[WeakMemoryCache 1a] Make Reference from Inspector to Resource weak, remove removedFromMemoryCache()

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 10 matching lines @@
     Boston, MA 02110-1301, USA.
 
     This class provides all functionality needed for loading images, style sheets and html
     pages from the web. It has a memory cache for these objects.
 */
 
 #include "core/fetch/CSSStyleSheetResource.h"
 
 #include "core/css/StyleSheetContents.h"
 #include "core/fetch/FetchRequest.h"
-#include "core/fetch/MemoryCache.h"
 #include "core/fetch/ResourceClientOrObserverWalker.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/fetch/StyleSheetResourceClient.h"
 #include "platform/SharedBuffer.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
 CSSStyleSheetResource* CSSStyleSheetResource::fetch(FetchRequest& request, ResourceFetcher* fetcher)
 {
     ASSERT(request.resourceRequest().frameType() == WebURLRequest::FrameTypeNone);
     request.mutableResourceRequest().setRequestContext(WebURLRequest::RequestContextStyle);
     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)
 {
 }
 
 CSSStyleSheetResource::~CSSStyleSheetResource()
 {
 }
 
-void CSSStyleSheetResource::removedFromMemoryCache()
+void CSSStyleSheetResource::willDestroyResourceInternal()
+{
+    setParsedStyleSheetCache(nullptr);
+}
+
+void CSSStyleSheetResource::setParsedStyleSheetCache(StyleSheetContents* newSheet)
 {
     if (m_parsedStyleSheetCache)
-        m_parsedStyleSheetCache->removedFromMemoryCache();
-    m_parsedStyleSheetCache.clear();
-    Resource::removedFromMemoryCache();
+        m_parsedStyleSheetCache->setReferencedFromResource(false);
+    m_parsedStyleSheetCache = newSheet;
+    if (m_parsedStyleSheetCache)
+        m_parsedStyleSheetCache->setReferencedFromResource(true);
 }
 
 DEFINE_TRACE(CSSStyleSheetResource)
 {
     visitor->trace(m_parsedStyleSheetCache);
     StyleSheetResource::trace(visitor);
 }
 
 void CSSStyleSheetResource::didAddClient(ResourceClient* c)
 {
@@ skipping 37 matching lines @@
 bool CSSStyleSheetResource::isSafeToUnlock() const
 {
     return m_data->hasOneRef();
 }
 
 void CSSStyleSheetResource::destroyDecodedDataIfPossible()
 {
     if (!m_parsedStyleSheetCache)
         return;
 
-    m_parsedStyleSheetCache->removedFromMemoryCache();
-    m_parsedStyleSheetCache.clear();
-
+    setParsedStyleSheetCache(nullptr);
     setDecodedSize(0);
 }
 
 bool CSSStyleSheetResource::canUseSheet(MIMETypeCheck mimeTypeCheck) const
 {
     if (errorOccurred())
         return false;
 
     // This check exactly matches Firefox. Note that we grab the Content-Type
     // header directly because we want to see what the value is BEFORE content
     // sniffing. Firefox does this by setting a "type hint" on the channel.
     // This implementation should be observationally equivalent.
     //
     // This code defaults to allowing the stylesheet for non-HTTP protocols so
     // folks can use standards mode for local HTML documents.
     if (mimeTypeCheck == MIMETypeCheck::Lax)
         return true;
     AtomicString contentType = httpContentType();
     return contentType.isEmpty() || equalIgnoringCase(contentType, "text/css") || equalIgnoringCase(contentType, "application/x-unknown-content-type");
 }
 
 StyleSheetContents* CSSStyleSheetResource::restoreParsedStyleSheet(const CSSParserContext& context)
 {
     if (!m_parsedStyleSheetCache)
         return nullptr;
     if (m_parsedStyleSheetCache->hasFailedOrCanceledSubresources()) {
-        m_parsedStyleSheetCache->removedFromMemoryCache();
-        m_parsedStyleSheetCache.clear();
+        setParsedStyleSheetCache(nullptr);
         return nullptr;
     }
 
     ASSERT(m_parsedStyleSheetCache->isCacheable());
-    ASSERT(m_parsedStyleSheetCache->isInMemoryCache());
+    ASSERT(m_parsedStyleSheetCache->isReferencedFromResource());
 
     // Contexts must be identical so we know we would get the same exact result if we parsed again.
     if (m_parsedStyleSheetCache->parserContext() != context)
         return nullptr;
 
     didAccessDecodedData();
 
     return m_parsedStyleSheetCache;
 }
 
 void CSSStyleSheetResource::saveParsedStyleSheet(StyleSheetContents* sheet)
 {
     ASSERT(sheet && sheet->isCacheable());
 
-    if (m_parsedStyleSheetCache)
-        m_parsedStyleSheetCache->removedFromMemoryCache();
-    m_parsedStyleSheetCache = sheet;
-
+    setParsedStyleSheetCache(sheet);
     setDecodedSize(m_parsedStyleSheetCache->estimatedSizeInBytes());
-
-    // Check if this stylesheet resource didn't conflict with
-    // another resource and has indeed been added to the cache.
-    if (memoryCache()->contains(this))
-        m_parsedStyleSheetCache->addedToMemoryCache();
 }
 
 } // namespace blink