Page Speed Optimization Libraries  1.5.27.2
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_filter.h"
00031 #include "net/instaweb/rewriter/public/rewrite_options.h"
00032 #include "net/instaweb/rewriter/public/single_rewrite_context.h"
00033 #include "net/instaweb/util/public/basictypes.h"
00034 #include "net/instaweb/util/public/google_url.h"
00035 #include "net/instaweb/util/public/scoped_ptr.h"
00036 #include "net/instaweb/util/public/string.h"
00037 #include "net/instaweb/util/public/string_util.h"
00038 
00039 namespace Css {
00040 
00041 class Stylesheet;
00042 
00043 }  
00044 
00045 namespace net_instaweb {
00046 
00047 class AssociationTransformer;
00048 class CssImageRewriter;
00049 class CacheExtender;
00050 class HtmlCharactersNode;
00051 class ImageCombineFilter;
00052 class ImageRewriteFilter;
00053 class MessageHandler;
00054 class OutputPartitions;
00055 class ResourceContext;
00056 class RewriteContext;
00057 class RewriteDriver;
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 void EncodeUserAgentIntoResourceContext(
00107       ResourceContext* context) const;
00108 
00109   static const char kBlocksRewritten[];
00110   static const char kParseFailures[];
00111   static const char kFallbackRewrites[];
00112   static const char kFallbackFailures[];
00113   static const char kRewritesDropped[];
00114   static const char kTotalBytesSaved[];
00115   static const char kTotalOriginalBytes[];
00116   static const char kUses[];
00117   static const char kCharsetMismatch[];
00118   static const char kInvalidUrl[];
00119   static const char kLimitExceeded[];
00120   static const char kMinifyFailed[];
00121   static const char kRecursion[];
00122   static const char kComplexQueries[];
00123 
00124   RewriteContext* MakeNestedFlatteningContextInNewSlot(
00125       const ResourcePtr& resource, const GoogleString& location,
00126       CssFilter::Context* rewriter, RewriteContext* parent,
00127       CssHierarchy* hierarchy);
00128 
00129   virtual const RewriteOptions::Filter* RelatedFilters(int* num_filters) const;
00130   virtual const RewriteOptions::OptionEnum* RelatedOptions(
00131       int* num_options) const;
00132 
00133  protected:
00134   virtual RewriteContext* MakeRewriteContext();
00135   virtual const UrlSegmentEncoder* encoder() const;
00136   virtual RewriteContext* MakeNestedRewriteContext(
00137       RewriteContext* parent, const ResourceSlotPtr& slot);
00138 
00139  private:
00140   friend class Context;
00141   friend class CssFlattenImportsContext; 
00142   friend class CssHierarchy; 
00143 
00144   enum InlineCssKind {
00145     kInsideStyleTag,
00146     kAttributeWithoutUrls,
00147     kAttributeWithUrls
00148   };
00149 
00150   Context* MakeContext(RewriteDriver* driver,
00151                        RewriteContext* parent);
00152 
00154   void StartInlineRewrite(HtmlCharactersNode* text);
00155 
00158   void StartAttributeRewrite(HtmlElement* element,
00159                              HtmlElement::Attribute* style,
00160                              InlineCssKind inline_css_kind);
00161 
00164   void StartExternalRewrite(HtmlElement* link, HtmlElement::Attribute* src);
00165 
00166   ResourceSlot* MakeSlotForInlineCss(const StringPiece& content);
00167   CssFilter::Context* StartRewriting(const ResourceSlotPtr& slot);
00168 
00174   bool GetApplicableCharset(const HtmlElement* element,
00175                             GoogleString* charset) const;
00176 
00179   bool GetApplicableMedia(const HtmlElement* element,
00180                           StringVector* media) const;
00181 
00182   bool in_style_element_; 
00183 
00184   HtmlElement* style_element_; 
00185 
00187   GoogleString meta_tag_charset_;
00188 
00190   CacheExtender* cache_extender_;
00191   ImageRewriteFilter* image_rewrite_filter_;
00192   ImageCombineFilter* image_combiner_;
00193 
00197   Variable* num_blocks_rewritten_;
00199   Variable* num_parse_failures_;
00202   Variable* num_fallback_rewrites_;
00204   Variable* num_fallback_failures_;
00207   Variable* num_rewrites_dropped_;
00213   Variable* total_bytes_saved_;
00217   Variable* total_original_bytes_;
00220   Variable* num_uses_;
00222   Variable* num_flatten_imports_charset_mismatch_;
00224   Variable* num_flatten_imports_invalid_url_;
00226   Variable* num_flatten_imports_limit_exceeded_;
00228   Variable* num_flatten_imports_minify_failed_;
00230   Variable* num_flatten_imports_recursion_;
00232   Variable* num_flatten_imports_complex_queries_;
00233 
00234   CssUrlEncoder encoder_;
00235 
00236   DISALLOW_COPY_AND_ASSIGN(CssFilter);
00237 };
00238 
00240 class CssFilter::Context : public SingleRewriteContext {
00241  public:
00242   Context(CssFilter* filter, RewriteDriver* driver,
00243           RewriteContext* parent,
00244           CacheExtender* cache_extender,
00245           ImageRewriteFilter* image_rewriter,
00246           ImageCombineFilter* image_combiner,
00247           ResourceContext* context);
00248   virtual ~Context();
00249 
00251   void SetupInlineRewrite(HtmlElement* style_element, HtmlCharactersNode* text);
00252   void SetupAttributeRewrite(HtmlElement* element,
00253                              HtmlElement::Attribute* src,
00254                              InlineCssKind inline_css_kind);
00255   void SetupExternalRewrite(const GoogleUrl& base_gurl,
00256                             const GoogleUrl& trim_gurl);
00257 
00260   void RewriteCssFromNested(RewriteContext* parent, CssHierarchy* hierarchy);
00261 
00264   virtual bool AbsolutifyIfNeeded(const StringPiece& input_contents,
00265                                   Writer* writer, MessageHandler* handler);
00266 
00267   CssResourceSlotFactory* slot_factory() { return &slot_factory_; }
00268 
00269   CssHierarchy* mutable_hierarchy() { return &hierarchy_; }
00270 
00271  protected:
00272   virtual void Render();
00273   virtual void Harvest();
00274   virtual bool Partition(OutputPartitions* partitions,
00275                          OutputResourceVector* outputs);
00276   virtual void RewriteSingle(const ResourcePtr& input,
00277                              const OutputResourcePtr& output);
00278   virtual const char* id() const { return filter_->id(); }
00279   virtual OutputResourceKind kind() const { return kRewrittenResource; }
00280   virtual GoogleString CacheKeySuffix() const;
00281   virtual const UrlSegmentEncoder* encoder() const;
00282 
00284   virtual GoogleString UserAgentCacheKey(
00285       const ResourceContext* resource_context) const;
00286 
00287  private:
00288   bool RewriteCssText(const GoogleUrl& css_base_gurl,
00289                       const GoogleUrl& css_trim_gurl,
00290                       const StringPiece& in_text,
00291                       int64 in_text_size,
00292                       bool text_is_declarations,
00293                       MessageHandler* handler);
00294 
00296   void RewriteCssFromRoot(const StringPiece& in_text, int64 in_text_size,
00297                           bool has_unparseables, Css::Stylesheet* stylesheet);
00298 
00304   bool FallbackRewriteUrls(const StringPiece& in_text);
00305 
00308   bool SerializeCss(int64 in_text_size,
00309                     const Css::Stylesheet* stylesheet,
00310                     const GoogleUrl& css_base_gurl,
00311                     const GoogleUrl& css_trim_gurl,
00312                     bool previously_optimized,
00313                     bool stylesheet_is_declarations,
00314                     bool add_utf8_bom,
00315                     GoogleString* out_text,
00316                     MessageHandler* handler);
00317 
00321   bool IsInlineAttribute() const {
00322     return (rewrite_inline_attribute_ != NULL);
00323   }
00324 
00328   int64 ImageInlineMaxBytes() const;
00329 
00330   CssFilter* filter_;
00331   RewriteDriver* driver_;
00332   scoped_ptr<CssImageRewriter> css_image_rewriter_;
00333   CssResourceSlotFactory slot_factory_;
00334   CssHierarchy hierarchy_;
00335   bool css_rewritten_;
00336   bool has_utf8_bom_;
00337 
00339   bool fallback_mode_;
00342   scoped_ptr<AssociationTransformer> fallback_transformer_;
00345   scoped_ptr<RewriteDomainTransformer> absolutifier_;
00346 
00350   HtmlElement* rewrite_inline_element_;
00351 
00353   HtmlCharactersNode* rewrite_inline_char_node_;
00354 
00358   HtmlElement::Attribute* rewrite_inline_attribute_;
00359 
00363   InlineCssKind rewrite_inline_css_kind_;
00364 
00366   int64 in_text_size_;
00367   GoogleUrl css_base_gurl_;
00368   GoogleUrl css_trim_gurl_;
00369   ResourcePtr input_resource_;
00370   OutputResourcePtr output_resource_;
00371 
00372   DISALLOW_COPY_AND_ASSIGN(Context);
00373 };
00374 
00375 }  
00376 
00377 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_CSS_FILTER_H_
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