Page Speed Optimization Libraries  1.7.30.2
net/instaweb/rewriter/public/insert_dns_prefetch_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_INSERT_DNS_PREFETCH_FILTER_H_
00019 #define NET_INSTAWEB_REWRITER_PUBLIC_INSERT_DNS_PREFETCH_FILTER_H_
00020 
00021 #include "net/instaweb/htmlparse/public/html_element.h"
00022 #include "net/instaweb/rewriter/public/common_filter.h"
00023 #include "net/instaweb/util/public/basictypes.h"
00024 #include "net/instaweb/util/public/string_util.h"  
00025 
00026 namespace net_instaweb {
00027 
00028 class FlushEarlyInfo;
00029 class RewriteDriver;
00030 
00033 class InsertDnsPrefetchFilter : public CommonFilter {
00034  public:
00035   explicit InsertDnsPrefetchFilter(RewriteDriver* driver);
00036   virtual ~InsertDnsPrefetchFilter();
00037 
00038   virtual void StartDocumentImpl();
00039   virtual void EndDocument();
00040   virtual void StartElementImpl(HtmlElement* element);
00041   virtual void EndElementImpl(HtmlElement* element);
00042 
00043   virtual const char* Name() const { return "InsertDnsPrefetchFilter"; }
00046   virtual void DetermineEnabled();
00047   virtual const char* id() const { return "idp"; }
00048 
00049  private:
00050   void Clear();
00051 
00054   void MarkAlreadyInHead(HtmlElement::Attribute* urlattr);
00055 
00059   bool IsDomainListStable(const FlushEarlyInfo& flush_early_info) const;
00060   void DebugPrint(const char* msg);
00061 
00064   bool dns_prefetch_inserted_;
00065 
00067   bool in_head_;
00068 
00071   StringSet domains_to_ignore_;
00072 
00075   StringSet domains_in_body_;
00076 
00079   StringVector dns_prefetch_domains_;
00080 
00082   bool user_agent_supports_dns_prefetch_;
00083 
00084   DISALLOW_COPY_AND_ASSIGN(InsertDnsPrefetchFilter);
00085 };
00086 
00087 }  
00088 
00089 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_INSERT_DNS_PREFETCH_FILTER_H_
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