xpcom/ds/nsObserverList.cpp

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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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  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #include "nsObserverList.h"
  39
  40 #include "nsAutoPtr.h"
  41 #include "nsCOMArray.h"
  42 #include "nsISimpleEnumerator.h"
  43
  44 nsresult
  45 nsObserverList::AddObserver(nsIObserver* anObserver, PRBool ownsWeak)
  46 {
  47     NS_ASSERTION(anObserver, "Null input");
  48
  49     if (!ownsWeak) {
  50         ObserverRef* o = mObservers.AppendElement(anObserver);
  51         if (!o)
  52             return NS_ERROR_OUT_OF_MEMORY;
  53
  54         return NS_OK;
  55     }
  56
  57     nsCOMPtr<nsIWeakReference> weak = do_GetWeakReference(anObserver);
  58     if (!weak)
  59         return NS_NOINTERFACE;
  60
  61     ObserverRef *o = mObservers.AppendElement(weak);
  62     if (!o)
  63         return NS_ERROR_OUT_OF_MEMORY;
  64
  65     return NS_OK;
  66 }
  67
  68 nsresult
  69 nsObserverList::RemoveObserver(nsIObserver* anObserver)
  70 {
  71     NS_ASSERTION(anObserver, "Null input");
  72
  73     if (mObservers.RemoveElement(static_cast<nsISupports*>(anObserver)))
  74         return NS_OK;
  75
  76     nsCOMPtr<nsIWeakReference> observerRef = do_GetWeakReference(anObserver);
  77     if (!observerRef)
  78         return NS_ERROR_FAILURE;
  79
  80     if (!mObservers.RemoveElement(observerRef))
  81         return NS_ERROR_FAILURE;
  82
  83     return NS_OK;
  84 }
  85
  86 nsresult
  87 nsObserverList::GetObserverList(nsISimpleEnumerator** anEnumerator)
  88 {
  89     nsRefPtr<nsObserverEnumerator> e(new nsObserverEnumerator(this));
  90     if (!e)
  91         return NS_ERROR_OUT_OF_MEMORY;
  92
  93     NS_ADDREF(*anEnumerator = e);
  94     return NS_OK;
  95 }
  96
  97 void
  98 nsObserverList::FillObserverArray(nsCOMArray<nsIObserver> &aArray)
  99 {
 100     aArray.SetCapacity(mObservers.Length());
 101
 102     nsTArray<ObserverRef> observers(mObservers);
 103
 104     for (PRInt32 i = observers.Length() - 1; i >= 0; --i) {
 105         if (observers[i].isWeakRef) {
 106             nsCOMPtr<nsIObserver> o(do_QueryReferent(observers[i].asWeak()));
 107             if (o) {
 108                 aArray.AppendObject(o);
 109             }
 110             else {
 111                 // the object has gone away, remove the weakref
 112                 mObservers.RemoveElement(observers[i].asWeak());
 113             }
 114         }
 115         else {
 116             aArray.AppendObject(observers[i].asObserver());
 117         }
 118     }
 119 }
 120
 121 void
 122 nsObserverList::NotifyObservers(nsISupports *aSubject,
 123                                 const char *aTopic,
 124                                 const PRUnichar *someData)
 125 {
 126     nsCOMArray<nsIObserver> observers;
 127     FillObserverArray(observers);
 128
 129     for (PRInt32 i = 0; i < observers.Count(); ++i) {
 130         observers[i]->Observe(aSubject, aTopic, someData);
 131     }
 132 }
 133
 134 NS_IMPL_ISUPPORTS1(nsObserverEnumerator, nsISimpleEnumerator)
 135
 136 nsObserverEnumerator::nsObserverEnumerator(nsObserverList* aObserverList)
 137     : mIndex(0)
 138 {
 139     aObserverList->FillObserverArray(mObservers);
 140 }
 141
 142 NS_IMETHODIMP
 143 nsObserverEnumerator::HasMoreElements(PRBool *aResult)
 144 {
 145     *aResult = (mIndex < mObservers.Count());
 146     return NS_OK;
 147 }
 148
 149 NS_IMETHODIMP
 150 nsObserverEnumerator::GetNext(nsISupports* *aResult)
 151 {
 152     if (mIndex == mObservers.Count()) {
 153         NS_ERROR("Enumerating after HasMoreElements returned false.");
 154         return NS_ERROR_UNEXPECTED;
 155     }
 156
 157     NS_ADDREF(*aResult = mObservers[mIndex]);
 158     ++mIndex;
 159     return NS_OK;
 160 }