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gecko-dev/accessible/base/NotificationController.cpp

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/* -*- 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 "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();
}
////////////////////////////////////////////////////////////////////////////////
// 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)) {
mObservingState = eNotObservingRefresh;
}
// 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;
mPresShell = nullptr;
mTextHash.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 planed yet start notification flush
// asynchronously (after style and layout).
if (mObservingState == eNotObservingRefresh) {
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 ||
mTextHash.Count() != 0 ||
!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 && 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 && aIdx != bIdx);
return false;
}
};
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 the document accessible that notification collector was created for is
// now shut down, don't process notifications anymore.
NS_ASSERTION(
mDocument,
"The document was shut down while refresh observer is attached!");
if (!mDocument || 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.
for (nsIContent* textNode : mTextHash) {
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);
}
}
}
mTextHash.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->ClearMovedAccessibles();
}
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());
}
}
}
mObservingState = eRefreshObserving;
if (!mDocument) return;
// 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() && mTextHash.Count() == 0 &&
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;
}
}
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