CachedCSSStyleSheet.cpp revision 5f1ab04193ad0130ca8204aadaceae083aca9881 
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 "CachedResourceClient.h"
31#include "CachedResourceClientWalker.h"
32#include "HTTPParsers.h"
33#include "TextResourceDecoder.h"
34#include "loader.h"
35#include <wtf/Vector.h>
36
37namespace WebCore {
38
39CachedCSSStyleSheet::CachedCSSStyleSheet(const String& url, const String& charset)
40    : CachedResource(url, CSSStyleSheet)
41    , m_decoder(TextResourceDecoder::create("text/css", charset))
42{
43    // Prefer text/css but accept any type (dell.com serves a stylesheet
44    // as text/html; see <http://bugs.webkit.org/show_bug.cgi?id=11451>).
45    setAccept("text/css,*/*;q=0.1");
46}
47
48CachedCSSStyleSheet::~CachedCSSStyleSheet()
49{
50}
51
52void CachedCSSStyleSheet::addClient(CachedResourceClient *c)
53{
54    CachedResource::addClient(c);
55
56    if (!m_loading)
57        c->setCSSStyleSheet(m_url, m_decoder->encoding().name(), this);
58}
59
60void CachedCSSStyleSheet::allClientsRemoved()
61{
62    if (isSafeToMakePurgeable())
63        makePurgeable(true);
64}
65
66void CachedCSSStyleSheet::setEncoding(const String& chs)
67{
68    m_decoder->setEncoding(chs, TextResourceDecoder::EncodingFromHTTPHeader);
69}
70
71String CachedCSSStyleSheet::encoding() const
72{
73    return m_decoder->encoding().name();
74}
75
76const String CachedCSSStyleSheet::sheetText(bool enforceMIMEType) const
77{
78    ASSERT(!isPurgeable());
79
80    if (!m_data || m_data->isEmpty() || !canUseSheet(enforceMIMEType))
81        return String();
82
83    if (!m_decodedSheetText.isNull())
84        return m_decodedSheetText;
85
86    // Don't cache the decoded text, regenerating is cheap and it can use quite a bit of memory
87    String sheetText = m_decoder->decode(m_data->data(), m_data->size());
88    sheetText += m_decoder->flush();
89    return sheetText;
90}
91
92void CachedCSSStyleSheet::data(PassRefPtr<SharedBuffer> data, bool allDataReceived)
93{
94    if (!allDataReceived)
95        return;
96
97    m_data = data;
98    setEncodedSize(m_data.get() ? m_data->size() : 0);
99    // Decode the data to find out the encoding and keep the sheet text around during checkNotify()
100    if (m_data) {
101        m_decodedSheetText = m_decoder->decode(m_data->data(), m_data->size());
102        m_decodedSheetText += m_decoder->flush();
103    }
104    m_loading = false;
105    checkNotify();
106    // Clear the decoded text as it is unlikely to be needed immediately again and is cheap to regenerate.
107    m_decodedSheetText = String();
108}
109
110void CachedCSSStyleSheet::checkNotify()
111{
112    if (m_loading)
113        return;
114
115    CachedResourceClientWalker w(m_clients);
116    while (CachedResourceClient *c = w.next())
117        c->setCSSStyleSheet(m_response.url().string(), m_decoder->encoding().name(), this);
118}
119
120void CachedCSSStyleSheet::error()
121{
122    m_loading = false;
123    m_errorOccurred = true;
124    checkNotify();
125}
126
127bool CachedCSSStyleSheet::canUseSheet(bool enforceMIMEType) const
128{
129    if (errorOccurred())
130        return false;
131
132    if (!enforceMIMEType)
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    return mimeType.isEmpty() || equalIgnoringCase(mimeType, "text/css") || equalIgnoringCase(mimeType, "application/x-unknown-content-type");
144}
145
146}
147