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/* -*- 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
#include "PlacesObservers.h"
#include "PlacesWeakCallbackWrapper.h"
#include "nsIWeakReferenceUtils.h"
#include "nsIXPConnect.h"
#include "mozilla/ClearOnShutdown.h"
namespace mozilla::dom {
template <class T>
struct Flagged {
Flagged(uint32_t aFlags, T&& aValue)
: flags(aFlags), value(std::forward<T>(aValue)) {}
Flagged(Flagged&& aOther)
: Flagged(std::move(aOther.flags), std::move(aOther.value)) {}
Flagged(const Flagged& aOther) = default;
~Flagged() = default;
uint32_t flags = 0;
T value;
};
template <class T>
using FlaggedArray = nsTArray<Flagged<T>>;
template <class T>
struct ListenerCollection {
static StaticAutoPtr<FlaggedArray<T>> gListeners;
static StaticAutoPtr<FlaggedArray<T>> gListenersToRemove;
static FlaggedArray<T>* GetListeners(bool aDoNotInit = false) {
MOZ_ASSERT(NS_IsMainThread());
if (!gListeners && !aDoNotInit) {
gListeners = new FlaggedArray<T>();
ClearOnShutdown(&gListeners);
}
return gListeners;
}
static FlaggedArray<T>* GetListenersToRemove(bool aDoNotInit = false) {
MOZ_ASSERT(NS_IsMainThread());
if (!gListenersToRemove && !aDoNotInit) {
gListenersToRemove = new FlaggedArray<T>();
ClearOnShutdown(&gListenersToRemove);
}
return gListenersToRemove;
}
};
template <class T>
StaticAutoPtr<FlaggedArray<T>> ListenerCollection<T>::gListeners;
template <class T>
StaticAutoPtr<FlaggedArray<T>> ListenerCollection<T>::gListenersToRemove;
using JSListeners = ListenerCollection<RefPtr<PlacesEventCallback>>;
using WeakJSListeners = ListenerCollection<WeakPtr<PlacesWeakCallbackWrapper>>;
using WeakNativeListeners =
ListenerCollection<WeakPtr<places::INativePlacesEventCallback>>;
// Even if NotifyListeners is called any timing, we mange the notifications with
// adding to this queue, then sending in sequence. This avoids sending nested
// notifications while previous ones are still being sent.
static nsTArray<Sequence<OwningNonNull<PlacesEvent>>> gNotificationQueue;
uint32_t GetEventTypeFlag(PlacesEventType aEventType) {
if (aEventType == PlacesEventType::None) {
return 0;
}
return 1 << ((uint32_t)aEventType - 1);
}
uint32_t GetFlagsForEventTypes(const nsTArray<PlacesEventType>& aEventTypes) {
uint32_t flags = 0;
for (PlacesEventType eventType : aEventTypes) {
flags |= GetEventTypeFlag(eventType);
}
return flags;
}
uint32_t GetFlagsForEvents(
const nsTArray<OwningNonNull<PlacesEvent>>& aEvents) {
uint32_t flags = 0;
for (const PlacesEvent& event : aEvents) {
flags |= GetEventTypeFlag(event.Type());
}
return flags;
}
template <class TWrapped, class TUnwrapped, class TListenerCollection>
MOZ_CAN_RUN_SCRIPT void CallListeners(
uint32_t aEventFlags, const Sequence<OwningNonNull<PlacesEvent>>& aEvents,
unsigned long aListenersLengthToCall,
const std::function<TUnwrapped(TWrapped&)>& aUnwrapListener,
const std::function<void(TUnwrapped&,
const Sequence<OwningNonNull<PlacesEvent>>&)>&
aCallListener) {
auto& listeners = *TListenerCollection::GetListeners();
for (uint32_t i = 0; i < aListenersLengthToCall; i++) {
Flagged<TWrapped>& listener = listeners[i];
TUnwrapped unwrapped = aUnwrapListener(listener.value);
if (!unwrapped) {
continue;
}
if ((listener.flags & aEventFlags) == aEventFlags) {
aCallListener(unwrapped, aEvents);
} else if (listener.flags & aEventFlags) {
Sequence<OwningNonNull<PlacesEvent>> filtered;
for (const OwningNonNull<PlacesEvent>& event : aEvents) {
if (listener.flags & GetEventTypeFlag(event->Type())) {
bool success = !!filtered.AppendElement(event, fallible);
MOZ_RELEASE_ASSERT(success);
}
}
aCallListener(unwrapped, filtered);
}
}
}
StaticRefPtr<PlacesEventCounts> PlacesObservers::sCounts;
static void EnsureCountsInitialized() {
if (!PlacesObservers::sCounts) {
PlacesObservers::sCounts = new PlacesEventCounts();
ClearOnShutdown(&PlacesObservers::sCounts);
}
}
void PlacesObservers::AddListener(GlobalObject& aGlobal,
const nsTArray<PlacesEventType>& aEventTypes,
PlacesEventCallback& aCallback,
ErrorResult& rv) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
FlaggedArray<RefPtr<PlacesEventCallback>>* listeners =
JSListeners::GetListeners();
Flagged<RefPtr<PlacesEventCallback>> pair(flags, &aCallback);
listeners->AppendElement(pair);
}
void PlacesObservers::AddListener(GlobalObject& aGlobal,
const nsTArray<PlacesEventType>& aEventTypes,
PlacesWeakCallbackWrapper& aCallback,
ErrorResult& rv) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
FlaggedArray<WeakPtr<PlacesWeakCallbackWrapper>>* listeners =
WeakJSListeners::GetListeners();
WeakPtr<PlacesWeakCallbackWrapper> weakCb(&aCallback);
MOZ_ASSERT(weakCb.get());
Flagged<WeakPtr<PlacesWeakCallbackWrapper>> flagged(flags, std::move(weakCb));
listeners->AppendElement(flagged);
}
void PlacesObservers::AddListener(
const nsTArray<PlacesEventType>& aEventTypes,
places::INativePlacesEventCallback* aCallback) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
FlaggedArray<WeakPtr<places::INativePlacesEventCallback>>* listeners =
WeakNativeListeners::GetListeners();
Flagged<WeakPtr<places::INativePlacesEventCallback>> pair(flags, aCallback);
listeners->AppendElement(pair);
}
void PlacesObservers::RemoveListener(
GlobalObject& aGlobal, const nsTArray<PlacesEventType>& aEventTypes,
PlacesEventCallback& aCallback, ErrorResult& rv) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
if (!gNotificationQueue.IsEmpty()) {
FlaggedArray<RefPtr<PlacesEventCallback>>* listeners =
JSListeners::GetListenersToRemove();
Flagged<RefPtr<PlacesEventCallback>> pair(flags, &aCallback);
listeners->AppendElement(pair);
} else {
RemoveListener(flags, aCallback);
}
}
void PlacesObservers::RemoveListener(
GlobalObject& aGlobal, const nsTArray<PlacesEventType>& aEventTypes,
PlacesWeakCallbackWrapper& aCallback, ErrorResult& rv) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
if (!gNotificationQueue.IsEmpty()) {
FlaggedArray<WeakPtr<PlacesWeakCallbackWrapper>>* listeners =
WeakJSListeners::GetListenersToRemove();
WeakPtr<PlacesWeakCallbackWrapper> weakCb(&aCallback);
MOZ_ASSERT(weakCb.get());
Flagged<WeakPtr<PlacesWeakCallbackWrapper>> flagged(flags,
std::move(weakCb));
listeners->AppendElement(flagged);
} else {
RemoveListener(flags, aCallback);
}
}
void PlacesObservers::RemoveListener(
const nsTArray<PlacesEventType>& aEventTypes,
places::INativePlacesEventCallback* aCallback) {
uint32_t flags = GetFlagsForEventTypes(aEventTypes);
if (!gNotificationQueue.IsEmpty()) {
FlaggedArray<WeakPtr<places::INativePlacesEventCallback>>* listeners =
WeakNativeListeners::GetListenersToRemove();
Flagged<WeakPtr<places::INativePlacesEventCallback>> pair(flags, aCallback);
listeners->AppendElement(pair);
} else {
RemoveListener(flags, aCallback);
}
}
void PlacesObservers::RemoveListener(uint32_t aFlags,
PlacesEventCallback& aCallback) {
FlaggedArray<RefPtr<PlacesEventCallback>>* listeners =
JSListeners::GetListeners(/* aDoNotInit: */ true);
if (!listeners) {
return;
}
for (uint32_t i = 0; i < listeners->Length(); i++) {
Flagged<RefPtr<PlacesEventCallback>>& l = listeners->ElementAt(i);
if (!(*l.value == aCallback)) {
continue;
}
if (l.flags == (aFlags & l.flags)) {
listeners->RemoveElementAt(i);
i--;
} else {
l.flags &= ~aFlags;
}
}
}
void PlacesObservers::RemoveListener(uint32_t aFlags,
PlacesWeakCallbackWrapper& aCallback) {
FlaggedArray<WeakPtr<PlacesWeakCallbackWrapper>>* listeners =
WeakJSListeners::GetListeners(/* aDoNotInit: */ true);
if (!listeners) {
return;
}
for (uint32_t i = 0; i < listeners->Length(); i++) {
Flagged<WeakPtr<PlacesWeakCallbackWrapper>>& l = listeners->ElementAt(i);
RefPtr<PlacesWeakCallbackWrapper> unwrapped = l.value.get();
if (unwrapped != &aCallback) {
continue;
}
if (l.flags == (aFlags & l.flags)) {
listeners->RemoveElementAt(i);
i--;
} else {
l.flags &= ~aFlags;
}
}
}
void PlacesObservers::RemoveListener(
uint32_t aFlags, places::INativePlacesEventCallback* aCallback) {
FlaggedArray<WeakPtr<places::INativePlacesEventCallback>>* listeners =
WeakNativeListeners::GetListeners(/* aDoNotInit: */ true);
if (!listeners) {
return;
}
for (uint32_t i = 0; i < listeners->Length(); i++) {
Flagged<WeakPtr<places::INativePlacesEventCallback>>& l =
listeners->ElementAt(i);
RefPtr<places::INativePlacesEventCallback> unwrapped = l.value.get();
if (unwrapped != aCallback) {
continue;
}
if (l.flags == (aFlags & l.flags)) {
listeners->RemoveElementAt(i);
i--;
} else {
l.flags &= ~aFlags;
}
}
}
template <class TWrapped, class TUnwrapped, class TListenerCollection>
void CleanupListeners(
const std::function<TUnwrapped(TWrapped&)>& aUnwrapListener,
const std::function<void(Flagged<TWrapped>&)>& aRemoveListener) {
auto& listeners = *TListenerCollection::GetListeners();
for (uint32_t i = 0; i < listeners.Length(); i++) {
Flagged<TWrapped>& listener = listeners[i];
TUnwrapped unwrapped = aUnwrapListener(listener.value);
if (!unwrapped) {
listeners.RemoveElementAt(i);
i--;
}
}
auto& listenersToRemove = *TListenerCollection::GetListenersToRemove();
for (auto& listener : listenersToRemove) {
aRemoveListener(listener);
}
listenersToRemove.Clear();
}
void PlacesObservers::NotifyListeners(
GlobalObject& aGlobal, const Sequence<OwningNonNull<PlacesEvent>>& aEvents,
ErrorResult& rv) {
NotifyListeners(aEvents);
}
void PlacesObservers::NotifyListeners(
const Sequence<OwningNonNull<PlacesEvent>>& aEvents) {
MOZ_ASSERT(aEvents.Length() > 0, "Must pass a populated array of events");
if (aEvents.Length() == 0) {
return;
}
EnsureCountsInitialized();
for (const auto& event : aEvents) {
DebugOnly<nsresult> rv = sCounts->Increment(event->Type());
MOZ_ASSERT(NS_SUCCEEDED(rv));
}
#ifdef DEBUG
if (!gNotificationQueue.IsEmpty()) {
NS_WARNING(
"Avoid nested Places notifications if possible, the order of events "
"cannot be guaranteed");
nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
Unused << xpc->DebugDumpJSStack(false, false, false);
}
#endif
gNotificationQueue.AppendElement(aEvents);
// If gNotificationQueue has only the events we added now, start to notify.
// Otherwise, as it already started the notification processing,
// rely on the processing.
if (gNotificationQueue.Length() == 1) {
NotifyNext();
}
}
void PlacesObservers::NotifyNext() {
auto events = gNotificationQueue[0];
uint32_t flags = GetFlagsForEvents(events);
// Send up to the number of current listeners, to avoid handling listeners
// added during this notification.
unsigned long jsListenersLength = JSListeners::GetListeners()->Length();
unsigned long weakNativeListenersLength =
WeakNativeListeners::GetListeners()->Length();
unsigned long weakJSListenersLength =
WeakJSListeners::GetListeners()->Length();
CallListeners<RefPtr<PlacesEventCallback>, RefPtr<PlacesEventCallback>,
JSListeners>(
flags, events, jsListenersLength, [](auto& cb) { return cb; },
// MOZ_CAN_RUN_SCRIPT_BOUNDARY because on Windows this gets called from
// some internals of the std::function implementation that we can't
// annotate. We handle this by annotating CallListeners and making sure
// it holds a strong ref to the callback.
[&](auto& cb, const auto& events)
MOZ_CAN_RUN_SCRIPT_BOUNDARY { MOZ_KnownLive(cb)->Call(events); });
CallListeners<WeakPtr<places::INativePlacesEventCallback>,
RefPtr<places::INativePlacesEventCallback>,
WeakNativeListeners>(
flags, events, weakNativeListenersLength,
[](auto& cb) { return cb.get(); },
[&](auto& cb, const Sequence<OwningNonNull<PlacesEvent>>& events) {
cb->HandlePlacesEvent(events);
});
CallListeners<WeakPtr<PlacesWeakCallbackWrapper>,
RefPtr<PlacesWeakCallbackWrapper>, WeakJSListeners>(
flags, events, weakJSListenersLength, [](auto& cb) { return cb.get(); },
// MOZ_CAN_RUN_SCRIPT_BOUNDARY because on Windows this gets called from
// some internals of the std::function implementation that we can't
// annotate. We handle this by annotating CallListeners and making sure
// it holds a strong ref to the callback.
[&](auto& cb, const auto& events) MOZ_CAN_RUN_SCRIPT_BOUNDARY {
RefPtr<PlacesEventCallback> callback(cb->mCallback);
callback->Call(events);
});
gNotificationQueue.RemoveElementAt(0);
CleanupListeners<RefPtr<PlacesEventCallback>, RefPtr<PlacesEventCallback>,
JSListeners>(
[](auto& cb) { return cb; },
[&](auto& cb) { RemoveListener(cb.flags, *cb.value); });
CleanupListeners<WeakPtr<PlacesWeakCallbackWrapper>,
RefPtr<PlacesWeakCallbackWrapper>, WeakJSListeners>(
[](auto& cb) { return cb.get(); },
[&](auto& cb) { RemoveListener(cb.flags, *cb.value.get()); });
CleanupListeners<WeakPtr<places::INativePlacesEventCallback>,
RefPtr<places::INativePlacesEventCallback>,
WeakNativeListeners>(
[](auto& cb) { return cb.get(); },
[&](auto& cb) { RemoveListener(cb.flags, cb.value.get()); });
if (!gNotificationQueue.IsEmpty()) {
NotifyNext();
}
}
already_AddRefed<PlacesEventCounts> PlacesObservers::Counts(
const GlobalObject& global) {
EnsureCountsInitialized();
return do_AddRef(sCounts);
};
} // namespace mozilla::dom