Page Speed Optimization Libraries  1.7.30.3
net/instaweb/rewriter/public/cacheable_resource_base.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 
00025 
00026 #ifndef NET_INSTAWEB_REWRITER_PUBLIC_CACHEABLE_RESOURCE_BASE_H_
00027 #define NET_INSTAWEB_REWRITER_PUBLIC_CACHEABLE_RESOURCE_BASE_H_
00028 
00029 #include "net/instaweb/http/public/request_context.h"
00030 #include "net/instaweb/rewriter/public/resource.h"
00031 #include "net/instaweb/rewriter/public/server_context.h"
00032 #include "net/instaweb/util/public/basictypes.h"
00033 #include "net/instaweb/util/public/string_util.h"
00034 #include "pagespeed/kernel/base/string.h"
00035 
00036 namespace net_instaweb {
00037 
00038 struct ContentType;
00039 class HTTPCache;
00040 class HTTPValue;
00041 class MessageHandler;
00042 class RequestHeaders;
00043 class ResponseHeaders;
00044 class RewriteDriver;
00045 class RewriteOptions;
00046 class Statistics;
00047 class Timer;
00048 class Variable;
00049 
00050 class CacheableResourceBase : public Resource {
00051  public:
00053 
00055   virtual bool UseHttpCache() const { return true; }
00056 
00057   virtual bool IsValidAndCacheable() const;
00058 
00060   virtual void LoadAndCallback(NotCacheablePolicy not_cacheable_policy,
00061                                const RequestContextPtr& request_context,
00062                                AsyncCallback* callback);
00063 
00064   virtual void Freshen(FreshenCallback* callback, MessageHandler* handler);
00065   virtual void RefreshIfImminentlyExpiring();
00066   virtual GoogleString url() const { return url_; }
00067   virtual GoogleString cache_key() const { return cache_key_; }
00068 
00069  protected:
00071   CacheableResourceBase(StringPiece stat_prefix,
00072                         StringPiece url,
00073                         StringPiece cache_key,
00074                         const ContentType* type,
00075                         RewriteDriver* rewrite_driver);
00076   virtual ~CacheableResourceBase();
00077 
00078   static void InitStats(StringPiece stat_prefix, Statistics* statistics);
00079 
00082   virtual void PrepareRequest(const RequestContextPtr& request_context,
00083                               RequestHeaders* headers);
00084 
00089   virtual void PrepareResponseHeaders(ResponseHeaders* headers);
00090 
00091   HTTPCache* http_cache() const { return server_context()->http_cache(); }
00092   RewriteDriver* rewrite_driver() const { return rewrite_driver_; }
00093   const RewriteOptions* rewrite_options() const;
00094 
00097   bool ShouldSkipBackgroundFetch() const;
00098 
00099  private:
00100   class FreshenHttpCacheCallback;
00101   class LoadHttpCacheCallback;
00102   class FetchCallbackBase;
00103   class FreshenFetchCallback;
00104   class LoadFetchCallback;
00105   friend class CacheableResourceBaseTest;
00106 
00110   bool UpdateInputInfoForFreshen(const ResponseHeaders& headers,
00111                                  const HTTPValue& value,
00112                                  Resource::FreshenCallback* callback);
00113 
00116   bool IsValidAndCacheableImpl(const ResponseHeaders& headers) const;
00117 
00118   Timer* timer() const { return server_context()->timer(); }
00119   MessageHandler* message_handler() const {
00120     return server_context()->message_handler();
00121   }
00122 
00123   GoogleString url_;
00124   GoogleString cache_key_;
00125 
00126   RewriteDriver* rewrite_driver_;
00127   Variable* hits_;
00128   Variable* recent_fetch_failures_;
00129   Variable* recent_uncacheables_treated_as_miss_;
00130   Variable* recent_uncacheables_treated_as_failure_;
00131   Variable* misses_;
00132 
00133   DISALLOW_COPY_AND_ASSIGN(CacheableResourceBase);
00134 };
00135 
00136 }  
00137 
00138 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CACHEABLE_RESOURCE_BASE_H_
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