| // Copyright 2022 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "ash/accessibility/accessibility_event_handler_manager.h" |
| #include "ash/shell.h" |
| #include "base/ranges/algorithm.h" |
| #include "ui/events/event_handler.h" |
| |
| namespace ash { |
| |
| AccessibilityEventHandlerManager::AccessibilityEventHandlerManager() |
| : event_handlers_(static_cast<int>(HandlerType::kMaxValue) + 1, nullptr) {} |
| |
| AccessibilityEventHandlerManager::~AccessibilityEventHandlerManager() = default; |
| |
| void AccessibilityEventHandlerManager::AddAccessibilityEventHandler( |
| ui::EventHandler* handler, |
| HandlerType type) { |
| DCHECK(handler); |
| int index = static_cast<int>(type); |
| if (event_handlers_[index] == handler) |
| return; |
| |
| DCHECK_EQ(event_handlers_[index], nullptr) |
| << "Multiple event handlers should not share a priority level."; |
| event_handlers_[index] = handler; |
| UpdateEventHandlers(); |
| } |
| |
| void AccessibilityEventHandlerManager::RemoveAccessibilityEventHandler( |
| ui::EventHandler* handler) { |
| DCHECK(handler); |
| auto it = base::ranges::find(event_handlers_, handler); |
| DCHECK(it != event_handlers_.end()); |
| |
| // Remove it from our list. |
| *it = nullptr; |
| |
| // No need to call UpdateEventHandlers as nothing is re-ordered. |
| ash::Shell::Get()->RemovePreTargetHandler(handler); |
| } |
| |
| void AccessibilityEventHandlerManager::UpdateEventHandlers() { |
| // Remove them all and add them again so they are guaranteed to be in the |
| // right order. |
| for (ui::EventHandler* handler : event_handlers_) { |
| if (handler == nullptr) |
| continue; |
| ash::Shell::Get()->RemovePreTargetHandler(handler); |
| } |
| // Add the event handlers in reverse order. Pre-target handlers are |
| // pushed into the font of the EventHandler list, so by adding the |
| // highest priority EventHandler last we ensure it's at the top. |
| for (auto it = event_handlers_.rbegin(); it != event_handlers_.rend(); ++it) { |
| if (*it == nullptr) |
| continue; |
| ash::Shell::Get()->AddPreTargetHandler( |
| *it, ui::EventTarget::Priority::kAccessibility); |
| } |
| } |
| } // namespace ash |