xpcom/ds/nsObserverList.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 nsObserverList_h___
   8 #define nsObserverList_h___
   9
  10 #include "nsISupports.h"
  11 #include "nsCOMArray.h"
  12 #include "nsIObserver.h"
  13 #include "nsHashKeys.h"
  14 #include "nsMaybeWeakPtr.h"
  15 #include "nsSimpleEnumerator.h"
  16 #include "mozilla/Attributes.h"
  17
  18 class nsObserverList : public nsCharPtrHashKey {
  19   friend class nsObserverService;
  20
  21  public:
  22   explicit nsObserverList(const char* aKey) : nsCharPtrHashKey(aKey) {
  23     MOZ_COUNT_CTOR(nsObserverList);
  24   }
  25
  26   nsObserverList(nsObserverList&& aOther)
  27       : nsCharPtrHashKey(std::move(aOther)),
  28         mObservers(std::move(aOther.mObservers)) {
  29     MOZ_COUNT_CTOR(nsObserverList);
  30   }
  31
  32   MOZ_COUNTED_DTOR(nsObserverList)
  33
  34   [[nodiscard]] nsresult AddObserver(nsIObserver* aObserver, bool aOwnsWeak);
  35   [[nodiscard]] nsresult RemoveObserver(nsIObserver* aObserver);
  36
  37   void NotifyObservers(nsISupports* aSubject, const char* aTopic,
  38                        const char16_t* aSomeData);
  39   void GetObserverList(nsISimpleEnumerator** aEnumerator);
  40
  41   // Clone an array with the observers of this category.
  42   // The array is filled in last-added-first order.
  43   nsCOMArray<nsIObserver> ReverseCloneObserverArray();
  44
  45   // Like FillObserverArray(), but only for strongly held observers.
  46   void AppendStrongObservers(nsCOMArray<nsIObserver>& aArray);
  47
  48  private:
  49   nsMaybeWeakPtrArray<nsIObserver> mObservers;
  50 };
  51
  52 class nsObserverEnumerator final : public nsSimpleEnumerator {
  53  public:
  54   NS_DECL_NSISIMPLEENUMERATOR
  55
  56   explicit nsObserverEnumerator(nsObserverList* aObserverList);
  57
  58   const nsID& DefaultInterface() override { return NS_GET_IID(nsIObserver); }
  59
  60  private:
  61   ~nsObserverEnumerator() override = default;
  62
  63   int32_t mIndex;  // Counts up from 0
  64   nsCOMArray<nsIObserver> mObservers;
  65 };
  66
  67 #endif /* nsObserverList_h___ */