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Viewing changes to external/nrefactory/ICSharpCode.NRefactory/Utils/CompositeFormatStringParser/CompositeFormatStringParser.cs

  • Committer: Package Import Robot
  • Author(s): Jo Shields
  • Date: 2013-05-12 09:46:03 UTC
  • mto: This revision was merged to the branch mainline in revision 29.
  • Revision ID: package-import@ubuntu.com-20130512094603-mad323bzcxvmcam0
Tags: upstream-4.0.5+dfsg
Import upstream version 4.0.5+dfsg

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external/nrefactory/ICSharpCode.NRefactory/Utils/CompositeFormatStringParser/CompositeFormatStringParser.cs
 
1
//
 
2
// CompositeFormatStringParser.cs
 
3
//
 
4
// Authors:
 
5
//   Simon Lindgren <simon.n.lindgren@gmail.com>
 
6
//
 
7
// Copyright (c) 2012 Simon Lindgren
 
8
//
 
9
// Permission is hereby granted, free of charge, to any person obtaining a copy
 
10
// of this software and associated documentation files (the "Software"), to deal
 
11
// in the Software without restriction, including without limitation the rights
 
12
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 
13
// copies of the Software, and to permit persons to whom the Software is
 
14
// furnished to do so, subject to the following conditions:
 
15
//
 
16
// The above copyright notice and this permission notice shall be included in
 
17
// all copies or substantial portions of the Software.
 
18
//
 
19
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 
20
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 
21
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 
22
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 
23
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 
24
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 
25
// THE SOFTWARE.
 
26
using System;
 
27
using System.Collections.Generic;
 
28
using System.Linq;
 
29
 
 
30
namespace ICSharpCode.NRefactory.Utils
 
31
{
 
32
        /// <summary>
 
33
        /// Composite format string parser.
 
34
        /// </summary>
 
35
        /// <remarks>
 
36
        /// Implements a complete parser for valid strings as well as
 
37
        /// error reporting and best-effort parsing for invalid strings.
 
38
        /// </remarks>          
 
39
        public class CompositeFormatStringParser
 
40
        {
 
41
 
 
42
                public CompositeFormatStringParser ()
 
43
                {
 
44
                        errors = new List<IFormatStringError> ();
 
45
                }
 
46
 
 
47
                /// <summary>
 
48
                /// Parse the specified format string.
 
49
                /// </summary>
 
50
                /// <param name='format'>
 
51
                /// The format string.
 
52
                /// </param>
 
53
                public FormatStringParseResult Parse (string format)
 
54
                {
 
55
                        if (format == null)
 
56
                                throw new ArgumentNullException ("format");
 
57
 
 
58
                        var result = new FormatStringParseResult();
 
59
 
 
60
                        // Format string syntax: http://msdn.microsoft.com/en-us/library/txafckwd.aspx
 
61
                        int textStart = 0;
 
62
                        var length = format.Length;
 
63
                        for (int i = 0; i < length; i++) {
 
64
                                // Get fixed text
 
65
                                GetText (format, ref i);
 
66
 
 
67
                                if (i < format.Length && format [i] == '{') {
 
68
                                        int formatItemStart = i;
 
69
                                        int index;
 
70
                                        int? alignment;
 
71
                                        string argumentFormat;
 
72
                                        var textSegmentErrors = new List<IFormatStringError>(GetErrors());
 
73
 
 
74
                                        // Try to parse the parts of the format item
 
75
                                        ++i;
 
76
                                        index = ParseIndex (format, ref i);
 
77
                                        CheckForMissingEndBrace (format, i, length);
 
78
 
 
79
                                        alignment = ParseAlignment (format, ref i, length);
 
80
                                        CheckForMissingEndBrace (format, i, length);
 
81
 
 
82
                                        argumentFormat = ParseSubFormatString (format, ref i, length);
 
83
                                        CheckForMissingEndBrace (format, i, length);
 
84
 
 
85
                                        // Check what we parsed
 
86
                                        if (i == formatItemStart + 1 && (i == length || (i < length && format[i] != '}'))) {
 
87
                                                // There were no format item after all, this was just an
 
88
                                                // unescaped left brace, or the initial brace of an escape sequence
 
89
                                                SetErrors(textSegmentErrors);
 
90
                                                if (i >= length || format[i] != '{') {
 
91
                                                        AddError (new DefaultFormatStringError {
 
92
                                                                Message = "Unescaped '{'",
 
93
                                                                StartLocation = formatItemStart,
 
94
                                                                EndLocation = formatItemStart + 1,
 
95
                                                                OriginalText = "{",
 
96
                                                                SuggestedReplacementText = "{{"
 
97
                                                        });
 
98
                                                }
 
99
                                                continue;
 
100
                                        }
 
101
 
 
102
                                        if (formatItemStart - textStart > 0) {
 
103
                                                // We have parsed a format item, end the text segment
 
104
                                                var textSegment = new TextSegment (UnEscape (format.Substring (textStart, formatItemStart - textStart)));
 
105
                                                textSegment.Errors = textSegmentErrors;
 
106
                                                result.Segments.Add (textSegment);
 
107
                                        }
 
108
                                        
 
109
                                        // Unclosed format items in fixed text advances i one step too far
 
110
                                        if (i < length && format [i] != '}')
 
111
                                                --i;
 
112
 
 
113
                                        // i may actually point outside of format if there is a syntactical error
 
114
                                        // if that happens, we want the last position
 
115
                                        var endLocation = Math.Min (length, i + 1);
 
116
                                        result.Segments.Add (new FormatItem (index, alignment, argumentFormat) {
 
117
                                                StartLocation = formatItemStart,
 
118
                                                EndLocation = endLocation,
 
119
                                                Errors = GetErrors ()
 
120
                                        });
 
121
                                        ClearErrors ();
 
122
 
 
123
                                        // The next potential text segment starts after this format item
 
124
                                        textStart = i + 1;
 
125
                                }
 
126
                        }
 
127
                        // Handle remaining text
 
128
                        if (textStart < length) {
 
129
                                var textSegment = new TextSegment (UnEscape (format.Substring (textStart)), textStart);
 
130
                                textSegment.Errors = GetErrors();
 
131
                                result.Segments.Add (textSegment);
 
132
 
 
133
                        }
 
134
                        return result;
 
135
                }
 
136
 
 
137
                int ParseIndex (string format, ref int i)
 
138
                {
 
139
                        int parsedCharacters;
 
140
                        int? maybeIndex = GetAndCheckNumber (format, ",:}", ref i, i, out parsedCharacters);
 
141
                        if (parsedCharacters == 0) {
 
142
                                AddError (new DefaultFormatStringError {
 
143
                                        StartLocation = i,
 
144
                                        EndLocation = i,
 
145
                                        Message = "Missing index",
 
146
                                        OriginalText = "",
 
147
                                        SuggestedReplacementText = "0"
 
148
                                });
 
149
                        }
 
150
                        return maybeIndex ?? 0;
 
151
                }
 
152
 
 
153
                int? ParseAlignment(string format, ref int i, int length)
 
154
                {
 
155
                        if (i < length && format [i] == ',') {
 
156
                                int alignmentBegin = i;
 
157
                                ++i;
 
158
                                while (i < length && char.IsWhiteSpace(format [i]))
 
159
                                        ++i;
 
160
 
 
161
                                int parsedCharacters;
 
162
                                var number = GetAndCheckNumber (format, ",:}", ref i, alignmentBegin + 1, out parsedCharacters);
 
163
                                if (parsedCharacters == 0) {
 
164
                                        AddError (new DefaultFormatStringError {
 
165
                                                StartLocation = i,
 
166
                                                EndLocation = i,
 
167
                                                Message = "Missing alignment",
 
168
                                                OriginalText = "",
 
169
                                                SuggestedReplacementText = "0"
 
170
                                        });
 
171
                                }
 
172
                                return number ?? 0;
 
173
                        }
 
174
                        return null;
 
175
                }
 
176
 
 
177
                string ParseSubFormatString(string format, ref int i, int length)
 
178
                {
 
179
                        if (i < length && format [i] == ':') {
 
180
                                ++i;
 
181
                                int begin = i;
 
182
                                GetText(format, ref i, "", true);
 
183
                                var escaped = format.Substring (begin, i - begin);
 
184
                                return UnEscape (escaped);
 
185
                        }
 
186
                        return null;
 
187
                }
 
188
 
 
189
                void CheckForMissingEndBrace (string format, int i, int length)
 
190
                {
 
191
                        if (i == length) {
 
192
                                int j;
 
193
                                for (j = i - 1; format[j] == '}'; j--);
 
194
                                var oddEndBraceCount = (i - j) % 2 == 1;
 
195
                                if (oddEndBraceCount) {
 
196
                                        AddMissingEndBraceError(i, i, "Missing '}'", "");
 
197
                                }
 
198
                                return;
 
199
                        }
 
200
                        return;
 
201
                }
 
202
                
 
203
                void GetText (string format, ref int index, string delimiters = "", bool allowEscape = false)
 
204
                {
 
205
                        while (index < format.Length) {
 
206
                                if (format [index] == '{' || format[index] == '}') {
 
207
                                        if (index + 1 < format.Length && format [index + 1] == format[index] && allowEscape)
 
208
                                                ++index;
 
209
                                        else
 
210
                                                break;
 
211
                                } else if (delimiters.Contains(format[index].ToString())) {
 
212
                                        break;
 
213
                                }
 
214
                                ++index;
 
215
                        };
 
216
                }
 
217
                
 
218
                int? GetNumber (string format, ref int index)
 
219
                {
 
220
                        if (format.Length == 0) {
 
221
                                return null;
 
222
                        }
 
223
                        int sum = 0;
 
224
                        int i = index;
 
225
                        bool positive = format [i] != '-';
 
226
                        if (!positive)
 
227
                                ++i;
 
228
                        int numberStartIndex = i;
 
229
                        while (i < format.Length && format[i] >= '0' && format[i] <= '9') {
 
230
                                sum = 10 * sum + format [i] - '0';
 
231
                                ++i;
 
232
                        }
 
233
                        if (i == numberStartIndex)
 
234
                                return null;
 
235
 
 
236
                        index = i;
 
237
                        return positive ? sum : -sum;
 
238
                }
 
239
 
 
240
                int? GetAndCheckNumber (string format, string delimiters, ref int index, int numberFieldStart, out int parsedCharacters)
 
241
                {
 
242
                        int fieldIndex = index;
 
243
                        GetText (format, ref fieldIndex, delimiters);
 
244
                        int fieldEnd = fieldIndex;
 
245
                        var numberText = format.Substring(index, fieldEnd - index);
 
246
                        parsedCharacters = numberText.Length;
 
247
                        int numberLength = 0;
 
248
                        int? number = GetNumber (numberText, ref numberLength);
 
249
                        if (numberLength != parsedCharacters && fieldEnd < format.Length && delimiters.Contains (format [fieldEnd])) {
 
250
                                // Not the entire number field could be parsed
 
251
                                // The field actually ended as intended, so set the index to the end of the field
 
252
                                index = fieldEnd;
 
253
                                var suggestedNumber = (number ?? 0).ToString ();
 
254
                                AddInvalidNumberFormatError (numberFieldStart, format.Substring (numberFieldStart, index - numberFieldStart), suggestedNumber);
 
255
                        } else {
 
256
                                var endingChar = index + numberLength;
 
257
                                if (numberLength != parsedCharacters) {
 
258
                                        // Not the entire number field could be parsed
 
259
                                        // The field didn't end, it was cut off so we are missing an ending brace
 
260
                                        index = endingChar;
 
261
                                        AddMissingEndBraceError (index, index, "Missing ending '}'", "");
 
262
                                } else {
 
263
                                        index = endingChar;
 
264
                                }
 
265
                        }
 
266
                        return number;
 
267
                }
 
268
 
 
269
                public static string UnEscape (string unEscaped)
 
270
                {
 
271
                        return unEscaped.Replace ("{{", "{").Replace ("}}", "}");
 
272
                }
 
273
 
 
274
                IList<IFormatStringError> errors;
 
275
                
 
276
                bool hasMissingEndBrace = false;
 
277
 
 
278
                void AddError (IFormatStringError error)
 
279
                {
 
280
                        errors.Add (error);
 
281
                }
 
282
 
 
283
                void AddMissingEndBraceError(int start, int end, string message, string originalText)
 
284
                {
 
285
                        // Only add a single missing end brace per format item
 
286
                        if (hasMissingEndBrace)
 
287
                                return;
 
288
                        AddError (new DefaultFormatStringError {
 
289
                                StartLocation = start,
 
290
                                EndLocation = end,
 
291
                                Message = message,
 
292
                                OriginalText = originalText,
 
293
                                SuggestedReplacementText = "}"
 
294
                        });
 
295
                        hasMissingEndBrace = true;
 
296
                }
 
297
 
 
298
                void AddInvalidNumberFormatError (int i, string number, string replacementText)
 
299
                {
 
300
                        AddError (new DefaultFormatStringError {
 
301
                                StartLocation = i,
 
302
                                EndLocation = i + number.Length,
 
303
                                Message = string.Format ("Invalid number '{0}'", number),
 
304
                                OriginalText = number,
 
305
                                SuggestedReplacementText = replacementText
 
306
                        });
 
307
                }
 
308
 
 
309
                IList<IFormatStringError> GetErrors ()
 
310
                {
 
311
                        return errors;
 
312
                }
 
313
                
 
314
                void SetErrors (IList<IFormatStringError> errors)
 
315
                {
 
316
                        this.errors = errors;
 
317
                }
 
318
 
 
319
                void ClearErrors ()
 
320
                {
 
321
                        hasMissingEndBrace = false;
 
322
                        errors = new List<IFormatStringError> ();
 
323
                }
 
324
        }
 
325
 
 
326
        public class FormatStringParseResult
 
327
        {
 
328
                public FormatStringParseResult()
 
329
                {
 
330
                        Segments = new List<IFormatStringSegment>();
 
331
                }
 
332
 
 
333
                public IList<IFormatStringSegment> Segments { get; private set; }
 
334
 
 
335
                public bool HasErrors
 
336
                {
 
337
                        get {
 
338
                                return Segments.SelectMany(segment => segment.Errors).Any();
 
339
                        }
 
340
                }
 
341
        }
 
342
}
 
343