tor-browser

The Tor Browser
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nsXULPrototypeCache.h (5214B)

      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 "js/experimental/JSStencil.h"
     10 #include "mozilla/RefPtr.h"
     11 #include "mozilla/scache/StartupCache.h"
     12 #include "nsBaseHashtable.h"
     13 #include "nsCOMPtr.h"
     14 #include "nsIObserver.h"
     15 #include "nsIStorageStream.h"
     16 #include "nsInterfaceHashtable.h"
     17 #include "nsRefPtrHashtable.h"
     18 #include "nsURIHashKey.h"
     19 #include "nsXULPrototypeDocument.h"
     20 
     21 class nsIHandleReportCallback;
     22 namespace mozilla {
     23 class StyleSheet;
     24 }  // namespace mozilla
     25 
     26 /**
     27 * The XUL prototype cache can be used to store and retrieve shared data for
     28 * XUL documents, style sheets, XBL, and scripts.
     29 *
     30 * The cache has two levels:
     31 *  1. In-memory hashtables
     32 *  2. The on-disk cache file.
     33 */
     34 class nsXULPrototypeCache : public nsIObserver {
     35 public:
     36  enum class CacheType { Prototype, Script };
     37 
     38  // nsISupports
     39  NS_DECL_THREADSAFE_ISUPPORTS
     40  NS_DECL_NSIOBSERVER
     41 
     42  bool IsCached(nsIURI* aURI) { return GetPrototype(aURI) != nullptr; }
     43  void AbortCaching();
     44 
     45  /**
     46   * Whether the prototype cache is enabled.
     47   */
     48  bool IsEnabled();
     49 
     50  /**
     51   * Flush the cache; remove all XUL prototype documents, style
     52   * sheets, and scripts.
     53   */
     54  void Flush();
     55 
     56  // The following methods are used to put and retrive various items into and
     57  // from the cache.
     58 
     59  nsXULPrototypeDocument* GetPrototype(nsIURI* aURI);
     60  nsresult PutPrototype(nsXULPrototypeDocument* aDocument);
     61  void RemovePrototype(nsIURI* aURI) { mPrototypeTable.Remove(aURI); }
     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__