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1 /*
2     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
3     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
4     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
5     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
6     Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
7 
8     This library is free software; you can redistribute it and/or
9     modify it under the terms of the GNU Library General Public
10     License as published by the Free Software Foundation; either
11     version 2 of the License, or (at your option) any later version.
12 
13     This library is distributed in the hope that it will be useful,
14     but WITHOUT ANY WARRANTY; without even the implied warranty of
15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16     Library General Public License for more details.
17 
18     You should have received a copy of the GNU Library General Public License
19     along with this library; see the file COPYING.LIB.  If not, write to
20     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21     Boston, MA 02110-1301, USA.
22 
23     This class provides all functionality needed for loading images, style sheets and html
24     pages from the web. It has a memory cache for these objects.
25 */
26 
27 #include "config.h"
28 #include "CachedCSSStyleSheet.h"
29 
30 #include "MemoryCache.h"
31 #include "CachedResourceClient.h"
32 #include "CachedResourceClientWalker.h"
33 #include "HTTPParsers.h"
34 #include "TextResourceDecoder.h"
35 #include "SharedBuffer.h"
36 #include <wtf/Vector.h>
37 
38 namespace WebCore {
39 
CachedCSSStyleSheet(const String & url,const String & charset)40 CachedCSSStyleSheet::CachedCSSStyleSheet(const String& url, const String& charset)
41     : CachedResource(url, CSSStyleSheet)
42     , m_decoder(TextResourceDecoder::create("text/css", charset))
43 {
44     // Prefer text/css but accept any type (dell.com serves a stylesheet
45     // as text/html; see <http://bugs.webkit.org/show_bug.cgi?id=11451>).
46     setAccept("text/css,*/*;q=0.1");
47 }
48 
~CachedCSSStyleSheet()49 CachedCSSStyleSheet::~CachedCSSStyleSheet()
50 {
51 }
52 
didAddClient(CachedResourceClient * c)53 void CachedCSSStyleSheet::didAddClient(CachedResourceClient *c)
54 {
55     if (!isLoading())
56         c->setCSSStyleSheet(m_url, m_response.url(), m_decoder->encoding().name(), this);
57 }
58 
allClientsRemoved()59 void CachedCSSStyleSheet::allClientsRemoved()
60 {
61     if (!MemoryCache::shouldMakeResourcePurgeableOnEviction() && isSafeToMakePurgeable())
62         makePurgeable(true);
63 }
64 
setEncoding(const String & chs)65 void CachedCSSStyleSheet::setEncoding(const String& chs)
66 {
67     m_decoder->setEncoding(chs, TextResourceDecoder::EncodingFromHTTPHeader);
68 }
69 
encoding() const70 String CachedCSSStyleSheet::encoding() const
71 {
72     return m_decoder->encoding().name();
73 }
74 
sheetText(bool enforceMIMEType,bool * hasValidMIMEType) const75 const String CachedCSSStyleSheet::sheetText(bool enforceMIMEType, bool* hasValidMIMEType) const
76 {
77     ASSERT(!isPurgeable());
78 
79     if (!m_data || m_data->isEmpty() || !canUseSheet(enforceMIMEType, hasValidMIMEType))
80         return String();
81 
82     if (!m_decodedSheetText.isNull())
83         return m_decodedSheetText;
84 
85     // Don't cache the decoded text, regenerating is cheap and it can use quite a bit of memory
86     String sheetText = m_decoder->decode(m_data->data(), m_data->size());
87     sheetText += m_decoder->flush();
88     return sheetText;
89 }
90 
data(PassRefPtr<SharedBuffer> data,bool allDataReceived)91 void CachedCSSStyleSheet::data(PassRefPtr<SharedBuffer> data, bool allDataReceived)
92 {
93     if (!allDataReceived)
94         return;
95 
96     m_data = data;
97     setEncodedSize(m_data.get() ? m_data->size() : 0);
98     // Decode the data to find out the encoding and keep the sheet text around during checkNotify()
99     if (m_data) {
100         m_decodedSheetText = m_decoder->decode(m_data->data(), m_data->size());
101         m_decodedSheetText += m_decoder->flush();
102     }
103     setLoading(false);
104     checkNotify();
105     // Clear the decoded text as it is unlikely to be needed immediately again and is cheap to regenerate.
106     m_decodedSheetText = String();
107 }
108 
checkNotify()109 void CachedCSSStyleSheet::checkNotify()
110 {
111     if (isLoading())
112         return;
113 
114     CachedResourceClientWalker w(m_clients);
115     while (CachedResourceClient *c = w.next())
116         c->setCSSStyleSheet(m_url, m_response.url(), m_decoder->encoding().name(), this);
117 }
118 
error(CachedResource::Status status)119 void CachedCSSStyleSheet::error(CachedResource::Status status)
120 {
121     setStatus(status);
122     ASSERT(errorOccurred());
123     setLoading(false);
124     checkNotify();
125 }
126 
canUseSheet(bool enforceMIMEType,bool * hasValidMIMEType) const127 bool CachedCSSStyleSheet::canUseSheet(bool enforceMIMEType, bool* hasValidMIMEType) const
128 {
129     if (errorOccurred())
130         return false;
131 
132     if (!enforceMIMEType && !hasValidMIMEType)
133         return true;
134 
135     // This check exactly matches Firefox.  Note that we grab the Content-Type
136     // header directly because we want to see what the value is BEFORE content
137     // sniffing.  Firefox does this by setting a "type hint" on the channel.
138     // This implementation should be observationally equivalent.
139     //
140     // This code defaults to allowing the stylesheet for non-HTTP protocols so
141     // folks can use standards mode for local HTML documents.
142     String mimeType = extractMIMETypeFromMediaType(response().httpHeaderField("Content-Type"));
143     bool typeOK = mimeType.isEmpty() || equalIgnoringCase(mimeType, "text/css") || equalIgnoringCase(mimeType, "application/x-unknown-content-type");
144     if (hasValidMIMEType)
145         *hasValidMIMEType = typeOK;
146     if (!enforceMIMEType)
147         return true;
148     return typeOK;
149 }
150 
151 }
152