google_analytics_filter.h

Go to the documentation of this file.

/*
 * 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_GOOGLE_ANALYTICS_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_GOOGLE_ANALYTICS_FILTER_H_

#include <vector>

#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/scoped_ptr.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/html/empty_html_filter.h"
#include "pagespeed/kernel/html/html_filter.h"

namespace net_instaweb {
class HtmlCdataNode;
class HtmlCharactersNode;
class HtmlCommentNode;
class HtmlElement;
class HtmlIEDirectiveNode;
class HtmlParse;
class Statistics;
class Variable;


class ScriptEditor {
 public:
  enum Type {
    kGaJsScriptSrcLoad = 0,
    kGaJsDocWriteLoad,
    kGaJsInit,
  };
  ScriptEditor(HtmlElement* script_element_,
               HtmlCharactersNode* characters_node,
               GoogleString::size_type pos,
               GoogleString::size_type len,
               Type editor_type);

  HtmlElement* GetScriptElement() const { return script_element_; }
  HtmlCharactersNode* GetScriptCharactersNode() const {
    return script_characters_node_;
  }
  Type GetType() const { return editor_type_; }

  void NewContents(const StringPiece &replacement,
                   GoogleString* contents) const;

 private:
  HtmlElement* script_element_;
  HtmlCharactersNode* script_characters_node_;

  GoogleString::size_type pos_;
  GoogleString::size_type len_;

  Type editor_type_;
  
};


class GoogleAnalyticsFilter : public EmptyHtmlFilter {
 public:
  typedef StringPieceVector MethodVector;

  explicit GoogleAnalyticsFilter(HtmlParse* html_parse,
                                 Statistics* statistics);
  virtual ~GoogleAnalyticsFilter();

  explicit GoogleAnalyticsFilter(HtmlParse* html_parse,
                                 Statistics* statistics,
                                 MethodVector* glue_methods,
                                 MethodVector* unhandled_methods);

  static void InitStats(Statistics* statistics);

  virtual void StartDocument();
  virtual void EndDocument();
  virtual void StartElement(HtmlElement* element);
  virtual void EndElement(HtmlElement* element);

  virtual void Flush();

  virtual void Characters(HtmlCharactersNode* characters_node);

  virtual void Comment(HtmlCommentNode* comment);
  virtual void Cdata(HtmlCdataNode* cdata);
  virtual void IEDirective(HtmlIEDirectiveNode* directive);

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

  static const char kPageLoadCount[];
  static const char kRewrittenCount[];

 private:
  void ResetFilter();

  bool MatchSyncLoad(StringPiece contents,
                     GoogleString::size_type* pos,
                     GoogleString::size_type* len) const;
  bool MatchSyncInit(StringPiece contents,
                     GoogleString::size_type start_pos,
                     GoogleString::size_type* pos,
                     GoogleString::size_type* len) const;
  bool MatchUnhandledCalls(StringPiece contents,
                           GoogleString::size_type start_pos) const;
  void FindRewritableScripts();
  void GetSyncToAsyncScript(GoogleString* buffer) const;
  bool RewriteAsAsync();

  bool is_load_found_;
  bool is_init_found_;
  std::vector<ScriptEditor*> script_editors_;

  scoped_ptr<MethodVector> glue_methods_; 
  scoped_ptr<MethodVector> unhandled_methods_; 

  HtmlParse* html_parse_;
  HtmlElement* script_element_; 
  HtmlCharactersNode* script_characters_node_; 

  Variable* page_load_count_;
  Variable* rewritten_count_;

  
};

}  

#endif