From e4688fedd544e03f732ac8563bb0e10ed441fd64 Mon Sep 17 00:00:00 2001
From: Luke Wilde <lukew@serenityos.org>
Date: Sat, 5 Nov 2022 15:36:03 +0000
Subject: [PATCH] LibWeb: Make keyboard events properly fire into a focused
 iframe

Google Docs focuses a "text event target" iframe using Window.focus on
the iframe's contentWindow. Doing so makes the iframe's document the
focused element we have to fire text events at. However, in the top
level browsing context, the focused element is still the iframe, so we
have to repeat the keyboard event steps but with the iframe's nested
browsing context instead.
---
 .../Libraries/LibWeb/Page/EventHandler.cpp    | 50 +++++++++++--------
 Userland/Libraries/LibWeb/Page/EventHandler.h |  2 +
 2 files changed, 30 insertions(+), 22 deletions(-)

diff --git a/Userland/Libraries/LibWeb/Page/EventHandler.cpp b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
index 47343d2cff..6e304be957 100644
--- a/Userland/Libraries/LibWeb/Page/EventHandler.cpp
+++ b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
@@ -657,6 +657,32 @@ constexpr bool should_ignore_keydown_event(u32 code_point)
     return code_point == 0 || code_point == 27;
 }
 
+bool EventHandler::fire_keyboard_event(FlyString const& event_name, HTML::BrowsingContext& browsing_context, KeyCode key, unsigned int modifiers, u32 code_point)
+{
+    JS::NonnullGCPtr<DOM::Document> document = *browsing_context.active_document();
+    if (!document)
+        return false;
+
+    if (JS::GCPtr<DOM::Element> focused_element = document->focused_element()) {
+        if (is<HTML::BrowsingContextContainer>(*focused_element)) {
+            auto& browsing_context_container = verify_cast<HTML::BrowsingContextContainer>(*focused_element);
+            if (browsing_context_container.nested_browsing_context())
+                return fire_keyboard_event(event_name, *browsing_context_container.nested_browsing_context(), key, modifiers, code_point);
+        }
+
+        auto event = UIEvents::KeyboardEvent::create_from_platform_event(document->realm(), event_name, key, modifiers, code_point);
+        return focused_element->dispatch_event(*event);
+    }
+
+    // FIXME: De-duplicate this. This is just to prevent wasting a KeyboardEvent alloction when recursing into an (i)frame.
+    auto event = UIEvents::KeyboardEvent::create_from_platform_event(document->realm(), event_name, key, modifiers, code_point);
+
+    if (JS::GCPtr<HTML::HTMLElement> body = document->body())
+        return body->dispatch_event(*event);
+
+    return document->root().dispatch_event(*event);
+}
+
 bool EventHandler::handle_keydown(KeyCode key, unsigned modifiers, u32 code_point)
 {
     if (!m_browsing_context.active_document())
@@ -745,32 +771,12 @@ bool EventHandler::handle_keydown(KeyCode key, unsigned modifiers, u32 code_poin
         return true;
     }
 
-    auto event = UIEvents::KeyboardEvent::create_from_platform_event(document->realm(), UIEvents::EventNames::keydown, key, modifiers, code_point);
-
-    if (JS::GCPtr<DOM::Element> focused_element = document->focused_element())
-        return focused_element->dispatch_event(*event);
-
-    if (JS::GCPtr<HTML::HTMLElement> body = m_browsing_context.active_document()->body())
-        return body->dispatch_event(*event);
-
-    return document->root().dispatch_event(*event);
+    return fire_keyboard_event(UIEvents::EventNames::keydown, m_browsing_context, key, modifiers, code_point);
 }
 
 bool EventHandler::handle_keyup(KeyCode key, unsigned modifiers, u32 code_point)
 {
-    JS::GCPtr<DOM::Document> document = m_browsing_context.active_document();
-    if (!document)
-        return false;
-
-    auto event = UIEvents::KeyboardEvent::create_from_platform_event(document->realm(), UIEvents::EventNames::keyup, key, modifiers, code_point);
-
-    if (JS::GCPtr<DOM::Element> focused_element = document->focused_element())
-        return document->focused_element()->dispatch_event(*event);
-
-    if (JS::GCPtr<HTML::HTMLElement> body = document->body())
-        return body->dispatch_event(*event);
-
-    return document->root().dispatch_event(*event);
+    return fire_keyboard_event(UIEvents::EventNames::keyup, m_browsing_context, key, modifiers, code_point);
 }
 
 void EventHandler::set_mouse_event_tracking_layout_node(Layout::Node* layout_node)
diff --git a/Userland/Libraries/LibWeb/Page/EventHandler.h b/Userland/Libraries/LibWeb/Page/EventHandler.h
index fa302c9695..e5ef43c7e6 100644
--- a/Userland/Libraries/LibWeb/Page/EventHandler.h
+++ b/Userland/Libraries/LibWeb/Page/EventHandler.h
@@ -39,6 +39,8 @@ private:
     bool focus_next_element();
     bool focus_previous_element();
 
+    bool fire_keyboard_event(FlyString const& event_name, HTML::BrowsingContext& browsing_context, KeyCode key, unsigned modifiers, u32 code_point);
+
     Layout::InitialContainingBlock* layout_root();
     Layout::InitialContainingBlock const* layout_root() const;