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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/events/event_processor.h"
#include "ui/events/event_target.h"
#include "ui/events/event_targeter.h"
namespace ui {
EventProcessor::EventProcessor() = default;
EventProcessor::~EventProcessor() = default;
EventDispatchDetails EventProcessor::OnEventFromSource(Event* event) {
base::WeakPtr<EventProcessor> weak_this = weak_ptr_factory_.GetWeakPtr();
// If |event| is in the process of being dispatched or has already been
// dispatched, then dispatch a copy of the event instead. We expect event
// target to be already set if event phase is after EP_PREDISPATCH.
bool dispatch_original_event = event->phase() == EP_PREDISPATCH;
DCHECK(dispatch_original_event || event->target());
Event* event_to_dispatch = event;
std::unique_ptr<Event> event_copy;
if (!dispatch_original_event) {
event_copy = event->Clone();
event_to_dispatch = event_copy.get();
}
EventDispatchDetails details;
OnEventProcessingStarted(event_to_dispatch);
EventTarget* target = nullptr;
if (!event_to_dispatch->handled()) {
EventTarget* root = GetRootForEvent(event_to_dispatch);
DCHECK(root);
EventTargeter* targeter = root->GetEventTargeter();
base::WeakPtr<EventTargeter> weak_targeter;
if (targeter) {
weak_targeter = targeter->GetWeakPtr();
target = targeter->FindTargetForEvent(root, event_to_dispatch);
} else {
targeter = GetDefaultEventTargeter();
weak_targeter = targeter->GetWeakPtr();
if (event_to_dispatch->target())
target = root;
else
target = targeter->FindTargetForEvent(root, event_to_dispatch);
}
DCHECK(targeter);
// FindTargetForEvent may dispatch event, which may delete the event
// processor or targeter.
// TODO(crbug.com/40232309): Remove these returns and change this to DCHECK.
if (!weak_this) {
details.dispatcher_destroyed = true;
return details;
}
if (!weak_targeter) {
return details;
}
auto* new_event_sink =
targeter->GetNewEventSinkForEvent(root, target, event_to_dispatch);
if (new_event_sink) {
std::ignore = new_event_sink->OnEventFromSource(event_to_dispatch);
if (!weak_this) {
details.dispatcher_destroyed = true;
return details;
}
} else {
while (target) {
details = DispatchEvent(target, event_to_dispatch);
if (!dispatch_original_event) {
if (event_to_dispatch->stopped_propagation()) {
event->StopPropagation();
} else if (event_to_dispatch->handled()) {
event->SetHandled();
}
}
if (details.dispatcher_destroyed) {
return details;
}
if (!weak_this) {
details.dispatcher_destroyed = true;
return details;
}
if (details.target_destroyed || event->handled() || !target ||
!weak_targeter) {
break;
}
DCHECK(targeter);
target = targeter->FindNextBestTarget(target, event_to_dispatch);
}
}
}
OnEventProcessingFinished(event);
return details;
}
void EventProcessor::OnEventProcessingStarted(Event* event) {
}
void EventProcessor::OnEventProcessingFinished(Event* event) {}
} // namespace ui
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