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
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
|
//------------------------------------------------------------------------------
// <copyright file="XPathScanner.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
//------------------------------------------------------------------------------
namespace MS.Internal.Xml.XPath {
using System;
using System.Xml;
using System.Xml.XPath;
using System.Diagnostics;
using System.Globalization;
using System.Text;
using System.Collections;
internal sealed class XPathScanner {
private string xpathExpr;
private int xpathExprIndex;
private LexKind kind;
private char currentChar;
private string name;
private string prefix;
private string stringValue;
private double numberValue = double.NaN;
private bool canBeFunction;
private XmlCharType xmlCharType = XmlCharType.Instance;
public XPathScanner(string xpathExpr) {
if (xpathExpr == null) {
throw XPathException.Create(Res.Xp_ExprExpected, string.Empty);
}
this.xpathExpr = xpathExpr;
NextChar();
NextLex();
}
public string SourceText { get { return this.xpathExpr; } }
private char CurerntChar { get { return currentChar; } }
private bool NextChar() {
Debug.Assert(0 <= xpathExprIndex && xpathExprIndex <= xpathExpr.Length);
if (xpathExprIndex < xpathExpr.Length) {
currentChar = xpathExpr[xpathExprIndex ++];
return true;
}
else {
currentChar = '\0';
return false;
}
}
#if XML10_FIFTH_EDITION
private char PeekNextChar() {
Debug.Assert(0 <= xpathExprIndex && xpathExprIndex <= xpathExpr.Length);
if (xpathExprIndex < xpathExpr.Length) {
return xpathExpr[xpathExprIndex];
}
else {
Debug.Assert(xpathExprIndex == xpathExpr.Length);
return '\0';
}
}
#endif
public LexKind Kind { get { return this.kind; } }
public string Name {
get {
Debug.Assert(this.kind == LexKind.Name || this.kind == LexKind.Axe);
Debug.Assert(this.name != null);
return this.name;
}
}
public string Prefix {
get {
Debug.Assert(this.kind == LexKind.Name);
Debug.Assert(this.prefix != null);
return this.prefix;
}
}
public string StringValue {
get {
Debug.Assert(this.kind == LexKind.String);
Debug.Assert(this.stringValue != null);
return this.stringValue;
}
}
public double NumberValue {
get {
Debug.Assert(this.kind == LexKind.Number);
Debug.Assert(this.numberValue != double.NaN);
return this.numberValue;
}
}
// To parse PathExpr we need a way to distinct name from function.
// THis distinction can't be done without context: "or (1 != 0)" this this a function or 'or' in OrExp
public bool CanBeFunction {
get {
Debug.Assert(this.kind == LexKind.Name);
return this.canBeFunction;
}
}
void SkipSpace() {
while (xmlCharType.IsWhiteSpace(this.CurerntChar) && NextChar()) ;
}
public bool NextLex() {
SkipSpace();
switch (this.CurerntChar) {
case '\0' :
kind = LexKind.Eof;
return false;
case ',': case '@': case '(': case ')':
case '|': case '*': case '[': case ']':
case '+': case '-': case '=': case '#':
case '$':
kind = (LexKind) Convert.ToInt32(this.CurerntChar, CultureInfo.InvariantCulture);
NextChar();
break;
case '<':
kind = LexKind.Lt;
NextChar();
if (this.CurerntChar == '=') {
kind = LexKind.Le;
NextChar();
}
break;
case '>':
kind = LexKind.Gt;
NextChar();
if (this.CurerntChar == '=') {
kind = LexKind.Ge;
NextChar();
}
break;
case '!':
kind = LexKind.Bang;
NextChar();
if (this.CurerntChar == '=') {
kind = LexKind.Ne;
NextChar();
}
break;
case '.':
kind = LexKind.Dot;
NextChar();
if (this.CurerntChar == '.') {
kind = LexKind.DotDot;
NextChar();
}
else if (XmlCharType.IsDigit(this.CurerntChar)) {
kind = LexKind.Number;
numberValue = ScanFraction();
}
break;
case '/':
kind = LexKind.Slash;
NextChar();
if (this.CurerntChar == '/') {
kind = LexKind.SlashSlash;
NextChar();
}
break;
case '"':
case '\'':
this.kind = LexKind.String;
this.stringValue = ScanString();
break;
default:
if (XmlCharType.IsDigit(this.CurerntChar)) {
kind = LexKind.Number;
numberValue = ScanNumber();
}
else if (xmlCharType.IsStartNCNameSingleChar(this.CurerntChar)
#if XML10_FIFTH_EDITION
|| xmlCharType.IsNCNameHighSurrogateChar(this.CurerntChar)
#endif
) {
kind = LexKind.Name;
this.name = ScanName();
this.prefix = string.Empty;
// "foo:bar" is one lexem not three because it doesn't allow spaces in between
// We should distinct it from "foo::" and need process "foo ::" as well
if (this.CurerntChar == ':') {
NextChar();
// can be "foo:bar" or "foo::"
if (this.CurerntChar == ':') { // "foo::"
NextChar();
kind = LexKind.Axe;
}
else { // "foo:*", "foo:bar" or "foo: "
this.prefix = this.name;
if (this.CurerntChar == '*') {
NextChar();
this.name = "*";
}
else if (xmlCharType.IsStartNCNameSingleChar(this.CurerntChar)
#if XML10_FIFTH_EDITION
|| xmlCharType.IsNCNameHighSurrogateChar(this.CurerntChar)
#endif
) {
this.name = ScanName();
}
else {
throw XPathException.Create(Res.Xp_InvalidName, SourceText);
}
}
}
else {
SkipSpace();
if (this.CurerntChar == ':') {
NextChar();
// it can be "foo ::" or just "foo :"
if (this.CurerntChar == ':') {
NextChar();
kind = LexKind.Axe;
}
else {
throw XPathException.Create(Res.Xp_InvalidName, SourceText);
}
}
}
SkipSpace();
this.canBeFunction = (this.CurerntChar == '(');
}
else {
throw XPathException.Create(Res.Xp_InvalidToken, SourceText);
}
break;
}
return true;
}
private double ScanNumber() {
Debug.Assert(this.CurerntChar == '.' || XmlCharType.IsDigit(this.CurerntChar));
int start = xpathExprIndex - 1;
int len = 0;
while (XmlCharType.IsDigit(this.CurerntChar)) {
NextChar(); len ++;
}
if (this.CurerntChar == '.') {
NextChar(); len ++;
while (XmlCharType.IsDigit(this.CurerntChar)) {
NextChar(); len ++;
}
}
return XmlConvert.ToXPathDouble(this.xpathExpr.Substring(start, len));
}
private double ScanFraction() {
Debug.Assert(XmlCharType.IsDigit(this.CurerntChar));
int start = xpathExprIndex - 2;
Debug.Assert(0 <= start && this.xpathExpr[start] == '.');
int len = 1; // '.'
while (XmlCharType.IsDigit(this.CurerntChar)) {
NextChar(); len ++;
}
return XmlConvert.ToXPathDouble(this.xpathExpr.Substring(start, len));
}
private string ScanString() {
char endChar = this.CurerntChar;
NextChar();
int start = xpathExprIndex - 1;
int len = 0;
while(this.CurerntChar != endChar) {
if (! NextChar()) {
throw XPathException.Create(Res.Xp_UnclosedString);
}
len ++;
}
Debug.Assert(this.CurerntChar == endChar);
NextChar();
return this.xpathExpr.Substring(start, len);
}
private string ScanName() {
Debug.Assert(xmlCharType.IsStartNCNameSingleChar(this.CurerntChar)
#if XML10_FIFTH_EDITION
|| xmlCharType.IsNCNameHighSurrogateChar(this.CurerntChar)
#endif
);
int start = xpathExprIndex - 1;
int len = 0;
for (;;) {
if (xmlCharType.IsNCNameSingleChar(this.CurerntChar)) {
NextChar();
len ++;
}
#if XML10_FIFTH_EDITION
else if (xmlCharType.IsNCNameSurrogateChar(this.PeekNextChar(), this.CurerntChar)) {
NextChar();
NextChar();
len += 2;
}
#endif
else {
break;
}
}
return this.xpathExpr.Substring(start, len);
}
public enum LexKind {
Comma = ',',
Slash = '/',
At = '@',
Dot = '.',
LParens = '(',
RParens = ')',
LBracket = '[',
RBracket = ']',
Star = '*',
Plus = '+',
Minus = '-',
Eq = '=',
Lt = '<',
Gt = '>',
Bang = '!',
Dollar = '$',
Apos = '\'',
Quote = '"',
Union = '|',
Ne = 'N', // !=
Le = 'L', // <=
Ge = 'G', // >=
And = 'A', // &&
Or = 'O', // ||
DotDot = 'D', // ..
SlashSlash = 'S', // //
Name = 'n', // XML _Name
String = 's', // Quoted string constant
Number = 'd', // _Number constant
Axe = 'a', // Axe (like child::)
Eof = 'E',
};
}
}
|
