image_rewrite_filter.h

Go to the documentation of this file.

/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http:///www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


#ifndef NET_INSTAWEB_REWRITER_PUBLIC_IMAGE_REWRITE_FILTER_H_
#define NET_INSTAWEB_REWRITER_PUBLIC_IMAGE_REWRITE_FILTER_H_

#include <map>

#include "net/instaweb/rewriter/cached_result.pb.h"
#include "net/instaweb/rewriter/public/image.h"
#include "net/instaweb/rewriter/public/image_url_encoder.h"
#include "net/instaweb/rewriter/public/resource.h"
#include "net/instaweb/rewriter/public/resource_slot.h"
#include "net/instaweb/rewriter/public/rewrite_context.h"
#include "net/instaweb/rewriter/public/rewrite_driver.h"
#include "net/instaweb/rewriter/public/rewrite_filter.h"
#include "net/instaweb/rewriter/public/rewrite_options.h"
#include "net/instaweb/rewriter/public/rewrite_result.h"
#include "net/instaweb/rewriter/public/server_context.h"
#include "pagespeed/kernel/base/basictypes.h"
#include "pagespeed/kernel/base/printf_format.h"
#include "pagespeed/kernel/base/statistics.h"
#include "pagespeed/kernel/base/string.h"
#include "pagespeed/kernel/base/string_util.h"
#include "pagespeed/kernel/html/html_element.h"
#include "pagespeed/kernel/http/content_type.h"
#include "pagespeed/kernel/http/image_types.pb.h"
#include "pagespeed/kernel/util/url_segment_encoder.h"

namespace net_instaweb {

enum InlineResult {
  INLINE_SUCCESS,
  INLINE_UNSUPPORTED_DEVICE,
  INLINE_NOT_CRITICAL,
  INLINE_NO_DATA,
  INLINE_TOO_LARGE,
  INLINE_CACHE_SMALL_IMAGES_UNREWRITTEN,
  INLINE_RESPONSIVE,
  INLINE_SHORTCUT,
  INLINE_INTERNAL_ERROR,
};

class ImageRewriteFilter : public RewriteFilter {
  class Context;
 public:
  typedef std::map<GoogleString, AssociatedImageInfo> AssociatedImageInfoMap;

  static const char kImageNoRewritesHighResolution[];
  static const char kImageOngoingRewrites[];
  static const char kImageResizedUsingRenderedDimensions[];
  static const char kImageRewriteLatencyFailedMs[];
  static const char kImageRewriteLatencyOkMs[];
  static const char kImageRewriteLatencyTotalMs[];
  static const char kImageRewritesDroppedDecodeFailure[];
  static const char kImageRewritesDroppedDueToLoad[];
  static const char kImageRewritesDroppedMIMETypeUnknown[];
  static const char kImageRewritesDroppedNoSavingNoResize[];
  static const char kImageRewritesDroppedNoSavingResize[];
  static const char kImageRewritesDroppedServerWriteFail[];
  static const char kImageRewritesSquashingForMobileScreen[];
  static const char kImageRewrites[];
  static const char kImageWebpRewrites[];
  static const char kImageWebpFromGifFailureMs[];
  static const char kImageWebpFromGifSuccessMs[];
  static const char kImageWebpFromGifTimeouts[];
  static const char kImageWebpFromJpegFailureMs[];
  static const char kImageWebpFromJpegSuccessMs[];
  static const char kImageWebpFromJpegTimeouts[];
  static const char kImageWebpFromPngFailureMs[];
  static const char kImageWebpFromPngSuccessMs[];
  static const char kImageWebpFromPngTimeouts[];
  static const char kImageWebpOpaqueFailureMs[];
  static const char kImageWebpOpaqueSuccessMs[];
  static const char kImageWebpOpaqueTimeouts[];
  static const char kImageWebpWithAlphaFailureMs[];
  static const char kImageWebpWithAlphaSuccessMs[];
  static const char kImageWebpWithAlphaTimeouts[];
  static const char kImageWebpFromGifAnimatedFailureMs[];
  static const char kImageWebpFromGifAnimatedSuccessMs[];
  static const char kImageWebpFromGifAnimatedTimeouts[];

  static const char kInlinableImageUrlsPropertyName[];

  static const RewriteOptions::Filter kRelatedFilters[];
  static const int kRelatedFiltersSize;

  explicit ImageRewriteFilter(RewriteDriver* driver);
  virtual ~ImageRewriteFilter();
  static void InitStats(Statistics* statistics);
  static void Initialize();
  static void Terminate();
  static void AddRelatedOptions(StringPieceVector* target);
  virtual void StartDocumentImpl();
  virtual void EndDocument();
  virtual void RenderDone();
  virtual void StartElementImpl(HtmlElement* element);
  virtual void EndElementImpl(HtmlElement* element) {}
  virtual const char* Name() const { return "ImageRewrite"; }
  virtual const char* id() const { return RewriteOptions::kImageCompressionId; }
  virtual void EncodeUserAgentIntoResourceContext(
      ResourceContext* context) const;

  void RegisterImageInfo(const AssociatedImageInfo& image_info);

  static bool ExtractAssociatedImageInfo(const CachedResult* in,
                                         RewriteContext* context,
                                         AssociatedImageInfo* out);

  InlineResult TryInline(bool is_html, bool is_critical,
      int64 image_inline_max_bytes, const CachedResult* cached_result,
      ResourceSlot* slot, GoogleString* data_url);

  static bool ParseDimensionAttribute(const char* position, int* value);

  RewriteContext* MakeNestedRewriteContextForCss(
      int64 css_image_inline_max_bytes,
      RewriteContext* parent,
      const ResourceSlotPtr& slot);

  virtual RewriteContext* MakeNestedRewriteContext(RewriteContext* parent,
                                                   const ResourceSlotPtr& slot);

  bool UpdateDesiredImageDimsIfNecessary(
      const ImageDim& image_dim, const ResourceContext& resource_context,
      ImageDim* desired_dim);

  bool ShouldResize(const ResourceContext& context,
                    const GoogleString& url,
                    Image* image,
                    ImageDim* desired_dimensions);

  bool ResizeImageIfNecessary(
      const Context* rewrite_context, const GoogleString& url,
      ResourceContext* context, Image* image, CachedResult* cached);

  Image::CompressionOptions* ImageOptionsForLoadedResource(
      const ResourceContext& context, const ResourcePtr& input_resource);

  virtual const RewriteOptions::Filter* RelatedFilters(int* num_filters) const;
  virtual const StringPieceVector* RelatedOptions() const {
    return related_options_;
  }

  static void DisableRelatedFilters(RewriteOptions* options);

  void ReportDroppedRewrite();

 protected:
  virtual const UrlSegmentEncoder* encoder() const;

  virtual RewriteContext* MakeRewriteContext();

 private:
  friend class Context;

  void InfoAndTrace(Context* context, const char* format, ...)
      INSTAWEB_PRINTF_FORMAT(3, 4);
  const ContentType* ImageToContentType(const GoogleString& origin_url,
                                        Image* image);
  void BeginRewriteImageUrl(HtmlElement* element, HtmlElement::Attribute* src);
  void BeginRewriteSrcSet(HtmlElement* element, HtmlElement::Attribute* srcset);

  void ComputePreserveUrls(const RewriteOptions* options, ResourceSlot* slot);

  RewriteResult RewriteLoadedResourceImpl(Context* context,
                                          const ResourcePtr& input_resource,
                                          const OutputResourcePtr& result);

  bool FinishRewriteCssImageUrl(
      int64 css_image_inline_max_bytes,
      const CachedResult* cached, ResourceSlot* slot,
      InlineResult* inline_result);

  bool FinishRewriteImageUrl(
      const CachedResult* cached, const ResourceContext* resource_context,
      HtmlElement* element, HtmlElement::Attribute* src, int image_index,
      HtmlResourceSlot* slot, InlineResult* inline_result);

  void SaveIfInlinable(const StringPiece& contents,
                       const ImageType image_type,
                       CachedResult* cached);

  void GetDimensions(HtmlElement* element, ImageDim* page_dim,
                     const HtmlElement::Attribute* src,
                     bool* is_resized_using_rendered_dimensions);

  bool HasAnyDimensions(HtmlElement* element);

  void ResizeLowQualityImage(
      Image* low_image, const ResourcePtr& input_resource,
      CachedResult* cached);

  bool IsHtmlCriticalImage(StringPiece image_url) const;

  bool StoreUrlInPropertyCache(const StringPiece& url);

  void SaveDebugMessageToCache(const GoogleString& message,
                               CachedResult* cached_result);

  GoogleString UrlForDebugMessages(const Context* context) const;


  Variable* image_rewrites_;
  Variable* image_resized_using_rendered_dimensions_;
  Variable* image_norewrites_high_resolution_;
  Variable* image_rewrites_dropped_intentionally_;
  Variable* image_rewrites_dropped_decode_failure_;
  Variable* image_rewrites_dropped_mime_type_unknown_;
  Variable* image_rewrites_dropped_server_write_fail_;
  Variable* image_rewrites_dropped_nosaving_resize_;
  Variable* image_rewrites_dropped_nosaving_noresize_;
  TimedVariable* image_rewrites_dropped_due_to_load_;
  TimedVariable* image_rewrites_squashing_for_mobile_screen_;
  Variable* image_rewrite_total_bytes_saved_;
  Variable* image_rewrite_total_original_bytes_;
  Variable* image_rewrite_uses_;
  Variable* image_inline_count_;
  Variable* image_webp_rewrites_;
  UpDownCounter* image_ongoing_rewrites_;

  Variable* image_rewrite_latency_total_ms_;
  Histogram* image_rewrite_latency_ok_ms_;
  Histogram* image_rewrite_latency_failed_ms_;

  ImageUrlEncoder encoder_;

  int image_counter_;

  StringSet inlinable_urls_;

  Image::ConversionVariables webp_conversion_variables_;

  static StringPieceVector* related_options_;

  std::map<GoogleString, AssociatedImageInfo> image_info_;
  bool saw_end_document_;

  
};

}  

#endif