Page Speed Optimization Libraries  1.8.31.2
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/http/public/semantic_type.h"
00023 #include "net/instaweb/rewriter/public/css_summarizer_base.h"
00024 #include "net/instaweb/rewriter/public/rewrite_driver.h"
00025 #include "net/instaweb/rewriter/public/rewrite_options.h"
00026 #include "net/instaweb/util/public/basictypes.h"
00027 #include "net/instaweb/util/public/string.h"
00028 #include "net/instaweb/util/public/string_util.h"
00029 
00030 namespace Css {
00031 
00032 class Ruleset;
00033 class Stylesheet;
00034 
00035 }  
00036 
00037 namespace net_instaweb {
00038 
00039 struct BeaconMetadata;
00040 class HtmlElement;
00041 class Statistics;
00042 class Variable;
00043 
00049 class CriticalCssBeaconFilter : public CssSummarizerBase {
00050  public:
00051   static const char kInitializePageSpeedJs[];
00052 
00054   static const char kCriticalCssBeaconAddedCount[];
00055   static const char kCriticalCssNoBeaconDueToMissingData[];
00056   static const char kCriticalCssSkippedDueToCharset[];
00057 
00058   explicit CriticalCssBeaconFilter(RewriteDriver* driver);
00059   virtual ~CriticalCssBeaconFilter();
00060 
00061   static void InitStats(Statistics* statistics);
00062 
00063   virtual const char* Name() const { return "CriticalCssBeacon"; }
00064   virtual const char* id() const { return "cb"; }
00065 
00070   virtual RewriteDriver::InlineAuthorizationPolicy AllowUnauthorizedDomain()
00071       const {
00072     return driver()->options()->HasInlineUnauthorizedResourceType(
00073                semantic_type::kStylesheet) ?
00074            RewriteDriver::kInlineUnauthorizedResources :
00075            RewriteDriver::kInlineOnlyAuthorizedResources;
00076   }
00077 
00079   virtual bool IntendedForInlining() const { return true; }
00080 
00081  protected:
00082   virtual bool MustSummarize(HtmlElement* element) const;
00083   virtual void Summarize(Css::Stylesheet* stylesheet,
00084                          GoogleString* out) const;
00085   virtual void SummariesDone();
00086 
00087   virtual void DetermineEnabled();
00088 
00089  private:
00090   static void FindSelectorsFromRuleset(const Css::Ruleset& ruleset,
00091                                        StringSet* selectors);
00093   static void FindSelectorsFromStylesheet(const Css::Stylesheet& css,
00094                                           StringSet* selectors);
00095 
00097   void AppendSelectorsInitJs(GoogleString* script, const StringSet& selectors);
00098 
00100   void AppendBeaconInitJs(const BeaconMetadata& metadata, GoogleString* script);
00101 
00103   Variable* critical_css_beacon_added_count_;
00106   Variable* critical_css_no_beacon_due_to_missing_data_;
00109   Variable* critical_css_skipped_due_to_charset_;
00110 
00111   DISALLOW_COPY_AND_ASSIGN(CriticalCssBeaconFilter);
00112 };
00113 
00114 }  
00115 
00116 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_CSS_BEACON_FILTER_H_
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