dom/xul/nsXULPrototypeCache.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsXULPrototypeCache_h__
   7 #define nsXULPrototypeCache_h__
   8
   9 #include "nsBaseHashtable.h"
  10 #include "nsCOMPtr.h"
  11 #include "nsIObserver.h"
  12 #include "nsInterfaceHashtable.h"
  13 #include "nsRefPtrHashtable.h"
  14 #include "nsURIHashKey.h"
  15 #include "nsXULPrototypeDocument.h"
  16 #include "nsIStorageStream.h"
  17
  18 #include "mozilla/scache/StartupCache.h"
  19 #include "js/experimental/JSStencil.h"
  20 #include "mozilla/RefPtr.h"
  21
  22 class nsIHandleReportCallback;
  23 namespace mozilla {
  24 class StyleSheet;
  25 }  // namespace mozilla
  26
  27 /**
  28  * The XUL prototype cache can be used to store and retrieve shared data for
  29  * XUL documents, style sheets, XBL, and scripts.
  30  *
  31  * The cache has two levels:
  32  *  1. In-memory hashtables
  33  *  2. The on-disk cache file.
  34  */
  35 class nsXULPrototypeCache : public nsIObserver {
  36  public:
  37   enum class CacheType { Prototype, Script };
  38
  39   // nsISupports
  40   NS_DECL_THREADSAFE_ISUPPORTS
  41   NS_DECL_NSIOBSERVER
  42
  43   bool IsCached(nsIURI* aURI) { return GetPrototype(aURI) != nullptr; }
  44   void AbortCaching();
  45
  46   /**
  47    * Whether the prototype cache is enabled.
  48    */
  49   bool IsEnabled();
  50
  51   /**
  52    * Flush the cache; remove all XUL prototype documents, style
  53    * sheets, and scripts.
  54    */
  55   void Flush();
  56
  57   // The following methods are used to put and retrive various items into and
  58   // from the cache.
  59
  60   nsXULPrototypeDocument* GetPrototype(nsIURI* aURI);
  61   nsresult PutPrototype(nsXULPrototypeDocument* aDocument);
  62
  63   JS::Stencil* GetStencil(nsIURI* aURI);
  64   nsresult PutStencil(nsIURI* aURI, JS::Stencil* aStencil);
  65
  66   /**
  67    * Write the XUL prototype document to a cache file. The proto must be
  68    * fully loaded.
  69    */
  70   nsresult WritePrototype(nsXULPrototypeDocument* aPrototypeDocument);
  71
  72   /**
  73    * This interface allows partial reads and writes from the buffers in the
  74    * startupCache.
  75    */
  76
  77   inline nsresult GetPrototypeInputStream(nsIURI* aURI,
  78                                           nsIObjectInputStream** objectInput) {
  79     return GetInputStream(CacheType::Prototype, aURI, objectInput);
  80   }
  81   inline nsresult GetScriptInputStream(nsIURI* aURI,
  82                                        nsIObjectInputStream** objectInput) {
  83     return GetInputStream(CacheType::Script, aURI, objectInput);
  84   }
  85   inline nsresult FinishScriptInputStream(nsIURI* aURI) {
  86     return FinishInputStream(aURI);
  87   }
  88
  89   inline nsresult GetPrototypeOutputStream(
  90       nsIURI* aURI, nsIObjectOutputStream** objectOutput) {
  91     return GetOutputStream(aURI, objectOutput);
  92   }
  93   inline nsresult GetScriptOutputStream(nsIURI* aURI,
  94                                         nsIObjectOutputStream** objectOutput) {
  95     return GetOutputStream(aURI, objectOutput);
  96   }
  97
  98   inline nsresult FinishPrototypeOutputStream(nsIURI* aURI) {
  99     return FinishOutputStream(CacheType::Prototype, aURI);
 100   }
 101   inline nsresult FinishScriptOutputStream(nsIURI* aURI) {
 102     return FinishOutputStream(CacheType::Script, aURI);
 103   }
 104
 105   inline nsresult HasPrototype(nsIURI* aURI, bool* exists) {
 106     return HasData(CacheType::Prototype, aURI, exists);
 107   }
 108   inline nsresult HasScript(nsIURI* aURI, bool* exists) {
 109     return HasData(CacheType::Script, aURI, exists);
 110   }
 111
 112  private:
 113   nsresult GetInputStream(CacheType cacheType, nsIURI* uri,
 114                           nsIObjectInputStream** stream);
 115   nsresult FinishInputStream(nsIURI* aURI);
 116
 117   nsresult GetOutputStream(nsIURI* aURI, nsIObjectOutputStream** objectOutput);
 118   nsresult FinishOutputStream(CacheType cacheType, nsIURI* aURI);
 119   nsresult HasData(CacheType cacheType, nsIURI* aURI, bool* exists);
 120
 121  public:
 122   static nsXULPrototypeCache* GetInstance();
 123   static nsXULPrototypeCache* MaybeGetInstance() { return sInstance; }
 124
 125   static void ReleaseGlobals() { NS_IF_RELEASE(sInstance); }
 126
 127   void MarkInCCGeneration(uint32_t aGeneration);
 128
 129   static void CollectMemoryReports(nsIHandleReportCallback* aHandleReport,
 130                                    nsISupports* aData);
 131
 132  protected:
 133   friend nsresult NS_NewXULPrototypeCache(REFNSIID aIID, void** aResult);
 134
 135   nsXULPrototypeCache();
 136   virtual ~nsXULPrototypeCache() = default;
 137
 138   static nsXULPrototypeCache* sInstance;
 139
 140   nsRefPtrHashtable<nsURIHashKey, nsXULPrototypeDocument>
 141       mPrototypeTable;  // owns the prototypes
 142
 143   class StencilHashKey : public nsURIHashKey {
 144    public:
 145     explicit StencilHashKey(const nsIURI* aKey) : nsURIHashKey(aKey) {}
 146     StencilHashKey(StencilHashKey&&) = default;
 147
 148     RefPtr<JS::Stencil> mStencil;
 149   };
 150
 151   nsTHashtable<StencilHashKey> mStencilTable;
 152
 153   // URIs already written to the startup cache, to prevent double-caching.
 154   nsTHashtable<nsURIHashKey> mStartupCacheURITable;
 155
 156   nsInterfaceHashtable<nsURIHashKey, nsIStorageStream> mOutputStreamTable;
 157   nsInterfaceHashtable<nsURIHashKey, nsIObjectInputStream> mInputStreamTable;
 158
 159   // Bootstrap caching service
 160   nsresult BeginCaching(nsIURI* aDocumentURI);
 161 };
 162
 163 #endif  // nsXULPrototypeCache_h__