|
163
|
1 using Implab.Parsing;
|
|
|
2 using System;
|
|
|
3 using System.Diagnostics;
|
|
|
4 using System.IO;
|
|
|
5
|
|
|
6 namespace Implab.JSON {
|
|
|
7 /// <summary>
|
|
|
8 /// internal
|
|
|
9 /// </summary>
|
|
|
10 public struct JSONParserContext {
|
|
|
11 public string memberName;
|
|
|
12 public JSONElementContext elementContext;
|
|
|
13 }
|
|
|
14
|
|
|
15 /// <summary>
|
|
|
16 /// Pull парсер JSON данных.
|
|
|
17 /// </summary>
|
|
|
18 /// <remarks>
|
|
|
19 /// Следует отметить отдельную интерпретацию свойства <see cref="Level"/>,
|
|
|
20 /// оно означает текущий уровень вложенности объектов, однако закрывающий
|
|
|
21 /// элемент объекта и массива имеет уровень меньше, чем сам объект.
|
|
|
22 /// <code>
|
|
|
23 /// { // Level = 1
|
|
|
24 /// "name" : "Peter", // Level = 1
|
|
|
25 /// "address" : { // Level = 2
|
|
|
26 /// city : "Stern" // Level = 2
|
|
|
27 /// } // Level = 1
|
|
|
28 /// } // Level = 0
|
|
|
29 /// </code>
|
|
|
30 /// </remarks>
|
|
|
31 public class JSONParser : DFAutomaton<JSONParserContext>, IDisposable {
|
|
|
32
|
|
|
33 enum MemberContext {
|
|
|
34 MemberName,
|
|
|
35 MemberValue
|
|
|
36 }
|
|
|
37
|
|
|
38 static readonly EnumAlphabet<JsonTokenType> _alphabet = EnumAlphabet<JsonTokenType>.FullAlphabet;
|
|
|
39 static readonly DFAStateDescriptior[] _jsonDFA;
|
|
|
40 static readonly DFAStateDescriptior[] _objectDFA;
|
|
|
41 static readonly DFAStateDescriptior[] _arrayDFA;
|
|
|
42
|
|
|
43 static JSONParser() {
|
|
|
44
|
|
|
45
|
|
|
46 var valueExpression = Token.New(JsonTokenType.BeginArray, JsonTokenType.BeginObject, JsonTokenType.Literal, JsonTokenType.Number, JsonTokenType.String);
|
|
|
47 var memberExpression = Token.New(JsonTokenType.String).Cat(Token.New(JsonTokenType.NameSeparator)).Cat(valueExpression);
|
|
|
48
|
|
|
49 var objectExpression = memberExpression
|
|
|
50 .Cat(
|
|
|
51 Token.New(JsonTokenType.ValueSeparator)
|
|
|
52 .Cat(memberExpression)
|
|
|
53 .EClosure()
|
|
|
54 )
|
|
|
55 .Optional()
|
|
|
56 .Cat(Token.New(JsonTokenType.EndObject))
|
|
|
57 .Tag(0);
|
|
|
58 var arrayExpression = valueExpression
|
|
|
59 .Cat(
|
|
|
60 Token.New(JsonTokenType.ValueSeparator)
|
|
|
61 .Cat(valueExpression)
|
|
|
62 .EClosure()
|
|
|
63 )
|
|
|
64 .Optional()
|
|
|
65 .Cat(Token.New(JsonTokenType.EndArray))
|
|
|
66 .Tag(0);
|
|
|
67
|
|
|
68 var jsonExpression = valueExpression.Tag(0);
|
|
|
69
|
|
|
70 _jsonDFA = BuildDFA(jsonExpression).States;
|
|
|
71 _objectDFA = BuildDFA(objectExpression).States;
|
|
|
72 _arrayDFA = BuildDFA(arrayExpression).States;
|
|
|
73 }
|
|
|
74
|
|
|
75 static EDFADefinition<JsonTokenType> BuildDFA(Token expr) {
|
|
|
76 var builder = new DFABuilder();
|
|
|
77 var dfa = new EDFADefinition<JsonTokenType>(_alphabet);
|
|
|
78 expr.Accept(builder);
|
|
|
79
|
|
|
80 builder.BuildDFA(dfa);
|
|
|
81 return dfa;
|
|
|
82 }
|
|
|
83
|
|
|
84 JSONScanner m_scanner;
|
|
|
85 MemberContext m_memberContext;
|
|
|
86
|
|
|
87 JSONElementType m_elementType;
|
|
|
88 object m_elementValue;
|
|
|
89
|
|
|
90 /// <summary>
|
|
|
91 /// Создает новый парсер на основе строки, содержащей JSON
|
|
|
92 /// </summary>
|
|
|
93 /// <param name="text"></param>
|
|
|
94 public JSONParser(string text)
|
|
|
95 : base(_jsonDFA, INITIAL_STATE, new JSONParserContext { elementContext = JSONElementContext.None, memberName = String.Empty }) {
|
|
|
96 Safe.ArgumentNotEmpty(text, "text");
|
|
|
97 m_scanner = new JSONScanner();
|
|
|
98 m_scanner.Feed(text.ToCharArray());
|
|
|
99 }
|
|
|
100
|
|
|
101 /// <summary>
|
|
|
102 /// Создает новый экземпляр парсера, на основе текстового потока.
|
|
|
103 /// </summary>
|
|
|
104 /// <param name="reader">Текстовый поток.</param>
|
|
|
105 /// <param name="dispose">Признак того, что парсер должен конролировать время жизни входного потока.</param>
|
|
|
106 public JSONParser(TextReader reader, bool dispose)
|
|
|
107 : base(_jsonDFA, INITIAL_STATE, new JSONParserContext { elementContext = JSONElementContext.None, memberName = String.Empty }) {
|
|
|
108 Safe.ArgumentNotNull(reader, "reader");
|
|
|
109 m_scanner = new JSONScanner();
|
|
|
110 m_scanner.Feed(reader, dispose);
|
|
|
111 }
|
|
|
112
|
|
|
113 /// <summary>
|
|
|
114 /// Тип текущего элемента на котором стоит парсер.
|
|
|
115 /// </summary>
|
|
|
116 public JSONElementType ElementType {
|
|
|
117 get { return m_elementType; }
|
|
|
118 }
|
|
|
119
|
|
|
120 /// <summary>
|
|
|
121 /// Имя элемента - имя свойства родительского контейнера. Для элементов массивов и корневого всегда
|
|
|
122 /// пустая строка.
|
|
|
123 /// </summary>
|
|
|
124 public string ElementName {
|
|
|
125 get { return m_context.info.memberName; }
|
|
|
126 }
|
|
|
127
|
|
|
128 /// <summary>
|
|
|
129 /// Значение элемента. Только для элементов типа <see cref="JSONElementType.Value"/>, для остальных <c>null</c>
|
|
|
130 /// </summary>
|
|
|
131 public object ElementValue {
|
|
|
132 get { return m_elementValue; }
|
|
|
133 }
|
|
|
134
|
|
|
135 /// <summary>
|
|
|
136 /// Читает слеюудущий объект из потока
|
|
|
137 /// </summary>
|
|
|
138 /// <returns><c>true</c> - операция чтения прошла успешно, <c>false</c> - конец данных</returns>
|
|
|
139 public bool Read() {
|
|
|
140 if (m_context.current == UNREACHEBLE_STATE)
|
|
|
141 throw new InvalidOperationException("The parser is in invalid state");
|
|
|
142 object tokenValue;
|
|
|
143 JsonTokenType tokenType;
|
|
|
144 m_context.info.memberName = String.Empty;
|
|
|
145 while (m_scanner.ReadToken(out tokenValue, out tokenType)) {
|
|
|
146 Move((int)tokenType);
|
|
|
147 if (m_context.current == UNREACHEBLE_STATE)
|
|
|
148 UnexpectedToken(tokenValue, tokenType);
|
|
|
149 switch (tokenType) {
|
|
|
150 case JsonTokenType.BeginObject:
|
|
|
151 Switch(
|
|
|
152 _objectDFA,
|
|
|
153 INITIAL_STATE,
|
|
|
154 new JSONParserContext {
|
|
|
155 memberName = m_context.info.memberName,
|
|
|
156 elementContext = JSONElementContext.Object
|
|
|
157 }
|
|
|
158 );
|
|
|
159 m_elementValue = null;
|
|
|
160 m_memberContext = MemberContext.MemberName;
|
|
|
161 m_elementType = JSONElementType.BeginObject;
|
|
|
162 return true;
|
|
|
163 case JsonTokenType.EndObject:
|
|
|
164 Restore();
|
|
|
165 m_elementValue = null;
|
|
|
166 m_elementType = JSONElementType.EndObject;
|
|
|
167 return true;
|
|
|
168 case JsonTokenType.BeginArray:
|
|
|
169 Switch(
|
|
|
170 _arrayDFA,
|
|
|
171 INITIAL_STATE,
|
|
|
172 new JSONParserContext {
|
|
|
173 memberName = m_context.info.memberName,
|
|
|
174 elementContext = JSONElementContext.Array
|
|
|
175 }
|
|
|
176 );
|
|
|
177 m_elementValue = null;
|
|
|
178 m_memberContext = MemberContext.MemberValue;
|
|
|
179 m_elementType = JSONElementType.BeginArray;
|
|
|
180 return true;
|
|
|
181 case JsonTokenType.EndArray:
|
|
|
182 Restore();
|
|
|
183 m_elementValue = null;
|
|
|
184 m_elementType = JSONElementType.EndArray;
|
|
|
185 return true;
|
|
|
186 case JsonTokenType.String:
|
|
|
187 if (m_memberContext == MemberContext.MemberName) {
|
|
|
188 m_context.info.memberName = (string)tokenValue;
|
|
|
189 break;
|
|
|
190 }
|
|
|
191 m_elementType = JSONElementType.Value;
|
|
|
192 m_elementValue = tokenValue;
|
|
|
193 return true;
|
|
|
194 case JsonTokenType.Number:
|
|
|
195 m_elementType = JSONElementType.Value;
|
|
|
196 m_elementValue = tokenValue;
|
|
|
197 return true;
|
|
|
198 case JsonTokenType.Literal:
|
|
|
199 m_elementType = JSONElementType.Value;
|
|
|
200 m_elementValue = ParseLiteral((string)tokenValue);
|
|
|
201 return true;
|
|
|
202 case JsonTokenType.NameSeparator:
|
|
|
203 m_memberContext = MemberContext.MemberValue;
|
|
|
204 break;
|
|
|
205 case JsonTokenType.ValueSeparator:
|
|
|
206 m_memberContext = m_context.info.elementContext == JSONElementContext.Object ? MemberContext.MemberName : MemberContext.MemberValue;
|
|
|
207 break;
|
|
|
208 default:
|
|
|
209 UnexpectedToken(tokenValue, tokenType);
|
|
|
210 break;
|
|
|
211 }
|
|
|
212 }
|
|
|
213 if (m_context.info.elementContext != JSONElementContext.None)
|
|
|
214 throw new ParserException("Unexpedted end of data");
|
|
|
215 return false;
|
|
|
216 }
|
|
|
217
|
|
|
218 object ParseLiteral(string literal) {
|
|
|
219 switch (literal) {
|
|
|
220 case "null":
|
|
|
221 return null;
|
|
|
222 case "false":
|
|
|
223 return false;
|
|
|
224 case "true":
|
|
|
225 return true;
|
|
|
226 default:
|
|
|
227 UnexpectedToken(literal, JsonTokenType.Literal);
|
|
|
228 return null; // avoid compliler error
|
|
|
229 }
|
|
|
230 }
|
|
|
231
|
|
|
232 void UnexpectedToken(object value, JsonTokenType tokenType) {
|
|
|
233 throw new ParserException(String.Format("Unexpected token {0}: '{1}'", tokenType, value));
|
|
|
234 }
|
|
|
235
|
|
|
236
|
|
|
237 /// <summary>
|
|
|
238 /// Признак конца потока
|
|
|
239 /// </summary>
|
|
|
240 public bool EOF {
|
|
|
241 get {
|
|
|
242 return m_scanner.EOF;
|
|
|
243 }
|
|
|
244 }
|
|
|
245
|
|
|
246 protected virtual void Dispose(bool disposing) {
|
|
|
247 if (disposing) {
|
|
|
248 m_scanner.Dispose();
|
|
|
249 }
|
|
|
250 }
|
|
|
251
|
|
|
252 /// <summary>
|
|
|
253 /// Освобождает парсер и связанный с ним сканнер.
|
|
|
254 /// </summary>
|
|
|
255 public void Dispose() {
|
|
|
256 Dispose(true);
|
|
|
257 GC.SuppressFinalize(this);
|
|
|
258 }
|
|
|
259
|
|
|
260 ~JSONParser() {
|
|
|
261 Dispose(false);
|
|
|
262 }
|
|
|
263
|
|
|
264 /// <summary>
|
|
|
265 /// Переходит в конец текущего объекта.
|
|
|
266 /// </summary>
|
|
|
267 public void SeekElementEnd() {
|
|
|
268 var level = Level - 1;
|
|
|
269
|
|
|
270 Debug.Assert(level >= 0);
|
|
|
271
|
|
|
272 while (Level != level)
|
|
|
273 Read();
|
|
|
274 }
|
|
|
275 }
|
|
|
276
|
|
|
277 }
|
