add_instrumentation_filter.h

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/*
 * Copyright 2010 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_ADD_INSTRUMENTATION_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_ADD_INSTRUMENTATION_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"

namespace net_instaweb {

class Statistics;
class Variable;

class AddInstrumentationFilter : public CommonFilter {
 public:
  static const char kLoadTag[];
  static const char kUnloadTag[];
  static GoogleString* kUnloadScriptFormatXhtml;
  static GoogleString* kTailScriptFormatXhtml;

  static const char kInstrumentationScriptAddedCount[];

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

  static void InitStats(Statistics* statistics);

  virtual void StartDocumentImpl();
  virtual void EndDocument();
  virtual void StartElementImpl(HtmlElement* element);
  virtual void EndElementImpl(HtmlElement* element);
  virtual const char* Name() const { return "AddInstrumentation"; }

  ScriptUsage GetScriptUsage() const override { return kWillInjectScripts; }

 protected:
  virtual void DetermineEnabled(GoogleString* disabled_reason);

  Variable* instrumentation_script_added_count_;

 private:
  GoogleString GetScriptJs(StringPiece event);

  void AddHeadScript(HtmlElement* element);

  bool found_head_;
  bool added_head_script_;
  bool added_unload_script_;

  
};

}  

#endif