xpcom/ds/nsObserverList.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   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 #include "nsObserverList.h"
   7
   8 #include "nsAutoPtr.h"
   9 #include "nsCOMArray.h"
  10 #include "nsISimpleEnumerator.h"
  11 #include "xpcpublic.h"
  12
  13 nsresult
  14 nsObserverList::AddObserver(nsIObserver* anObserver, bool ownsWeak)
  15 {
  16     NS_ASSERTION(anObserver, "Null input");
  17
  18     if (!ownsWeak) {
  19         ObserverRef* o = mObservers.AppendElement(anObserver);
  20         if (!o)
  21             return NS_ERROR_OUT_OF_MEMORY;
  22
  23         return NS_OK;
  24     }
  25
  26     nsCOMPtr<nsIWeakReference> weak = do_GetWeakReference(anObserver);
  27     if (!weak)
  28         return NS_NOINTERFACE;
  29
  30     ObserverRef *o = mObservers.AppendElement(weak);
  31     if (!o)
  32         return NS_ERROR_OUT_OF_MEMORY;
  33
  34     return NS_OK;
  35 }
  36
  37 nsresult
  38 nsObserverList::RemoveObserver(nsIObserver* anObserver)
  39 {
  40     NS_ASSERTION(anObserver, "Null input");
  41
  42     if (mObservers.RemoveElement(static_cast<nsISupports*>(anObserver)))
  43         return NS_OK;
  44
  45     nsCOMPtr<nsIWeakReference> observerRef = do_GetWeakReference(anObserver);
  46     if (!observerRef)
  47         return NS_ERROR_FAILURE;
  48
  49     if (!mObservers.RemoveElement(observerRef))
  50         return NS_ERROR_FAILURE;
  51
  52     return NS_OK;
  53 }
  54
  55 nsresult
  56 nsObserverList::GetObserverList(nsISimpleEnumerator** anEnumerator)
  57 {
  58     nsRefPtr<nsObserverEnumerator> e(new nsObserverEnumerator(this));
  59     e.forget(anEnumerator);
  60     return NS_OK;
  61 }
  62
  63 void
  64 nsObserverList::FillObserverArray(nsCOMArray<nsIObserver> &aArray)
  65 {
  66     aArray.SetCapacity(mObservers.Length());
  67
  68     nsTArray<ObserverRef> observers(mObservers);
  69
  70     for (int32_t i = observers.Length() - 1; i >= 0; --i) {
  71         if (observers[i].isWeakRef) {
  72             nsCOMPtr<nsIObserver> o(do_QueryReferent(observers[i].asWeak()));
  73             if (o) {
  74                 aArray.AppendObject(o);
  75             }
  76             else {
  77                 // the object has gone away, remove the weakref
  78                 mObservers.RemoveElement(observers[i].asWeak());
  79             }
  80         }
  81         else {
  82             aArray.AppendObject(observers[i].asObserver());
  83         }
  84     }
  85 }
  86
  87 void
  88 nsObserverList::NotifyObservers(nsISupports *aSubject,
  89                                 const char *aTopic,
  90                                 const char16_t *someData)
  91 {
  92     nsCOMArray<nsIObserver> observers;
  93     FillObserverArray(observers);
  94
  95     for (int32_t i = 0; i < observers.Count(); ++i) {
  96         observers[i]->Observe(aSubject, aTopic, someData);
  97     }
  98 }
  99
 100 void
 101 nsObserverList::UnmarkGrayStrongObservers()
 102 {
 103     for (uint32_t i = 0; i < mObservers.Length(); ++i) {
 104         if (!mObservers[i].isWeakRef) {
 105             xpc_TryUnmarkWrappedGrayObject(mObservers[i].asObserver());
 106         }
 107     }
 108 }
 109
 110 NS_IMPL_ISUPPORTS1(nsObserverEnumerator, nsISimpleEnumerator)
 111
 112 nsObserverEnumerator::nsObserverEnumerator(nsObserverList* aObserverList)
 113     : mIndex(0)
 114 {
 115     aObserverList->FillObserverArray(mObservers);
 116 }
 117
 118 NS_IMETHODIMP
 119 nsObserverEnumerator::HasMoreElements(bool *aResult)
 120 {
 121     *aResult = (mIndex < mObservers.Count());
 122     return NS_OK;
 123 }
 124
 125 NS_IMETHODIMP
 126 nsObserverEnumerator::GetNext(nsISupports* *aResult)
 127 {
 128     if (mIndex == mObservers.Count()) {
 129         NS_ERROR("Enumerating after HasMoreElements returned false.");
 130         return NS_ERROR_UNEXPECTED;
 131     }
 132
 133     NS_ADDREF(*aResult = mObservers[mIndex]);
 134     ++mIndex;
 135     return NS_OK;
 136 }