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1 /* | |
2 Copyright (C) 1999 Lars Knoll (knoll@mpi-hd.mpg.de) | |
3 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All
rights reserved. | |
4 Copyright (C) 2005, 2006, 2007 Alexey Proskuryakov (ap@nypop.com) | |
5 | |
6 This library is free software; you can redistribute it and/or | |
7 modify it under the terms of the GNU Library General Public | |
8 License as published by the Free Software Foundation; either | |
9 version 2 of the License, or (at your option) any later version. | |
10 | |
11 This library is distributed in the hope that it will be useful, | |
12 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 Library General Public License for more details. | |
15 | |
16 You should have received a copy of the GNU Library General Public License | |
17 along with this library; see the file COPYING.LIB. If not, write to | |
18 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, | |
19 Boston, MA 02110-1301, USA. | |
20 */ | |
21 | |
22 | |
23 #include "config.h" | |
24 #include "core/html/parser/TextResourceDecoder.h" | |
25 | |
26 #include "HTMLNames.h" | |
27 #include "core/dom/DOMImplementation.h" | |
28 #include "core/html/parser/HTMLMetaCharsetParser.h" | |
29 #include "platform/text/TextEncodingDetector.h" | |
30 #include "wtf/StringExtras.h" | |
31 #include "wtf/text/TextCodec.h" | |
32 #include "wtf/text/TextEncodingRegistry.h" | |
33 | |
34 using namespace WTF; | |
35 | |
36 namespace WebCore { | |
37 | |
38 using namespace HTMLNames; | |
39 | |
40 static inline bool bytesEqual(const char* p, char b0, char b1, char b2, char b3,
char b4) | |
41 { | |
42 return p[0] == b0 && p[1] == b1 && p[2] == b2 && p[3] == b3 && p[4] == b4; | |
43 } | |
44 | |
45 static inline bool bytesEqual(const char* p, char b0, char b1, char b2, char b3,
char b4, char b5) | |
46 { | |
47 return p[0] == b0 && p[1] == b1 && p[2] == b2 && p[3] == b3 && p[4] == b4 &&
p[5] == b5; | |
48 } | |
49 | |
50 static inline bool bytesEqual(const char* p, char b0, char b1, char b2, char b3,
char b4, char b5, char b6, char b7) | |
51 { | |
52 return p[0] == b0 && p[1] == b1 && p[2] == b2 && p[3] == b3 && p[4] == b4 &&
p[5] == b5 && p[6] == b6 && p[7] == b7; | |
53 } | |
54 | |
55 static inline bool bytesEqual(const char* p, char b0, char b1, char b2, char b3,
char b4, char b5, char b6, char b7, char b8, char b9) | |
56 { | |
57 return p[0] == b0 && p[1] == b1 && p[2] == b2 && p[3] == b3 && p[4] == b4 &&
p[5] == b5 && p[6] == b6 && p[7] == b7 && p[8] == b8 && p[9] == b9; | |
58 } | |
59 | |
60 // You might think we should put these find functions elsewhere, perhaps with th
e | |
61 // similar functions that operate on UChar, but arguably only the decoder has | |
62 // a reason to process strings of char rather than UChar. | |
63 | |
64 static int find(const char* subject, size_t subjectLength, const char* target) | |
65 { | |
66 size_t targetLength = strlen(target); | |
67 if (targetLength > subjectLength) | |
68 return -1; | |
69 for (size_t i = 0; i <= subjectLength - targetLength; ++i) { | |
70 bool match = true; | |
71 for (size_t j = 0; j < targetLength; ++j) { | |
72 if (subject[i + j] != target[j]) { | |
73 match = false; | |
74 break; | |
75 } | |
76 } | |
77 if (match) | |
78 return i; | |
79 } | |
80 return -1; | |
81 } | |
82 | |
83 static WTF::TextEncoding findTextEncoding(const char* encodingName, int length) | |
84 { | |
85 Vector<char, 64> buffer(length + 1); | |
86 memcpy(buffer.data(), encodingName, length); | |
87 buffer[length] = '\0'; | |
88 return buffer.data(); | |
89 } | |
90 | |
91 TextResourceDecoder::ContentType TextResourceDecoder::determineContentType(const
String& mimeType) | |
92 { | |
93 if (equalIgnoringCase(mimeType, "text/css")) | |
94 return CSSContent; | |
95 if (equalIgnoringCase(mimeType, "text/html")) | |
96 return HTMLContent; | |
97 if (DOMImplementation::isXMLMIMEType(mimeType)) | |
98 return XMLContent; | |
99 return PlainTextContent; | |
100 } | |
101 | |
102 const WTF::TextEncoding& TextResourceDecoder::defaultEncoding(ContentType conten
tType, const WTF::TextEncoding& specifiedDefaultEncoding) | |
103 { | |
104 // Despite 8.5 "Text/xml with Omitted Charset" of RFC 3023, we assume UTF-8
instead of US-ASCII | |
105 // for text/xml. This matches Firefox. | |
106 if (contentType == XMLContent) | |
107 return UTF8Encoding(); | |
108 if (!specifiedDefaultEncoding.isValid()) | |
109 return Latin1Encoding(); | |
110 return specifiedDefaultEncoding; | |
111 } | |
112 | |
113 TextResourceDecoder::TextResourceDecoder(const String& mimeType, const WTF::Text
Encoding& specifiedDefaultEncoding, bool usesEncodingDetector) | |
114 : m_contentType(determineContentType(mimeType)) | |
115 , m_encoding(defaultEncoding(m_contentType, specifiedDefaultEncoding)) | |
116 , m_source(DefaultEncoding) | |
117 , m_hintEncoding(0) | |
118 , m_checkedForBOM(false) | |
119 , m_checkedForCSSCharset(false) | |
120 , m_checkedForXMLCharset(false) | |
121 , m_checkedForMetaCharset(false) | |
122 , m_useLenientXMLDecoding(false) | |
123 , m_sawError(false) | |
124 , m_usesEncodingDetector(usesEncodingDetector) | |
125 { | |
126 } | |
127 | |
128 TextResourceDecoder::~TextResourceDecoder() | |
129 { | |
130 } | |
131 | |
132 void TextResourceDecoder::setEncoding(const WTF::TextEncoding& encoding, Encodin
gSource source) | |
133 { | |
134 // In case the encoding didn't exist, we keep the old one (helps some sites
specifying invalid encodings). | |
135 if (!encoding.isValid()) | |
136 return; | |
137 | |
138 // When encoding comes from meta tag (i.e. it cannot be XML files sent via X
HR), | |
139 // treat x-user-defined as windows-1252 (bug 18270) | |
140 if (source == EncodingFromMetaTag && !strcasecmp(encoding.name(), "x-user-de
fined")) | |
141 m_encoding = "windows-1252"; | |
142 else if (source == EncodingFromMetaTag || source == EncodingFromXMLHeader ||
source == EncodingFromCSSCharset) | |
143 m_encoding = encoding.closestByteBasedEquivalent(); | |
144 else | |
145 m_encoding = encoding; | |
146 | |
147 m_codec.clear(); | |
148 m_source = source; | |
149 } | |
150 | |
151 // Returns the position of the encoding string. | |
152 static int findXMLEncoding(const char* str, int len, int& encodingLength) | |
153 { | |
154 int pos = find(str, len, "encoding"); | |
155 if (pos == -1) | |
156 return -1; | |
157 pos += 8; | |
158 | |
159 // Skip spaces and stray control characters. | |
160 while (pos < len && str[pos] <= ' ') | |
161 ++pos; | |
162 | |
163 // Skip equals sign. | |
164 if (pos >= len || str[pos] != '=') | |
165 return -1; | |
166 ++pos; | |
167 | |
168 // Skip spaces and stray control characters. | |
169 while (pos < len && str[pos] <= ' ') | |
170 ++pos; | |
171 | |
172 // Skip quotation mark. | |
173 if (pos >= len) | |
174 return - 1; | |
175 char quoteMark = str[pos]; | |
176 if (quoteMark != '"' && quoteMark != '\'') | |
177 return -1; | |
178 ++pos; | |
179 | |
180 // Find the trailing quotation mark. | |
181 int end = pos; | |
182 while (end < len && str[end] != quoteMark) | |
183 ++end; | |
184 if (end >= len) | |
185 return -1; | |
186 | |
187 encodingLength = end - pos; | |
188 return pos; | |
189 } | |
190 | |
191 size_t TextResourceDecoder::checkForBOM(const char* data, size_t len) | |
192 { | |
193 // Check for UTF-16/32 or UTF-8 BOM mark at the beginning, which is a sure s
ign of a Unicode encoding. | |
194 // We let it override even a user-chosen encoding. | |
195 ASSERT(!m_checkedForBOM); | |
196 | |
197 size_t lengthOfBOM = 0; | |
198 | |
199 size_t bufferLength = m_buffer.size(); | |
200 | |
201 size_t buf1Len = bufferLength; | |
202 size_t buf2Len = len; | |
203 const unsigned char* buf1 = reinterpret_cast<const unsigned char*>(m_buffer.
data()); | |
204 const unsigned char* buf2 = reinterpret_cast<const unsigned char*>(data); | |
205 unsigned char c1 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *b
uf2++) : 0; | |
206 unsigned char c2 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *b
uf2++) : 0; | |
207 unsigned char c3 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *b
uf2++) : 0; | |
208 unsigned char c4 = buf2Len ? (--buf2Len, *buf2++) : 0; | |
209 | |
210 // Check for the BOM. | |
211 if (c1 == 0xFF && c2 == 0xFE) { | |
212 if (c3 || c4) { | |
213 setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding); | |
214 lengthOfBOM = 2; | |
215 } else { | |
216 setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding); | |
217 lengthOfBOM = 4; | |
218 } | |
219 } else if (c1 == 0xEF && c2 == 0xBB && c3 == 0xBF) { | |
220 setEncoding(UTF8Encoding(), AutoDetectedEncoding); | |
221 lengthOfBOM = 3; | |
222 } else if (c1 == 0xFE && c2 == 0xFF) { | |
223 setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding); | |
224 lengthOfBOM = 2; | |
225 } else if (!c1 && !c2 && c3 == 0xFE && c4 == 0xFF) { | |
226 setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding); | |
227 lengthOfBOM = 4; | |
228 } | |
229 | |
230 if (lengthOfBOM || bufferLength + len >= 4) | |
231 m_checkedForBOM = true; | |
232 | |
233 return lengthOfBOM; | |
234 } | |
235 | |
236 bool TextResourceDecoder::checkForCSSCharset(const char* data, size_t len, bool&
movedDataToBuffer) | |
237 { | |
238 if (m_source != DefaultEncoding && m_source != EncodingFromParentFrame) { | |
239 m_checkedForCSSCharset = true; | |
240 return true; | |
241 } | |
242 | |
243 size_t oldSize = m_buffer.size(); | |
244 m_buffer.grow(oldSize + len); | |
245 memcpy(m_buffer.data() + oldSize, data, len); | |
246 | |
247 movedDataToBuffer = true; | |
248 | |
249 if (m_buffer.size() <= 13) // strlen('@charset "x";') == 13 | |
250 return false; | |
251 | |
252 const char* dataStart = m_buffer.data(); | |
253 const char* dataEnd = dataStart + m_buffer.size(); | |
254 | |
255 if (bytesEqual(dataStart, '@', 'c', 'h', 'a', 'r', 's', 'e', 't', ' ', '"'))
{ | |
256 dataStart += 10; | |
257 const char* pos = dataStart; | |
258 | |
259 while (pos < dataEnd && *pos != '"') | |
260 ++pos; | |
261 if (pos == dataEnd) | |
262 return false; | |
263 | |
264 int encodingNameLength = pos - dataStart; | |
265 | |
266 ++pos; | |
267 | |
268 if (*pos == ';') | |
269 setEncoding(findTextEncoding(dataStart, encodingNameLength), Encodin
gFromCSSCharset); | |
270 } | |
271 | |
272 m_checkedForCSSCharset = true; | |
273 return true; | |
274 } | |
275 | |
276 bool TextResourceDecoder::checkForXMLCharset(const char* data, size_t len, bool&
movedDataToBuffer) | |
277 { | |
278 if (m_source != DefaultEncoding && m_source != EncodingFromParentFrame) { | |
279 m_checkedForXMLCharset = true; | |
280 return true; | |
281 } | |
282 | |
283 // This is not completely efficient, since the function might go | |
284 // through the HTML head several times. | |
285 | |
286 size_t oldSize = m_buffer.size(); | |
287 m_buffer.grow(oldSize + len); | |
288 memcpy(m_buffer.data() + oldSize, data, len); | |
289 | |
290 movedDataToBuffer = true; | |
291 | |
292 const char* ptr = m_buffer.data(); | |
293 const char* pEnd = ptr + m_buffer.size(); | |
294 | |
295 // Is there enough data available to check for XML declaration? | |
296 if (m_buffer.size() < 8) | |
297 return false; | |
298 | |
299 // Handle XML declaration, which can have encoding in it. This encoding is h
onored even for HTML documents. | |
300 // It is an error for an XML declaration not to be at the start of an XML do
cument, and it is ignored in HTML documents in such case. | |
301 if (bytesEqual(ptr, '<', '?', 'x', 'm', 'l')) { | |
302 const char* xmlDeclarationEnd = ptr; | |
303 while (xmlDeclarationEnd != pEnd && *xmlDeclarationEnd != '>') | |
304 ++xmlDeclarationEnd; | |
305 if (xmlDeclarationEnd == pEnd) | |
306 return false; | |
307 // No need for +1, because we have an extra "?" to lose at the end of XM
L declaration. | |
308 int len = 0; | |
309 int pos = findXMLEncoding(ptr, xmlDeclarationEnd - ptr, len); | |
310 if (pos != -1) | |
311 setEncoding(findTextEncoding(ptr + pos, len), EncodingFromXMLHeader)
; | |
312 // continue looking for a charset - it may be specified in an HTTP-Equiv
meta | |
313 } else if (bytesEqual(ptr, '<', 0, '?', 0, 'x', 0)) { | |
314 setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding); | |
315 } else if (bytesEqual(ptr, 0, '<', 0, '?', 0, 'x')) { | |
316 setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding); | |
317 } else if (bytesEqual(ptr, '<', 0, 0, 0, '?', 0, 0, 0)) { | |
318 setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding); | |
319 } else if (bytesEqual(ptr, 0, 0, 0, '<', 0, 0, 0, '?')) { | |
320 setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding); | |
321 } | |
322 | |
323 m_checkedForXMLCharset = true; | |
324 return true; | |
325 } | |
326 | |
327 void TextResourceDecoder::checkForMetaCharset(const char* data, size_t length) | |
328 { | |
329 if (m_source == UserChosenEncoding || m_source == EncodingFromHTTPHeader ||
m_source == AutoDetectedEncoding) { | |
330 m_checkedForMetaCharset = true; | |
331 return; | |
332 } | |
333 | |
334 if (!m_charsetParser) | |
335 m_charsetParser = HTMLMetaCharsetParser::create(); | |
336 | |
337 if (!m_charsetParser->checkForMetaCharset(data, length)) | |
338 return; | |
339 | |
340 setEncoding(m_charsetParser->encoding(), EncodingFromMetaTag); | |
341 m_charsetParser.clear(); | |
342 m_checkedForMetaCharset = true; | |
343 return; | |
344 } | |
345 | |
346 // We use the encoding detector in two cases: | |
347 // 1. Encoding detector is turned ON and no other encoding source is | |
348 // available (that is, it's DefaultEncoding). | |
349 // 2. Encoding detector is turned ON and the encoding is set to | |
350 // the encoding of the parent frame, which is also auto-detected. | |
351 // Note that condition #2 is NOT satisfied unless parent-child frame | |
352 // relationship is compliant to the same-origin policy. If they're from | |
353 // different domains, |m_source| would not be set to EncodingFromParentFrame | |
354 // in the first place. | |
355 bool TextResourceDecoder::shouldAutoDetect() const | |
356 { | |
357 // Just checking m_hintEncoding suffices here because it's only set | |
358 // in setHintEncoding when the source is AutoDetectedEncoding. | |
359 return m_usesEncodingDetector | |
360 && (m_source == DefaultEncoding || (m_source == EncodingFromParentFrame
&& m_hintEncoding)); | |
361 } | |
362 | |
363 String TextResourceDecoder::decode(const char* data, size_t len) | |
364 { | |
365 size_t lengthOfBOM = 0; | |
366 if (!m_checkedForBOM) | |
367 lengthOfBOM = checkForBOM(data, len); | |
368 | |
369 bool movedDataToBuffer = false; | |
370 | |
371 if (m_contentType == CSSContent && !m_checkedForCSSCharset) { | |
372 if (!checkForCSSCharset(data, len, movedDataToBuffer)) | |
373 return emptyString(); | |
374 } | |
375 | |
376 if ((m_contentType == HTMLContent || m_contentType == XMLContent) && !m_chec
kedForXMLCharset) { | |
377 if (!checkForXMLCharset(data, len, movedDataToBuffer)) | |
378 return emptyString(); | |
379 } | |
380 | |
381 const char* dataForDecode = data + lengthOfBOM; | |
382 size_t lengthForDecode = len - lengthOfBOM; | |
383 | |
384 if (!m_buffer.isEmpty()) { | |
385 if (!movedDataToBuffer) { | |
386 size_t oldSize = m_buffer.size(); | |
387 m_buffer.grow(oldSize + len); | |
388 memcpy(m_buffer.data() + oldSize, data, len); | |
389 } | |
390 | |
391 dataForDecode = m_buffer.data() + lengthOfBOM; | |
392 lengthForDecode = m_buffer.size() - lengthOfBOM; | |
393 } | |
394 | |
395 if (m_contentType == HTMLContent && !m_checkedForMetaCharset) | |
396 checkForMetaCharset(dataForDecode, lengthForDecode); | |
397 | |
398 if (shouldAutoDetect()) { | |
399 WTF::TextEncoding detectedEncoding; | |
400 if (detectTextEncoding(data, len, m_hintEncoding, &detectedEncoding)) | |
401 setEncoding(detectedEncoding, EncodingFromContentSniffing); | |
402 } | |
403 | |
404 ASSERT(m_encoding.isValid()); | |
405 | |
406 if (!m_codec) | |
407 m_codec = newTextCodec(m_encoding); | |
408 | |
409 String result = m_codec->decode(dataForDecode, lengthForDecode, false, m_con
tentType == XMLContent && !m_useLenientXMLDecoding, m_sawError); | |
410 | |
411 m_buffer.clear(); | |
412 return result; | |
413 } | |
414 | |
415 String TextResourceDecoder::flush() | |
416 { | |
417 // If we can not identify the encoding even after a document is completely | |
418 // loaded, we need to detect the encoding if other conditions for | |
419 // autodetection is satisfied. | |
420 if (m_buffer.size() && shouldAutoDetect() | |
421 && ((!m_checkedForXMLCharset && (m_contentType == HTMLContent || m_conte
ntType == XMLContent)) || (!m_checkedForCSSCharset && (m_contentType == CSSConte
nt)))) { | |
422 WTF::TextEncoding detectedEncoding; | |
423 if (detectTextEncoding(m_buffer.data(), m_buffer.size(), m_hintEncoding,
&detectedEncoding)) | |
424 setEncoding(detectedEncoding, EncodingFromContentSniffing); | |
425 } | |
426 | |
427 if (!m_codec) | |
428 m_codec = newTextCodec(m_encoding); | |
429 | |
430 String result = m_codec->decode(m_buffer.data(), m_buffer.size(), true, m_co
ntentType == XMLContent && !m_useLenientXMLDecoding, m_sawError); | |
431 m_buffer.clear(); | |
432 m_codec.clear(); | |
433 m_checkedForBOM = false; // Skip BOM again when re-decoding. | |
434 return result; | |
435 } | |
436 | |
437 } | |
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