Page Speed Optimization Libraries  1.5.27.2
net/instaweb/rewriter/public/critical_css_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_CSS_BEACON_FILTER_H_
00020 #define NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_CSS_BEACON_FILTER_H_
00021 
00022 #include "net/instaweb/rewriter/public/css_summarizer_base.h"
00023 #include "net/instaweb/util/public/basictypes.h"
00024 #include "net/instaweb/util/public/string.h"
00025 #include "net/instaweb/util/public/string_util.h"
00026 
00027 namespace Css {
00028 
00029 class Ruleset;
00030 class Stylesheet;
00031 
00032 }  
00033 
00034 namespace net_instaweb {
00035 
00036 class HtmlElement;
00037 class RewriteDriver;
00038 class Statistics;
00039 class Variable;
00040 
00046 class CriticalCssBeaconFilter : public CssSummarizerBase {
00047  public:
00049   static const char kCriticalCssBeaconAddedCount[];
00050   static const char kCriticalCssNoBeaconDueToMissingData[];
00051   static const char kCriticalCssSkippedDueToCharset[];
00052 
00053   explicit CriticalCssBeaconFilter(RewriteDriver* driver);
00054   virtual ~CriticalCssBeaconFilter();
00055 
00056   static void InitStats(Statistics* statistics);
00057 
00058   virtual const char* Name() const { return "CriticalCssBeacon"; }
00059   virtual const char* id() const { return "cb"; }
00060 
00061  protected:
00062   virtual bool MustSummarize(HtmlElement* element) const;
00063   virtual void Summarize(Css::Stylesheet* stylesheet,
00064                          GoogleString* out) const;
00065   virtual void SummariesDone();
00066 
00067   virtual void DetermineEnabled();
00068 
00069  private:
00070   static void FindSelectorsFromRuleset(const Css::Ruleset& ruleset,
00071                                        StringSet* selectors);
00073   static void FindSelectorsFromStylesheet(const Css::Stylesheet& css,
00074                                           StringSet* selectors);
00075 
00078   GoogleString BeaconBoilerplate();
00079 
00081   Variable* critical_css_beacon_added_count_;
00084   Variable* critical_css_no_beacon_due_to_missing_data_;
00087   Variable* critical_css_skipped_due_to_charset_;
00088 
00089   DISALLOW_COPY_AND_ASSIGN(CriticalCssBeaconFilter);
00090 };
00091 
00092 }  
00093 
00094 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_CSS_BEACON_FILTER_H_
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