Finch experiment: auto-detect text encoding

third_party/WebKit/Source/core/html/parser/TextResourceDecoder.cpp

 /*
     Copyright (C) 1999 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 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 "core/html/parser/TextResourceDecoder.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/DOMImplementation.h"
 #include "core/html/parser/HTMLMetaCharsetParser.h"
 #include "platform/text/TextEncodingDetector.h"
 #include "wtf/StringExtras.h"
 #include "wtf/text/TextCodec.h"
 #include "wtf/text/TextEncodingRegistry.h"
@@ skipping 361 matching lines @@
         }
 
         dataForDecode = m_buffer.data() + lengthOfBOM;
         lengthForDecode = m_buffer.size() - lengthOfBOM;
     }
 
     if (m_contentType == HTMLContent && !m_checkedForMetaCharset)
         checkForMetaCharset(dataForDecode, lengthForDecode);
 
     if (shouldAutoDetect()) {
-        WTF::TextEncoding detectedEncoding;
-        if (detectTextEncoding(data, len, m_hintEncoding, &detectedEncoding))
-            setEncoding(detectedEncoding, EncodingFromContentSniffing);
+        detectTextEncoding(data, len);
     }
 
     ASSERT(m_encoding.isValid());
 
     if (!m_codec)
         m_codec = newTextCodec(m_encoding);
 
     String result = m_codec->decode(dataForDecode, lengthForDecode, DoNotFlush, m_contentType == XMLContent && !m_useLenientXMLDecoding, m_sawError);
 
     m_buffer.clear();
     return result;
 }
 
+void TextResourceDecoder::detectTextEncoding(const char* data, size_t len)
+{
+    WTF::TextEncoding detectedEncoding;
+    bool detected = blink::detectTextEncoding(data, len, m_hintEncoding, &detectedEncoding);
+    if (detected && detectedEncoding != encoding())
+        setEncoding(detectedEncoding, EncodingFromContentSniffing);
+    else
+        setEncoding(detectedEncoding, DefaultEncodingAttemptedSniffing);
+}
+
 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_checkedForXMLCharset && (m_contentType == HTMLContent || m_contentType == XMLContent)) || (!m_checkedForCSSCharset && (m_contentType == CSSContent)))) {
-        WTF::TextEncoding detectedEncoding;
-        if (detectTextEncoding(m_buffer.data(), m_buffer.size(), m_hintEncoding, &detectedEncoding))
-            setEncoding(detectedEncoding, EncodingFromContentSniffing);
+        detectTextEncoding(m_buffer.data(), m_buffer.size());
     }
 
     if (!m_codec)
         m_codec = newTextCodec(m_encoding);
 
     String result = m_codec->decode(m_buffer.data(), m_buffer.size(), FetchEOF, m_contentType == XMLContent && !m_useLenientXMLDecoding, m_sawError);
     m_buffer.clear();
     m_codec.clear();
     m_checkedForBOM = false; // Skip BOM again when re-decoding.
     return result;
 }
 
 }