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3521fc20c7
This refactors the observer service code to improve readability, uses MOZ_TRY and other checking macros wherever possible to simplify error handling and replaces the ObserverRef class with the more generic nsMaybeWeakPtr class. This cuts away some code and halves the amount of memory needed to store an event listener. The external behavior is almost unchanged save for some error codes which are now more specific. Differential Revision: https://phabricator.services.mozilla.com/D11646 --HG-- extra : source : 10d910aa9f31435116a718bafe8a2b71c61fe23d
107 lines
2.6 KiB
C++
107 lines
2.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsObserverList.h"
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#include "mozilla/ResultExtensions.h"
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#include "nsAutoPtr.h"
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#include "nsCOMArray.h"
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#include "xpcpublic.h"
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nsresult
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nsObserverList::AddObserver(nsIObserver* anObserver, bool ownsWeak)
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{
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NS_ASSERTION(anObserver, "Null input");
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MOZ_TRY(mObservers.AppendWeakElement(anObserver, ownsWeak));
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return NS_OK;
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}
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nsresult
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nsObserverList::RemoveObserver(nsIObserver* anObserver)
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{
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NS_ASSERTION(anObserver, "Null input");
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MOZ_TRY(mObservers.RemoveWeakElement(anObserver));
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return NS_OK;
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}
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void
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nsObserverList::GetObserverList(nsISimpleEnumerator** anEnumerator)
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{
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RefPtr<nsObserverEnumerator> e(new nsObserverEnumerator(this));
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e.forget(anEnumerator);
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}
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void
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nsObserverList::FillObserverArray(nsCOMArray<nsIObserver>& aArray)
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{
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aArray.SetCapacity(mObservers.Length());
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nsMaybeWeakPtrArray<nsIObserver> observers(mObservers);
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for (int32_t i = observers.Length() - 1; i >= 0; --i) {
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nsCOMPtr<nsIObserver> observer = observers[i].GetValue();
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if (observer) {
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aArray.AppendObject(observer);
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} else {
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// the object has gone away, remove the weakref
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mObservers.RemoveElementAt(i);
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}
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}
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}
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void
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nsObserverList::AppendStrongObservers(nsCOMArray<nsIObserver>& aArray)
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{
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aArray.SetCapacity(aArray.Length() + mObservers.Length());
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for (int32_t i = mObservers.Length() - 1; i >= 0; --i) {
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if (!mObservers[i].IsWeak()) {
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nsCOMPtr<nsIObserver> observer = mObservers[i].GetValue();
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aArray.AppendObject(observer);
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}
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}
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}
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void
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nsObserverList::NotifyObservers(nsISupports* aSubject,
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const char* aTopic,
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const char16_t* someData)
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{
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nsCOMArray<nsIObserver> observers;
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FillObserverArray(observers);
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for (int32_t i = 0; i < observers.Count(); ++i) {
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observers[i]->Observe(aSubject, aTopic, someData);
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}
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}
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nsObserverEnumerator::nsObserverEnumerator(nsObserverList* aObserverList)
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: mIndex(0)
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{
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aObserverList->FillObserverArray(mObservers);
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}
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NS_IMETHODIMP
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nsObserverEnumerator::HasMoreElements(bool* aResult)
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{
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*aResult = (mIndex < mObservers.Count());
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return NS_OK;
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}
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NS_IMETHODIMP
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nsObserverEnumerator::GetNext(nsISupports** aResult)
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{
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if (mIndex == mObservers.Count()) {
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return NS_ERROR_FAILURE;
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}
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NS_ADDREF(*aResult = mObservers[mIndex]);
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++mIndex;
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return NS_OK;
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}
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