netwerk/dns/nsEffectiveTLDService.h

   1 //* -*- Mode: C++; tab-width: 2; 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 EffectiveTLDService_h
   7 #define EffectiveTLDService_h
   8
   9 #include "nsIEffectiveTLDService.h"
  10
  11 #include "mozilla/AutoMemMap.h"
  12 #include "mozilla/Attributes.h"
  13 #include "mozilla/Dafsa.h"
  14 #include "mozilla/Maybe.h"
  15 #include "mozilla/MemoryReporting.h"
  16 #include "mozilla/MruCache.h"
  17 #include "mozilla/RWLock.h"
  18
  19 #include "nsCOMPtr.h"
  20 #include "nsHashKeys.h"
  21 #include "nsIMemoryReporter.h"
  22 #include "nsString.h"
  23
  24 class nsIIDNService;
  25
  26 class nsEffectiveTLDService final : public nsIEffectiveTLDService,
  27                                     public nsIMemoryReporter {
  28  public:
  29   NS_DECL_THREADSAFE_ISUPPORTS
  30   NS_DECL_NSIEFFECTIVETLDSERVICE
  31   NS_DECL_NSIMEMORYREPORTER
  32
  33   nsEffectiveTLDService();
  34   nsresult Init();
  35
  36   static nsEffectiveTLDService* GetInstance();
  37
  38   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf);
  39
  40  private:
  41   nsresult GetBaseDomainInternal(nsCString& aHostname, int32_t aAdditionalParts,
  42                                  bool aOnlyKnownPublicSuffix,
  43                                  nsACString& aBaseDomain);
  44   ~nsEffectiveTLDService();
  45
  46   // The DAFSA provides a compact encoding of the rather large eTLD list.
  47   mozilla::Dafsa mGraph;
  48
  49   // Note that the cache entries here can record entries that were cached
  50   // successfully or unsuccessfully.  mResult must be checked before using an
  51   // entry.  If it's a success error code, the cache entry is valid and can be
  52   // used.
  53   struct TLDCacheEntry {
  54     nsCString mHost;
  55     nsCString mBaseDomain;
  56     nsresult mResult;
  57   };
  58
  59   // We use a small most recently used cache to compensate for DAFSA lookups
  60   // being slightly slower than a binary search on a larger table of strings.
  61   //
  62   // We first check the cache for a matching result and avoid a DAFSA lookup
  63   // if a match is found. Otherwise we lookup the domain in the DAFSA and then
  64   // cache the result. During standard browsing the same domains are repeatedly
  65   // fed into |GetBaseDomainInternal| so this ends up being an effective
  66   // mitigation getting about a 99% hit rate with four tabs open.
  67   struct TldCache
  68       : public mozilla::MruCache<nsACString, TLDCacheEntry, TldCache> {
  69     static mozilla::HashNumber Hash(const nsACString& aKey) {
  70       return mozilla::HashString(aKey);
  71     }
  72     static bool Match(const nsACString& aKey, const TLDCacheEntry& aVal) {
  73       return aKey == aVal.mHost;
  74     }
  75   };
  76
  77   // NOTE: Only used on the main thread, so not guarded by mGraphLock.
  78   TldCache mMruTable;
  79 };
  80
  81 #endif  // EffectiveTLDService_h