Page Speed Optimization Libraries  1.8.31.3
net/instaweb/rewriter/public/critical_images_beacon_filter.h
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00001 /*
00002  * Copyright 2013 Google Inc.
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *      http:///www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00018 
00019 #ifndef NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_IMAGES_BEACON_FILTER_H_
00020 #define NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_IMAGES_BEACON_FILTER_H_
00021 
00022 #include "net/instaweb/rewriter/public/common_filter.h"
00023 #include "net/instaweb/rewriter/public/critical_finder_support_util.h"
00024 #include "net/instaweb/util/public/basictypes.h"
00025 #include "pagespeed/kernel/base/string_util.h"
00026 
00027 namespace net_instaweb {
00028 
00029 class HtmlElement;
00030 class RewriteDriver;
00031 class Statistics;
00032 class Variable;
00033 
00038 class CriticalImagesBeaconFilter : public CommonFilter {
00039  public:
00040   static const char* kImageOnloadCode;
00042   static const char kCriticalImagesBeaconAddedCount[];
00043 
00044   explicit CriticalImagesBeaconFilter(RewriteDriver* driver);
00045   virtual ~CriticalImagesBeaconFilter();
00046 
00047   virtual void DetermineEnabled();
00048 
00049   static void InitStats(Statistics* statistics);
00050 
00051   virtual void StartDocumentImpl() { }
00052   virtual void EndDocument();
00053   virtual void StartElementImpl(HtmlElement* element) { }
00054   virtual void EndElementImpl(HtmlElement* element);
00055   virtual const char* Name() const { return "CriticalImagesBeacon"; }
00056 
00060   static bool ShouldApply(RewriteDriver* rewrite_driver);
00061 
00062  private:
00064   void Clear();
00065 
00068   void MaybeAddBeaconJavascript(HtmlElement* element);
00069 
00070   BeaconMetadata beacon_metadata_;
00071   StringSet image_url_hashes_;
00072   bool insert_beacon_js_;
00074   Variable* critical_images_beacon_added_count_;
00075 
00076   bool added_beacon_js_;
00077 
00078   DISALLOW_COPY_AND_ASSIGN(CriticalImagesBeaconFilter);
00079 };
00080 
00081 }  
00082 
00083 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_IMAGES_BEACON_FILTER_H_
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