insert_ga_filter.h

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/*
 * Copyright 2011 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_INSERT_GA_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_INSERT_GA_FILTER_H_

#include "net/instaweb/rewriter/public/common_filter.h"
#include "net/instaweb/rewriter/public/rewrite_driver.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/html/html_node.h"

namespace net_instaweb {

class Statistics;
class Variable;

extern const char kGAExperimentSnippet[];
extern const char kGAJsSnippet[];
extern const char kAnalyticsJsSnippet[];
extern const char kAnalyticsJsIncreaseSiteSpeedTracking[];
extern const char kAnalyticsJsIncreaseSiteSpeedTrackingMinimal[];
extern const char kContentExperimentsJsClientUrl[];
extern const char kContentExperimentsNonNumericVariantComment[];
extern const char kContentExperimentsSetChosenVariationSnippet[];
extern const char kContentExperimentsSetExpAndVariantSnippet[];
extern const char kGASpeedTracking[];

class InsertGAFilter : public CommonFilter {
 public:
  explicit InsertGAFilter(RewriteDriver* rewrite_driver);
  virtual ~InsertGAFilter();

  static void InitStats(Statistics* stats);

  virtual void StartDocumentImpl();
  virtual void StartElementImpl(HtmlElement* element);
  virtual void EndElementImpl(HtmlElement* element);
  virtual void Characters(HtmlCharactersNode* characters);

  virtual const char* Name() const { return "InsertGASnippet"; }
  ScriptUsage GetScriptUsage() const override { return kWillInjectScripts; }

 private:
  enum AnalyticsStatus {
    kGaJs,                  
    kAnalyticsJs,           
    kNoSnippetFound,        
    kUnusableSnippetFound,  
  };

  enum ParseState {
    kInitial,
    kGotGa,
    kGotGaFuncCall,
    kGotGaCreate,
    kGotGaSend,
    kGotGaCreateComma,
    kGotFieldsObject,
    kGotGaSendComma,
    kGotGaSendPageview,
    kSuccess
  };

  GoogleString ConstructExperimentSnippet() const;

  virtual void EndDocument();

  void HandleEndScript(HtmlElement* script);

  void RewriteInlineScript(HtmlCharactersNode* characters);

  AnalyticsStatus FindSnippetInScript(const GoogleString& s);

  GoogleString AnalyticsJsExperimentSnippet() const;
  GoogleString GaJsExperimentSnippet() const;

  bool ShouldInsertExperimentTracking(bool analytics_js);

  bool StringLiteralMatches(StringPiece literal, StringPiece desired);
  bool StringLiteralEndsWith(StringPiece literal, StringPiece desired);

  Variable* inserted_ga_snippets_count_;

  HtmlElement* script_element_;
  bool added_analytics_js_;
  bool added_experiment_snippet_;

  GoogleString ga_id_;

  bool found_snippet_;

  bool increase_speed_tracking_;

  bool seen_sync_ga_js_;

  GoogleString postponed_script_body_;

  
};

}  

#endif