Refactor the API for setting dynamic resource load priorities

third_party/WebKit/Source/core/fetch/ResourceFetcher.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) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     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 68 matching lines @@
     case Resource::Image:
     case Resource::LinkPrefetch:
     case Resource::LinkPreload:
         return ResourceLoadPriorityVeryLow;
     }
 
     ASSERT_NOT_REACHED();
     return ResourceLoadPriorityUnresolved;
 }
 
-ResourceLoadPriority ResourceFetcher::loadPriority(Resource::Type type, const FetchRequest& request)
+ResourceLoadPriority ResourceFetcher::loadPriority(Resource::Type type, const FetchRequest& request, ResourcePriority::VisibilityStatus visibility)
 {
     // TODO(yoav): Change it here so that priority can be changed even after it was resolved.
     if (request.priority() != ResourceLoadPriorityUnresolved)
         return request.priority();
 
     // Synchronous requests should always be max priority, lest they hang the renderer.
     if (request.options().synchronousPolicy == RequestSynchronously)
         return ResourceLoadPriorityHighest;
 
-    return context().modifyPriorityForExperiments(typeToPriority(type), type, request);
+    return context().modifyPriorityForExperiments(typeToPriority(type), type, request, visibility);
 }
 
 static void populateResourceTiming(ResourceTimingInfo* info, Resource* resource, bool clearLoadTimings)
 {
     info->setInitialRequest(resource->resourceRequest());
     info->setFinalResponse(resource->response());
     if (clearLoadTimings) {
         info->clearLoadTimings();
         info->setLoadFinishTime(info->initialTime());
     } else {
@@ skipping 255 matching lines @@
         return nullptr;
     }
 
     if (!resource->hasClients())
         m_deadStatsRecorder.update(policy);
 
     if (policy != Use)
         resource->setIdentifier(createUniqueIdentifier());
 
     if (!request.forPreload() || policy != Use) {
-        ResourceLoadPriority priority = loadPriority(factory.type(), request);
+        ResourceLoadPriority priority = loadPriority(factory.type(), request, ResourcePriority::NotVisible);
         // When issuing another request for a resource that is already in-flight make
         // sure to not demote the priority of the in-flight request. If the new request
         // isn't at the same priority as the in-flight request, only allow promotions.
         // This can happen when a visible image's priority is increased and then another
         // reference to the image is parsed (which would be at a lower priority).
-        if (priority > resource->resourceRequest().priority()) {
-            resource->mutableResourceRequest().setPriority(priority);
+        if (priority > resource->resourceRequest().priority())
             resource->didChangePriority(priority, 0);
-        }
     }
 
     if (resourceNeedsLoad(resource.get(), request, policy)) {
         if (!context().shouldLoadNewResource(factory.type())) {
             if (memoryCache()->contains(resource.get()))
                 memoryCache()->remove(resource.get());
             return nullptr;
         }
 
         if (!scheduleArchiveLoad(resource.get(), request.resourceRequest()))
@@ skipping 454 matching lines @@
             m_resourceTimingInfoMap.remove(it);
             populateResourceTiming(info.get(), resource, false);
             if (resource->options().requestInitiatorContext == DocumentContext)
                 context().addResourceTiming(*info);
             resource->reportResourceTimingToClients(*info);
         }
     }
     context().dispatchDidFinishLoading(resource->identifier(), finishTime, encodedDataLength);
 }
 
-void ResourceFetcher::didChangeLoadingPriority(const Resource* resource, ResourceLoadPriority loadPriority, int intraPriorityValue)
-{
-    TRACE_EVENT_ASYNC_STEP_INTO1("blink.net", "Resource", resource, "ChangePriority", "priority", loadPriority);
-    context().dispatchDidChangeResourcePriority(resource->identifier(), loadPriority, intraPriorityValue);
-}
-
 void ResourceFetcher::didFailLoading(const Resource* resource, const ResourceError& error)
 {
     TRACE_EVENT_ASYNC_END0("blink.net", "Resource", resource);
     willTerminateResourceLoader(resource->loader());
     bool isInternalRequest = resource->options().initiatorInfo.name == FetchInitiatorTypeNames::internal;
     context().dispatchDidFail(resource->identifier(), error, isInternalRequest);
 }
 
 void ResourceFetcher::willSendRequest(unsigned long identifier, ResourceRequest& request, const ResourceResponse& redirectResponse, const FetchInitiatorInfo& initiatorInfo)
 {
@@ skipping 117 matching lines @@
             resource->setCORSFailed();
             context().addConsoleMessage(errorMessage);
             return false;
         }
     }
     if (resource->type() == Resource::Image && shouldDeferImageLoad(newRequest.url()))
         return false;
     return true;
 }
 
+void ResourceFetcher::updateAllImageResourcePriorities()
+{
+    if (!m_loaders)
+        return;
+
+    TRACE_EVENT0("blink", "ResourceLoadPriorityOptimizer::updateAllImageResourcePriorities");
+    for (const auto& loader : m_loaders->hashSet()) {

[Nate Chapin, 2015/10/07 19:40:40]

This feels a little hacky, but it's the cleanest way to get the Resources loaded
by this ResourceFetcher that are currently loading. It omits mjpeg images (which
are in m_nonBlockingLoaders after the first payload http response), which should
probably be handled separately for prioritization, because of their long-running
nature.

+        Resource* resource = loader->cachedResource();
+        if (!resource->isImage())
+            continue;
+
+        ResourcePriority resourcePriority = resource->priorityFromClients();
+        ResourceLoadPriority resourceLoadPriority = loadPriority(Resource::Image, FetchRequest(resource->resourceRequest(), FetchInitiatorInfo()), resourcePriority.visibility);
+        if (resourceLoadPriority == resource->resourceRequest().priority())
+            continue;
+
+        resource->didChangePriority(resourceLoadPriority, resourcePriority.intraPriorityValue);
+        TRACE_EVENT_ASYNC_STEP_INTO1("blink.net", "Resource", resource, "ChangePriority", "priority", resourceLoadPriority);
+        context().dispatchDidChangeResourcePriority(resource->identifier(), resourceLoadPriority, resourcePriority.intraPriorityValue);
+    }
+}
+
 #if PRELOAD_DEBUG
 void ResourceFetcher::printPreloadStats()
 {
     if (!m_preloads)
         return;
 
     unsigned scripts = 0;
     unsigned scriptMisses = 0;
     unsigned stylesheets = 0;
     unsigned stylesheetMisses = 0;
@@ skipping 89 matching lines @@
     visitor->trace(m_archiveResourceCollection);
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
 #if ENABLE(OILPAN)
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 #endif
 }
 
 }