critical_css_beacon_filter.h

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/*
 * Copyright 2013 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.
 */


#ifndef NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_CSS_BEACON_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_CSS_BEACON_FILTER_H_

#include "net/instaweb/rewriter/public/critical_finder_support_util.h"
#include "net/instaweb/rewriter/public/css_summarizer_base.h"
#include "net/instaweb/rewriter/public/rewrite_driver.h"
#include "net/instaweb/rewriter/public/rewrite_options.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/html/html_element.h"
#include "pagespeed/kernel/html/html_filter.h"
#include "pagespeed/kernel/http/semantic_type.h"

namespace Css {

class Ruleset;
class Stylesheet;

}  

namespace net_instaweb {

class Statistics;
class Variable;

class CriticalCssBeaconFilter : public CssSummarizerBase {
 public:
  static const char kInitializePageSpeedJs[];

  static const char kCriticalCssBeaconAddedCount[];
  static const char kCriticalCssNoBeaconDueToMissingData[];
  static const char kCriticalCssSkippedDueToCharset[];

  explicit CriticalCssBeaconFilter(RewriteDriver* driver);
  virtual ~CriticalCssBeaconFilter();

  static void InitStats(Statistics* statistics);

  virtual const char* Name() const { return "CriticalCssBeacon"; }
  virtual const char* id() const { return "cb"; }

  virtual RewriteDriver::InlineAuthorizationPolicy AllowUnauthorizedDomain()
      const {
    return driver()->options()->HasInlineUnauthorizedResourceType(
               semantic_type::kStylesheet) ?
           RewriteDriver::kInlineUnauthorizedResources :
           RewriteDriver::kInlineOnlyAuthorizedResources;
  }

  virtual bool IntendedForInlining() const { return true; }
  ScriptUsage GetScriptUsage() const override { return kWillInjectScripts; }

 protected:
  virtual bool MustSummarize(HtmlElement* element) const;
  virtual void Summarize(Css::Stylesheet* stylesheet,
                         GoogleString* out) const;
  virtual void SummariesDone();

  virtual void DetermineEnabled(GoogleString* disabled_reason);

 private:
  static void FindSelectorsFromRuleset(const Css::Ruleset& ruleset,
                                       StringSet* selectors);
  static void FindSelectorsFromStylesheet(const Css::Stylesheet& css,
                                          StringSet* selectors);

  void AppendSelectorsInitJs(GoogleString* script, const StringSet& selectors);

  void AppendBeaconInitJs(const BeaconMetadata& metadata, GoogleString* script);

  Variable* critical_css_beacon_added_count_;
  Variable* critical_css_no_beacon_due_to_missing_data_;
  Variable* critical_css_skipped_due_to_charset_;

  
};

}  

#endif