third_party/WebKit/Source/core/fetch/CSSStyleSheetResource.cpp

   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 "core/fetch/CSSStyleSheetResource.h"
  29
  30 #include "core/css/StyleSheetContents.h"
  31 #include "core/fetch/FetchRequest.h"
  32 #include "core/fetch/ResourceClientWalker.h"
  33 #include "core/fetch/ResourceFetcher.h"
  34 #include "core/fetch/StyleSheetResourceClient.h"
  35 #include "platform/SharedBuffer.h"
  36 #include "platform/network/HTTPParsers.h"
  37 #include "wtf/CurrentTime.h"
  38
  39 namespace blink {
  40
  41 ResourcePtr<CSSStyleSheetResource> CSSStyleSheetResource::fetch(FetchRequest& request, ResourceFetcher* fetcher)
  42 {
  43     ASSERT(request.resourceRequest().frameType() == WebURLRequest::FrameTypeNone);
  44     request.mutableResourceRequest().setRequestContext(WebURLRequest::RequestContextStyle);
  45     return toCSSStyleSheetResource(fetcher->requestResource(request, CSSStyleSheetResourceFactory()));
  46 }
  47
  48 CSSStyleSheetResource::CSSStyleSheetResource(const ResourceRequest& resourceRequest, const String& charset)
  49     : StyleSheetResource(resourceRequest, CSSStyleSheet, "text/css", charset)
  50 {
  51     DEFINE_STATIC_LOCAL(const AtomicString, acceptCSS, ("text/css,*/*;q=0.1", AtomicString::ConstructFromLiteral));
  52
  53     // Prefer text/css but accept any type (dell.com serves a stylesheet
  54     // as text/html; see <http://bugs.webkit.org/show_bug.cgi?id=11451>).
  55     setAccept(acceptCSS);
  56 }
  57
  58 CSSStyleSheetResource::~CSSStyleSheetResource()
  59 {
  60     // Make sure dispose() was cllaed before destruction.
  61     ASSERT(!m_parsedStyleSheetCache);
  62 }
  63
  64 void CSSStyleSheetResource::dispose()
  65 {
  66     if (m_parsedStyleSheetCache)
  67         m_parsedStyleSheetCache->removedFromMemoryCache();
  68     m_parsedStyleSheetCache.clear();
  69 }
  70
  71 DEFINE_TRACE(CSSStyleSheetResource)
  72 {
  73     visitor->trace(m_parsedStyleSheetCache);
  74     StyleSheetResource::trace(visitor);
  75 }
  76
  77 void CSSStyleSheetResource::didAddClient(ResourceClient* c)
  78 {
  79     ASSERT(c->resourceClientType() == StyleSheetResourceClient::expectedType());
  80     // Resource::didAddClient() must be before setCSSStyleSheet(),
  81     // because setCSSStyleSheet() may cause scripts to be executed, which could destroy 'c' if it is an instance of HTMLLinkElement.
  82     // see the comment of HTMLLinkElement::setCSSStyleSheet.
  83     Resource::didAddClient(c);
  84
  85     if (!isLoading())
  86         static_cast<StyleSheetResourceClient*>(c)->setCSSStyleSheet(m_resourceRequest.url(), m_response.url(), encoding(), this);
  87 }
  88
  89 const String CSSStyleSheetResource::sheetText(MIMETypeCheck mimeTypeCheck) const
  90 {
  91     ASSERT(!isPurgeable());
  92
  93     if (!m_data || m_data->isEmpty() || !canUseSheet(mimeTypeCheck))
  94         return String();
  95
  96     if (!m_decodedSheetText.isNull())
  97         return m_decodedSheetText;
  98
  99     // Don't cache the decoded text, regenerating is cheap and it can use quite a bit of memory
 100     return decodedText();
 101 }
 102
 103 const AtomicString CSSStyleSheetResource::mimeType() const
 104 {
 105     return extractMIMETypeFromMediaType(response().httpHeaderField("Content-Type")).lower();
 106 }
 107
 108 void CSSStyleSheetResource::checkNotify()
 109 {
 110     // Decode the data to find out the encoding and keep the sheet text around during checkNotify()
 111     if (m_data)
 112         m_decodedSheetText = decodedText();
 113
 114     ResourceClientWalker<StyleSheetResourceClient> w(m_clients);
 115     while (StyleSheetResourceClient* c = w.next())
 116         c->setCSSStyleSheet(m_resourceRequest.url(), m_response.url(), encoding(), this);
 117     // Clear the decoded text as it is unlikely to be needed immediately again and is cheap to regenerate.
 118     m_decodedSheetText = String();
 119 }
 120
 121 bool CSSStyleSheetResource::isSafeToUnlock() const
 122 {
 123     return m_data->hasOneRef();
 124 }
 125
 126 void CSSStyleSheetResource::destroyDecodedDataIfPossible()
 127 {
 128     if (!m_parsedStyleSheetCache)
 129         return;
 130
 131     m_parsedStyleSheetCache->removedFromMemoryCache();
 132     m_parsedStyleSheetCache.clear();
 133
 134     setDecodedSize(0);
 135 }
 136
 137 bool CSSStyleSheetResource::canUseSheet(MIMETypeCheck mimeTypeCheck) const
 138 {
 139     if (errorOccurred())
 140         return false;
 141
 142     // This check exactly matches Firefox. Note that we grab the Content-Type
 143     // header directly because we want to see what the value is BEFORE content
 144     // sniffing. Firefox does this by setting a "type hint" on the channel.
 145     // This implementation should be observationally equivalent.
 146     //
 147     // This code defaults to allowing the stylesheet for non-HTTP protocols so
 148     // folks can use standards mode for local HTML documents.
 149     if (mimeTypeCheck == MIMETypeCheck::Lax)
 150         return true;
 151     return mimeType().isEmpty() || equalIgnoringCase(mimeType(), "text/css") || equalIgnoringCase(mimeType(), "application/x-unknown-content-type");
 152 }
 153
 154 PassRefPtrWillBeRawPtr<StyleSheetContents> CSSStyleSheetResource::restoreParsedStyleSheet(const CSSParserContext& context)
 155 {
 156     if (!m_parsedStyleSheetCache)
 157         return nullptr;
 158     if (m_parsedStyleSheetCache->hasFailedOrCanceledSubresources()) {
 159         m_parsedStyleSheetCache->removedFromMemoryCache();
 160         m_parsedStyleSheetCache.clear();
 161         return nullptr;
 162     }
 163
 164     ASSERT(m_parsedStyleSheetCache->isCacheable());
 165     ASSERT(m_parsedStyleSheetCache->isInMemoryCache());
 166
 167     // Contexts must be identical so we know we would get the same exact result if we parsed again.
 168     if (m_parsedStyleSheetCache->parserContext() != context)
 169         return nullptr;
 170
 171     didAccessDecodedData();
 172
 173     return m_parsedStyleSheetCache;
 174 }
 175
 176 void CSSStyleSheetResource::saveParsedStyleSheet(PassRefPtrWillBeRawPtr<StyleSheetContents> sheet)
 177 {
 178     ASSERT(sheet && sheet->isCacheable());
 179
 180     if (m_parsedStyleSheetCache)
 181         m_parsedStyleSheetCache->removedFromMemoryCache();
 182     m_parsedStyleSheetCache = sheet;
 183     m_parsedStyleSheetCache->addedToMemoryCache();
 184
 185     setDecodedSize(m_parsedStyleSheetCache->estimatedSizeInBytes());
 186 }
 187
 188 }