critical_selector_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_SELECTOR_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_CRITICAL_SELECTOR_FILTER_H_

#include <vector>

#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/html/html_node.h"
#include "pagespeed/kernel/http/semantic_type.h"

namespace Css {

class Stylesheet;

}  

namespace net_instaweb {

class CriticalSelectorFilter : public CssSummarizerBase {
 public:
  static const char kAddStylesFunction[];
  static const char kAddStylesInvocation[];
  static const char kNoscriptStylesClass[];

  explicit CriticalSelectorFilter(RewriteDriver* rewrite_driver);
  virtual ~CriticalSelectorFilter();

  virtual const char* Name() const { return "CriticalSelectorFilter"; }
  virtual const char* id() const { return "cl"; }

  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:
  void Summarize(Css::Stylesheet* stylesheet,
                 GoogleString* out) const override;
  void RenderSummary(int pos,
                     HtmlElement* element,
                     HtmlCharactersNode* char_node,
                     bool* is_element_deleted) override;
  void WillNotRenderSummary(int pos,
                            HtmlElement* element,
                            HtmlCharactersNode* char_node) override;

  virtual GoogleString CacheKeySuffix() const;

  virtual void StartDocumentImpl();
  virtual void EndDocument();
  virtual void RenderDone();

  virtual void DetermineEnabled(GoogleString* disabled_reason);

 private:
  class CssElement;
  class CssStyleElement;
  typedef std::vector<CssElement*> CssElementVector;

  void RememberFullCss(int pos,
                       HtmlElement* element,
                       HtmlCharactersNode* char_node);

  StringSet critical_selectors_;

  GoogleString cache_key_suffix_;

  CssElementVector css_elements_;

  bool saw_end_document_;

  bool any_rendered_;

  bool is_flush_script_added_;

  
};

}  

#endif