layout/style/nsLayoutStylesheetCache.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef nsLayoutStylesheetCache_h__
   8 #define nsLayoutStylesheetCache_h__
   9
  10 #include "nsIMemoryReporter.h"
  11 #include "nsIObserver.h"
  12 #include "base/shared_memory.h"
  13 #include "mozilla/Attributes.h"
  14 #include "mozilla/MemoryReporting.h"
  15 #include "mozilla/PreferenceSheet.h"
  16 #include "mozilla/NotNull.h"
  17 #include "mozilla/StaticPtr.h"
  18 #include "mozilla/css/Loader.h"
  19
  20 class nsIFile;
  21 class nsIURI;
  22
  23 namespace mozilla {
  24 class CSSStyleSheet;
  25 }  // namespace mozilla
  26
  27 namespace mozilla {
  28 namespace css {
  29
  30 // Enum defining how error should be handled.
  31 enum FailureAction { eCrash = 0, eLogToConsole };
  32
  33 }  // namespace css
  34 }  // namespace mozilla
  35
  36 // Reference counted wrapper around a base::SharedMemory that will store the
  37 // User Agent style sheets.
  38 struct nsLayoutStylesheetCacheShm final {
  39   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsLayoutStylesheetCacheShm)
  40   base::SharedMemory mShm;
  41
  42  private:
  43   ~nsLayoutStylesheetCacheShm() = default;
  44 };
  45
  46 class nsLayoutStylesheetCache final : public nsIObserver,
  47                                       public nsIMemoryReporter {
  48  public:
  49   using Shm = nsLayoutStylesheetCacheShm;
  50
  51   NS_DECL_ISUPPORTS
  52   NS_DECL_NSIOBSERVER
  53   NS_DECL_NSIMEMORYREPORTER
  54
  55   static nsLayoutStylesheetCache* Singleton();
  56
  57 #define STYLE_SHEET(identifier_, url_, shared_) \
  58   mozilla::NotNull<mozilla::StyleSheet*> identifier_##Sheet();
  59 #include "mozilla/UserAgentStyleSheetList.h"
  60 #undef STYLE_SHEET
  61
  62   mozilla::StyleSheet* GetUserContentSheet();
  63   mozilla::StyleSheet* GetUserChromeSheet();
  64   mozilla::StyleSheet* ChromePreferenceSheet();
  65   mozilla::StyleSheet* ContentPreferenceSheet();
  66
  67   static void InvalidatePreferenceSheets();
  68
  69   static void Shutdown();
  70
  71   static void SetUserContentCSSURL(nsIURI* aURI);
  72
  73   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
  74
  75   // Set the shared memory segment to load the shared UA sheets from.
  76   // Called early on in a content process' life from
  77   // ContentChild::InitSharedUASheets, before the nsLayoutStylesheetCache
  78   // singleton has been created.
  79   static void SetSharedMemory(const base::SharedMemoryHandle& aHandle,
  80                               uintptr_t aAddress);
  81
  82   // Obtain a shared memory handle for the shared UA sheets to pass into a
  83   // content process.  Called by ContentParent::InitInternal shortly after
  84   // a content process has been created.
  85   bool ShareToProcess(base::ProcessId aProcessId,
  86                       base::SharedMemoryHandle* aHandle);
  87
  88   // Returns the address of the shared memory segment that holds the shared UA
  89   // sheets.
  90   uintptr_t GetSharedMemoryAddress() {
  91     return mSharedMemory ? uintptr_t(mSharedMemory->mShm.memory()) : 0;
  92   }
  93
  94   // Size of the shared memory buffer we'll create to store the shared UA
  95   // sheets.  We choose a value that is big enough on both 64 bit and 32 bit.
  96   //
  97   // If this isn't big enough for the current contents of the shared UA
  98   // sheets, we'll crash under InitSharedSheetsInParent.
  99   static constexpr size_t kSharedMemorySize = 1024 * 450;
 100
 101  private:
 102   // Shared memory header.
 103   struct Header {
 104     static constexpr uint32_t kMagic = 0x55415353;
 105     uint32_t mMagic;  // Must be set to kMagic.
 106     const ServoCssRules* mSheets[size_t(mozilla::UserAgentStyleSheetID::Count)];
 107     uint8_t mBuffer[1];
 108   };
 109
 110   nsLayoutStylesheetCache();
 111   ~nsLayoutStylesheetCache();
 112
 113   void InitFromProfile();
 114   void InitSharedSheetsInParent();
 115   void InitSharedSheetsInChild(already_AddRefed<Shm> aSharedMemory);
 116   void InitMemoryReporter();
 117   RefPtr<mozilla::StyleSheet> LoadSheetURL(
 118       const char* aURL, mozilla::css::SheetParsingMode aParsingMode,
 119       mozilla::css::FailureAction aFailureAction);
 120   RefPtr<mozilla::StyleSheet> LoadSheetFile(
 121       nsIFile* aFile, mozilla::css::SheetParsingMode aParsingMode);
 122   RefPtr<mozilla::StyleSheet> LoadSheet(
 123       nsIURI* aURI, mozilla::css::SheetParsingMode aParsingMode,
 124       mozilla::css::FailureAction aFailureAction);
 125   void LoadSheetFromSharedMemory(const char* aURL,
 126                                  RefPtr<mozilla::StyleSheet>* aSheet,
 127                                  mozilla::css::SheetParsingMode aParsingMode,
 128                                  Shm* aSharedMemory, Header* aHeader,
 129                                  mozilla::UserAgentStyleSheetID aSheetID);
 130   void BuildPreferenceSheet(RefPtr<mozilla::StyleSheet>* aSheet,
 131                             const mozilla::PreferenceSheet::Prefs&);
 132
 133   static mozilla::StaticRefPtr<nsLayoutStylesheetCache> gStyleCache;
 134   static mozilla::StaticRefPtr<mozilla::css::Loader> gCSSLoader;
 135   static mozilla::StaticRefPtr<nsIURI> gUserContentSheetURL;
 136
 137 #define STYLE_SHEET(identifier_, url_, shared_) \
 138   RefPtr<mozilla::StyleSheet> m##identifier_##Sheet;
 139 #include "mozilla/UserAgentStyleSheetList.h"
 140 #undef STYLE_SHEET
 141
 142   RefPtr<mozilla::StyleSheet> mChromePreferenceSheet;
 143   RefPtr<mozilla::StyleSheet> mContentPreferenceSheet;
 144   RefPtr<mozilla::StyleSheet> mUserChromeSheet;
 145   RefPtr<mozilla::StyleSheet> mUserContentSheet;
 146
 147   // Shared memory segment storing shared style sheets.
 148   RefPtr<Shm> mSharedMemory;
 149
 150   // How much of the shared memory buffer we ended up using.  Used for memory
 151   // reporting.
 152   size_t mUsedSharedMemory;
 153
 154   // The shared memory to use once the nsLayoutStylesheetCache instance is
 155   // created.
 156   static mozilla::StaticRefPtr<Shm> sSharedMemory;
 157 };
 158
 159 #endif