--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/loader/TextResourceDecoder.cpp Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,854 @@
+/*
+ Copyright (C) 1999 Lars Knoll (knoll@mpi-hd.mpg.de)
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
+ Copyright (C) 2005, 2006, 2007 Alexey Proskuryakov (ap@nypop.com)
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public License
+ along with this library; see the file COPYING.LIB. If not, write to
+ the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA.
+*/
+
+
+#include "config.h"
+#include "TextResourceDecoder.h"
+
+#include "DOMImplementation.h"
+#include "HTMLNames.h"
+#include "TextCodec.h"
+#include "TextEncoding.h"
+#include "TextEncodingDetector.h"
+#include "TextEncodingRegistry.h"
+#include <wtf/ASCIICType.h>
+#include <wtf/StringExtras.h>
+
+using namespace WTF;
+
+namespace WebCore {
+
+using namespace HTMLNames;
+
+// You might think we should put these find functions elsewhere, perhaps with the
+// similar functions that operate on UChar, but arguably only the decoder has
+// a reason to process strings of char rather than UChar.
+
+static int find(const char* subject, size_t subjectLength, const char* target)
+{
+ size_t targetLength = strlen(target);
+ if (targetLength > subjectLength)
+ return -1;
+ for (size_t i = 0; i <= subjectLength - targetLength; ++i) {
+ bool match = true;
+ for (size_t j = 0; j < targetLength; ++j) {
+ if (subject[i + j] != target[j]) {
+ match = false;
+ break;
+ }
+ }
+ if (match)
+ return i;
+ }
+ return -1;
+}
+
+static int findIgnoringCase(const char* subject, size_t subjectLength, const char* target)
+{
+ size_t targetLength = strlen(target);
+ if (targetLength > subjectLength)
+ return -1;
+#ifndef NDEBUG
+ for (size_t i = 0; i < targetLength; ++i)
+ ASSERT(isASCIILower(target[i]));
+#endif
+ for (size_t i = 0; i <= subjectLength - targetLength; ++i) {
+ bool match = true;
+ for (size_t j = 0; j < targetLength; ++j) {
+ if (toASCIILower(subject[i + j]) != target[j]) {
+ match = false;
+ break;
+ }
+ }
+ if (match)
+ return i;
+ }
+ return -1;
+}
+
+static TextEncoding findTextEncoding(const char* encodingName, int length)
+{
+ Vector<char, 64> buffer(length + 1);
+ memcpy(buffer.data(), encodingName, length);
+ buffer[length] = '\0';
+ return buffer.data();
+}
+
+class KanjiCode {
+public:
+ enum Type { ASCII, JIS, EUC, SJIS, UTF16, UTF8 };
+ static enum Type judge(const char* str, int length);
+ static const int ESC = 0x1b;
+ static const unsigned char sjisMap[256];
+ static int ISkanji(int code)
+ {
+ if (code >= 0x100)
+ return 0;
+ return sjisMap[code & 0xff] & 1;
+ }
+ static int ISkana(int code)
+ {
+ if (code >= 0x100)
+ return 0;
+ return sjisMap[code & 0xff] & 2;
+ }
+};
+
+const unsigned char KanjiCode::sjisMap[256] = {
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0
+};
+
+/*
+ * EUC-JP is
+ * [0xa1 - 0xfe][0xa1 - 0xfe]
+ * 0x8e[0xa1 - 0xfe](SS2)
+ * 0x8f[0xa1 - 0xfe][0xa1 - 0xfe](SS3)
+ *
+ * Shift_Jis is
+ * [0x81 - 0x9f, 0xe0 - 0xef(0xfe?)][0x40 - 0x7e, 0x80 - 0xfc]
+ *
+ * Shift_Jis Hankaku Kana is
+ * [0xa1 - 0xdf]
+ */
+
+/*
+ * KanjiCode::judge() is based on judge_jcode() from jvim
+ * http://hp.vector.co.jp/authors/VA003457/vim/
+ *
+ * Special Thanks to Kenichi Tsuchida
+ */
+
+enum KanjiCode::Type KanjiCode::judge(const char* str, int size)
+{
+ enum Type code;
+ int i;
+ int bfr = false; /* Kana Moji */
+ int bfk = 0; /* EUC Kana */
+ int sjis = 0;
+ int euc = 0;
+
+ const unsigned char* ptr = reinterpret_cast<const unsigned char*>(str);
+
+ code = ASCII;
+
+ i = 0;
+ while (i < size) {
+ if (ptr[i] == ESC && (size - i >= 3)) {
+ if ((ptr[i + 1] == '$' && ptr[i + 2] == 'B')
+ || (ptr[i + 1] == '(' && ptr[i + 2] == 'B')) {
+ code = JIS;
+ goto breakBreak;
+ } else if ((ptr[i + 1] == '$' && ptr[i + 2] == '@')
+ || (ptr[i + 1] == '(' && ptr[i + 2] == 'J')) {
+ code = JIS;
+ goto breakBreak;
+ } else if (ptr[i + 1] == '(' && ptr[i + 2] == 'I') {
+ code = JIS;
+ i += 3;
+ } else if (ptr[i + 1] == ')' && ptr[i + 2] == 'I') {
+ code = JIS;
+ i += 3;
+ } else {
+ i++;
+ }
+ bfr = false;
+ bfk = 0;
+ } else {
+ if (ptr[i] < 0x20) {
+ bfr = false;
+ bfk = 0;
+ /* ?? check kudokuten ?? && ?? hiragana ?? */
+ if ((i >= 2) && (ptr[i - 2] == 0x81)
+ && (0x41 <= ptr[i - 1] && ptr[i - 1] <= 0x49)) {
+ code = SJIS;
+ sjis += 100; /* kudokuten */
+ } else if ((i >= 2) && (ptr[i - 2] == 0xa1)
+ && (0xa2 <= ptr[i - 1] && ptr[i - 1] <= 0xaa)) {
+ code = EUC;
+ euc += 100; /* kudokuten */
+ } else if ((i >= 2) && (ptr[i - 2] == 0x82) && (0xa0 <= ptr[i - 1])) {
+ sjis += 40; /* hiragana */
+ } else if ((i >= 2) && (ptr[i - 2] == 0xa4) && (0xa0 <= ptr[i - 1])) {
+ euc += 40; /* hiragana */
+ }
+ } else {
+ /* ?? check hiragana or katana ?? */
+ if ((size - i > 1) && (ptr[i] == 0x82) && (0xa0 <= ptr[i + 1])) {
+ sjis++; /* hiragana */
+ } else if ((size - i > 1) && (ptr[i] == 0x83)
+ && (0x40 <= ptr[i + 1] && ptr[i + 1] <= 0x9f)) {
+ sjis++; /* katakana */
+ } else if ((size - i > 1) && (ptr[i] == 0xa4) && (0xa0 <= ptr[i + 1])) {
+ euc++; /* hiragana */
+ } else if ((size - i > 1) && (ptr[i] == 0xa5) && (0xa0 <= ptr[i + 1])) {
+ euc++; /* katakana */
+ }
+ if (bfr) {
+ if ((i >= 1) && (0x40 <= ptr[i] && ptr[i] <= 0xa0) && ISkanji(ptr[i - 1])) {
+ code = SJIS;
+ goto breakBreak;
+ } else if ((i >= 1) && (0x81 <= ptr[i - 1] && ptr[i - 1] <= 0x9f) && ((0x40 <= ptr[i] && ptr[i] < 0x7e) || (0x7e < ptr[i] && ptr[i] <= 0xfc))) {
+ code = SJIS;
+ goto breakBreak;
+ } else if ((i >= 1) && (0xfd <= ptr[i] && ptr[i] <= 0xfe) && (0xa1 <= ptr[i - 1] && ptr[i - 1] <= 0xfe)) {
+ code = EUC;
+ goto breakBreak;
+ } else if ((i >= 1) && (0xfd <= ptr[i - 1] && ptr[i - 1] <= 0xfe) && (0xa1 <= ptr[i] && ptr[i] <= 0xfe)) {
+ code = EUC;
+ goto breakBreak;
+ } else if ((i >= 1) && (ptr[i] < 0xa0 || 0xdf < ptr[i]) && (0x8e == ptr[i - 1])) {
+ code = SJIS;
+ goto breakBreak;
+ } else if (ptr[i] <= 0x7f) {
+ code = SJIS;
+ goto breakBreak;
+ } else {
+ if (0xa1 <= ptr[i] && ptr[i] <= 0xa6) {
+ euc++; /* sjis hankaku kana kigo */
+ } else if (0xa1 <= ptr[i] && ptr[i] <= 0xdf) {
+ ; /* sjis hankaku kana */
+ } else if (0xa1 <= ptr[i] && ptr[i] <= 0xfe) {
+ euc++;
+ } else if (0x8e == ptr[i]) {
+ euc++;
+ } else if (0x20 <= ptr[i] && ptr[i] <= 0x7f) {
+ sjis++;
+ }
+ bfr = false;
+ bfk = 0;
+ }
+ } else if (0x8e == ptr[i]) {
+ if (size - i <= 1) {
+ ;
+ } else if (0xa1 <= ptr[i + 1] && ptr[i + 1] <= 0xdf) {
+ /* EUC KANA or SJIS KANJI */
+ if (bfk == 1) {
+ euc += 100;
+ }
+ bfk++;
+ i++;
+ } else {
+ /* SJIS only */
+ code = SJIS;
+ goto breakBreak;
+ }
+ } else if (0x81 <= ptr[i] && ptr[i] <= 0x9f) {
+ /* SJIS only */
+ code = SJIS;
+ if ((size - i >= 1)
+ && ((0x40 <= ptr[i + 1] && ptr[i + 1] <= 0x7e)
+ || (0x80 <= ptr[i + 1] && ptr[i + 1] <= 0xfc))) {
+ goto breakBreak;
+ }
+ } else if (0xfd <= ptr[i] && ptr[i] <= 0xfe) {
+ /* EUC only */
+ code = EUC;
+ if ((size - i >= 1)
+ && (0xa1 <= ptr[i + 1] && ptr[i + 1] <= 0xfe)) {
+ goto breakBreak;
+ }
+ } else if (ptr[i] <= 0x7f) {
+ ;
+ } else {
+ bfr = true;
+ bfk = 0;
+ }
+ }
+ i++;
+ }
+ }
+ if (code == ASCII) {
+ if (sjis > euc) {
+ code = SJIS;
+ } else if (sjis < euc) {
+ code = EUC;
+ }
+ }
+breakBreak:
+ return (code);
+}
+
+TextResourceDecoder::ContentType TextResourceDecoder::determineContentType(const String& mimeType)
+{
+ if (equalIgnoringCase(mimeType, "text/css"))
+ return CSS;
+ if (equalIgnoringCase(mimeType, "text/html"))
+ return HTML;
+ if (DOMImplementation::isXMLMIMEType(mimeType))
+ return XML;
+ return PlainText;
+}
+
+const TextEncoding& TextResourceDecoder::defaultEncoding(ContentType contentType, const TextEncoding& specifiedDefaultEncoding)
+{
+ // Despite 8.5 "Text/xml with Omitted Charset" of RFC 3023, we assume UTF-8 instead of US-ASCII
+ // for text/xml. This matches Firefox.
+ if (contentType == XML)
+ return UTF8Encoding();
+ if (!specifiedDefaultEncoding.isValid())
+ return Latin1Encoding();
+ return specifiedDefaultEncoding;
+}
+
+TextResourceDecoder::TextResourceDecoder(const String& mimeType, const TextEncoding& specifiedDefaultEncoding, bool usesEncodingDetector)
+ : m_contentType(determineContentType(mimeType))
+ , m_encoding(defaultEncoding(m_contentType, specifiedDefaultEncoding))
+ , m_source(DefaultEncoding)
+ , m_hintEncoding(0)
+ , m_checkedForBOM(false)
+ , m_checkedForCSSCharset(false)
+ , m_checkedForHeadCharset(false)
+ , m_useLenientXMLDecoding(false)
+ , m_sawError(false)
+ , m_usesEncodingDetector(usesEncodingDetector)
+{
+}
+
+TextResourceDecoder::~TextResourceDecoder()
+{
+}
+
+void TextResourceDecoder::setEncoding(const TextEncoding& encoding, EncodingSource source)
+{
+ // In case the encoding didn't exist, we keep the old one (helps some sites specifying invalid encodings).
+ if (!encoding.isValid())
+ return;
+
+ // When encoding comes from meta tag (i.e. it cannot be XML files sent via XHR),
+ // treat x-user-defined as windows-1252 (bug 18270)
+ if (source == EncodingFromMetaTag && strcasecmp(encoding.name(), "x-user-defined") == 0)
+ m_encoding = "windows-1252";
+ else if (source == EncodingFromMetaTag || source == EncodingFromXMLHeader || source == EncodingFromCSSCharset)
+ m_encoding = encoding.closestByteBasedEquivalent();
+ else
+ m_encoding = encoding;
+
+ m_codec.clear();
+ m_source = source;
+}
+
+// Returns the position of the encoding string.
+static int findXMLEncoding(const char* str, int len, int& encodingLength)
+{
+ int pos = find(str, len, "encoding");
+ if (pos == -1)
+ return -1;
+ pos += 8;
+
+ // Skip spaces and stray control characters.
+ while (pos < len && str[pos] <= ' ')
+ ++pos;
+
+ // Skip equals sign.
+ if (pos >= len || str[pos] != '=')
+ return -1;
+ ++pos;
+
+ // Skip spaces and stray control characters.
+ while (pos < len && str[pos] <= ' ')
+ ++pos;
+
+ // Skip quotation mark.
+ if (pos >= len)
+ return - 1;
+ char quoteMark = str[pos];
+ if (quoteMark != '"' && quoteMark != '\'')
+ return -1;
+ ++pos;
+
+ // Find the trailing quotation mark.
+ int end = pos;
+ while (end < len && str[end] != quoteMark)
+ ++end;
+ if (end >= len)
+ return -1;
+
+ encodingLength = end - pos;
+ return pos;
+}
+
+// true if there is more to parse
+static inline bool skipWhitespace(const char*& pos, const char* dataEnd)
+{
+ while (pos < dataEnd && (*pos == '\t' || *pos == ' '))
+ ++pos;
+ return pos != dataEnd;
+}
+
+size_t TextResourceDecoder::checkForBOM(const char* data, size_t len)
+{
+ // Check for UTF-16/32 or UTF-8 BOM mark at the beginning, which is a sure sign of a Unicode encoding.
+ // We let it override even a user-chosen encoding.
+ ASSERT(!m_checkedForBOM);
+
+ size_t lengthOfBOM = 0;
+
+ size_t bufferLength = m_buffer.size();
+
+ size_t buf1Len = bufferLength;
+ size_t buf2Len = len;
+ const unsigned char* buf1 = reinterpret_cast<const unsigned char*>(m_buffer.data());
+ const unsigned char* buf2 = reinterpret_cast<const unsigned char*>(data);
+ unsigned char c1 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *buf2++) : 0;
+ unsigned char c2 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *buf2++) : 0;
+ unsigned char c3 = buf1Len ? (--buf1Len, *buf1++) : buf2Len ? (--buf2Len, *buf2++) : 0;
+ unsigned char c4 = buf2Len ? (--buf2Len, *buf2++) : 0;
+
+ // Check for the BOM.
+ if (c1 == 0xFF && c2 == 0xFE) {
+ if (c3 != 0 || c4 != 0) {
+ setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding);
+ lengthOfBOM = 2;
+ } else {
+ setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding);
+ lengthOfBOM = 4;
+ }
+ } else if (c1 == 0xEF && c2 == 0xBB && c3 == 0xBF) {
+ setEncoding(UTF8Encoding(), AutoDetectedEncoding);
+ lengthOfBOM = 3;
+ } else if (c1 == 0xFE && c2 == 0xFF) {
+ setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding);
+ lengthOfBOM = 2;
+ } else if (c1 == 0 && c2 == 0 && c3 == 0xFE && c4 == 0xFF) {
+ setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding);
+ lengthOfBOM = 4;
+ }
+
+ if (lengthOfBOM || bufferLength + len >= 4)
+ m_checkedForBOM = true;
+
+ return lengthOfBOM;
+}
+
+bool TextResourceDecoder::checkForCSSCharset(const char* data, size_t len, bool& movedDataToBuffer)
+{
+ if (m_source != DefaultEncoding && m_source != EncodingFromParentFrame) {
+ m_checkedForCSSCharset = true;
+ return true;
+ }
+
+ size_t oldSize = m_buffer.size();
+ m_buffer.grow(oldSize + len);
+ memcpy(m_buffer.data() + oldSize, data, len);
+
+ movedDataToBuffer = true;
+
+ if (m_buffer.size() > 8) { // strlen("@charset") == 8
+ const char* dataStart = m_buffer.data();
+ const char* dataEnd = dataStart + m_buffer.size();
+
+ if (dataStart[0] == '@' && dataStart[1] == 'c' && dataStart[2] == 'h' && dataStart[3] == 'a' && dataStart[4] == 'r' &&
+ dataStart[5] == 's' && dataStart[6] == 'e' && dataStart[7] == 't') {
+
+ dataStart += 8;
+ const char* pos = dataStart;
+ if (!skipWhitespace(pos, dataEnd))
+ return false;
+
+ if (*pos == '"' || *pos == '\'') {
+ char quotationMark = *pos;
+ ++pos;
+ dataStart = pos;
+
+ while (pos < dataEnd && *pos != quotationMark)
+ ++pos;
+ if (pos == dataEnd)
+ return false;
+
+ int encodingNameLength = pos - dataStart + 1;
+
+ ++pos;
+ if (!skipWhitespace(pos, dataEnd))
+ return false;
+
+ if (*pos == ';')
+ setEncoding(findTextEncoding(dataStart, encodingNameLength), EncodingFromCSSCharset);
+ }
+ }
+ m_checkedForCSSCharset = true;
+ return true;
+ }
+ return false;
+}
+
+// Other browsers allow comments in the head section, so we need to also.
+// It's important not to look for tags inside the comments.
+static inline void skipComment(const char*& ptr, const char* pEnd)
+{
+ const char* p = ptr;
+ if (p == pEnd)
+ return;
+ // Allow <!-->; other browsers do.
+ if (*p == '>') {
+ p++;
+ } else {
+ while (p + 2 < pEnd) {
+ if (*p == '-') {
+ // This is the real end of comment, "-->".
+ if (p[1] == '-' && p[2] == '>') {
+ p += 3;
+ break;
+ }
+ // This is the incorrect end of comment that other browsers allow, "--!>".
+ if (p + 3 < pEnd && p[1] == '-' && p[2] == '!' && p[3] == '>') {
+ p += 4;
+ break;
+ }
+ }
+ p++;
+ }
+ }
+ ptr = p;
+}
+
+const int bytesToCheckUnconditionally = 1024; // That many input bytes will be checked for meta charset even if <head> section is over.
+
+bool TextResourceDecoder::checkForHeadCharset(const char* data, size_t len, bool& movedDataToBuffer)
+{
+ if (m_source != DefaultEncoding && m_source != EncodingFromParentFrame) {
+ m_checkedForHeadCharset = true;
+ return true;
+ }
+
+ // This is not completely efficient, since the function might go
+ // through the HTML head several times.
+
+ size_t oldSize = m_buffer.size();
+ m_buffer.grow(oldSize + len);
+ memcpy(m_buffer.data() + oldSize, data, len);
+
+ movedDataToBuffer = true;
+
+ const char* ptr = m_buffer.data();
+ const char* pEnd = ptr + m_buffer.size();
+
+ // Is there enough data available to check for XML declaration?
+ if (m_buffer.size() < 8)
+ return false;
+
+ // Handle XML declaration, which can have encoding in it. This encoding is honored even for HTML documents.
+ // It is an error for an XML declaration not to be at the start of an XML document, and it is ignored in HTML documents in such case.
+ if (ptr[0] == '<' && ptr[1] == '?' && ptr[2] == 'x' && ptr[3] == 'm' && ptr[4] == 'l') {
+ const char* xmlDeclarationEnd = ptr;
+ while (xmlDeclarationEnd != pEnd && *xmlDeclarationEnd != '>')
+ ++xmlDeclarationEnd;
+ if (xmlDeclarationEnd == pEnd)
+ return false;
+ // No need for +1, because we have an extra "?" to lose at the end of XML declaration.
+ int len = 0;
+ int pos = findXMLEncoding(ptr, xmlDeclarationEnd - ptr, len);
+ if (pos != -1)
+ setEncoding(findTextEncoding(ptr + pos, len), EncodingFromXMLHeader);
+ // continue looking for a charset - it may be specified in an HTTP-Equiv meta
+ } else if (ptr[0] == '<' && ptr[1] == 0 && ptr[2] == '?' && ptr[3] == 0 && ptr[4] == 'x' && ptr[5] == 0) {
+ setEncoding(UTF16LittleEndianEncoding(), AutoDetectedEncoding);
+ return true;
+ } else if (ptr[0] == 0 && ptr[1] == '<' && ptr[2] == 0 && ptr[3] == '?' && ptr[4] == 0 && ptr[5] == 'x') {
+ setEncoding(UTF16BigEndianEncoding(), AutoDetectedEncoding);
+ return true;
+ } else if (ptr[0] == '<' && ptr[1] == 0 && ptr[2] == 0 && ptr[3] == 0 && ptr[4] == '?' && ptr[5] == 0 && ptr[6] == 0 && ptr[7] == 0) {
+ setEncoding(UTF32LittleEndianEncoding(), AutoDetectedEncoding);
+ return true;
+ } else if (ptr[0] == 0 && ptr[1] == 0 && ptr[2] == 0 && ptr[3] == '<' && ptr[4] == 0 && ptr[5] == 0 && ptr[6] == 0 && ptr[7] == '?') {
+ setEncoding(UTF32BigEndianEncoding(), AutoDetectedEncoding);
+ return true;
+ }
+
+ // we still don't have an encoding, and are in the head
+ // the following tags are allowed in <head>:
+ // SCRIPT|STYLE|META|LINK|OBJECT|TITLE|BASE
+
+ // We stop scanning when a tag that is not permitted in <head>
+ // is seen, rather when </head> is seen, because that more closely
+ // matches behavior in other browsers; more details in
+ // <http://bugs.webkit.org/show_bug.cgi?id=3590>.
+
+ // Additionally, we ignore things that looks like tags in <title>, <script> and <noscript>; see
+ // <http://bugs.webkit.org/show_bug.cgi?id=4560>, <http://bugs.webkit.org/show_bug.cgi?id=12165>
+ // and <http://bugs.webkit.org/show_bug.cgi?id=12389>.
+
+ // Since many sites have charset declarations after <body> or other tags that are disallowed in <head>,
+ // we don't bail out until we've checked at least bytesToCheckUnconditionally bytes of input.
+
+ AtomicStringImpl* enclosingTagName = 0;
+ bool inHeadSection = true; // Becomes false when </head> or any tag not allowed in head is encountered.
+
+ // the HTTP-EQUIV meta has no effect on XHTML
+ if (m_contentType == XML)
+ return true;
+
+ while (ptr + 3 < pEnd) { // +3 guarantees that "<!--" fits in the buffer - and certainly we aren't going to lose any "charset" that way.
+ if (*ptr == '<') {
+ bool end = false;
+ ptr++;
+
+ // Handle comments.
+ if (ptr[0] == '!' && ptr[1] == '-' && ptr[2] == '-') {
+ ptr += 3;
+ skipComment(ptr, pEnd);
+ if (ptr - m_buffer.data() >= bytesToCheckUnconditionally && !inHeadSection) {
+ // Some pages that test bandwidth from within the browser do it by having
+ // huge comments and measuring the time they take to load. Repeatedly scanning
+ // these comments can take a lot of CPU time.
+ m_checkedForHeadCharset = true;
+ return true;
+ }
+ continue;
+ }
+
+ if (*ptr == '/') {
+ ++ptr;
+ end = true;
+ }
+
+ // Grab the tag name, but mostly ignore namespaces.
+ bool sawNamespace = false;
+ char tagBuffer[20];
+ int len = 0;
+ while (len < 19) {
+ if (ptr == pEnd)
+ return false;
+ char c = *ptr;
+ if (c == ':') {
+ len = 0;
+ sawNamespace = true;
+ ptr++;
+ continue;
+ }
+ if ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9'))
+ ;
+ else if (c >= 'A' && c <= 'Z')
+ c += 'a' - 'A';
+ else
+ break;
+ tagBuffer[len++] = c;
+ ptr++;
+ }
+ tagBuffer[len] = 0;
+ AtomicString tag(tagBuffer);
+
+ if (enclosingTagName) {
+ if (end && tag.impl() == enclosingTagName)
+ enclosingTagName = 0;
+ } else {
+ if (tag == titleTag)
+ enclosingTagName = titleTag.localName().impl();
+ else if (tag == scriptTag)
+ enclosingTagName = scriptTag.localName().impl();
+ else if (tag == noscriptTag)
+ enclosingTagName = noscriptTag.localName().impl();
+ }
+
+ // Find where the opening tag ends.
+ const char* tagContentStart = ptr;
+ if (!end) {
+ while (ptr != pEnd && *ptr != '>') {
+ if (*ptr == '\'' || *ptr == '"') {
+ char quoteMark = *ptr;
+ ++ptr;
+ while (ptr != pEnd && *ptr != quoteMark)
+ ++ptr;
+ if (ptr == pEnd)
+ return false;
+ }
+ ++ptr;
+ }
+ if (ptr == pEnd)
+ return false;
+ ++ptr;
+ }
+
+ if (!end && tag == metaTag && !sawNamespace) {
+ const char* str = tagContentStart;
+ int length = ptr - tagContentStart;
+ int pos = 0;
+ while (pos < length) {
+ int charsetPos = findIgnoringCase(str + pos, length - pos, "charset");
+ if (charsetPos == -1)
+ break;
+ pos += charsetPos + 7;
+ // skip whitespace
+ while (pos < length && str[pos] <= ' ')
+ pos++;
+ if (pos == length)
+ break;
+ if (str[pos++] != '=')
+ continue;
+ while ((pos < length) &&
+ (str[pos] <= ' ' || str[pos] == '=' || str[pos] == '"' || str[pos] == '\''))
+ pos++;
+
+ // end ?
+ if (pos == length)
+ break;
+ int end = pos;
+ while (end < length &&
+ str[end] != ' ' && str[end] != '"' && str[end] != '\'' &&
+ str[end] != ';' && str[end] != '>')
+ end++;
+ setEncoding(findTextEncoding(str + pos, end - pos), EncodingFromMetaTag);
+ if (m_source == EncodingFromMetaTag)
+ return true;
+
+ if (end >= length || str[end] == '/' || str[end] == '>')
+ break;
+
+ pos = end + 1;
+ }
+ } else {
+ if (!enclosingTagName && tag != scriptTag && tag != noscriptTag && tag != styleTag
+ && tag != linkTag && tag != metaTag && tag != objectTag && tag != titleTag && tag != baseTag
+ && (end || tag != htmlTag) && (end || tag != headTag) && isASCIIAlpha(tagBuffer[0])) {
+ inHeadSection = false;
+ }
+
+ if (ptr - m_buffer.data() >= bytesToCheckUnconditionally && !inHeadSection) {
+ m_checkedForHeadCharset = true;
+ return true;
+ }
+ }
+ } else
+ ++ptr;
+ }
+ return false;
+}
+
+void TextResourceDecoder::detectJapaneseEncoding(const char* data, size_t len)
+{
+ switch (KanjiCode::judge(data, len)) {
+ case KanjiCode::JIS:
+ setEncoding("ISO-2022-JP", AutoDetectedEncoding);
+ break;
+ case KanjiCode::EUC:
+ setEncoding("EUC-JP", AutoDetectedEncoding);
+ break;
+ case KanjiCode::SJIS:
+ setEncoding("Shift_JIS", AutoDetectedEncoding);
+ break;
+ case KanjiCode::ASCII:
+ case KanjiCode::UTF16:
+ case KanjiCode::UTF8:
+ break;
+ }
+}
+
+// We use the encoding detector in two cases:
+// 1. Encoding detector is turned ON and no other encoding source is
+// available (that is, it's DefaultEncoding).
+// 2. Encoding detector is turned ON and the encoding is set to
+// the encoding of the parent frame, which is also auto-detected.
+// Note that condition #2 is NOT satisfied unless parent-child frame
+// relationship is compliant to the same-origin policy. If they're from
+// different domains, |m_source| would not be set to EncodingFromParentFrame
+// in the first place.
+bool TextResourceDecoder::shouldAutoDetect() const
+{
+ // Just checking m_hintEncoding suffices here because it's only set
+ // in setHintEncoding when the source is AutoDetectedEncoding.
+ return m_usesEncodingDetector
+ && (m_source == DefaultEncoding || (m_source == EncodingFromParentFrame && m_hintEncoding));
+}
+
+String TextResourceDecoder::decode(const char* data, size_t len)
+{
+ size_t lengthOfBOM = 0;
+ if (!m_checkedForBOM)
+ lengthOfBOM = checkForBOM(data, len);
+
+ bool movedDataToBuffer = false;
+
+ if (m_contentType == CSS && !m_checkedForCSSCharset)
+ if (!checkForCSSCharset(data, len, movedDataToBuffer))
+ return "";
+
+ if ((m_contentType == HTML || m_contentType == XML) && !m_checkedForHeadCharset) // HTML and XML
+ if (!checkForHeadCharset(data, len, movedDataToBuffer))
+ return "";
+
+ // FIXME: It is wrong to change the encoding downstream after we have already done some decoding.
+ if (shouldAutoDetect()) {
+ if (m_encoding.isJapanese())
+ detectJapaneseEncoding(data, len); // FIXME: We should use detectTextEncoding() for all languages.
+ else {
+ TextEncoding detectedEncoding;
+ if (detectTextEncoding(data, len, m_hintEncoding, &detectedEncoding))
+ setEncoding(detectedEncoding, AutoDetectedEncoding);
+ }
+ }
+
+ ASSERT(m_encoding.isValid());
+
+ if (!m_codec)
+ m_codec = newTextCodec(m_encoding);
+
+ if (m_buffer.isEmpty())
+ return m_codec->decode(data + lengthOfBOM, len - lengthOfBOM, false, m_contentType == XML, m_sawError);
+
+ if (!movedDataToBuffer) {
+ size_t oldSize = m_buffer.size();
+ m_buffer.grow(oldSize + len);
+ memcpy(m_buffer.data() + oldSize, data, len);
+ }
+
+ String result = m_codec->decode(m_buffer.data() + lengthOfBOM, m_buffer.size() - lengthOfBOM, false, m_contentType == XML && !m_useLenientXMLDecoding, m_sawError);
+ m_buffer.clear();
+ return result;
+}
+
+String TextResourceDecoder::flush()
+{
+ // If we can not identify the encoding even after a document is completely
+ // loaded, we need to detect the encoding if other conditions for
+ // autodetection is satisfied.
+ if (m_buffer.size() && shouldAutoDetect()
+ && ((!m_checkedForHeadCharset && (m_contentType == HTML || m_contentType == XML)) || (!m_checkedForCSSCharset && (m_contentType == CSS)))) {
+ TextEncoding detectedEncoding;
+ if (detectTextEncoding(m_buffer.data(), m_buffer.size(),
+ m_hintEncoding, &detectedEncoding))
+ setEncoding(detectedEncoding, AutoDetectedEncoding);
+ }
+
+ if (!m_codec)
+ m_codec = newTextCodec(m_encoding);
+
+ String result = m_codec->decode(m_buffer.data(), m_buffer.size(), true, m_contentType == XML && !m_useLenientXMLDecoding, m_sawError);
+ m_buffer.clear();
+ m_codec.clear();
+ m_checkedForBOM = false; // Skip BOM again when re-decoding.
+ return result;
+}
+
+}