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 #include "nsObserverList.h"
8
9 #include "mozilla/ResultExtensions.h"
10 #include "nsCOMArray.h"
11 #include "xpcpublic.h"
12
AddObserver(nsIObserver * anObserver,bool ownsWeak)13 nsresult nsObserverList::AddObserver(nsIObserver* anObserver, bool ownsWeak) {
14 NS_ASSERTION(anObserver, "Null input");
15
16 MOZ_TRY(mObservers.AppendWeakElement(anObserver, ownsWeak));
17 return NS_OK;
18 }
19
RemoveObserver(nsIObserver * anObserver)20 nsresult nsObserverList::RemoveObserver(nsIObserver* anObserver) {
21 NS_ASSERTION(anObserver, "Null input");
22
23 MOZ_TRY(mObservers.RemoveWeakElement(anObserver));
24 return NS_OK;
25 }
26
GetObserverList(nsISimpleEnumerator ** anEnumerator)27 void nsObserverList::GetObserverList(nsISimpleEnumerator** anEnumerator) {
28 RefPtr<nsObserverEnumerator> e(new nsObserverEnumerator(this));
29 e.forget(anEnumerator);
30 }
31
ReverseCloneObserverArray()32 nsCOMArray<nsIObserver> nsObserverList::ReverseCloneObserverArray() {
33 nsCOMArray<nsIObserver> array;
34 array.SetCapacity(mObservers.Length());
35
36 // XXX This could also use RemoveElementsBy if we lifted the promise to fill
37 // aArray in reverse order. Although there shouldn't be anyone explicitly
38 // relying on the order, changing this might cause subtle problems, so we
39 // better leave it as it is.
40
41 for (int32_t i = mObservers.Length() - 1; i >= 0; --i) {
42 nsCOMPtr<nsIObserver> observer = mObservers[i].GetValue();
43 if (observer) {
44 array.AppendElement(observer.forget());
45 } else {
46 // the object has gone away, remove the weakref
47 mObservers.RemoveElementAt(i);
48 }
49 }
50
51 return array;
52 }
53
AppendStrongObservers(nsCOMArray<nsIObserver> & aArray)54 void nsObserverList::AppendStrongObservers(nsCOMArray<nsIObserver>& aArray) {
55 aArray.SetCapacity(aArray.Length() + mObservers.Length());
56
57 for (int32_t i = mObservers.Length() - 1; i >= 0; --i) {
58 if (!mObservers[i].IsWeak()) {
59 nsCOMPtr<nsIObserver> observer = mObservers[i].GetValue();
60 aArray.AppendObject(observer);
61 }
62 }
63 }
64
NotifyObservers(nsISupports * aSubject,const char * aTopic,const char16_t * someData)65 void nsObserverList::NotifyObservers(nsISupports* aSubject, const char* aTopic,
66 const char16_t* someData) {
67 const nsCOMArray<nsIObserver> observers = ReverseCloneObserverArray();
68
69 for (int32_t i = 0; i < observers.Count(); ++i) {
70 observers[i]->Observe(aSubject, aTopic, someData);
71 }
72 }
73
nsObserverEnumerator(nsObserverList * aObserverList)74 nsObserverEnumerator::nsObserverEnumerator(nsObserverList* aObserverList)
75 : mIndex(0), mObservers(aObserverList->ReverseCloneObserverArray()) {}
76
77 NS_IMETHODIMP
HasMoreElements(bool * aResult)78 nsObserverEnumerator::HasMoreElements(bool* aResult) {
79 *aResult = (mIndex < mObservers.Count());
80 return NS_OK;
81 }
82
83 NS_IMETHODIMP
GetNext(nsISupports ** aResult)84 nsObserverEnumerator::GetNext(nsISupports** aResult) {
85 if (mIndex == mObservers.Count()) {
86 return NS_ERROR_FAILURE;
87 }
88
89 NS_ADDREF(*aResult = mObservers[mIndex]);
90 ++mIndex;
91 return NS_OK;
92 }
93