| /* |
| * Copyright 2012 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| // Author: jud@google.com (Jud Porter) |
| |
| #ifndef NET_INSTAWEB_REWRITER_PUBLIC_BEACON_CRITICAL_IMAGES_FINDER_H_ |
| #define NET_INSTAWEB_REWRITER_PUBLIC_BEACON_CRITICAL_IMAGES_FINDER_H_ |
| |
| #include "net/instaweb/rewriter/public/critical_finder_support_util.h" |
| #include "net/instaweb/rewriter/public/critical_images_finder.h" |
| #include "net/instaweb/util/public/property_cache.h" |
| #include "pagespeed/kernel/base/string.h" |
| #include "pagespeed/kernel/base/string_util.h" |
| |
| namespace net_instaweb { |
| |
| class NonceGenerator; |
| class RenderedImages; |
| class RewriteDriver; |
| class Statistics; |
| class Timer; |
| |
| // Support critical (above the fold) image detection through a javascript beacon |
| // on the client. |
| class BeaconCriticalImagesFinder : public CriticalImagesFinder { |
| public: |
| // All constructor args are owned by the caller. |
| BeaconCriticalImagesFinder( |
| const PropertyCache::Cohort* cohort, |
| NonceGenerator* nonce_generator, |
| Statistics* stats); |
| virtual ~BeaconCriticalImagesFinder(); |
| |
| virtual Availability Available(RewriteDriver* driver); |
| |
| virtual int PercentSeenForCritical() const { |
| return kBeaconPercentSeenForCritical; |
| } |
| |
| virtual int SupportInterval() const { |
| return kBeaconImageSupportInterval; |
| } |
| |
| virtual void ComputeCriticalImages(RewriteDriver* driver) {} |
| |
| // Update the critical image entry in the property cache. This is meant to be |
| // called in the beacon handler, where there is no RewriteDriver available. |
| static bool UpdateCriticalImagesCacheEntry( |
| const StringSet* html_critical_images_set, |
| const StringSet* css_critical_images_set, |
| const RenderedImages* rendered_images_set, |
| const StringPiece& nonce, |
| const PropertyCache::Cohort* cohort, |
| AbstractPropertyPage* page, |
| Timer* timer); |
| |
| virtual bool ShouldBeacon(RewriteDriver* driver); |
| // Check beacon interval and nonce state, and return appropriate |
| // BeaconMetadata; result.status indicates whether beaconing should occur, and |
| // result.nonce contains the nonce (if required). |
| virtual BeaconMetadata PrepareForBeaconInsertion(RewriteDriver* driver); |
| |
| virtual void UpdateCandidateImagesForBeaconing(const StringSet& images, |
| RewriteDriver* driver, |
| bool beaconing); |
| |
| private: |
| virtual GoogleString GetKeyForUrl(StringPiece url); |
| |
| // 80% is a guess at a reasonable value for this param. |
| static const int kBeaconPercentSeenForCritical = 80; |
| // This is a guess for how many samples we need to get stable data. |
| static const int kBeaconImageSupportInterval = 10; |
| |
| NonceGenerator* nonce_generator_; |
| }; |
| |
| } // namespace net_instaweb |
| |
| #endif // NET_INSTAWEB_REWRITER_PUBLIC_BEACON_CRITICAL_IMAGES_FINDER_H_ |