Preload scan external CSS for @import

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

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006 Apple Computer, Inc.
 
     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
@@ skipping 33 matching lines @@
     return toCSSStyleSheetResource(fetcher->requestResource(request, CSSStyleSheetResourceFactory()));
 }
 
 CSSStyleSheetResource* CSSStyleSheetResource::createForTest(const ResourceRequest& request, const String& charset)
 {
     return new CSSStyleSheetResource(request, ResourceLoaderOptions(), charset);
 }
 
 CSSStyleSheetResource::CSSStyleSheetResource(const ResourceRequest& resourceRequest, const ResourceLoaderOptions& options, const String& charset)
     : StyleSheetResource(resourceRequest, CSSStyleSheet, options, "text/css", charset)
+    , m_didNotifyFirstData(false)
 {
 }
 
 CSSStyleSheetResource::~CSSStyleSheetResource()
 {
 }
 
 void CSSStyleSheetResource::setParsedStyleSheetCache(StyleSheetContents* newSheet)
 {
     if (m_parsedStyleSheetCache)
         m_parsedStyleSheetCache->clearReferencedFromResource();
     m_parsedStyleSheetCache = newSheet;
     if (m_parsedStyleSheetCache)
         m_parsedStyleSheetCache->setReferencedFromResource(this);
 }
 
 DEFINE_TRACE(CSSStyleSheetResource)
 {
     visitor->trace(m_parsedStyleSheetCache);
     StyleSheetResource::trace(visitor);
 }
 
 void CSSStyleSheetResource::didAddClient(ResourceClient* c)
 {
     ASSERT(StyleSheetResourceClient::isExpectedType(c));
     // Resource::didAddClient() must be before setCSSStyleSheet(),
     // because setCSSStyleSheet() may cause scripts to be executed, which could destroy 'c' if it is an instance of HTMLLinkElement.
     // see the comment of HTMLLinkElement::setCSSStyleSheet.
     Resource::didAddClient(c);
+    if (m_didNotifyFirstData)
+        static_cast<StyleSheetResourceClient*>(c)->didAppendFirstData(this);
 
-    if (!isLoading())
+    // |c| might be removed in didAppendFirstData, so ensure it is still a
+    // client.
+    if (hasClient(c) && !isLoading())
         static_cast<StyleSheetResourceClient*>(c)->setCSSStyleSheet(resourceRequest().url(), response().url(), encoding(), this);
 }
 
 const String CSSStyleSheetResource::sheetText(MIMETypeCheck mimeTypeCheck) const
 {
     if (!data() || data()->isEmpty() || !canUseSheet(mimeTypeCheck))
         return String();
 
     if (!m_decodedSheetText.isNull())
         return m_decodedSheetText;
 
     // Don't cache the decoded text, regenerating is cheap and it can use quite a bit of memory
     return decodedText();
 }
 
+void CSSStyleSheetResource::appendData(const char* data, size_t length)
+{
+    Resource::appendData(data, length);
+    if (m_didNotifyFirstData)
+        return;
+    ResourceClientWalker<StyleSheetResourceClient> w(clients());
+    while (StyleSheetResourceClient* c = w.next())
+        c->didAppendFirstData(this);
+    m_didNotifyFirstData = true;
+}
+
 void CSSStyleSheetResource::checkNotify()
 {
     // Decode the data to find out the encoding and keep the sheet text around during checkNotify()
     if (data())
         m_decodedSheetText = decodedText();
 
     ResourceClientWalker<StyleSheetResourceClient> w(clients());
     while (StyleSheetResourceClient* c = w.next())
         c->setCSSStyleSheet(resourceRequest().url(), response().url(), encoding(), this);
     // Clear the decoded text as it is unlikely to be needed immediately again and is cheap to regenerate.
@@ skipping 56 matching lines @@
         // This stylesheet resource did conflict with another resource and was
         // not added to the cache.
         setParsedStyleSheetCache(nullptr);
         return;
     }
     setParsedStyleSheetCache(sheet);
     setDecodedSize(m_parsedStyleSheetCache->estimatedSizeInBytes());
 }
 
 } // namespace blink