1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jsonparser.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,216 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef jsonparser_h
1.11 +#define jsonparser_h
1.12 +
1.13 +#include "mozilla/Attributes.h"
1.14 +
1.15 +#include "ds/IdValuePair.h"
1.16 +#include "vm/String.h"
1.17 +
1.18 +namespace js {
1.19 +
1.20 +class MOZ_STACK_CLASS JSONParser : private AutoGCRooter
1.21 +{
1.22 + public:
1.23 + enum ErrorHandling { RaiseError, NoError };
1.24 +
1.25 + private:
1.26 + /* Data members */
1.27 +
1.28 + JSContext * const cx;
1.29 + JS::ConstTwoByteChars current;
1.30 + const JS::ConstTwoByteChars begin, end;
1.31 +
1.32 + Value v;
1.33 +
1.34 + const ErrorHandling errorHandling;
1.35 +
1.36 + enum Token { String, Number, True, False, Null,
1.37 + ArrayOpen, ArrayClose,
1.38 + ObjectOpen, ObjectClose,
1.39 + Colon, Comma,
1.40 + OOM, Error };
1.41 +
1.42 + // State related to the parser's current position. At all points in the
1.43 + // parse this keeps track of the stack of arrays and objects which have
1.44 + // been started but not finished yet. The actual JS object is not
1.45 + // allocated until the literal is closed, so that the result can be sized
1.46 + // according to its contents and have its type and shape filled in using
1.47 + // caches.
1.48 +
1.49 + // State for an array that is currently being parsed. This includes all
1.50 + // elements that have been seen so far.
1.51 + typedef Vector<Value, 20> ElementVector;
1.52 +
1.53 + // State for an object that is currently being parsed. This includes all
1.54 + // the key/value pairs that have been seen so far.
1.55 + typedef Vector<IdValuePair, 10> PropertyVector;
1.56 +
1.57 + // Possible states the parser can be in between values.
1.58 + enum ParserState {
1.59 + // An array element has just being parsed.
1.60 + FinishArrayElement,
1.61 +
1.62 + // An object property has just been parsed.
1.63 + FinishObjectMember,
1.64 +
1.65 + // At the start of the parse, before any values have been processed.
1.66 + JSONValue
1.67 + };
1.68 +
1.69 + // Stack element for an in progress array or object.
1.70 + struct StackEntry {
1.71 + ElementVector &elements() {
1.72 + JS_ASSERT(state == FinishArrayElement);
1.73 + return * static_cast<ElementVector *>(vector);
1.74 + }
1.75 +
1.76 + PropertyVector &properties() {
1.77 + JS_ASSERT(state == FinishObjectMember);
1.78 + return * static_cast<PropertyVector *>(vector);
1.79 + }
1.80 +
1.81 + StackEntry(ElementVector *elements)
1.82 + : state(FinishArrayElement), vector(elements)
1.83 + {}
1.84 +
1.85 + StackEntry(PropertyVector *properties)
1.86 + : state(FinishObjectMember), vector(properties)
1.87 + {}
1.88 +
1.89 + ParserState state;
1.90 +
1.91 + private:
1.92 + void *vector;
1.93 + };
1.94 +
1.95 + // All in progress arrays and objects being parsed, in order from outermost
1.96 + // to innermost.
1.97 + Vector<StackEntry, 10> stack;
1.98 +
1.99 + // Unused element and property vectors for previous in progress arrays and
1.100 + // objects. These vectors are not freed until the end of the parse to avoid
1.101 + // unnecessary freeing and allocation.
1.102 + Vector<ElementVector*, 5> freeElements;
1.103 + Vector<PropertyVector*, 5> freeProperties;
1.104 +
1.105 +#ifdef DEBUG
1.106 + Token lastToken;
1.107 +#endif
1.108 +
1.109 + public:
1.110 + /* Public API */
1.111 +
1.112 + /* Create a parser for the provided JSON data. */
1.113 + JSONParser(JSContext *cx, JS::ConstTwoByteChars data, size_t length,
1.114 + ErrorHandling errorHandling = RaiseError)
1.115 + : AutoGCRooter(cx, JSONPARSER),
1.116 + cx(cx),
1.117 + current(data),
1.118 + begin(data),
1.119 + end((data + length).get(), data.get(), length),
1.120 + errorHandling(errorHandling),
1.121 + stack(cx),
1.122 + freeElements(cx),
1.123 + freeProperties(cx)
1.124 +#ifdef DEBUG
1.125 + , lastToken(Error)
1.126 +#endif
1.127 + {
1.128 + JS_ASSERT(current <= end);
1.129 + }
1.130 +
1.131 + ~JSONParser();
1.132 +
1.133 + /*
1.134 + * Parse the JSON data specified at construction time. If it parses
1.135 + * successfully, store the prescribed value in *vp and return true. If an
1.136 + * internal error (e.g. OOM) occurs during parsing, return false.
1.137 + * Otherwise, if invalid input was specifed but no internal error occurred,
1.138 + * behavior depends upon the error handling specified at construction: if
1.139 + * error handling is RaiseError then throw a SyntaxError and return false,
1.140 + * otherwise return true and set *vp to |undefined|. (JSON syntax can't
1.141 + * represent |undefined|, so the JSON data couldn't have specified it.)
1.142 + */
1.143 + bool parse(MutableHandleValue vp);
1.144 +
1.145 + private:
1.146 + Value numberValue() const {
1.147 + JS_ASSERT(lastToken == Number);
1.148 + JS_ASSERT(v.isNumber());
1.149 + return v;
1.150 + }
1.151 +
1.152 + Value stringValue() const {
1.153 + JS_ASSERT(lastToken == String);
1.154 + JS_ASSERT(v.isString());
1.155 + return v;
1.156 + }
1.157 +
1.158 + JSAtom *atomValue() const {
1.159 + Value strval = stringValue();
1.160 + return &strval.toString()->asAtom();
1.161 + }
1.162 +
1.163 + Token token(Token t) {
1.164 + JS_ASSERT(t != String);
1.165 + JS_ASSERT(t != Number);
1.166 +#ifdef DEBUG
1.167 + lastToken = t;
1.168 +#endif
1.169 + return t;
1.170 + }
1.171 +
1.172 + Token stringToken(JSString *str) {
1.173 + this->v = StringValue(str);
1.174 +#ifdef DEBUG
1.175 + lastToken = String;
1.176 +#endif
1.177 + return String;
1.178 + }
1.179 +
1.180 + Token numberToken(double d) {
1.181 + this->v = NumberValue(d);
1.182 +#ifdef DEBUG
1.183 + lastToken = Number;
1.184 +#endif
1.185 + return Number;
1.186 + }
1.187 +
1.188 + enum StringType { PropertyName, LiteralValue };
1.189 + template<StringType ST> Token readString();
1.190 +
1.191 + Token readNumber();
1.192 +
1.193 + Token advance();
1.194 + Token advancePropertyName();
1.195 + Token advancePropertyColon();
1.196 + Token advanceAfterProperty();
1.197 + Token advanceAfterObjectOpen();
1.198 + Token advanceAfterArrayElement();
1.199 +
1.200 + void error(const char *msg);
1.201 + bool errorReturn();
1.202 +
1.203 + JSObject *createFinishedObject(PropertyVector &properties);
1.204 + bool finishObject(MutableHandleValue vp, PropertyVector &properties);
1.205 + bool finishArray(MutableHandleValue vp, ElementVector &elements);
1.206 +
1.207 + void getTextPosition(uint32_t *column, uint32_t *line);
1.208 +
1.209 + friend void AutoGCRooter::trace(JSTracer *trc);
1.210 + void trace(JSTracer *trc);
1.211 +
1.212 + private:
1.213 + JSONParser(const JSONParser &other) MOZ_DELETE;
1.214 + void operator=(const JSONParser &other) MOZ_DELETE;
1.215 +};
1.216 +
1.217 +} /* namespace js */
1.218 +
1.219 +#endif /* jsonparser_h */
