gecko-dev/accessible/base/EventQueue.cpp
Trevor Saunders f3849011fc bug 1316163 - remove eCoalesceMutationTextChange event rule r=davidb
The only difference between it and eCoalesceReorder is that for
eCoalesceReorder we assert the target is one of a outer doc, application
accessible or xul tree.  However we never put events that have
eCoalesceMutationTextChange as there event rule in the queue, so there is no
reason for separate event rules, and we can remove eCoalesceMutationTextChange
and check that queued eCoalesceReorder events are in fact reorder events.
2016-11-15 22:07:39 -05:00

345 lines
13 KiB
C++

/* -*- 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 "EventQueue.h"
#include "Accessible-inl.h"
#include "nsEventShell.h"
#include "DocAccessible.h"
#include "DocAccessibleChild.h"
#include "nsAccessibilityService.h"
#include "nsTextEquivUtils.h"
#ifdef A11Y_LOG
#include "Logging.h"
#endif
using namespace mozilla;
using namespace mozilla::a11y;
// Defines the number of selection add/remove events in the queue when they
// aren't packed into single selection within event.
const unsigned int kSelChangeCountToPack = 5;
////////////////////////////////////////////////////////////////////////////////
// EventQueue
////////////////////////////////////////////////////////////////////////////////
bool
EventQueue::PushEvent(AccEvent* aEvent)
{
NS_ASSERTION((aEvent->mAccessible && aEvent->mAccessible->IsApplication()) ||
aEvent->Document() == mDocument,
"Queued event belongs to another document!");
if (!mEvents.AppendElement(aEvent))
return false;
// Filter events.
CoalesceEvents();
if (aEvent->mEventRule != AccEvent::eDoNotEmit &&
(aEvent->mEventType == nsIAccessibleEvent::EVENT_NAME_CHANGE ||
aEvent->mEventType == nsIAccessibleEvent::EVENT_TEXT_REMOVED ||
aEvent->mEventType == nsIAccessibleEvent::EVENT_TEXT_INSERTED)) {
PushNameChange(aEvent->mAccessible);
}
return true;
}
bool
EventQueue::PushNameChange(Accessible* aTarget)
{
// Fire name change event on parent given that this event hasn't been
// coalesced, the parent's name was calculated from its subtree, and the
// subtree was changed.
if (aTarget->HasNameDependentParent()) {
// Only continue traversing up the tree if it's possible that the parent
// accessible's name can depend on this accessible's name.
Accessible* parent = aTarget->Parent();
while (parent &&
nsTextEquivUtils::HasNameRule(parent, eNameFromSubtreeIfReqRule)) {
// Test possible name dependent parent.
if (nsTextEquivUtils::HasNameRule(parent, eNameFromSubtreeRule)) {
nsAutoString name;
ENameValueFlag nameFlag = parent->Name(name);
// If name is obtained from subtree, fire name change event.
if (nameFlag == eNameFromSubtree) {
RefPtr<AccEvent> nameChangeEvent =
new AccEvent(nsIAccessibleEvent::EVENT_NAME_CHANGE, parent);
return PushEvent(nameChangeEvent);
}
break;
}
parent = parent->Parent();
}
}
return false;
}
////////////////////////////////////////////////////////////////////////////////
// EventQueue: private
void
EventQueue::CoalesceEvents()
{
NS_ASSERTION(mEvents.Length(), "There should be at least one pending event!");
uint32_t tail = mEvents.Length() - 1;
AccEvent* tailEvent = mEvents[tail];
switch(tailEvent->mEventRule) {
case AccEvent::eCoalesceReorder:
{
DebugOnly<Accessible*> target = tailEvent->mAccessible.get();
MOZ_ASSERT(target->IsApplication() ||
target->IsOuterDoc() ||
target->IsXULTree(),
"Only app or outerdoc accessible reorder events are in the queue");
MOZ_ASSERT(tailEvent->GetEventType() == nsIAccessibleEvent::EVENT_REORDER, "only reorder events should be queued");
break; // case eCoalesceReorder
}
case AccEvent::eCoalesceOfSameType:
{
// Coalesce old events by newer event.
for (uint32_t index = tail - 1; index < tail; index--) {
AccEvent* accEvent = mEvents[index];
if (accEvent->mEventType == tailEvent->mEventType &&
accEvent->mEventRule == tailEvent->mEventRule) {
accEvent->mEventRule = AccEvent::eDoNotEmit;
return;
}
}
} break; // case eCoalesceOfSameType
case AccEvent::eCoalesceSelectionChange:
{
AccSelChangeEvent* tailSelChangeEvent = downcast_accEvent(tailEvent);
for (uint32_t index = tail - 1; index < tail; index--) {
AccEvent* thisEvent = mEvents[index];
if (thisEvent->mEventRule == tailEvent->mEventRule) {
AccSelChangeEvent* thisSelChangeEvent =
downcast_accEvent(thisEvent);
// Coalesce selection change events within same control.
if (tailSelChangeEvent->mWidget == thisSelChangeEvent->mWidget) {
CoalesceSelChangeEvents(tailSelChangeEvent, thisSelChangeEvent, index);
return;
}
}
}
} break; // eCoalesceSelectionChange
case AccEvent::eCoalesceStateChange:
{
// If state change event is duped then ignore previous event. If state
// change event is opposite to previous event then no event is emitted
// (accessible state wasn't changed).
for (uint32_t index = tail - 1; index < tail; index--) {
AccEvent* thisEvent = mEvents[index];
if (thisEvent->mEventRule != AccEvent::eDoNotEmit &&
thisEvent->mEventType == tailEvent->mEventType &&
thisEvent->mAccessible == tailEvent->mAccessible) {
AccStateChangeEvent* thisSCEvent = downcast_accEvent(thisEvent);
AccStateChangeEvent* tailSCEvent = downcast_accEvent(tailEvent);
if (thisSCEvent->mState == tailSCEvent->mState) {
thisEvent->mEventRule = AccEvent::eDoNotEmit;
if (thisSCEvent->mIsEnabled != tailSCEvent->mIsEnabled)
tailEvent->mEventRule = AccEvent::eDoNotEmit;
}
}
}
break; // eCoalesceStateChange
}
case AccEvent::eCoalesceTextSelChange:
{
// Coalesce older event by newer event for the same selection or target.
// Events for same selection may have different targets and vice versa one
// target may be pointed by different selections (for latter see
// bug 927159).
for (uint32_t index = tail - 1; index < tail; index--) {
AccEvent* thisEvent = mEvents[index];
if (thisEvent->mEventRule != AccEvent::eDoNotEmit &&
thisEvent->mEventType == tailEvent->mEventType) {
AccTextSelChangeEvent* thisTSCEvent = downcast_accEvent(thisEvent);
AccTextSelChangeEvent* tailTSCEvent = downcast_accEvent(tailEvent);
if (thisTSCEvent->mSel == tailTSCEvent->mSel ||
thisEvent->mAccessible == tailEvent->mAccessible)
thisEvent->mEventRule = AccEvent::eDoNotEmit;
}
}
} break; // eCoalesceTextSelChange
case AccEvent::eRemoveDupes:
{
// Check for repeat events, coalesce newly appended event by more older
// event.
for (uint32_t index = tail - 1; index < tail; index--) {
AccEvent* accEvent = mEvents[index];
if (accEvent->mEventType == tailEvent->mEventType &&
accEvent->mEventRule == tailEvent->mEventRule &&
accEvent->mAccessible == tailEvent->mAccessible) {
tailEvent->mEventRule = AccEvent::eDoNotEmit;
return;
}
}
} break; // case eRemoveDupes
default:
break; // case eAllowDupes, eDoNotEmit
} // switch
}
void
EventQueue::CoalesceSelChangeEvents(AccSelChangeEvent* aTailEvent,
AccSelChangeEvent* aThisEvent,
uint32_t aThisIndex)
{
aTailEvent->mPreceedingCount = aThisEvent->mPreceedingCount + 1;
// Pack all preceding events into single selection within event
// when we receive too much selection add/remove events.
if (aTailEvent->mPreceedingCount >= kSelChangeCountToPack) {
aTailEvent->mEventType = nsIAccessibleEvent::EVENT_SELECTION_WITHIN;
aTailEvent->mAccessible = aTailEvent->mWidget;
aThisEvent->mEventRule = AccEvent::eDoNotEmit;
// Do not emit any preceding selection events for same widget if they
// weren't coalesced yet.
if (aThisEvent->mEventType != nsIAccessibleEvent::EVENT_SELECTION_WITHIN) {
for (uint32_t jdx = aThisIndex - 1; jdx < aThisIndex; jdx--) {
AccEvent* prevEvent = mEvents[jdx];
if (prevEvent->mEventRule == aTailEvent->mEventRule) {
AccSelChangeEvent* prevSelChangeEvent =
downcast_accEvent(prevEvent);
if (prevSelChangeEvent->mWidget == aTailEvent->mWidget)
prevSelChangeEvent->mEventRule = AccEvent::eDoNotEmit;
}
}
}
return;
}
// Pack sequential selection remove and selection add events into
// single selection change event.
if (aTailEvent->mPreceedingCount == 1 &&
aTailEvent->mItem != aThisEvent->mItem) {
if (aTailEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd &&
aThisEvent->mSelChangeType == AccSelChangeEvent::eSelectionRemove) {
aThisEvent->mEventRule = AccEvent::eDoNotEmit;
aTailEvent->mEventType = nsIAccessibleEvent::EVENT_SELECTION;
aTailEvent->mPackedEvent = aThisEvent;
return;
}
if (aThisEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd &&
aTailEvent->mSelChangeType == AccSelChangeEvent::eSelectionRemove) {
aTailEvent->mEventRule = AccEvent::eDoNotEmit;
aThisEvent->mEventType = nsIAccessibleEvent::EVENT_SELECTION;
aThisEvent->mPackedEvent = aTailEvent;
return;
}
}
// Unpack the packed selection change event because we've got one
// more selection add/remove.
if (aThisEvent->mEventType == nsIAccessibleEvent::EVENT_SELECTION) {
if (aThisEvent->mPackedEvent) {
aThisEvent->mPackedEvent->mEventType =
aThisEvent->mPackedEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd ?
nsIAccessibleEvent::EVENT_SELECTION_ADD :
nsIAccessibleEvent::EVENT_SELECTION_REMOVE;
aThisEvent->mPackedEvent->mEventRule =
AccEvent::eCoalesceSelectionChange;
aThisEvent->mPackedEvent = nullptr;
}
aThisEvent->mEventType =
aThisEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd ?
nsIAccessibleEvent::EVENT_SELECTION_ADD :
nsIAccessibleEvent::EVENT_SELECTION_REMOVE;
return;
}
// Convert into selection add since control has single selection but other
// selection events for this control are queued.
if (aTailEvent->mEventType == nsIAccessibleEvent::EVENT_SELECTION)
aTailEvent->mEventType = nsIAccessibleEvent::EVENT_SELECTION_ADD;
}
////////////////////////////////////////////////////////////////////////////////
// EventQueue: event queue
void
EventQueue::ProcessEventQueue()
{
// Process only currently queued events.
nsTArray<RefPtr<AccEvent> > events;
events.SwapElements(mEvents);
uint32_t eventCount = events.Length();
#ifdef A11Y_LOG
if (eventCount > 0 && logging::IsEnabled(logging::eEvents)) {
logging::MsgBegin("EVENTS", "events processing");
logging::Address("document", mDocument);
logging::MsgEnd();
}
#endif
for (uint32_t idx = 0; idx < eventCount; idx++) {
AccEvent* event = events[idx];
if (event->mEventRule != AccEvent::eDoNotEmit) {
Accessible* target = event->GetAccessible();
if (!target || target->IsDefunct())
continue;
// Dispatch the focus event if target is still focused.
if (event->mEventType == nsIAccessibleEvent::EVENT_FOCUS) {
FocusMgr()->ProcessFocusEvent(event);
continue;
}
// Dispatch caret moved and text selection change events.
if (event->mEventType == nsIAccessibleEvent::EVENT_TEXT_SELECTION_CHANGED) {
SelectionMgr()->ProcessTextSelChangeEvent(event);
continue;
}
// Fire selected state change events in support to selection events.
if (event->mEventType == nsIAccessibleEvent::EVENT_SELECTION_ADD) {
nsEventShell::FireEvent(event->mAccessible, states::SELECTED,
true, event->mIsFromUserInput);
} else if (event->mEventType == nsIAccessibleEvent::EVENT_SELECTION_REMOVE) {
nsEventShell::FireEvent(event->mAccessible, states::SELECTED,
false, event->mIsFromUserInput);
} else if (event->mEventType == nsIAccessibleEvent::EVENT_SELECTION) {
AccSelChangeEvent* selChangeEvent = downcast_accEvent(event);
nsEventShell::FireEvent(event->mAccessible, states::SELECTED,
(selChangeEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd),
event->mIsFromUserInput);
if (selChangeEvent->mPackedEvent) {
nsEventShell::FireEvent(selChangeEvent->mPackedEvent->mAccessible,
states::SELECTED,
(selChangeEvent->mPackedEvent->mSelChangeType == AccSelChangeEvent::eSelectionAdd),
selChangeEvent->mPackedEvent->mIsFromUserInput);
}
}
nsEventShell::FireEvent(event);
}
if (!mDocument)
return;
}
}