Page Speed Optimization Libraries  1.2.24.1
net/instaweb/rewriter/public/css_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_FILTER_H_
00020 #define NET_INSTAWEB_REWRITER_PUBLIC_CSS_FILTER_H_
00021 
00022 #include "net/instaweb/htmlparse/public/html_element.h"
00023 #include "net/instaweb/rewriter/public/css_hierarchy.h"
00024 #include "net/instaweb/rewriter/public/css_resource_slot.h"
00025 #include "net/instaweb/rewriter/public/css_url_encoder.h"
00026 #include "net/instaweb/rewriter/public/output_resource_kind.h"
00027 #include "net/instaweb/rewriter/public/resource.h"
00028 #include "net/instaweb/rewriter/public/server_context.h"
00029 #include "net/instaweb/rewriter/public/resource_slot.h"
00030 #include "net/instaweb/rewriter/public/rewrite_driver.h"
00031 #include "net/instaweb/rewriter/public/rewrite_filter.h"
00032 #include "net/instaweb/rewriter/public/rewrite_options.h"
00033 #include "net/instaweb/rewriter/public/single_rewrite_context.h"
00034 #include "net/instaweb/util/public/basictypes.h"
00035 #include "net/instaweb/util/public/google_url.h"
00036 #include "net/instaweb/util/public/scoped_ptr.h"
00037 #include "net/instaweb/util/public/string.h"
00038 #include "net/instaweb/util/public/string_util.h"
00039 
00040 namespace Css {
00041 
00042 class Stylesheet;
00043 
00044 }  
00045 
00046 namespace net_instaweb {
00047 
00048 class AssociationTransformer;
00049 class CssImageRewriter;
00050 class CacheExtender;
00051 class HtmlCharactersNode;
00052 class ImageCombineFilter;
00053 class ImageRewriteFilter;
00054 class MessageHandler;
00055 class OutputPartitions;
00056 class ResourceContext;
00057 class RewriteContext;
00058 class RewriteDomainTransformer;
00059 class Statistics;
00060 class UrlSegmentEncoder;
00061 class Variable;
00062 class Writer;
00063 
00074 class CssFilter : public RewriteFilter {
00075  public:
00076   class Context;
00077 
00078   CssFilter(RewriteDriver* driver,
00081             CacheExtender* cache_extender,
00082             ImageRewriteFilter* image_rewriter,
00083             ImageCombineFilter* image_combiner);
00084   virtual ~CssFilter();
00085 
00088   static void InitStats(Statistics* statistics);
00089 
00091   static void Initialize();
00092   static void Terminate();
00093 
00097   static void InitializeAtExitManager();
00098 
00099   virtual void StartDocumentImpl();
00100   virtual void StartElementImpl(HtmlElement* element);
00101   virtual void Characters(HtmlCharactersNode* characters);
00102   virtual void EndElementImpl(HtmlElement* element);
00103 
00104   virtual const char* Name() const { return "CssFilter"; }
00105   virtual const char* id() const { return RewriteOptions::kCssFilterId; }
00106   virtual int FilterCacheFormatVersion() const;
00107 
00108   static const char kBlocksRewritten[];
00109   static const char kParseFailures[];
00110   static const char kFallbackRewrites[];
00111   static const char kFallbackFailures[];
00112   static const char kRewritesDropped[];
00113   static const char kTotalBytesSaved[];
00114   static const char kTotalOriginalBytes[];
00115   static const char kUses[];
00116   static const char kCharsetMismatch[];
00117   static const char kInvalidUrl[];
00118   static const char kLimitExceeded[];
00119   static const char kMinifyFailed[];
00120   static const char kRecursion[];
00121   static const char kComplexQueries[];
00122 
00123   RewriteContext* MakeNestedFlatteningContextInNewSlot(
00124       const ResourcePtr& resource, const GoogleString& location,
00125       CssFilter::Context* rewriter, RewriteContext* parent,
00126       CssHierarchy* hierarchy);
00127 
00128  protected:
00129   virtual RewriteContext* MakeRewriteContext();
00130   virtual const UrlSegmentEncoder* encoder() const;
00131   virtual RewriteContext* MakeNestedRewriteContext(
00132       RewriteContext* parent, const ResourceSlotPtr& slot);
00133 
00134  private:
00135   friend class Context;
00136   friend class CssFlattenImportsContext; 
00137   friend class CssHierarchy; 
00138 
00139   enum InlineCssKind {
00140     kInsideStyleTag,
00141     kAttributeWithoutUrls,
00142     kAttributeWithUrls
00143   };
00144 
00145   Context* MakeContext(RewriteDriver* driver,
00146                        RewriteContext* parent);
00147 
00149   void StartInlineRewrite(HtmlCharactersNode* text);
00150 
00153   void StartAttributeRewrite(HtmlElement* element,
00154                              HtmlElement::Attribute* style,
00155                              InlineCssKind inline_css_kind);
00156 
00159   void StartExternalRewrite(HtmlElement* link, HtmlElement::Attribute* src);
00160 
00161   ResourceSlot* MakeSlotForInlineCss(const StringPiece& content);
00162   CssFilter::Context* StartRewriting(const ResourceSlotPtr& slot);
00163 
00169   bool GetApplicableCharset(const HtmlElement* element,
00170                             GoogleString* charset) const;
00171 
00174   bool GetApplicableMedia(const HtmlElement* element,
00175                           StringVector* media) const;
00176 
00177   bool in_style_element_; 
00178 
00179   HtmlElement* style_element_; 
00180 
00182   GoogleString meta_tag_charset_;
00183 
00185   CacheExtender* cache_extender_;
00186   ImageRewriteFilter* image_rewrite_filter_;
00187   ImageCombineFilter* image_combiner_;
00188 
00192   Variable* num_blocks_rewritten_;
00194   Variable* num_parse_failures_;
00197   Variable* num_fallback_rewrites_;
00199   Variable* num_fallback_failures_;
00202   Variable* num_rewrites_dropped_;
00208   Variable* total_bytes_saved_;
00212   Variable* total_original_bytes_;
00215   Variable* num_uses_;
00217   Variable* num_flatten_imports_charset_mismatch_;
00219   Variable* num_flatten_imports_invalid_url_;
00221   Variable* num_flatten_imports_limit_exceeded_;
00223   Variable* num_flatten_imports_minify_failed_;
00225   Variable* num_flatten_imports_recursion_;
00227   Variable* num_flatten_imports_complex_queries_;
00228 
00229   CssUrlEncoder encoder_;
00230 
00231   DISALLOW_COPY_AND_ASSIGN(CssFilter);
00232 };
00233 
00235 class CssFilter::Context : public SingleRewriteContext {
00236  public:
00237   Context(CssFilter* filter, RewriteDriver* driver,
00238           RewriteContext* parent,
00239           CacheExtender* cache_extender,
00240           ImageRewriteFilter* image_rewriter,
00241           ImageCombineFilter* image_combiner,
00242           ResourceContext* context);
00243   virtual ~Context();
00244 
00246   void SetupInlineRewrite(HtmlElement* style_element, HtmlCharactersNode* text);
00247   void SetupAttributeRewrite(HtmlElement* element,
00248                              HtmlElement::Attribute* src,
00249                              InlineCssKind inline_css_kind);
00250   void SetupExternalRewrite(const GoogleUrl& base_gurl,
00251                             const GoogleUrl& trim_gurl);
00252 
00255   void RewriteCssFromNested(RewriteContext* parent, CssHierarchy* hierarchy);
00256 
00259   virtual bool AbsolutifyIfNeeded(const StringPiece& input_contents,
00260                                   Writer* writer, MessageHandler* handler);
00261 
00262   CssResourceSlotFactory* slot_factory() { return &slot_factory_; }
00263 
00264   CssHierarchy* mutable_hierarchy() { return &hierarchy_; }
00265 
00266  protected:
00267   virtual void Render();
00268   virtual void Harvest();
00269   virtual bool Partition(OutputPartitions* partitions,
00270                          OutputResourceVector* outputs);
00271   virtual void RewriteSingle(const ResourcePtr& input,
00272                              const OutputResourcePtr& output);
00273   virtual const char* id() const { return filter_->id(); }
00274   virtual OutputResourceKind kind() const { return kRewrittenResource; }
00275   virtual GoogleString CacheKeySuffix() const;
00276   virtual const UrlSegmentEncoder* encoder() const;
00277 
00278  private:
00279   bool RewriteCssText(const GoogleUrl& css_base_gurl,
00280                       const GoogleUrl& css_trim_gurl,
00281                       const StringPiece& in_text,
00282                       int64 in_text_size,
00283                       bool text_is_declarations,
00284                       MessageHandler* handler);
00285 
00287   void RewriteCssFromRoot(const StringPiece& in_text, int64 in_text_size,
00288                           bool has_unparseables, Css::Stylesheet* stylesheet);
00289 
00295   bool FallbackRewriteUrls(const StringPiece& in_text);
00296 
00299   bool SerializeCss(int64 in_text_size,
00300                     const Css::Stylesheet* stylesheet,
00301                     const GoogleUrl& css_base_gurl,
00302                     const GoogleUrl& css_trim_gurl,
00303                     bool previously_optimized,
00304                     bool stylesheet_is_declarations,
00305                     bool add_utf8_bom,
00306                     GoogleString* out_text,
00307                     MessageHandler* handler);
00308 
00312   bool IsInlineAttribute() const {
00313     return (rewrite_inline_attribute_ != NULL);
00314   }
00315 
00319   int64 ImageInlineMaxBytes() const {
00320     if (rewrite_inline_element_ != NULL) {
00322       return driver_->options()->ImageInlineMaxBytes();
00323     } else {
00325       return driver_->options()->CssImageInlineMaxBytes();
00326     }
00327   }
00328 
00329   CssFilter* filter_;
00330   RewriteDriver* driver_;
00331   scoped_ptr<CssImageRewriter> css_image_rewriter_;
00332   CssResourceSlotFactory slot_factory_;
00333   CssHierarchy hierarchy_;
00334   bool css_rewritten_;
00335   bool has_utf8_bom_;
00336 
00338   bool fallback_mode_;
00341   scoped_ptr<AssociationTransformer> fallback_transformer_;
00344   scoped_ptr<RewriteDomainTransformer> absolutifier_;
00345 
00349   HtmlElement* rewrite_inline_element_;
00350 
00352   HtmlCharactersNode* rewrite_inline_char_node_;
00353 
00357   HtmlElement::Attribute* rewrite_inline_attribute_;
00358 
00362   InlineCssKind rewrite_inline_css_kind_;
00363 
00365   int64 in_text_size_;
00366   GoogleUrl css_base_gurl_;
00367   GoogleUrl css_trim_gurl_;
00368   ResourcePtr input_resource_;
00369   OutputResourcePtr output_resource_;
00370 
00371   DISALLOW_COPY_AND_ASSIGN(Context);
00372 };
00373 
00374 }  
00375 
00376 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CSS_FILTER_H_
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