layout/style/SharedStyleSheetCache.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 mozilla_SharedStyleSheetCache_h__
   8 #define mozilla_SharedStyleSheetCache_h__
   9
  10 // The shared style sheet cache is a cache that allows us to share sheets across
  11 // documents.
  12 //
  13 // It's generally a singleton, but it is different from GlobalStyleSheetCache in
  14 // the sense that:
  15 //
  16 //  * It needs to be cycle-collectable, as it can keep alive style sheets from
  17 //    various documents.
  18 //
  19 //  * It is conceptually a singleton, but given its cycle-collectable nature, we
  20 //    might re-create it.
  21
  22 #include "mozilla/SharedSubResourceCache.h"
  23 #include "nsRefPtrHashtable.h"
  24 #include "mozilla/MemoryReporting.h"
  25 #include "mozilla/css/Loader.h"
  26
  27 namespace mozilla {
  28
  29 class StyleSheet;
  30 class SheetLoadDataHashKey;
  31
  32 namespace css {
  33 class SheetLoadData;
  34 class Loader;
  35 }  // namespace css
  36
  37 struct SharedStyleSheetCacheTraits {
  38   using Loader = css::Loader;
  39   using Key = SheetLoadDataHashKey;
  40   using Value = StyleSheet;
  41   using LoadingValue = css::SheetLoadData;
  42
  43   static SheetLoadDataHashKey KeyFromLoadingValue(const LoadingValue& aValue) {
  44     return SheetLoadDataHashKey(aValue);
  45   }
  46 };
  47
  48 class SharedStyleSheetCache final
  49     : public SharedSubResourceCache<SharedStyleSheetCacheTraits,
  50                                     SharedStyleSheetCache>,
  51       public nsIMemoryReporter {
  52  public:
  53   using Base = SharedSubResourceCache<SharedStyleSheetCacheTraits,
  54                                       SharedStyleSheetCache>;
  55
  56   NS_DECL_ISUPPORTS
  57   NS_DECL_NSIMEMORYREPORTER
  58
  59   SharedStyleSheetCache();
  60   void Init();
  61
  62   // This has to be static because it's also called for loaders that don't have
  63   // a sheet cache (loaders that are not owned by a document).
  64   static void LoadCompleted(SharedStyleSheetCache*, css::SheetLoadData&,
  65                             nsresult);
  66   using Base::LoadCompleted;
  67   static void LoadCompletedInternal(SharedStyleSheetCache*, css::SheetLoadData&,
  68                                     nsTArray<RefPtr<css::SheetLoadData>>&);
  69   static void Clear(nsIPrincipal* aForPrincipal = nullptr,
  70                     const nsACString* aBaseDomain = nullptr);
  71
  72  protected:
  73   void InsertIfNeeded(css::SheetLoadData&);
  74
  75   ~SharedStyleSheetCache();
  76 };
  77
  78 }  // namespace mozilla
  79
  80 #endif