/
StringWriter.cs
322 lines (268 loc) · 10 KB
/
StringWriter.cs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Globalization;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace System.IO
{
// This class implements a text writer that writes to a string buffer and allows
// the resulting sequence of characters to be presented as a string.
public class StringWriter : TextWriter
{
private static volatile UnicodeEncoding? s_encoding;
private readonly StringBuilder _sb;
private bool _isOpen;
// Constructs a new StringWriter. A new StringBuilder is automatically
// created and associated with the new StringWriter.
public StringWriter()
: this(new StringBuilder(), CultureInfo.CurrentCulture)
{
}
public StringWriter(IFormatProvider? formatProvider)
: this(new StringBuilder(), formatProvider)
{
}
// Constructs a new StringWriter that writes to the given StringBuilder.
//
public StringWriter(StringBuilder sb) : this(sb, CultureInfo.CurrentCulture)
{
}
public StringWriter(StringBuilder sb, IFormatProvider? formatProvider) : base(formatProvider)
{
ArgumentNullException.ThrowIfNull(sb);
_sb = sb;
_isOpen = true;
}
public override void Close()
{
Dispose(true);
}
protected override void Dispose(bool disposing)
{
// Do not destroy _sb, so that we can extract this after we are
// done writing (similar to MemoryStream's GetBuffer & ToArray methods)
_isOpen = false;
base.Dispose(disposing);
}
public override Encoding Encoding => s_encoding ??= new UnicodeEncoding(false, false);
// Returns the underlying StringBuilder. This is either the StringBuilder
// that was passed to the constructor, or the StringBuilder that was
// automatically created.
//
public virtual StringBuilder GetStringBuilder()
{
return _sb;
}
// Writes a character to the underlying string buffer.
//
public override void Write(char value)
{
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(value);
}
// Writes a range of a character array to the underlying string buffer.
// This method will write count characters of data into this
// StringWriter from the buffer character array starting at position
// index.
//
public override void Write(char[] buffer, int index, int count)
{
ArgumentNullException.ThrowIfNull(buffer);
if (index < 0)
{
throw new ArgumentOutOfRangeException(nameof(index), SR.ArgumentOutOfRange_NeedNonNegNum);
}
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count), SR.ArgumentOutOfRange_NeedNonNegNum);
}
if (buffer.Length - index < count)
{
throw new ArgumentException(SR.Argument_InvalidOffLen);
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(buffer, index, count);
}
public override void Write(ReadOnlySpan<char> buffer)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the Write(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
base.Write(buffer);
return;
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(buffer);
}
// Writes a string to the underlying string buffer. If the given string is
// null, nothing is written.
//
public override void Write(string? value)
{
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
if (value != null)
{
_sb.Append(value);
}
}
public override void Write(StringBuilder? value)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the Write(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
base.Write(value);
return;
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(value);
}
public override void WriteLine(ReadOnlySpan<char> buffer)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the WriteLine(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
base.WriteLine(buffer);
return;
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(buffer);
WriteLine();
}
public override void WriteLine(StringBuilder? value)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the WriteLine(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
base.WriteLine(value);
return;
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(value);
WriteLine();
}
#region Task based Async APIs
public override Task WriteAsync(char value)
{
Write(value);
return Task.CompletedTask;
}
public override Task WriteAsync(string? value)
{
Write(value);
return Task.CompletedTask;
}
public override Task WriteAsync(char[] buffer, int index, int count)
{
Write(buffer, index, count);
return Task.CompletedTask;
}
public override Task WriteAsync(ReadOnlyMemory<char> buffer, CancellationToken cancellationToken = default)
{
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled(cancellationToken);
}
Write(buffer.Span);
return Task.CompletedTask;
}
public override Task WriteAsync(StringBuilder? value, CancellationToken cancellationToken = default)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the WriteAsync(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
return base.WriteAsync(value, cancellationToken);
}
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled(cancellationToken);
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(value);
return Task.CompletedTask;
}
public override Task WriteLineAsync(char value)
{
WriteLine(value);
return Task.CompletedTask;
}
public override Task WriteLineAsync(string? value)
{
WriteLine(value);
return Task.CompletedTask;
}
public override Task WriteLineAsync(StringBuilder? value, CancellationToken cancellationToken = default)
{
if (GetType() != typeof(StringWriter))
{
// This overload was added after the WriteLineAsync(char[], ...) overload, and so in case
// a derived type may have overridden it, we need to delegate to it, which the base does.
return base.WriteLineAsync(value, cancellationToken);
}
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled(cancellationToken);
}
if (!_isOpen)
{
throw new ObjectDisposedException(null, SR.ObjectDisposed_WriterClosed);
}
_sb.Append(value);
WriteLine();
return Task.CompletedTask;
}
public override Task WriteLineAsync(char[] buffer, int index, int count)
{
WriteLine(buffer, index, count);
return Task.CompletedTask;
}
public override Task WriteLineAsync(ReadOnlyMemory<char> buffer, CancellationToken cancellationToken = default)
{
if (cancellationToken.IsCancellationRequested)
{
return Task.FromCanceled(cancellationToken);
}
WriteLine(buffer.Span);
return Task.CompletedTask;
}
public override Task FlushAsync()
{
return Task.CompletedTask;
}
#endregion
// Returns a string containing the characters written to this TextWriter so far.
public override string ToString()
{
return _sb.ToString();
}
}
}