Page Speed Optimization Libraries  1.7.30.3
net/instaweb/rewriter/public/device_properties.h
00001 // Copyright 2012 Google Inc. All Rights Reserved.
00014 
00015 #ifndef NET_INSTAWEB_REWRITER_PUBLIC_DEVICE_PROPERTIES_H_
00016 #define NET_INSTAWEB_REWRITER_PUBLIC_DEVICE_PROPERTIES_H_
00017 
00018 #include <vector>
00019 
00020 #include "net/instaweb/http/public/user_agent_matcher.h"
00021 #include "net/instaweb/util/public/basictypes.h"
00022 #include "net/instaweb/util/public/gtest_prod.h"
00023 #include "net/instaweb/util/public/string.h"
00024 #include "net/instaweb/util/public/string_util.h"
00025 
00026 namespace net_instaweb {
00027 
00030 class DeviceProperties {
00031  public:
00032   explicit DeviceProperties(UserAgentMatcher* matcher);
00033   virtual ~DeviceProperties();
00034 
00035   void set_user_agent(const StringPiece& user_agent_string);
00036   bool SupportsImageInlining() const;
00037   bool SupportsLazyloadImages() const;
00038   bool SupportsCriticalImagesBeacon() const;
00039   bool SupportsJsDefer(bool enable_mobile) const;
00040   bool SupportsWebp() const;
00041   bool SupportsWebpLosslessAlpha() const;
00042   bool IsBot() const;
00043   bool SupportsSplitHtml(bool enable_mobile) const;
00044   bool CanPreloadResources() const;
00045   bool GetScreenResolution(int* width, int* height) const;
00046   UserAgentMatcher::DeviceType GetDeviceType() const;
00047   bool IsMobile() const {
00048     return GetDeviceType() == UserAgentMatcher::kMobile;
00049   }
00050 
00051   enum ImageQualityPreference {
00053     kImageQualityDefault,
00055     kImageQualityLow,
00057     kImageQualityMedium,
00059     kImageQualityHigh,
00060   };
00061   static const int kMediumScreenWidthThreshold = 720;
00062   static const int kLargeScreenWidthThreshold = 1500;
00063 
00066   void SetPreferredImageQualities(
00067       const std::vector<int>* webp,  const std::vector<int>* jpeg);
00069   bool GetPreferredImageQualities(
00070       ImageQualityPreference preference, int* webp, int* jpeg) const;
00071   static int GetPreferredImageQualityCount();
00072 
00073  private:
00074   friend class ImageRewriteTest;
00075   friend class RequestProperties;
00076   FRIEND_TEST(ImageRewriteTest, SquashImagesForMobileScreen);
00077   FRIEND_TEST(DevicePropertiesTest, GetScreenGroupIndex);
00078 
00081   static bool GetScreenGroupIndex(int screen_width, int* screen_index);
00082   void SetScreenResolution(int width, int height) const;
00084   bool HasPreferredImageQualities() const;
00085 
00086   GoogleString user_agent_;
00087   UserAgentMatcher* ua_matcher_;
00088 
00089   mutable LazyBool supports_image_inlining_;
00090   mutable LazyBool supports_js_defer_;
00091   mutable LazyBool supports_lazyload_images_;
00092   mutable LazyBool supports_webp_;
00093   mutable LazyBool supports_webp_lossless_alpha_;
00094   mutable LazyBool is_bot_;
00095   mutable LazyBool is_mobile_user_agent_;
00096   mutable LazyBool supports_split_html_;
00097   mutable LazyBool supports_flush_early_;
00098   mutable LazyBool screen_dimensions_set_;
00099   mutable int screen_width_;
00100   mutable int screen_height_;
00101   const std::vector<int>* preferred_webp_qualities_;
00102   const std::vector<int>* preferred_jpeg_qualities_;
00104   mutable LazyBool device_type_set_;
00105   mutable UserAgentMatcher::DeviceType device_type_;
00106 
00107   DISALLOW_COPY_AND_ASSIGN(DeviceProperties);
00108 };
00109 
00110 }  
00111 
00112 #endif  ///< NET_INSTAWEB_REWRITER_PUBLIC_DEVICE_PROPERTIES_H_
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