xpcom/ds/nsObserverList.h

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   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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  15  * The Original Code is mozilla.org code.
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  17  * The Initial Developer of the Original Code is
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  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
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  24  * Alternatively, the contents of this file may be used under the terms of
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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef nsObserverList_h___
  39 #define nsObserverList_h___
  40
  41 #include "nsISupports.h"
  42 #include "nsTArray.h"
  43 #include "nsCOMPtr.h"
  44 #include "nsCOMArray.h"
  45 #include "nsIObserver.h"
  46 #include "nsIWeakReference.h"
  47 #include "nsHashKeys.h"
  48 #include "nsISimpleEnumerator.h"
  49
  50 struct ObserverRef
  51 {
  52   ObserverRef(const ObserverRef& o) :
  53     isWeakRef(o.isWeakRef), ref(o.ref) { }
  54
  55   ObserverRef(nsIObserver* aObserver) : isWeakRef(PR_FALSE), ref(aObserver) { }
  56   ObserverRef(nsIWeakReference* aWeak) : isWeakRef(PR_TRUE), ref(aWeak) { }
  57
  58   PRBool isWeakRef;
  59   nsCOMPtr<nsISupports> ref;
  60
  61   nsIObserver* asObserver() {
  62     NS_ASSERTION(!isWeakRef, "Isn't a strong ref.");
  63     return static_cast<nsIObserver*>((nsISupports*) ref);
  64   }
  65
  66   nsIWeakReference* asWeak() {
  67     NS_ASSERTION(isWeakRef, "Isn't a weak ref.");
  68     return static_cast<nsIWeakReference*>((nsISupports*) ref);
  69   }
  70
  71   PRBool operator==(nsISupports* b) const { return ref == b; }
  72 };
  73
  74 class nsObserverList : public nsCharPtrHashKey
  75 {
  76 public:
  77   nsObserverList(const char *key) : nsCharPtrHashKey(key)
  78   { MOZ_COUNT_CTOR(nsObserverList); }
  79
  80   ~nsObserverList() { MOZ_COUNT_DTOR(nsObserverList); }
  81
  82   nsresult AddObserver(nsIObserver* anObserver, PRBool ownsWeak);
  83   nsresult RemoveObserver(nsIObserver* anObserver);
  84
  85   void NotifyObservers(nsISupports *aSubject,
  86                        const char *aTopic,
  87                        const PRUnichar *someData);
  88   nsresult GetObserverList(nsISimpleEnumerator** anEnumerator);
  89
  90   // Fill an array with the observers of this category.
  91   // The array is filled in last-added-first order.
  92   void FillObserverArray(nsCOMArray<nsIObserver> &aArray);
  93
  94 private:
  95   nsTArray<ObserverRef> mObservers;
  96 };
  97
  98 class nsObserverEnumerator : public nsISimpleEnumerator
  99 {
 100 public:
 101     NS_DECL_ISUPPORTS
 102     NS_DECL_NSISIMPLEENUMERATOR
 103
 104     nsObserverEnumerator(nsObserverList* aObserverList);
 105
 106 private:
 107     ~nsObserverEnumerator() { }
 108
 109     PRInt32 mIndex; // Counts up from 0
 110     nsCOMArray<nsIObserver> mObservers;
 111 };
 112
 113 #endif /* nsObserverList_h___ */