1/*
2    Copyright (C) 1999 Lars Knoll (knoll@mpi-hd.mpg.de)
3    Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
4    Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
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#ifndef TextResourceDecoder_h
24#define TextResourceDecoder_h
25
26#include "wtf/RefCounted.h"
27#include "wtf/text/TextEncoding.h"
28
29namespace blink {
30
31class DocumentEncodingData;
32class HTMLMetaCharsetParser;
33
34class TextResourceDecoder {
35public:
36    enum EncodingSource {
37        DefaultEncoding,
38        AutoDetectedEncoding,
39        EncodingFromContentSniffing,
40        EncodingFromXMLHeader,
41        EncodingFromMetaTag,
42        EncodingFromCSSCharset,
43        EncodingFromHTTPHeader,
44        UserChosenEncoding,
45        EncodingFromParentFrame
46    };
47
48    static PassOwnPtr<TextResourceDecoder> create(const String& mimeType, const WTF::TextEncoding& defaultEncoding = WTF::TextEncoding(), bool usesEncodingDetector = false)
49    {
50        return adoptPtr(new TextResourceDecoder(mimeType, defaultEncoding, usesEncodingDetector));
51    }
52    ~TextResourceDecoder();
53
54    void setEncoding(const WTF::TextEncoding&, EncodingSource);
55    const WTF::TextEncoding& encoding() const { return m_encoding; }
56    bool encodingWasDetectedHeuristically() const
57    {
58        return m_source == AutoDetectedEncoding
59            || m_source == EncodingFromContentSniffing;
60    }
61
62    String decode(const char* data, size_t length);
63    String flush();
64
65    void setHintEncoding(const WTF::TextEncoding& encoding)
66    {
67        m_hintEncoding = encoding.name();
68    }
69
70    void useLenientXMLDecoding() { m_useLenientXMLDecoding = true; }
71    bool sawError() const { return m_sawError; }
72
73private:
74    TextResourceDecoder(const String& mimeType, const WTF::TextEncoding& defaultEncoding, bool usesEncodingDetector);
75
76    enum ContentType { PlainTextContent, HTMLContent, XMLContent, CSSContent }; // PlainText only checks for BOM.
77    static ContentType determineContentType(const String& mimeType);
78    static const WTF::TextEncoding& defaultEncoding(ContentType, const WTF::TextEncoding& defaultEncoding);
79
80    size_t checkForBOM(const char*, size_t);
81    bool checkForCSSCharset(const char*, size_t, bool& movedDataToBuffer);
82    bool checkForXMLCharset(const char*, size_t, bool& movedDataToBuffer);
83    void checkForMetaCharset(const char*, size_t);
84    void detectJapaneseEncoding(const char*, size_t);
85    bool shouldAutoDetect() const;
86
87    ContentType m_contentType;
88    WTF::TextEncoding m_encoding;
89    OwnPtr<TextCodec> m_codec;
90    EncodingSource m_source;
91    const char* m_hintEncoding;
92    Vector<char> m_buffer;
93    bool m_checkedForBOM;
94    bool m_checkedForCSSCharset;
95    bool m_checkedForXMLCharset;
96    bool m_checkedForMetaCharset;
97    bool m_useLenientXMLDecoding; // Don't stop on XML decoding errors.
98    bool m_sawError;
99    bool m_usesEncodingDetector;
100
101    OwnPtr<HTMLMetaCharsetParser> m_charsetParser;
102};
103
104}
105
106#endif
107