LibWeb: Fire "input" and "change" events when editing a text <input>

This isn't entirely on-spec, but will hopefully allow us to make
progress in other areas.

Userland/Libraries/LibWeb/DOM/Text.cpp

@@ -1,11 +1,12 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibWeb/DOM/Text.h>
 #include <LibWeb/DOM/Window.h>
+#include <LibWeb/HTML/HTMLInputElement.h>
 #include <LibWeb/Layout/TextNode.h>
 
 namespace Web::DOM {
@@ -25,4 +26,9 @@ NonnullRefPtr<Text> Text::create_with_global_object(Bindings::WindowObject& wind
     return make_ref_counted<Text>(window.impl().associated_document(), data);
 }
 
+void Text::set_owner_input_element(Badge<HTML::HTMLInputElement>, HTML::HTMLInputElement& input_element)
+{
+    m_owner_input_element = input_element;
+}
+
 }

Userland/Libraries/LibWeb/DOM/Text.h

@@ -27,7 +27,12 @@ public:
 
     void set_always_editable(bool b) { m_always_editable = b; }
 
+    void set_owner_input_element(Badge<HTML::HTMLInputElement>, HTML::HTMLInputElement&);
+    HTML::HTMLInputElement* owner_input_element() { return m_owner_input_element; }
+
 private:
+    WeakPtr<HTML::HTMLInputElement> m_owner_input_element;
+
     bool m_always_editable { false };
 };
 

Userland/Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -11,6 +11,7 @@
 #include <LibWeb/HTML/BrowsingContextContainer.h>
 #include <LibWeb/HTML/EventLoop/EventLoop.h>
 #include <LibWeb/HTML/HTMLAnchorElement.h>
+#include <LibWeb/HTML/HTMLInputElement.h>
 #include <LibWeb/Layout/BreakNode.h>
 #include <LibWeb/Layout/InitialContainingBlock.h>
 #include <LibWeb/Layout/TextNode.h>
@@ -41,6 +42,12 @@ BrowsingContext::~BrowsingContext()
 void BrowsingContext::did_edit(Badge<EditEventHandler>)
 {
     reset_cursor_blink_cycle();
+
+    if (m_cursor_position.node() && is<DOM::Text>(*m_cursor_position.node())) {
+        auto& text_node = static_cast<DOM::Text&>(*m_cursor_position.node());
+        if (auto* input_element = text_node.owner_input_element())
+            input_element->did_edit_text_node({});
+    }
 }
 
 void BrowsingContext::reset_cursor_blink_cycle()

Userland/Libraries/LibWeb/HTML/HTMLInputElement.cpp

@@ -112,6 +112,23 @@ void HTMLInputElement::run_input_activation_behavior()
     }
 }
 
+void HTMLInputElement::did_edit_text_node(Badge<BrowsingContext>)
+{
+    // NOTE: This is a bit ad-hoc, but basically implements part of "4.10.5.5 Common event behaviors"
+    //       https://html.spec.whatwg.org/multipage/input.html#common-input-element-events
+    queue_an_element_task(HTML::Task::Source::UserInteraction, [this] {
+        auto input_event = DOM::Event::create(HTML::EventNames::input);
+        input_event->set_bubbles(true);
+        input_event->set_composed(true);
+        dispatch_event(move(input_event));
+
+        // FIXME: This should only fire when the input is "committed", whatever that means.
+        auto change_event = DOM::Event::create(HTML::EventNames::change);
+        change_event->set_bubbles(true);
+        dispatch_event(move(change_event));
+    });
+}
+
 bool HTMLInputElement::enabled() const
 {
     return !has_attribute(HTML::AttributeNames::disabled);
@@ -147,6 +164,7 @@ void HTMLInputElement::create_shadow_tree_if_needed()
     element->set_attribute(HTML::AttributeNames::style, "white-space: pre");
     m_text_node = adopt_ref(*new DOM::Text(document(), initial_value));
     m_text_node->set_always_editable(true);
+    m_text_node->set_owner_input_element({}, *this);
     element->append_child(*m_text_node);
     shadow_root->append_child(move(element));
     set_shadow_root(move(shadow_root));

Userland/Libraries/LibWeb/HTML/HTMLInputElement.h

@@ -42,6 +42,8 @@ public:
 
     void did_click_button(Badge<Layout::ButtonBox>);
 
+    void did_edit_text_node(Badge<BrowsingContext>);
+
     virtual bool is_focusable() const override;
 
     virtual void parse_attribute(FlyString const&, String const&) override;