Remove resource type-specific fetching logic from ResourceFetcher

Source/core/html/parser/HTMLResourcePreloader.cpp

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 #include "config.h"
 #include "core/html/parser/HTMLResourcePreloader.h"
 
 #include "core/dom/Document.h"
+#include "core/fetch/CSSStyleSheetResource.h"
 #include "core/fetch/FetchInitiatorInfo.h"
+#include "core/fetch/ImageResource.h"
 #include "core/fetch/ResourceFetcher.h"
+#include "core/fetch/ScriptResource.h"
 #include "platform/network/NetworkHints.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 inline HTMLResourcePreloader::HTMLResourcePreloader(Document& document)
     : m_document(document)
 {
 }
 
@@ skipping 23 matching lines @@
     }
     preconnect(host, crossOrigin);
 }
 
 void HTMLResourcePreloader::preload(PassOwnPtr<PreloadRequest> preload)
 {
     if (preload->isPreconnect()) {
         preconnectHost(preload.get());
         return;
     }
+

[Yoav Weiss, 2015/06/08 06:44:18]

Can't say that I like adding all that resource type specific logic here... Is it
possible to abstract is away somewhere in fetch? (e.g. maybe move it out of
ResourceFetcher into a "ResourceTypeHandler")

[Nate Chapin, 2015/06/08 19:01:22]

For this patch by itself, yes. However, for the proposed followup of moving
Resource subclasses out of fetch/, ResourceTypeHandler would need to not be in
fetch in order to call ImageResource::fetch().

I think I'm missing a bit of context. HTMLPreloadScanner is well aware of
Resource types, is there a particular reason HTMLResourcePreloader shouldn't be?

+    // Ensure main resources aren't preloaded, since the cache can't actually reuse the preload.
+    if (preload->resourceType() == Resource::MainResource)

[Yoav Weiss, 2015/06/08 06:44:17]

Is there a scenario where we preload a main resource?

[Nate Chapin, 2015/06/08 19:01:22]

I think there was hope a year or two ago that we would be able to preload a main
resource, but I don't think it ever got fully hooked up (and we never really got
MemoryCache to support main resource). Will remove.

+        return;
+    ASSERT(preload->resourceType() == Resource::Script || preload->resourceType() == Resource::CSSStyleSheet || preload->resourceType() == Resource::Image);
+
     FetchRequest request = preload->resourceRequest(m_document);
+    if (preload->resourceType() == Resource::Script || preload->resourceType() == Resource::CSSStyleSheet)
+        request.setCharset(preload->charset().isEmpty() ? m_document->charset().string() : preload->charset());
+    request.setForPreload(true);
     Platform::current()->histogramCustomCounts("WebCore.PreloadDelayMs", static_cast<int>(1000 * (monotonicallyIncreasingTime() - preload->discoveryTime())), 0, 2000, 20);
-    m_document->fetcher()->preload(preload->resourceType(), request, preload->charset());
+
+    ResourcePtr<Resource> resource;
+    if (preload->resourceType() == Resource::Image)
+        resource = ImageResource::fetch(request, m_document->fetcher());
+    else if (preload->resourceType() == Resource::Script)
+        resource = ScriptResource::fetch(request, m_document->fetcher());
+    else
+        resource = CSSStyleSheetResource::fetch(request, m_document->fetcher());
+
+    if (resource)
+        m_document->fetcher()->preloadStarted(resource.get());
 }
 
 } // namespace blink