Page Speed Optimization Libraries  1.8.31.3
net/instaweb/rewriter/public/css_combine_filter.h
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00001 /*
00002  * Copyright 2010 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  */
00016 
00018 
00019 #ifndef NET_INSTAWEB_REWRITER_PUBLIC_CSS_COMBINE_FILTER_H_
00020 #define NET_INSTAWEB_REWRITER_PUBLIC_CSS_COMBINE_FILTER_H_
00021 
00022 #include "net/instaweb/rewriter/public/css_tag_scanner.h"
00023 #include "net/instaweb/rewriter/public/rewrite_filter.h"
00024 #include "net/instaweb/rewriter/public/rewrite_options.h"
00025 #include "net/instaweb/util/public/basictypes.h"
00026 #include "net/instaweb/util/public/scoped_ptr.h"
00027 #include "net/instaweb/util/public/string_util.h"
00028 #include "net/instaweb/util/public/url_multipart_encoder.h"
00029 
00030 namespace net_instaweb {
00031 
00032 class HtmlElement;
00033 class HtmlIEDirectiveNode;
00034 class RewriteContext;
00035 class RewriteDriver;
00036 class Statistics;
00037 class UrlSegmentEncoder;
00038 class Variable;
00039 
00040 class CssCombineFilter : public RewriteFilter {
00041  public:
00045   static const char kCssCombineOpportunities[];
00047   static const char kCssFileCountReduction[];
00048 
00049   explicit CssCombineFilter(RewriteDriver* rewrite_driver);
00050   virtual ~CssCombineFilter();
00051 
00052   static void InitStats(Statistics* statistics);
00053 
00054   virtual void StartDocumentImpl();
00055   virtual void EndDocument();
00056   virtual void StartElementImpl(HtmlElement* element);
00057   virtual void EndElementImpl(HtmlElement* element) {}
00058   virtual void Flush();
00059   virtual void DetermineEnabled();
00060   virtual void IEDirective(HtmlIEDirectiveNode* directive);
00061   virtual const char* Name() const { return "CssCombine"; }
00062   virtual const UrlSegmentEncoder* encoder() const {
00063     return &multipart_encoder_;
00064   }
00065 
00066   virtual RewriteContext* MakeRewriteContext();
00067   virtual const char* id() const { return RewriteOptions::kCssCombinerId; }
00068 
00069  private:
00070   class Context;
00071   class CssCombiner;
00072 
00073   CssCombiner* combiner();
00074   void NextCombination(StringPiece debug_help);
00075   Context* MakeContext();
00076 
00077   CssTagScanner css_tag_scanner_;
00078   scoped_ptr<Context> context_;
00079   UrlMultipartEncoder multipart_encoder_;
00080   bool end_document_found_;
00081   int css_links_; 
00082 
00083   Variable* css_combine_opportunities_;
00084 
00085   DISALLOW_COPY_AND_ASSIGN(CssCombineFilter);
00086 };
00087 
00088 }  
00089 
00090 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CSS_COMBINE_FILTER_H_
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