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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /accessible/base/NotificationController.cpp
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'accessible/base/NotificationController.cpp')
-rw-r--r--accessible/base/NotificationController.cpp1107
1 files changed, 1107 insertions, 0 deletions
diff --git a/accessible/base/NotificationController.cpp b/accessible/base/NotificationController.cpp
new file mode 100644
index 0000000000..63786861f1
--- /dev/null
+++ b/accessible/base/NotificationController.cpp
@@ -0,0 +1,1107 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "NotificationController.h"
+
+#include "DocAccessible-inl.h"
+#include "DocAccessibleChild.h"
+#include "LocalAccessible-inl.h"
+#include "nsEventShell.h"
+#include "TextLeafAccessible.h"
+#include "TextUpdater.h"
+
+#include "nsIContentInlines.h"
+
+#include "mozilla/dom/BrowserChild.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/ipc/ProcessChild.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/ProfilerMarkers.h"
+#include "nsAccessibilityService.h"
+#include "mozilla/Telemetry.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+using namespace mozilla::dom;
+
+////////////////////////////////////////////////////////////////////////////////
+// NotificationCollector
+////////////////////////////////////////////////////////////////////////////////
+
+NotificationController::NotificationController(DocAccessible* aDocument,
+ PresShell* aPresShell)
+ : EventQueue(aDocument),
+ mObservingState(eNotObservingRefresh),
+ mPresShell(aPresShell),
+ mEventGeneration(0) {
+ // Schedule initial accessible tree construction.
+ ScheduleProcessing();
+}
+
+NotificationController::~NotificationController() {
+ NS_ASSERTION(!mDocument, "Controller wasn't shutdown properly!");
+ if (mDocument) {
+ Shutdown();
+ }
+ MOZ_RELEASE_ASSERT(mObservingState == eNotObservingRefresh,
+ "Must unregister before being destroyed");
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NotificationCollector: AddRef/Release and cycle collection
+
+NS_IMPL_CYCLE_COLLECTING_NATIVE_ADDREF(NotificationController)
+NS_IMPL_CYCLE_COLLECTING_NATIVE_RELEASE(NotificationController)
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(NotificationController)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(NotificationController)
+ if (tmp->mDocument) {
+ tmp->Shutdown();
+ }
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(NotificationController)
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mHangingChildDocuments)
+ for (const auto& entry : tmp->mContentInsertions) {
+ NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mContentInsertions key");
+ cb.NoteXPCOMChild(entry.GetKey());
+ nsTArray<nsCOMPtr<nsIContent>>* list = entry.GetData().get();
+ for (uint32_t i = 0; i < list->Length(); i++) {
+ NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mContentInsertions value item");
+ cb.NoteXPCOMChild(list->ElementAt(i));
+ }
+ }
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFocusEvent)
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEvents)
+ NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRelocations)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+////////////////////////////////////////////////////////////////////////////////
+// NotificationCollector: public
+
+void NotificationController::Shutdown() {
+ if (mObservingState != eNotObservingRefresh &&
+ mPresShell->RemoveRefreshObserver(this, FlushType::Display)) {
+ // Note, this was our last chance to unregister, since we're about to
+ // clear mPresShell further down in this function.
+ mObservingState = eNotObservingRefresh;
+ }
+ MOZ_RELEASE_ASSERT(mObservingState == eNotObservingRefresh,
+ "Must unregister before being destroyed (and we just "
+ "passed our last change to unregister)");
+ // Immediately null out mPresShell, to prevent us from being registered as a
+ // refresh observer again.
+ mPresShell = nullptr;
+
+ // Shutdown handling child documents.
+ int32_t childDocCount = mHangingChildDocuments.Length();
+ for (int32_t idx = childDocCount - 1; idx >= 0; idx--) {
+ if (!mHangingChildDocuments[idx]->IsDefunct()) {
+ mHangingChildDocuments[idx]->Shutdown();
+ }
+ }
+
+ mHangingChildDocuments.Clear();
+
+ mDocument = nullptr;
+
+ mTextArray.Clear();
+ mContentInsertions.Clear();
+ mNotifications.Clear();
+ mFocusEvent = nullptr;
+ mEvents.Clear();
+ mRelocations.Clear();
+}
+
+void NotificationController::CoalesceHideEvent(AccHideEvent* aHideEvent) {
+ LocalAccessible* parent = aHideEvent->LocalParent();
+ while (parent) {
+ if (parent->IsDoc()) {
+ break;
+ }
+
+ if (parent->HideEventTarget()) {
+ DropMutationEvent(aHideEvent);
+ break;
+ }
+
+ if (parent->ShowEventTarget()) {
+ AccShowEvent* showEvent =
+ downcast_accEvent(mMutationMap.GetEvent(parent, EventMap::ShowEvent));
+ if (showEvent->EventGeneration() < aHideEvent->EventGeneration()) {
+ DropMutationEvent(aHideEvent);
+ break;
+ }
+ }
+
+ parent = parent->LocalParent();
+ }
+}
+
+bool NotificationController::QueueMutationEvent(AccTreeMutationEvent* aEvent) {
+ if (aEvent->GetEventType() == nsIAccessibleEvent::EVENT_HIDE) {
+ // We have to allow there to be a hide and then a show event for a target
+ // because of targets getting moved. However we need to coalesce a show and
+ // then a hide for a target which means we need to check for that here.
+ if (aEvent->GetAccessible()->ShowEventTarget()) {
+ AccTreeMutationEvent* showEvent =
+ mMutationMap.GetEvent(aEvent->GetAccessible(), EventMap::ShowEvent);
+ DropMutationEvent(showEvent);
+ return false;
+ }
+
+ // Don't queue a hide event on an accessible that's already being moved. It
+ // or an ancestor should already have a hide event queued.
+ if (mDocument &&
+ mDocument->IsAccessibleBeingMoved(aEvent->GetAccessible())) {
+ return false;
+ }
+
+ // If this is an additional hide event, the accessible may be hidden, or
+ // moved again after a move. Preserve the original hide event since
+ // its properties are consistent with the tree that existed before
+ // the next batch of mutation events is processed.
+ if (aEvent->GetAccessible()->HideEventTarget()) {
+ return false;
+ }
+ }
+
+ AccMutationEvent* mutEvent = downcast_accEvent(aEvent);
+ mEventGeneration++;
+ mutEvent->SetEventGeneration(mEventGeneration);
+
+ if (!mFirstMutationEvent) {
+ mFirstMutationEvent = aEvent;
+ ScheduleProcessing();
+ }
+
+ if (mLastMutationEvent) {
+ NS_ASSERTION(!mLastMutationEvent->NextEvent(),
+ "why isn't the last event the end?");
+ mLastMutationEvent->SetNextEvent(aEvent);
+ }
+
+ aEvent->SetPrevEvent(mLastMutationEvent);
+ mLastMutationEvent = aEvent;
+ mMutationMap.PutEvent(aEvent);
+
+ // Because we could be hiding the target of a show event we need to get rid
+ // of any such events.
+ if (aEvent->GetEventType() == nsIAccessibleEvent::EVENT_HIDE) {
+ CoalesceHideEvent(downcast_accEvent(aEvent));
+
+ // mLastMutationEvent will point to something other than aEvent if and only
+ // if aEvent was just coalesced away. In that case a parent accessible
+ // must already have the required reorder and text change events so we are
+ // done here.
+ if (mLastMutationEvent != aEvent) {
+ return false;
+ }
+ }
+
+ // We need to fire a reorder event after all of the events targeted at shown
+ // or hidden children of a container. So either queue a new one, or move an
+ // existing one to the end of the queue if the container already has a
+ // reorder event.
+ LocalAccessible* container = aEvent->GetAccessible()->LocalParent();
+ RefPtr<AccReorderEvent> reorder;
+ if (!container->ReorderEventTarget()) {
+ reorder = new AccReorderEvent(container);
+ container->SetReorderEventTarget(true);
+ mMutationMap.PutEvent(reorder);
+
+ // Since this is the first child of container that is changing, the name
+ // and/or description of dependent Accessibles may be changing.
+ if (PushNameOrDescriptionChange(aEvent)) {
+ ScheduleProcessing();
+ }
+ } else {
+ AccReorderEvent* event = downcast_accEvent(
+ mMutationMap.GetEvent(container, EventMap::ReorderEvent));
+ reorder = event;
+ if (mFirstMutationEvent == event) {
+ mFirstMutationEvent = event->NextEvent();
+ } else {
+ event->PrevEvent()->SetNextEvent(event->NextEvent());
+ }
+
+ event->NextEvent()->SetPrevEvent(event->PrevEvent());
+ event->SetNextEvent(nullptr);
+ }
+
+ reorder->SetEventGeneration(mEventGeneration);
+ reorder->SetPrevEvent(mLastMutationEvent);
+ mLastMutationEvent->SetNextEvent(reorder);
+ mLastMutationEvent = reorder;
+
+ // It is not possible to have a text change event for something other than a
+ // hyper text accessible.
+ if (!container->IsHyperText()) {
+ return true;
+ }
+
+ MOZ_ASSERT(mutEvent);
+
+ nsString text;
+ aEvent->GetAccessible()->AppendTextTo(text);
+ if (text.IsEmpty()) {
+ return true;
+ }
+
+ LocalAccessible* target = aEvent->GetAccessible();
+ int32_t offset = container->AsHyperText()->GetChildOffset(target);
+ AccTreeMutationEvent* prevEvent = aEvent->PrevEvent();
+ while (prevEvent &&
+ prevEvent->GetEventType() == nsIAccessibleEvent::EVENT_REORDER) {
+ prevEvent = prevEvent->PrevEvent();
+ }
+
+ if (prevEvent &&
+ prevEvent->GetEventType() == nsIAccessibleEvent::EVENT_HIDE &&
+ mutEvent->IsHide()) {
+ AccHideEvent* prevHide = downcast_accEvent(prevEvent);
+ AccTextChangeEvent* prevTextChange = prevHide->mTextChangeEvent;
+ if (prevTextChange && prevHide->LocalParent() == mutEvent->LocalParent()) {
+ if (prevHide->mNextSibling == target) {
+ target->AppendTextTo(prevTextChange->mModifiedText);
+ prevHide->mTextChangeEvent.swap(mutEvent->mTextChangeEvent);
+ } else if (prevHide->mPrevSibling == target) {
+ nsString temp;
+ target->AppendTextTo(temp);
+
+ uint32_t extraLen = temp.Length();
+ temp += prevTextChange->mModifiedText;
+ ;
+ prevTextChange->mModifiedText = temp;
+ prevTextChange->mStart -= extraLen;
+ prevHide->mTextChangeEvent.swap(mutEvent->mTextChangeEvent);
+ }
+ }
+ } else if (prevEvent && mutEvent->IsShow() &&
+ prevEvent->GetEventType() == nsIAccessibleEvent::EVENT_SHOW) {
+ AccShowEvent* prevShow = downcast_accEvent(prevEvent);
+ AccTextChangeEvent* prevTextChange = prevShow->mTextChangeEvent;
+ if (prevTextChange && prevShow->LocalParent() == target->LocalParent()) {
+ int32_t index = target->IndexInParent();
+ int32_t prevIndex = prevShow->GetAccessible()->IndexInParent();
+ if (prevIndex + 1 == index) {
+ target->AppendTextTo(prevTextChange->mModifiedText);
+ prevShow->mTextChangeEvent.swap(mutEvent->mTextChangeEvent);
+ } else if (index + 1 == prevIndex) {
+ nsString temp;
+ target->AppendTextTo(temp);
+ prevTextChange->mStart -= temp.Length();
+ temp += prevTextChange->mModifiedText;
+ prevTextChange->mModifiedText = temp;
+ prevShow->mTextChangeEvent.swap(mutEvent->mTextChangeEvent);
+ }
+ }
+ }
+
+ if (!mutEvent->mTextChangeEvent) {
+ mutEvent->mTextChangeEvent = new AccTextChangeEvent(
+ container, offset, text, mutEvent->IsShow(),
+ aEvent->mIsFromUserInput ? eFromUserInput : eNoUserInput);
+ }
+
+ return true;
+}
+
+void NotificationController::DropMutationEvent(AccTreeMutationEvent* aEvent) {
+ const uint32_t eventType = aEvent->GetEventType();
+ MOZ_ASSERT(eventType != nsIAccessibleEvent::EVENT_INNER_REORDER,
+ "Inner reorder has already been dropped, cannot drop again");
+ if (eventType == nsIAccessibleEvent::EVENT_REORDER) {
+ // We don't fully drop reorder events, we just change them to inner reorder
+ // events.
+ AccReorderEvent* reorderEvent = downcast_accEvent(aEvent);
+
+ MOZ_ASSERT(reorderEvent);
+ reorderEvent->SetInner();
+ return;
+ }
+ if (eventType == nsIAccessibleEvent::EVENT_SHOW) {
+ // unset the event bits since the event isn't being fired any more.
+ aEvent->GetAccessible()->SetShowEventTarget(false);
+ } else if (eventType == nsIAccessibleEvent::EVENT_HIDE) {
+ // unset the event bits since the event isn't being fired any more.
+ aEvent->GetAccessible()->SetHideEventTarget(false);
+
+ AccHideEvent* hideEvent = downcast_accEvent(aEvent);
+ MOZ_ASSERT(hideEvent);
+
+ if (hideEvent->NeedsShutdown()) {
+ mDocument->ShutdownChildrenInSubtree(aEvent->GetAccessible());
+ }
+ } else {
+ MOZ_ASSERT_UNREACHABLE("Mutation event has non-mutation event type");
+ }
+
+ // Do the work to splice the event out of the list.
+ if (mFirstMutationEvent == aEvent) {
+ mFirstMutationEvent = aEvent->NextEvent();
+ } else {
+ aEvent->PrevEvent()->SetNextEvent(aEvent->NextEvent());
+ }
+
+ if (mLastMutationEvent == aEvent) {
+ mLastMutationEvent = aEvent->PrevEvent();
+ } else {
+ aEvent->NextEvent()->SetPrevEvent(aEvent->PrevEvent());
+ }
+
+ aEvent->SetPrevEvent(nullptr);
+ aEvent->SetNextEvent(nullptr);
+ mMutationMap.RemoveEvent(aEvent);
+}
+
+void NotificationController::CoalesceMutationEvents() {
+ AccTreeMutationEvent* event = mFirstMutationEvent;
+ while (event) {
+ AccTreeMutationEvent* nextEvent = event->NextEvent();
+ uint32_t eventType = event->GetEventType();
+ if (event->GetEventType() == nsIAccessibleEvent::EVENT_REORDER) {
+ LocalAccessible* acc = event->GetAccessible();
+ while (acc) {
+ if (acc->IsDoc()) {
+ break;
+ }
+
+ // if a parent of the reorder event's target is being hidden that
+ // hide event's target must have a parent that is also a reorder event
+ // target. That means we don't need this reorder event.
+ if (acc->HideEventTarget()) {
+ DropMutationEvent(event);
+ break;
+ }
+
+ LocalAccessible* parent = acc->LocalParent();
+ if (parent && parent->ReorderEventTarget()) {
+ AccReorderEvent* reorder = downcast_accEvent(
+ mMutationMap.GetEvent(parent, EventMap::ReorderEvent));
+
+ // We want to make sure that a reorder event comes after any show or
+ // hide events targeted at the children of its target. We keep the
+ // invariant that event generation goes up as you are farther in the
+ // queue, so we want to use the spot of the event with the higher
+ // generation number, and keep that generation number.
+ if (reorder &&
+ reorder->EventGeneration() < event->EventGeneration()) {
+ reorder->SetEventGeneration(event->EventGeneration());
+
+ // It may be true that reorder was before event, and we coalesced
+ // away all the show / hide events between them. In that case
+ // event is already immediately after reorder in the queue and we
+ // do not need to rearrange the list of events.
+ if (event != reorder->NextEvent()) {
+ // There really should be a show or hide event before the first
+ // reorder event.
+ if (reorder->PrevEvent()) {
+ reorder->PrevEvent()->SetNextEvent(reorder->NextEvent());
+ } else {
+ mFirstMutationEvent = reorder->NextEvent();
+ }
+
+ reorder->NextEvent()->SetPrevEvent(reorder->PrevEvent());
+ event->PrevEvent()->SetNextEvent(reorder);
+ reorder->SetPrevEvent(event->PrevEvent());
+ event->SetPrevEvent(reorder);
+ reorder->SetNextEvent(event);
+ }
+ }
+ DropMutationEvent(event);
+ break;
+ }
+
+ acc = parent;
+ }
+ } else if (eventType == nsIAccessibleEvent::EVENT_SHOW) {
+ LocalAccessible* parent = event->GetAccessible()->LocalParent();
+ while (parent) {
+ if (parent->IsDoc()) {
+ break;
+ }
+
+ // if the parent of a show event is being either shown or hidden then
+ // we don't need to fire a show event for a subtree of that change.
+ if (parent->ShowEventTarget() || parent->HideEventTarget()) {
+ DropMutationEvent(event);
+ break;
+ }
+
+ parent = parent->LocalParent();
+ }
+ } else if (eventType == nsIAccessibleEvent::EVENT_HIDE) {
+ MOZ_ASSERT(eventType == nsIAccessibleEvent::EVENT_HIDE,
+ "mutation event list has an invalid event");
+
+ AccHideEvent* hideEvent = downcast_accEvent(event);
+ CoalesceHideEvent(hideEvent);
+ }
+
+ event = nextEvent;
+ }
+}
+
+void NotificationController::ScheduleChildDocBinding(DocAccessible* aDocument) {
+ // Schedule child document binding to the tree.
+ mHangingChildDocuments.AppendElement(aDocument);
+ ScheduleProcessing();
+}
+
+void NotificationController::ScheduleContentInsertion(
+ LocalAccessible* aContainer, nsTArray<nsCOMPtr<nsIContent>>& aInsertions) {
+ if (!aInsertions.IsEmpty()) {
+ mContentInsertions.GetOrInsertNew(aContainer)->AppendElements(aInsertions);
+ ScheduleProcessing();
+ }
+}
+
+void NotificationController::ScheduleProcessing() {
+ // If notification flush isn't planned yet, start notification flush
+ // asynchronously (after style and layout).
+ // Note: the mPresShell null-check might be unnecessary; it's just to prevent
+ // a null-deref here, if we somehow get called after we've been shut down.
+ if (mObservingState == eNotObservingRefresh && mPresShell) {
+ if (mPresShell->AddRefreshObserver(this, FlushType::Display,
+ "Accessibility notifications")) {
+ mObservingState = eRefreshObserving;
+ }
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NotificationCollector: protected
+
+bool NotificationController::IsUpdatePending() {
+ return mPresShell->IsLayoutFlushObserver() ||
+ mObservingState == eRefreshProcessingForUpdate || WaitingForParent() ||
+ mContentInsertions.Count() != 0 || mNotifications.Length() != 0 ||
+ !mTextArray.IsEmpty() ||
+ !mDocument->HasLoadState(DocAccessible::eTreeConstructed);
+}
+
+bool NotificationController::WaitingForParent() {
+ DocAccessible* parentdoc = mDocument->ParentDocument();
+ if (!parentdoc) {
+ return false;
+ }
+
+ NotificationController* parent = parentdoc->mNotificationController;
+ if (!parent || parent == this) {
+ // Do not wait for nothing or ourselves
+ return false;
+ }
+
+ // Wait for parent's notifications processing
+ return parent->mContentInsertions.Count() != 0 ||
+ parent->mNotifications.Length() != 0;
+}
+
+void NotificationController::ProcessMutationEvents() {
+ // Firing an event can indirectly run script; e.g. an XPCOM event observer
+ // or querying a XUL interface. Further mutations might be queued as a result.
+ // It's important that the mutation queue and state bits from one tick don't
+ // interfere with the next tick. Otherwise, we can end up dropping events.
+ // Therefore:
+ // 1. Clear the state bits, which we only need for coalescence.
+ for (AccTreeMutationEvent* event = mFirstMutationEvent; event;
+ event = event->NextEvent()) {
+ LocalAccessible* acc = event->GetAccessible();
+ acc->SetShowEventTarget(false);
+ acc->SetHideEventTarget(false);
+ acc->SetReorderEventTarget(false);
+ }
+ // 2. Keep the current queue locally, but clear the queue on the instance.
+ RefPtr<AccTreeMutationEvent> firstEvent = mFirstMutationEvent;
+ mFirstMutationEvent = mLastMutationEvent = nullptr;
+ mMutationMap.Clear();
+ mEventGeneration = 0;
+
+ // Group the show events by the parent of their target.
+ nsTHashMap<nsPtrHashKey<LocalAccessible>, nsTArray<AccTreeMutationEvent*>>
+ showEvents;
+ for (AccTreeMutationEvent* event = firstEvent; event;
+ event = event->NextEvent()) {
+ if (event->GetEventType() != nsIAccessibleEvent::EVENT_SHOW) {
+ continue;
+ }
+
+ LocalAccessible* parent = event->GetAccessible()->LocalParent();
+ showEvents.LookupOrInsert(parent).AppendElement(event);
+ }
+
+ // We need to fire show events for the children of an accessible in the order
+ // of their indices at this point. So sort each set of events for the same
+ // container by the index of their target. We do this before firing any events
+ // because firing an event might indirectly run script which might alter the
+ // tree, breaking our sort. However, we don't actually fire the events yet.
+ for (auto iter = showEvents.Iter(); !iter.Done(); iter.Next()) {
+ struct AccIdxComparator {
+ bool LessThan(const AccTreeMutationEvent* a,
+ const AccTreeMutationEvent* b) const {
+ int32_t aIdx = a->GetAccessible()->IndexInParent();
+ int32_t bIdx = b->GetAccessible()->IndexInParent();
+ MOZ_ASSERT(aIdx >= 0 && bIdx >= 0 && (a == b || aIdx != bIdx));
+ return aIdx < bIdx;
+ }
+ bool Equals(const AccTreeMutationEvent* a,
+ const AccTreeMutationEvent* b) const {
+ DebugOnly<int32_t> aIdx = a->GetAccessible()->IndexInParent();
+ DebugOnly<int32_t> bIdx = b->GetAccessible()->IndexInParent();
+ MOZ_ASSERT(aIdx >= 0 && bIdx >= 0 && (a == b || aIdx != bIdx));
+ return a == b;
+ }
+ };
+
+ nsTArray<AccTreeMutationEvent*>& events = iter.Data();
+ events.Sort(AccIdxComparator());
+ }
+
+ // there is no reason to fire a hide event for a child of a show event
+ // target. That can happen if something is inserted into the tree and
+ // removed before the next refresh driver tick, but it should not be
+ // observable outside gecko so it should be safe to coalesce away any such
+ // events. This means that it should be fine to fire all of the hide events
+ // first, and then deal with any shown subtrees.
+ for (AccTreeMutationEvent* event = firstEvent; event;
+ event = event->NextEvent()) {
+ if (event->GetEventType() != nsIAccessibleEvent::EVENT_HIDE) {
+ continue;
+ }
+
+ nsEventShell::FireEvent(event);
+ if (!mDocument) {
+ return;
+ }
+
+ AccMutationEvent* mutEvent = downcast_accEvent(event);
+ if (mutEvent->mTextChangeEvent) {
+ nsEventShell::FireEvent(mutEvent->mTextChangeEvent);
+ if (!mDocument) {
+ return;
+ }
+ }
+
+ // Fire menupopup end event before a hide event if a menu goes away.
+
+ // XXX: We don't look into children of hidden subtree to find hiding
+ // menupopup (as we did prior bug 570275) because we don't do that when
+ // menu is showing (and that's impossible until bug 606924 is fixed).
+ // Nevertheless we should do this at least because layout coalesces
+ // the changes before our processing and we may miss some menupopup
+ // events. Now we just want to be consistent in content insertion/removal
+ // handling.
+ if (event->mAccessible->ARIARole() == roles::MENUPOPUP) {
+ nsEventShell::FireEvent(nsIAccessibleEvent::EVENT_MENUPOPUP_END,
+ event->mAccessible);
+ if (!mDocument) {
+ return;
+ }
+ }
+
+ AccHideEvent* hideEvent = downcast_accEvent(event);
+ if (hideEvent->NeedsShutdown()) {
+ mDocument->ShutdownChildrenInSubtree(event->mAccessible);
+ }
+ }
+
+ // Fire the show events we sorted earlier.
+ for (auto iter = showEvents.Iter(); !iter.Done(); iter.Next()) {
+ nsTArray<AccTreeMutationEvent*>& events = iter.Data();
+ for (AccTreeMutationEvent* event : events) {
+ nsEventShell::FireEvent(event);
+ if (!mDocument) {
+ return;
+ }
+
+ AccMutationEvent* mutEvent = downcast_accEvent(event);
+ if (mutEvent->mTextChangeEvent) {
+ nsEventShell::FireEvent(mutEvent->mTextChangeEvent);
+ if (!mDocument) {
+ return;
+ }
+ }
+ }
+ }
+
+ // Now we can fire the reorder events after all the show and hide events.
+ for (const uint32_t reorderType : {nsIAccessibleEvent::EVENT_INNER_REORDER,
+ nsIAccessibleEvent::EVENT_REORDER}) {
+ for (AccTreeMutationEvent* event = firstEvent; event;
+ event = event->NextEvent()) {
+ if (event->GetEventType() != reorderType) {
+ continue;
+ }
+
+ if (event->GetAccessible()->IsDefunct()) {
+ // An inner reorder target may have been hidden itself and no
+ // longer bound to the document.
+ MOZ_ASSERT(reorderType == nsIAccessibleEvent::EVENT_INNER_REORDER,
+ "An 'outer' reorder target should not be defunct");
+ continue;
+ }
+
+ nsEventShell::FireEvent(event);
+ if (!mDocument) {
+ return;
+ }
+
+ LocalAccessible* target = event->GetAccessible();
+ target->Document()->MaybeNotifyOfValueChange(target);
+ if (!mDocument) {
+ return;
+ }
+ }
+ }
+
+ // Our events are in a doubly linked list. Clear the pointers to reduce
+ // pressure on the cycle collector. Even though clearing the previous pointers
+ // removes cycles, this isn't enough. The cycle collector still gets bogged
+ // down when there are lots of mutation events if the next pointers aren't
+ // cleared. Even without the cycle collector, not clearing the next pointers
+ // potentially results in deep recursion because releasing each event releases
+ // its next event.
+ RefPtr<AccTreeMutationEvent> event = firstEvent;
+ while (event) {
+ RefPtr<AccTreeMutationEvent> next = event->NextEvent();
+ event->SetNextEvent(nullptr);
+ event->SetPrevEvent(nullptr);
+ event = next;
+ }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NotificationCollector: private
+
+void NotificationController::WillRefresh(mozilla::TimeStamp aTime) {
+ AUTO_PROFILER_MARKER_TEXT("NotificationController::WillRefresh", A11Y, {},
+ ""_ns);
+ Telemetry::AutoTimer<Telemetry::A11Y_TREE_UPDATE_TIMING_MS> timer;
+ // DO NOT ADD CODE ABOVE THIS BLOCK: THIS CODE IS MEASURING TIMINGS.
+
+ AUTO_PROFILER_LABEL("NotificationController::WillRefresh", A11Y);
+
+ // If mDocument is null, the document accessible that this notification
+ // controller was created for is now shut down. This means we've lost our
+ // ability to unregister ourselves, which is bad. (However, it also shouldn't
+ // be logically possible for us to get here with a null mDocument; the only
+ // thing that clears that pointer is our Shutdown() method, which first
+ // unregisters and fatally asserts if that fails).
+ MOZ_RELEASE_ASSERT(
+ mDocument,
+ "The document was shut down while refresh observer is attached!");
+
+ if (ipc::ProcessChild::ExpectingShutdown()) {
+ return;
+ }
+
+ // Wait until an update, we have started, or an interruptible reflow is
+ // finished. We also check the existance of our pres context and root pres
+ // context, since if we can't reach either of these the frame tree is being
+ // destroyed.
+ nsPresContext* pc = mPresShell->GetPresContext();
+ if (mObservingState == eRefreshProcessing ||
+ mObservingState == eRefreshProcessingForUpdate ||
+ mPresShell->IsReflowInterrupted() || !pc || !pc->GetRootPresContext()) {
+ return;
+ }
+
+ // Process parent's notifications before ours, to get proper ordering between
+ // e.g. tab event and content event.
+ if (WaitingForParent()) {
+ mDocument->ParentDocument()->mNotificationController->WillRefresh(aTime);
+ if (!mDocument || ipc::ProcessChild::ExpectingShutdown()) {
+ return;
+ }
+ }
+
+ // Any generic notifications should be queued if we're processing content
+ // insertions or generic notifications.
+ mObservingState = eRefreshProcessingForUpdate;
+
+ // Initial accessible tree construction.
+ if (!mDocument->HasLoadState(DocAccessible::eTreeConstructed)) {
+ // (1) If document is not bound to parent at this point, or
+ // (2) the PresShell is not initialized (and it isn't about:blank),
+ // then the document is not ready yet (process notifications later).
+ if (!mDocument->IsBoundToParent() ||
+ (!mPresShell->DidInitialize() &&
+ !mDocument->DocumentNode()->IsInitialDocument())) {
+ mObservingState = eRefreshObserving;
+ return;
+ }
+
+#ifdef A11Y_LOG
+ if (logging::IsEnabled(logging::eTree)) {
+ logging::MsgBegin("TREE", "initial tree created");
+ logging::Address("document", mDocument);
+ logging::MsgEnd();
+ }
+#endif
+
+ mDocument->DoInitialUpdate();
+ if (ipc::ProcessChild::ExpectingShutdown()) {
+ return;
+ }
+
+ NS_ASSERTION(mContentInsertions.Count() == 0,
+ "Pending content insertions while initial accessible tree "
+ "isn't created!");
+ }
+
+ mDocument->ProcessPendingUpdates();
+
+ // Process rendered text change notifications. Even though we want to process
+ // them in the order in which they were queued, we still want to avoid
+ // duplicates.
+ nsTHashSet<nsIContent*> textHash;
+ for (nsIContent* textNode : mTextArray) {
+ if (!textHash.EnsureInserted(textNode)) {
+ continue; // Already processed.
+ }
+ LocalAccessible* textAcc = mDocument->GetAccessible(textNode);
+
+ // If the text node is not in tree or doesn't have a frame, or placed in
+ // another document, then this case should have been handled already by
+ // content removal notifications.
+ nsINode* containerNode = textNode->GetFlattenedTreeParentNode();
+ if (!containerNode || textNode->OwnerDoc() != mDocument->DocumentNode()) {
+ MOZ_ASSERT(!textAcc,
+ "Text node was removed but accessible is kept alive!");
+ continue;
+ }
+
+ nsIFrame* textFrame = textNode->GetPrimaryFrame();
+ if (!textFrame) {
+ MOZ_ASSERT(!textAcc,
+ "Text node isn't rendered but accessible is kept alive!");
+ continue;
+ }
+
+#ifdef A11Y_LOG
+ nsIContent* containerElm =
+ containerNode->IsElement() ? containerNode->AsElement() : nullptr;
+#endif
+
+ nsIFrame::RenderedText text = textFrame->GetRenderedText(
+ 0, UINT32_MAX, nsIFrame::TextOffsetType::OffsetsInContentText,
+ nsIFrame::TrailingWhitespace::DontTrim);
+
+ // Remove text accessible if rendered text is empty.
+ if (textAcc) {
+ if (text.mString.IsEmpty()) {
+#ifdef A11Y_LOG
+ if (logging::IsEnabled(logging::eTree | logging::eText)) {
+ logging::MsgBegin("TREE", "text node lost its content; doc: %p",
+ mDocument);
+ logging::Node("container", containerElm);
+ logging::Node("content", textNode);
+ logging::MsgEnd();
+ }
+#endif
+
+ mDocument->ContentRemoved(textAcc);
+ continue;
+ }
+
+ // Update text of the accessible and fire text change events.
+#ifdef A11Y_LOG
+ if (logging::IsEnabled(logging::eText)) {
+ logging::MsgBegin("TEXT", "text may be changed; doc: %p", mDocument);
+ logging::Node("container", containerElm);
+ logging::Node("content", textNode);
+ logging::MsgEntry(
+ "old text '%s'",
+ NS_ConvertUTF16toUTF8(textAcc->AsTextLeaf()->Text()).get());
+ logging::MsgEntry("new text: '%s'",
+ NS_ConvertUTF16toUTF8(text.mString).get());
+ logging::MsgEnd();
+ }
+#endif
+
+ TextUpdater::Run(mDocument, textAcc->AsTextLeaf(), text.mString);
+ continue;
+ }
+
+ // Append an accessible if rendered text is not empty.
+ if (!text.mString.IsEmpty()) {
+#ifdef A11Y_LOG
+ if (logging::IsEnabled(logging::eTree | logging::eText)) {
+ logging::MsgBegin("TREE", "text node gains new content; doc: %p",
+ mDocument);
+ logging::Node("container", containerElm);
+ logging::Node("content", textNode);
+ logging::MsgEnd();
+ }
+#endif
+
+ MOZ_ASSERT(mDocument->AccessibleOrTrueContainer(containerNode),
+ "Text node having rendered text hasn't accessible document!");
+
+ LocalAccessible* container =
+ mDocument->AccessibleOrTrueContainer(containerNode, true);
+ if (container) {
+ nsTArray<nsCOMPtr<nsIContent>>* list =
+ mContentInsertions.GetOrInsertNew(container);
+ list->AppendElement(textNode);
+ }
+ }
+ }
+ textHash.Clear();
+ mTextArray.Clear();
+
+ // Process content inserted notifications to update the tree.
+ // Processing an insertion can indirectly run script (e.g. querying a XUL
+ // interface), which might result in another insertion being queued.
+ // We don't want to lose any queued insertions if this happens. Therefore, we
+ // move the current insertions into a temporary data structure and process
+ // them from there. Any insertions queued during processing will get handled
+ // in subsequent refresh driver ticks.
+ const auto contentInsertions = std::move(mContentInsertions);
+ for (const auto& entry : contentInsertions) {
+ mDocument->ProcessContentInserted(entry.GetKey(), entry.GetData().get());
+ if (!mDocument) {
+ return;
+ }
+ }
+
+ // Bind hanging child documents unless we are using IPC and the
+ // document has no IPC actor. If we fail to bind the child doc then
+ // shut it down.
+ uint32_t hangingDocCnt = mHangingChildDocuments.Length();
+ nsTArray<RefPtr<DocAccessible>> newChildDocs;
+ for (uint32_t idx = 0; idx < hangingDocCnt; idx++) {
+ DocAccessible* childDoc = mHangingChildDocuments[idx];
+ if (childDoc->IsDefunct()) {
+ continue;
+ }
+
+ if (IPCAccessibilityActive() && !mDocument->IPCDoc()) {
+ childDoc->Shutdown();
+ continue;
+ }
+
+ nsIContent* ownerContent = childDoc->DocumentNode()->GetEmbedderElement();
+ if (ownerContent) {
+ LocalAccessible* outerDocAcc = mDocument->GetAccessible(ownerContent);
+ if (outerDocAcc && outerDocAcc->AppendChild(childDoc)) {
+ if (mDocument->AppendChildDocument(childDoc)) {
+ newChildDocs.AppendElement(std::move(mHangingChildDocuments[idx]));
+ continue;
+ }
+
+ outerDocAcc->RemoveChild(childDoc);
+ }
+
+ // Failed to bind the child document, destroy it.
+ childDoc->Shutdown();
+ }
+ }
+
+ // Clear the hanging documents list, even if we didn't bind them.
+ mHangingChildDocuments.Clear();
+ MOZ_ASSERT(mDocument, "Illicit document shutdown");
+ if (!mDocument) {
+ return;
+ }
+
+ // If the document is ready and all its subdocuments are completely loaded
+ // then process the document load.
+ if (mDocument->HasLoadState(DocAccessible::eReady) &&
+ !mDocument->HasLoadState(DocAccessible::eCompletelyLoaded) &&
+ hangingDocCnt == 0) {
+ uint32_t childDocCnt = mDocument->ChildDocumentCount(), childDocIdx = 0;
+ for (; childDocIdx < childDocCnt; childDocIdx++) {
+ DocAccessible* childDoc = mDocument->GetChildDocumentAt(childDocIdx);
+ if (!childDoc->HasLoadState(DocAccessible::eCompletelyLoaded)) {
+ break;
+ }
+ }
+
+ if (childDocIdx == childDocCnt) {
+ mDocument->ProcessLoad();
+ if (!mDocument) {
+ return;
+ }
+ }
+ }
+
+ // Process invalidation list of the document after all accessible tree
+ // mutation is done.
+ mDocument->ProcessInvalidationList();
+
+ // Process relocation list.
+ for (uint32_t idx = 0; idx < mRelocations.Length(); idx++) {
+ // owner should be in a document and have na associated DOM node (docs
+ // sometimes don't)
+ if (mRelocations[idx]->IsInDocument() &&
+ mRelocations[idx]->HasOwnContent()) {
+ mDocument->DoARIAOwnsRelocation(mRelocations[idx]);
+ }
+ }
+ mRelocations.Clear();
+
+ // Process only currently queued generic notifications.
+ // These are used for processing aria-activedescendant, DOMMenuItemActive,
+ // etc. Therefore, they must be processed after relocations, since relocated
+ // subtrees might not have been created before relocation processing and the
+ // target might be inside a relocated subtree.
+ const nsTArray<RefPtr<Notification>> notifications =
+ std::move(mNotifications);
+
+ uint32_t notificationCount = notifications.Length();
+ for (uint32_t idx = 0; idx < notificationCount; idx++) {
+ notifications[idx]->Process();
+ if (!mDocument) {
+ return;
+ }
+ }
+
+ if (ipc::ProcessChild::ExpectingShutdown()) {
+ return;
+ }
+
+ // If a generic notification occurs after this point then we may be allowed to
+ // process it synchronously. However we do not want to reenter if fireing
+ // events causes script to run.
+ mObservingState = eRefreshProcessing;
+
+ mDocument->SendAccessiblesWillMove();
+
+ // Send any queued cache updates before we fire any mutation events so the
+ // cache is up to date when mutation events are fired. We do this after
+ // insertions (but not their events) so that cache updates dependent on the
+ // tree work correctly; e.g. line start calculation.
+ if (IPCAccessibilityActive() && mDocument) {
+ mDocument->ProcessQueuedCacheUpdates();
+ }
+
+ CoalesceMutationEvents();
+ ProcessMutationEvents();
+
+ // When firing mutation events, mObservingState is set to
+ // eRefreshProcessing. Any calls to ScheduleProcessing() that
+ // occur before mObservingState is reset will be dropped because we only
+ // schedule a tick if mObservingState == eNotObservingRefresh.
+ // This sometimes results in our viewport cache being out-of-date after
+ // processing mutation events. Call ProcessQueuedCacheUpdates again to
+ // ensure it is updated.
+ if (IPCAccessibilityActive() && mDocument) {
+ mDocument->ProcessQueuedCacheUpdates();
+ }
+
+ if (mDocument) {
+ mDocument->ClearMutationData();
+ }
+
+ if (ipc::ProcessChild::ExpectingShutdown()) {
+ return;
+ }
+
+ ProcessEventQueue();
+
+ if (IPCAccessibilityActive()) {
+ size_t newDocCount = newChildDocs.Length();
+ for (size_t i = 0; i < newDocCount; i++) {
+ DocAccessible* childDoc = newChildDocs[i];
+ if (childDoc->IsDefunct()) {
+ continue;
+ }
+
+ LocalAccessible* parent = childDoc->LocalParent();
+ DocAccessibleChild* parentIPCDoc = mDocument->IPCDoc();
+ MOZ_DIAGNOSTIC_ASSERT(parentIPCDoc);
+ uint64_t id = reinterpret_cast<uintptr_t>(parent->UniqueID());
+ MOZ_DIAGNOSTIC_ASSERT(id);
+ DocAccessibleChild* ipcDoc = childDoc->IPCDoc();
+ if (ipcDoc) {
+ parentIPCDoc->SendBindChildDoc(WrapNotNull(ipcDoc), id);
+ continue;
+ }
+
+ ipcDoc = new DocAccessibleChild(childDoc, parentIPCDoc->Manager());
+ childDoc->SetIPCDoc(ipcDoc);
+
+ nsCOMPtr<nsIBrowserChild> browserChild =
+ do_GetInterface(mDocument->DocumentNode()->GetDocShell());
+ if (browserChild) {
+ static_cast<BrowserChild*>(browserChild.get())
+ ->SendPDocAccessibleConstructor(
+ ipcDoc, parentIPCDoc, id,
+ childDoc->DocumentNode()->GetBrowsingContext());
+ }
+ }
+ }
+
+ if (!mDocument) {
+ // A null mDocument means we've gotten a Shutdown() call (presumably via
+ // some script that we triggered above), and that means we're done here.
+ // Note: in this case, it's important that don't modify mObservingState;
+ // Shutdown() will have *unregistered* us as a refresh observer, and we
+ // don't want to mistakenly overwrite mObservingState and fool ourselves
+ // into thinking we've re-registered when we really haven't!
+ MOZ_ASSERT(mObservingState == eNotObservingRefresh,
+ "We've been shutdown, which means we should've been "
+ "unregistered as a refresh observer");
+ return;
+ }
+ mObservingState = eRefreshObserving;
+
+ // Stop further processing if there are no new notifications of any kind or
+ // events and document load is processed.
+ if (mContentInsertions.Count() == 0 && mNotifications.IsEmpty() &&
+ !mFocusEvent && mEvents.IsEmpty() && mTextArray.IsEmpty() &&
+ mHangingChildDocuments.IsEmpty() &&
+ mDocument->HasLoadState(DocAccessible::eCompletelyLoaded) &&
+ mPresShell->RemoveRefreshObserver(this, FlushType::Display)) {
+ mObservingState = eNotObservingRefresh;
+ }
+}
+
+void NotificationController::EventMap::PutEvent(AccTreeMutationEvent* aEvent) {
+ EventType type = GetEventType(aEvent);
+ uint64_t addr = reinterpret_cast<uintptr_t>(aEvent->GetAccessible());
+ MOZ_ASSERT((addr & 0x3) == 0, "accessible is not 4 byte aligned");
+ addr |= type;
+ mTable.InsertOrUpdate(addr, RefPtr{aEvent});
+}
+
+AccTreeMutationEvent* NotificationController::EventMap::GetEvent(
+ LocalAccessible* aTarget, EventType aType) {
+ uint64_t addr = reinterpret_cast<uintptr_t>(aTarget);
+ MOZ_ASSERT((addr & 0x3) == 0, "target is not 4 byte aligned");
+
+ addr |= aType;
+ return mTable.GetWeak(addr);
+}
+
+void NotificationController::EventMap::RemoveEvent(
+ AccTreeMutationEvent* aEvent) {
+ EventType type = GetEventType(aEvent);
+ uint64_t addr = reinterpret_cast<uintptr_t>(aEvent->GetAccessible());
+ MOZ_ASSERT((addr & 0x3) == 0, "accessible is not 4 byte aligned");
+ addr |= type;
+
+ MOZ_ASSERT(mTable.GetWeak(addr) == aEvent, "mTable has the wrong event");
+ mTable.Remove(addr);
+}
+
+NotificationController::EventMap::EventType
+NotificationController::EventMap::GetEventType(AccTreeMutationEvent* aEvent) {
+ switch (aEvent->GetEventType()) {
+ case nsIAccessibleEvent::EVENT_SHOW:
+ return ShowEvent;
+ case nsIAccessibleEvent::EVENT_HIDE:
+ return HideEvent;
+ case nsIAccessibleEvent::EVENT_REORDER:
+ case nsIAccessibleEvent::EVENT_INNER_REORDER:
+ return ReorderEvent;
+ default:
+ MOZ_ASSERT_UNREACHABLE("event has invalid type");
+ return ShowEvent;
+ }
+}