xpcom/ds/nsObserverList.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 nsObserverList_h___
   7 #define nsObserverList_h___
   8
   9 #include "nsISupports.h"
  10 #include "nsTArray.h"
  11 #include "nsCOMPtr.h"
  12 #include "nsCOMArray.h"
  13 #include "nsIObserver.h"
  14 #include "nsIWeakReference.h"
  15 #include "nsHashKeys.h"
  16 #include "nsISimpleEnumerator.h"
  17 #include "mozilla/Attributes.h"
  18
  19 namespace mozilla {
  20 class ObserverServiceReporter;
  21 } // namespace mozilla
  22
  23 struct ObserverRef
  24 {
  25   ObserverRef(const ObserverRef& aO) : isWeakRef(aO.isWeakRef), ref(aO.ref) {}
  26   explicit ObserverRef(nsIObserver* aObserver) : isWeakRef(false), ref(aObserver) {}
  27   explicit ObserverRef(nsIWeakReference* aWeak) : isWeakRef(true), ref(aWeak) {}
  28
  29   bool isWeakRef;
  30   nsCOMPtr<nsISupports> ref;
  31
  32   nsIObserver* asObserver()
  33   {
  34     NS_ASSERTION(!isWeakRef, "Isn't a strong ref.");
  35     return static_cast<nsIObserver*>((nsISupports*)ref);
  36   }
  37
  38   nsIWeakReference* asWeak()
  39   {
  40     NS_ASSERTION(isWeakRef, "Isn't a weak ref.");
  41     return static_cast<nsIWeakReference*>((nsISupports*)ref);
  42   }
  43
  44   bool operator==(nsISupports* aRhs) const { return ref == aRhs; }
  45 };
  46
  47 class nsObserverList : public nsCharPtrHashKey
  48 {
  49   friend class nsObserverService;
  50
  51 public:
  52   explicit nsObserverList(const char* aKey) : nsCharPtrHashKey(aKey)
  53   {
  54     MOZ_COUNT_CTOR(nsObserverList);
  55   }
  56
  57   ~nsObserverList()
  58   {
  59     MOZ_COUNT_DTOR(nsObserverList);
  60   }
  61
  62   nsresult AddObserver(nsIObserver* aObserver, bool aOwnsWeak);
  63   nsresult RemoveObserver(nsIObserver* aObserver);
  64
  65   void NotifyObservers(nsISupports* aSubject,
  66                        const char* aTopic,
  67                        const char16_t* aSomeData);
  68   nsresult GetObserverList(nsISimpleEnumerator** aEnumerator);
  69
  70   // Fill an array with the observers of this category.
  71   // The array is filled in last-added-first order.
  72   void FillObserverArray(nsCOMArray<nsIObserver>& aArray);
  73
  74   // Like FillObserverArray(), but only for strongly held observers.
  75   void AppendStrongObservers(nsCOMArray<nsIObserver>& aArray);
  76
  77 private:
  78   nsTArray<ObserverRef> mObservers;
  79 };
  80
  81 class nsObserverEnumerator MOZ_FINAL : public nsISimpleEnumerator
  82 {
  83 public:
  84   NS_DECL_ISUPPORTS
  85   NS_DECL_NSISIMPLEENUMERATOR
  86
  87   explicit nsObserverEnumerator(nsObserverList* aObserverList);
  88
  89 private:
  90   ~nsObserverEnumerator() {}
  91
  92   int32_t mIndex; // Counts up from 0
  93   nsCOMArray<nsIObserver> mObservers;
  94 };
  95
  96 #endif /* nsObserverList_h___ */