EventReceiver.cpp 5.1 KB

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  1. /*
  2. * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
  3. * Copyright (c) 2022, the SerenityOS developers.
  4. *
  5. * SPDX-License-Identifier: BSD-2-Clause
  6. */
  7. #include <AK/Assertions.h>
  8. #include <AK/Badge.h>
  9. #include <AK/JsonObject.h>
  10. #include <LibCore/Event.h>
  11. #include <LibCore/EventLoop.h>
  12. #include <LibCore/EventReceiver.h>
  13. #include <stdio.h>
  14. namespace Core {
  15. EventReceiver::EventReceiver(EventReceiver* parent)
  16. : m_parent(parent)
  17. {
  18. if (m_parent)
  19. m_parent->add_child(*this);
  20. }
  21. EventReceiver::~EventReceiver()
  22. {
  23. // NOTE: We move our children out to a stack vector to prevent other
  24. // code from trying to iterate over them.
  25. auto children = move(m_children);
  26. // NOTE: We also unparent the children, so that they won't try to unparent
  27. // themselves in their own destructors.
  28. for (auto& child : children)
  29. child->m_parent = nullptr;
  30. stop_timer();
  31. if (m_parent)
  32. m_parent->remove_child(*this);
  33. }
  34. void EventReceiver::event(Core::Event& event)
  35. {
  36. switch (event.type()) {
  37. case Core::Event::Timer:
  38. return timer_event(static_cast<TimerEvent&>(event));
  39. case Core::Event::ChildAdded:
  40. case Core::Event::ChildRemoved:
  41. return child_event(static_cast<ChildEvent&>(event));
  42. case Core::Event::Invalid:
  43. VERIFY_NOT_REACHED();
  44. break;
  45. case Core::Event::Custom:
  46. return custom_event(static_cast<CustomEvent&>(event));
  47. default:
  48. break;
  49. }
  50. }
  51. ErrorOr<void> EventReceiver::try_add_child(EventReceiver& object)
  52. {
  53. // FIXME: Should we support reparenting objects?
  54. VERIFY(!object.parent() || object.parent() == this);
  55. TRY(m_children.try_append(object));
  56. object.m_parent = this;
  57. Core::ChildEvent child_event(Core::Event::ChildAdded, object);
  58. event(child_event);
  59. return {};
  60. }
  61. void EventReceiver::add_child(EventReceiver& object)
  62. {
  63. MUST(try_add_child(object));
  64. }
  65. void EventReceiver::insert_child_before(EventReceiver& new_child, EventReceiver& before_child)
  66. {
  67. // FIXME: Should we support reparenting objects?
  68. VERIFY(!new_child.parent() || new_child.parent() == this);
  69. new_child.m_parent = this;
  70. m_children.insert_before_matching(new_child, [&](auto& existing_child) { return existing_child.ptr() == &before_child; });
  71. Core::ChildEvent child_event(Core::Event::ChildAdded, new_child, &before_child);
  72. event(child_event);
  73. }
  74. void EventReceiver::remove_child(EventReceiver& object)
  75. {
  76. for (size_t i = 0; i < m_children.size(); ++i) {
  77. if (m_children[i] == &object) {
  78. // NOTE: We protect the child so it survives the handling of ChildRemoved.
  79. NonnullRefPtr<EventReceiver> protector = object;
  80. object.m_parent = nullptr;
  81. m_children.remove(i);
  82. Core::ChildEvent child_event(Core::Event::ChildRemoved, object);
  83. event(child_event);
  84. return;
  85. }
  86. }
  87. VERIFY_NOT_REACHED();
  88. }
  89. void EventReceiver::remove_all_children()
  90. {
  91. while (!m_children.is_empty())
  92. m_children.first()->remove_from_parent();
  93. }
  94. void EventReceiver::timer_event(Core::TimerEvent&)
  95. {
  96. }
  97. void EventReceiver::child_event(Core::ChildEvent&)
  98. {
  99. }
  100. void EventReceiver::custom_event(CustomEvent&)
  101. {
  102. }
  103. void EventReceiver::start_timer(int ms, TimerShouldFireWhenNotVisible fire_when_not_visible)
  104. {
  105. if (m_timer_id) {
  106. dbgln("{} {:p} already has a timer!", class_name(), this);
  107. VERIFY_NOT_REACHED();
  108. }
  109. m_timer_id = Core::EventLoop::register_timer(*this, ms, true, fire_when_not_visible);
  110. }
  111. void EventReceiver::stop_timer()
  112. {
  113. if (!m_timer_id)
  114. return;
  115. bool success = Core::EventLoop::unregister_timer(m_timer_id);
  116. if (!success) {
  117. dbgln("{} {:p} could not unregister timer {}", class_name(), this, m_timer_id);
  118. }
  119. m_timer_id = 0;
  120. }
  121. void EventReceiver::deferred_invoke(Function<void()> invokee)
  122. {
  123. Core::deferred_invoke([invokee = move(invokee), strong_this = NonnullRefPtr(*this)] { invokee(); });
  124. }
  125. bool EventReceiver::is_ancestor_of(EventReceiver const& other) const
  126. {
  127. if (&other == this)
  128. return false;
  129. for (auto* ancestor = other.parent(); ancestor; ancestor = ancestor->parent()) {
  130. if (ancestor == this)
  131. return true;
  132. }
  133. return false;
  134. }
  135. void EventReceiver::dispatch_event(Core::Event& e, EventReceiver* stay_within)
  136. {
  137. VERIFY(!stay_within || stay_within == this || stay_within->is_ancestor_of(*this));
  138. auto* target = this;
  139. do {
  140. // If there's an event filter on this target, ask if it wants to swallow this event.
  141. if (target->m_event_filter && !target->m_event_filter(e))
  142. return;
  143. target->event(e);
  144. target = target->parent();
  145. if (target == stay_within) {
  146. // Prevent the event from bubbling any further.
  147. return;
  148. }
  149. } while (target && !e.is_accepted());
  150. }
  151. bool EventReceiver::is_visible_for_timer_purposes() const
  152. {
  153. if (parent())
  154. return parent()->is_visible_for_timer_purposes();
  155. return true;
  156. }
  157. void EventReceiver::set_event_filter(Function<bool(Core::Event&)> filter)
  158. {
  159. m_event_filter = move(filter);
  160. }
  161. }