Page Speed Optimization Libraries  1.7.30.3
net/instaweb/rewriter/public/cache_extender.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_CACHE_EXTENDER_H_
00020 #define NET_INSTAWEB_REWRITER_PUBLIC_CACHE_EXTENDER_H_
00021 
00022 #include "net/instaweb/rewriter/public/resource.h"  
00023 #include "net/instaweb/rewriter/public/server_context.h"
00024 #include "net/instaweb/rewriter/public/resource_slot.h"
00025 #include "net/instaweb/rewriter/public/rewrite_filter.h"
00026 #include "net/instaweb/rewriter/public/rewrite_options.h"
00027 #include "net/instaweb/rewriter/public/rewrite_result.h"
00028 #include "net/instaweb/util/public/basictypes.h"
00029 #include "net/instaweb/util/public/string_util.h"
00030 
00031 namespace net_instaweb {
00032 
00033 class HtmlElement;
00034 class ResponseHeaders;
00035 class RewriteContext;
00036 class RewriteDriver;
00037 class Statistics;
00038 class Variable;
00039 
00048 class CacheExtender : public RewriteFilter {
00049  public:
00050   static const char kCacheExtensions[];
00051   static const char kNotCacheable[];
00052 
00053   explicit CacheExtender(RewriteDriver* driver);
00054   virtual ~CacheExtender();
00055 
00056   static void InitStats(Statistics* statistics);
00057 
00058   virtual void StartDocumentImpl() {}
00059   virtual void StartElementImpl(HtmlElement* element);
00060   virtual void EndElementImpl(HtmlElement* element) {}
00061 
00062   virtual const char* Name() const { return "CacheExtender"; }
00063   virtual const char* id() const { return RewriteOptions::kCacheExtenderId; }
00064 
00067   RewriteContext* MakeNestedContext(RewriteContext* parent,
00068                                     const ResourceSlotPtr& slot);
00069 
00070  protected:
00071   virtual bool ComputeOnTheFly() const;
00072   virtual RewriteContext* MakeRewriteContext();
00073 
00074  private:
00075   class Context;
00076   friend class Context;
00077 
00078   RewriteResult RewriteLoadedResource(const ResourcePtr& input_resource,
00079                                       const OutputResourcePtr& output_resource);
00080 
00081   bool ShouldRewriteResource(
00082       const ResponseHeaders* headers, int64 now_ms,
00083       const ResourcePtr& input_resource, const StringPiece& url) const;
00084 
00085   Variable* extension_count_;
00086   Variable* not_cacheable_count_;
00087 
00088   DISALLOW_COPY_AND_ASSIGN(CacheExtender);
00089 };
00090 
00091 }  
00092 
00093 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CACHE_EXTENDER_H_
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