b(ii). */
RootedId id(cx);
RootedValue newElement(cx);
for (size_t i = 0, len = keys.length(); i < len; i++) {
/* Step 2b(ii)(1). */
id = keys[i];
if (!Walk(cx, obj, id, reviver, &newElement))
return false;
if (newElement.isUndefined()) {
/* Step 2b(ii)(2). */
bool succeeded;
if (!JSObject::deleteGeneric(cx, obj, id, &succeeded))
return false;
} else {
/* Step 2b(ii)(3). */
// XXX This definition should ignore success/failure, when
// our property-definition APIs indicate that.
if (!JSObject::defineGeneric(cx, obj, id, newElement))
return false;
}
}
}
}
/* Step 3. */
RootedString key(cx, IdToString(cx, name));
if (!key)
return false;
InvokeArgs args(cx);
if (!args.init(2))
return false;
args.setCallee(reviver);
args.setThis(ObjectValue(*holder));
args[0].setString(key);
args[1].set(val);
if (!Invoke(cx, args))
return false;
vp.set(args.rval());
return true;
}
static bool
Revive(JSContext* cx, HandleValue reviver, MutableHandleValue vp)
{
RootedObject obj(cx, NewBuiltinClassInstance(cx, &JSObject::class_));
if (!obj)
return false;
if (!JSObject::defineProperty(cx, obj, cx->names().empty, vp))
return false;
Rooted<jsid> id(cx, NameToId(cx->names().empty));
return Walk(cx, obj, id, reviver, vp);
}
template <typename CharT>
bool
js::ParseJSONWithReviver(JSContext* cx, const mozilla::Range<const CharT> chars, HandleValue reviver,
MutableHandleValue vp)
{
/* 15.12.2 steps 2-3. */
JSONParser<CharT> parser(cx, chars);
if (!parser.parse(vp))
return false;
/* 15.12.2 steps 4-5. */
if (IsCallable(reviver))
return Revive(cx, reviver, vp);
return true;
}
template bool
js::ParseJSONWithReviver(JSContext* cx, const mozilla::Range<const Latin1Char> chars,
HandleValue reviver, MutableHandleValue vp);
template bool
js::ParseJSONWithReviver(JSContext* cx, const mozilla::Range<const jschar> chars, HandleValue reviver,
MutableHandleValue vp);
#if JS_HAS_TOSOURCE
static bool
json_toSource(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
args.rval().setString(cx->names().JSON);
return true;
}
#endif
/* ES5 15.12.2. */
static bool
json_parse(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
/* Step 1. */
JSString* str = (args.length() >= 1)
? ToString<CanGC>(cx, args[0])
: cx->names().undefined;
if (!str)
return false;
JSFlatString* flat = str->ensureFlat(cx);
if (!flat)
return false;
JS::Anchor<JSString*> anchor(flat);
AutoStableStringChars flatChars(cx);
if (!flatChars.init(cx, flat))
return false;
RootedValue reviver(cx, args.get(1));
/* Steps 2-5. */
return flatChars.isLatin1()
? ParseJSONWithReviver(cx, flatChars.latin1Range(), reviver, args.rval())
: ParseJSONWithReviver(cx, flatChars.twoByteRange(), reviver, args.rval());
}
/* ES5 15.12.3. */
bool
json_stringify(JSContext* cx, unsigned argc, Value* vp)
{
CallArgs args = CallArgsFromVp(argc, vp);
RootedObject replacer(cx, args.get(1).isObject() ? &args[1].toObject() : nullptr);
RootedValue value(cx, args.get(0));
RootedValue space(cx, args.get(2));
StringBuffer sb(cx);
if (!js_Stringify(cx, &value, replacer, space, sb))
return false;
// XXX This can never happen to nsJSON.cpp, but the JSON object
// needs to support returning undefined. So this is a little awkward
// for the API, because we want to support streaming writers.
if (!sb.empty()) {
JSString* str = sb.finishString();
if (!str)
return false;
args.rval().setString(str);
} else {
args.rval().setUndefined();
}
return true;
}
static const JSFunctionSpec json_static_methods[] = {
#if JS_HAS_TOSOURCE
JS_FN(js_toSource_str, json_toSource, 0, 0),
#endif
JS_FN("parse", json_parse, 2, 0),
JS_FN("stringify", json_stringify, 3, 0),
JS_FS_END
};
JSObject*
js_InitJSONClass(JSContext* cx, HandleObject obj)
{
Rooted<GlobalObject*> global(cx, &obj->as<GlobalObject>());
RootedObject proto(cx, global->getOrCreateObjectPrototype(cx));
if (!proto)
return nullptr;
RootedObject JSON(cx, NewObjectWithGivenProto(cx, &JSONClass, proto, global, SingletonObject));
if (!JSON)
return nullptr;
if (!JS_DefineProperty(cx, global, js_JSON_str, JSON, 0,
JS_PropertyStub, JS_StrictPropertyStub))
return nullptr;
if (!JS_DefineFunctions(cx, JSON, json_static_methods))
return nullptr;
global->setConstructor(JSProto_JSON, ObjectValue(*JSON));
return JSON;
}