Page Speed Optimization Libraries
1.3.25.1
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00001 /* 00002 * Copyright 2011 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_LAZYLOAD_IMAGES_FILTER_H_ 00020 #define NET_INSTAWEB_REWRITER_PUBLIC_LAZYLOAD_IMAGES_FILTER_H_ 00021 00022 #include "net/instaweb/rewriter/public/common_filter.h" 00023 #include "net/instaweb/util/public/string.h" 00024 00025 namespace net_instaweb { 00026 00027 class HtmlElement; 00028 class RewriteDriver; 00029 class RewriteOptions; 00030 class StaticAssetManager; 00031 class Statistics; 00032 00074 class LazyloadImagesFilter : public CommonFilter { 00075 public: 00076 static const char* kImageLazyloadCode; 00077 static const char* kImageOnloadCode; 00078 static const char* kLoadAllImages; 00079 static const char* kOverrideAttributeFunctions; 00080 static const char* kIsLazyloadScriptInsertedPropertyName; 00081 00082 explicit LazyloadImagesFilter(RewriteDriver* driver); 00083 virtual ~LazyloadImagesFilter(); 00084 00085 virtual const char* Name() const { return "Lazyload Images"; } 00086 00087 static void InitStats(Statistics* statistics); 00088 static void Terminate(); 00089 00091 static bool ShouldApply(RewriteDriver* driver); 00092 static GoogleString GetLazyloadJsSnippet( 00093 const RewriteOptions* options, 00094 StaticAssetManager* static_asset_manager); 00095 00096 private: 00097 virtual void StartDocumentImpl(); 00098 virtual void EndDocument(); 00099 virtual void StartElementImpl(HtmlElement* element); 00100 virtual void EndElementImpl(HtmlElement* element); 00101 virtual void DetermineEnabled(); 00102 00104 void Clear(); 00105 00106 static GoogleString GetBlankImageSrc( 00107 const RewriteOptions* options, 00108 const StaticAssetManager* static_asset_manager); 00109 00111 void InsertLazyloadJsCode(HtmlElement* element); 00112 00115 void InsertOverrideAttributesScript(HtmlElement* element, 00116 bool is_before_script); 00117 00119 GoogleString blank_image_url_; 00122 HtmlElement* skip_rewrite_; 00124 bool main_script_inserted_; 00126 bool abort_rewrite_; 00129 bool abort_script_inserted_; 00132 int num_images_lazily_loaded_; 00133 }; 00134 00135 } 00136 00137 #endif ///< NET_INSTAWEB_REWRITER_PUBLIC_LAZYLOAD_IMAGES_FILTER_H_