Page Speed Optimization Libraries  1.5.27.2
net/instaweb/rewriter/public/flush_early_content_writer_filter.h
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00001 /*
00002  * Copyright 2012 Google Inc.
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *      http:///www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00017 
00018 #ifndef NET_INSTAWEB_REWRITER_PUBLIC_FLUSH_EARLY_CONTENT_WRITER_FILTER_H_
00019 #define NET_INSTAWEB_REWRITER_PUBLIC_FLUSH_EARLY_CONTENT_WRITER_FILTER_H_
00020 
00021 #include <list>
00022 
00023 #include "net/instaweb/htmlparse/public/html_writer_filter.h"
00024 #include "net/instaweb/http/public/logging_proto.h"
00025 #include "net/instaweb/http/public/logging_proto_impl.h"
00026 #include "net/instaweb/http/public/semantic_type.h"
00027 #include "net/instaweb/http/public/user_agent_matcher.h"
00028 #include "net/instaweb/util/public/basictypes.h"
00029 #include "net/instaweb/util/public/null_writer.h"
00030 #include "net/instaweb/util/public/scoped_ptr.h"
00031 #include "net/instaweb/util/public/string.h"
00032 #include "net/instaweb/util/public/string_util.h"
00033 
00034 namespace net_instaweb {
00035 
00036 class GoogleUrl;
00037 class HtmlCharactersNode;
00038 class HtmlElement;
00039 class RewriteDriver;
00040 class TimedVariable;
00041 class Writer;
00042 
00043 struct ResourceInfo;
00044 
00049 class FlushEarlyContentWriterFilter : public HtmlWriterFilter {
00050  public:
00051   static const char kPrefetchLinkRelSubresourceHtml[];
00052   static const char kPrefetchImageTagHtml[];
00053   static const char kPrefetchStartTimeScript[];
00054   static const char kNumResourcesFlushedEarly[];
00055   static const char kPrefetchScriptTagHtml[];
00056   static const char kPrefetchLinkTagHtml[];
00057   static const char kInlineCriticalCssLinkTemplate[];
00058   static const char kDisableLinkTag[];
00059 
00060   explicit FlushEarlyContentWriterFilter(RewriteDriver* driver);
00061 
00062   virtual void StartDocument();
00063   virtual void EndDocument();
00064 
00065   virtual void StartElement(HtmlElement* element);
00066   virtual void EndElement(HtmlElement* element);
00067 
00068   virtual void Characters(HtmlCharactersNode* characters_node);
00069 
00070  protected:
00071   virtual void Clear();
00072 
00073  private:
00075   void WriteToOriginalWriter(const GoogleString& in);
00076 
00078   bool IsFlushable(const GoogleUrl& gurl,
00079                    const FlushEarlyResourceInfo::ResourceType& resource_type);
00080 
00082   void FlushResources(
00083       StringPiece url,
00084       int64 time_to_download,
00085       bool is_pagespeed_resource,
00086       semantic_type::Category category);
00087 
00088   void FlushDeferJavascriptEarly();
00089   void UpdateStats(int64 time_to_download, bool is_pagespeed_resource);
00090   GoogleString ComputeFlushEarlyCriticalCss(const GoogleString& style_id);
00091 
00093   FlushEarlyResourceInfo::ResourceType GetResourceType(
00094       const GoogleUrl& gurl, bool is_pagespeed_resource);
00095 
00096   RewriteDriver* driver_;
00097   TimedVariable* num_resources_flushed_early_;
00099   bool in_body_;
00100   bool insert_close_script_;
00101   int num_resources_flushed_;
00102   NullWriter null_writer_;
00103   Writer* original_writer_;
00104   HtmlElement* current_element_;
00105   UserAgentMatcher::PrefetchMechanism prefetch_mechanism_;
00106   scoped_ptr<StringSet> private_cacheable_resources_;
00107   scoped_ptr<StringSet> public_cacheable_resources_;
00108   int64 time_consumed_ms_;
00109   int64 max_available_time_ms_;
00110   typedef std::list<ResourceInfo*> ResourceInfoList;
00111   ResourceInfoList js_resources_info_;
00112   bool defer_javascript_enabled_;
00113   bool split_html_enabled_;
00114   bool is_flushing_critical_style_element_;
00115   GoogleString css_output_content_;
00116   GoogleString flush_early_content_;
00117   bool flush_more_resources_early_if_time_permits_;
00118 
00119   DISALLOW_COPY_AND_ASSIGN(FlushEarlyContentWriterFilter);
00120 };
00121 
00122 }  
00123 
00124 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_FLUSH_EARLY_CONTENT_WRITER_FILTER_H_
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