gecko-dev/xpcom/components/nsCategoryCache.cpp
Ehsan Akhgari 772e364199 Bug 1360971 - Part 1: Add the nsCategoryCache<T>::GetCachedEntries() API; r=froydnj
This provides a more efficient way to read the entries out of an
XPCOM category cache.
2017-05-08 10:31:13 -04:00

179 lines
4.9 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "nsIObserverService.h"
#include "mozilla/Services.h"
#include "nsISupportsPrimitives.h"
#include "nsIStringEnumerator.h"
#include "nsXPCOMCID.h"
#include "nsCategoryCache.h"
nsCategoryObserver::nsCategoryObserver(const char* aCategory)
: mCategory(aCategory)
, mCallback(nullptr)
, mClosure(nullptr)
, mObserversRemoved(false)
{
MOZ_ASSERT(NS_IsMainThread());
// First, enumerate the currently existing entries
nsCOMPtr<nsICategoryManager> catMan =
do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
if (!catMan) {
return;
}
nsCOMPtr<nsISimpleEnumerator> enumerator;
nsresult rv = catMan->EnumerateCategory(aCategory,
getter_AddRefs(enumerator));
if (NS_FAILED(rv)) {
return;
}
nsCOMPtr<nsIUTF8StringEnumerator> strings = do_QueryInterface(enumerator);
MOZ_ASSERT(strings);
bool more;
while (NS_SUCCEEDED(strings->HasMore(&more)) && more) {
nsAutoCString entryName;
strings->GetNext(entryName);
nsCString entryValue;
rv = catMan->GetCategoryEntry(aCategory,
entryName.get(),
getter_Copies(entryValue));
if (NS_SUCCEEDED(rv)) {
nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
if (service) {
mHash.Put(entryName, service);
}
}
}
// Now, listen for changes
nsCOMPtr<nsIObserverService> serv =
mozilla::services::GetObserverService();
if (serv) {
serv->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID, false);
serv->AddObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID, false);
serv->AddObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID, false);
}
}
nsCategoryObserver::~nsCategoryObserver() = default;
NS_IMPL_ISUPPORTS(nsCategoryObserver, nsIObserver)
void
nsCategoryObserver::ListenerDied()
{
MOZ_ASSERT(NS_IsMainThread());
RemoveObservers();
mCallback = nullptr;
mClosure = nullptr;
}
void
nsCategoryObserver::SetListener(void(aCallback)(void*), void* aClosure)
{
MOZ_ASSERT(NS_IsMainThread());
mCallback = aCallback;
mClosure = aClosure;
}
void
nsCategoryObserver::RemoveObservers()
{
MOZ_ASSERT(NS_IsMainThread());
if (mObserversRemoved) {
return;
}
if (mCallback) {
mCallback(mClosure);
}
mObserversRemoved = true;
nsCOMPtr<nsIObserverService> obsSvc =
mozilla::services::GetObserverService();
if (obsSvc) {
obsSvc->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID);
obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID);
obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID);
obsSvc->RemoveObserver(this, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID);
}
}
NS_IMETHODIMP
nsCategoryObserver::Observe(nsISupports* aSubject, const char* aTopic,
const char16_t* aData)
{
MOZ_ASSERT(NS_IsMainThread());
if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
mHash.Clear();
RemoveObservers();
return NS_OK;
}
if (!aData ||
!nsDependentString(aData).Equals(NS_ConvertASCIItoUTF16(mCategory))) {
return NS_OK;
}
nsAutoCString str;
nsCOMPtr<nsISupportsCString> strWrapper(do_QueryInterface(aSubject));
if (strWrapper) {
strWrapper->GetData(str);
}
if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_ADDED_OBSERVER_ID) == 0) {
// We may get an add notification even when we already have an entry. This
// is due to the notification happening asynchronously, so if the entry gets
// added and an nsCategoryObserver gets instantiated before events get
// processed, we'd get the notification for an existing entry.
// Do nothing in that case.
if (mHash.GetWeak(str)) {
return NS_OK;
}
nsCOMPtr<nsICategoryManager> catMan =
do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
if (!catMan) {
return NS_OK;
}
nsCString entryValue;
catMan->GetCategoryEntry(mCategory.get(),
str.get(),
getter_Copies(entryValue));
nsCOMPtr<nsISupports> service = do_GetService(entryValue.get());
if (service) {
mHash.Put(str, service);
}
if (mCallback) {
mCallback(mClosure);
}
} else if (strcmp(aTopic, NS_XPCOM_CATEGORY_ENTRY_REMOVED_OBSERVER_ID) == 0) {
mHash.Remove(str);
if (mCallback) {
mCallback(mClosure);
}
} else if (strcmp(aTopic, NS_XPCOM_CATEGORY_CLEARED_OBSERVER_ID) == 0) {
mHash.Clear();
if (mCallback) {
mCallback(mClosure);
}
}
return NS_OK;
}