V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
json-parser.h
1 // Copyright 2011 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef V8_JSON_PARSER_H_
6 #define V8_JSON_PARSER_H_
7 
8 #include "src/heap/factory.h"
9 #include "src/isolate.h"
10 #include "src/objects.h"
11 #include "src/zone/zone-containers.h"
12 
13 namespace v8 {
14 namespace internal {
15 
16 enum ParseElementResult { kElementFound, kElementNotFound, kNullHandle };
17 
19  public:
20  static MaybeHandle<Object> Internalize(Isolate* isolate,
21  Handle<Object> object,
22  Handle<Object> reviver);
23 
24  private:
26  : isolate_(isolate), reviver_(reviver) {}
27 
28  MaybeHandle<Object> InternalizeJsonProperty(Handle<JSReceiver> holder,
29  Handle<String> key);
30 
31  bool RecurseAndApply(Handle<JSReceiver> holder, Handle<String> name);
32 
33  Isolate* isolate_;
34  Handle<JSReceiver> reviver_;
35 };
36 
37 // A simple json parser.
38 template <bool seq_one_byte>
39 class JsonParser {
40  public:
41  V8_WARN_UNUSED_RESULT static MaybeHandle<Object> Parse(
42  Isolate* isolate, Handle<String> source, Handle<Object> reviver) {
43  Handle<Object> result;
44  ASSIGN_RETURN_ON_EXCEPTION(isolate, result,
45  JsonParser(isolate, source).ParseJson(), Object);
46  if (reviver->IsCallable()) {
47  return JsonParseInternalizer::Internalize(isolate, result, reviver);
48  }
49  return result;
50  }
51 
52  static const int kEndOfString = -1;
53 
54  private:
55  JsonParser(Isolate* isolate, Handle<String> source);
56 
57  // Parse a string containing a single JSON value.
58  MaybeHandle<Object> ParseJson();
59 
60  V8_INLINE void Advance();
61 
62  // The JSON lexical grammar is specified in the ECMAScript 5 standard,
63  // section 15.12.1.1. The only allowed whitespace characters between tokens
64  // are tab, carriage-return, newline and space.
65 
66  V8_INLINE void AdvanceSkipWhitespace();
67  V8_INLINE void SkipWhitespace();
68  V8_INLINE uc32 AdvanceGetChar();
69 
70  // Checks that current charater is c.
71  // If so, then consume c and skip whitespace.
72  V8_INLINE bool MatchSkipWhiteSpace(uc32 c);
73 
74  // A JSON string (production JSONString) is subset of valid JavaScript string
75  // literals. The string must only be double-quoted (not single-quoted), and
76  // the only allowed backslash-escapes are ", /, \, b, f, n, r, t and
77  // four-digit hex escapes (uXXXX). Any other use of backslashes is invalid.
78  bool ParseJsonString(Handle<String> expected);
79 
80  Handle<String> ParseJsonString() {
81  Handle<String> result = ScanJsonString();
82  if (result.is_null()) return result;
83  return factory()->InternalizeString(result);
84  }
85 
86  Handle<String> ScanJsonString();
87  // Creates a new string and copies prefix[start..end] into the beginning
88  // of it. Then scans the rest of the string, adding characters after the
89  // prefix. Called by ScanJsonString when reaching a '\' or non-Latin1 char.
90  template <typename StringType, typename SinkChar>
91  Handle<String> SlowScanJsonString(Handle<String> prefix, int start, int end);
92 
93  // A JSON number (production JSONNumber) is a subset of the valid JavaScript
94  // decimal number literals.
95  // It includes an optional minus sign, must have at least one
96  // digit before and after a decimal point, may not have prefixed zeros (unless
97  // the integer part is zero), and may include an exponent part (e.g., "e-10").
98  // Hexadecimal and octal numbers are not allowed.
99  Handle<Object> ParseJsonNumber();
100 
101  // Parse a single JSON value from input (grammar production JSONValue).
102  // A JSON value is either a (double-quoted) string literal, a number literal,
103  // one of "true", "false", or "null", or an object or array literal.
104  Handle<Object> ParseJsonValue();
105 
106  // Parse a JSON object literal (grammar production JSONObject).
107  // An object literal is a squiggly-braced and comma separated sequence
108  // (possibly empty) of key/value pairs, where the key is a JSON string
109  // literal, the value is a JSON value, and the two are separated by a colon.
110  // A JSON array doesn't allow numbers and identifiers as keys, like a
111  // JavaScript array.
112  Handle<Object> ParseJsonObject();
113 
114  // Helper for ParseJsonObject. Parses the form "123": obj, which is recorded
115  // as an element, not a property.
116  ParseElementResult ParseElement(Handle<JSObject> json_object);
117 
118  // Parses a JSON array literal (grammar production JSONArray). An array
119  // literal is a square-bracketed and comma separated sequence (possibly empty)
120  // of JSON values.
121  // A JSON array doesn't allow leaving out values from the sequence, nor does
122  // it allow a terminal comma, like a JavaScript array does.
123  Handle<Object> ParseJsonArray();
124 
125 
126  // Mark that a parsing error has happened at the current token, and
127  // return a null handle. Primarily for readability.
128  inline Handle<Object> ReportUnexpectedCharacter() {
129  return Handle<Object>::null();
130  }
131 
132  inline Isolate* isolate() { return isolate_; }
133  inline Factory* factory() { return isolate_->factory(); }
134  inline Handle<JSFunction> object_constructor() { return object_constructor_; }
135 
136  static const int kInitialSpecialStringLength = 32;
137  static const int kPretenureTreshold = 100 * 1024;
138 
139  private:
140  Zone* zone() { return &zone_; }
141 
142  void CommitStateToJsonObject(Handle<JSObject> json_object, Handle<Map> map,
143  Vector<const Handle<Object>> properties);
144 
145  Handle<String> source_;
146  int source_length_;
147  Handle<SeqOneByteString> seq_source_;
148 
149  PretenureFlag pretenure_;
150  Isolate* isolate_;
151  Zone zone_;
152  Handle<JSFunction> object_constructor_;
153  uc32 c0_;
154  int position_;
155 
156  // Property handles are stored here inside ParseJsonObject.
157  ZoneVector<Handle<Object>> properties_;
158 };
159 
160 } // namespace internal
161 } // namespace v8
162 
163 #endif // V8_JSON_PARSER_H_
Definition: libplatform.h:13