From dc58f6567f8f22151170b4b6a6d839563060cdef Mon Sep 17 00:00:00 2001
From: Sam Atkins <sam@ladybird.org>
Date: Fri, 31 Jan 2025 15:34:34 +0000
Subject: [PATCH] LibWeb: Support :open for file and color `<input>` elements

---
 Libraries/LibWeb/CSS/SelectorEngine.cpp    | 18 +++++++-----
 Libraries/LibWeb/DOM/Node.h                |  1 +
 Libraries/LibWeb/HTML/HTMLInputElement.cpp | 32 ++++++++++++++++++++--
 Libraries/LibWeb/HTML/HTMLInputElement.h   |  6 ++++
 4 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/Libraries/LibWeb/CSS/SelectorEngine.cpp b/Libraries/LibWeb/CSS/SelectorEngine.cpp
index 233b773c23c..f806dc8aaa4 100644
--- a/Libraries/LibWeb/CSS/SelectorEngine.cpp
+++ b/Libraries/LibWeb/CSS/SelectorEngine.cpp
@@ -386,20 +386,24 @@ static bool matches_read_write_pseudo_class(DOM::Element const& element)
     return element.is_editable_or_editing_host();
 }
 
-// https://www.w3.org/TR/selectors-4/#open-state
+// https://drafts.csswg.org/selectors-4/#open-state
 static bool matches_open_state_pseudo_class(DOM::Element const& element, bool open)
 {
     // The :open pseudo-class represents an element that has both “open” and “closed” states,
     // and which is currently in the “open” state.
-    // The :closed pseudo-class represents an element that has both “open” and “closed” states,
-    // and which is currently in the closed state.
 
-    // NOTE: Spec specifically suggests supporting <details>, <dialog>, and <select>.
-    //       There may be others we want to treat as open or closed.
+    // https://html.spec.whatwg.org/multipage/semantics-other.html#selector-open
+    // The :open pseudo-class must match any element falling into one of the following categories:
+    // - details elements that have an open attribute
+    // - dialog elements that have an open attribute
     if (is<HTML::HTMLDetailsElement>(element) || is<HTML::HTMLDialogElement>(element))
         return open == element.has_attribute(HTML::AttributeNames::open);
-    if (is<HTML::HTMLSelectElement>(element))
-        return open == static_cast<HTML::HTMLSelectElement const&>(element).is_open();
+    // - select elements that are a drop-down box and whose drop-down boxes are open
+    if (auto const* select = as_if<HTML::HTMLSelectElement>(element))
+        return open == select->is_open();
+    // - input elements that support a picker and whose pickers are open
+    if (auto const* input = as_if<HTML::HTMLInputElement>(element))
+        return open == (input->supports_a_picker() && input->is_open());
 
     return false;
 }
diff --git a/Libraries/LibWeb/DOM/Node.h b/Libraries/LibWeb/DOM/Node.h
index 46c9b05802b..e732ead43c9 100644
--- a/Libraries/LibWeb/DOM/Node.h
+++ b/Libraries/LibWeb/DOM/Node.h
@@ -78,6 +78,7 @@ enum class ShouldComputeRole {
     X(HTMLHyperlinkElementHrefChange)               \
     X(HTMLIFrameElementGeometryChange)              \
     X(HTMLInputElementSetChecked)                   \
+    X(HTMLInputElementSetIsOpen)                    \
     X(HTMLObjectElementUpdateLayoutAndChildObjects) \
     X(HTMLOptionElementSelectedChange)              \
     X(HTMLSelectElementSetIsOpen)                   \
diff --git a/Libraries/LibWeb/HTML/HTMLInputElement.cpp b/Libraries/LibWeb/HTML/HTMLInputElement.cpp
index 78d7bfc4f91..9ea5c0a9e31 100644
--- a/Libraries/LibWeb/HTML/HTMLInputElement.cpp
+++ b/Libraries/LibWeb/HTML/HTMLInputElement.cpp
@@ -299,7 +299,11 @@ static void show_the_picker_if_applicable(HTMLInputElement& element)
     // 3. Consume user activation given element's relevant global object.
     relevant_global_object.consume_user_activation();
 
-    // 4. If element's type attribute is in the File Upload state, then run these steps in parallel:
+    // 4. If element does not support a picker, then return.
+    if (!element.supports_a_picker())
+        return;
+
+    // 5. If element's type attribute is in the File Upload state, then run these steps in parallel:
     if (element.type_state() == HTMLInputElement::TypeAttributeState::FileUpload) {
         // NOTE: These steps cannot be fully implemented here, and must be done in the PageClient when the response comes back from the PageHost
 
@@ -317,11 +321,12 @@ static void show_the_picker_if_applicable(HTMLInputElement& element)
         auto allow_multiple_files = element.has_attribute(HTML::AttributeNames::multiple) ? AllowMultipleFiles::Yes : AllowMultipleFiles::No;
         auto weak_element = element.make_weak_ptr<HTMLInputElement>();
 
+        element.set_is_open(true);
         element.document().browsing_context()->top_level_browsing_context()->page().did_request_file_picker(weak_element, move(accepted_file_types), allow_multiple_files);
         return;
     }
 
-    // 5. Otherwise, the user agent should show any relevant user interface for selecting a value for element,
+    // 6. Otherwise, the user agent should show any relevant user interface for selecting a value for element,
     //    in the way it normally would when the user interacts with the control. (If no such UI applies to element, then this step does nothing.)
     //    If such a user interface is shown, it must respect the requirements stated in the relevant parts of the specification for how element
     //    behaves given its type attribute state. (For example, various sections describe restrictions on the resulting value string.)
@@ -329,6 +334,7 @@ static void show_the_picker_if_applicable(HTMLInputElement& element)
     //    (If this closes a file selection picker, then per the above that will lead to firing either input and change events, or a cancel event.)
     if (element.type_state() == HTMLInputElement::TypeAttributeState::Color) {
         auto weak_element = element.make_weak_ptr<HTMLInputElement>();
+        element.set_is_open(true);
         element.document().browsing_context()->top_level_browsing_context()->page().did_request_color_picker(weak_element, Color::from_string(element.value()).value_or(Color(0, 0, 0)));
     }
 }
@@ -469,6 +475,8 @@ void HTMLInputElement::did_edit_text_node()
 
 void HTMLInputElement::did_pick_color(Optional<Color> picked_color, ColorPickerUpdateState state)
 {
+    set_is_open(false);
+
     if (type_state() == TypeAttributeState::Color && picked_color.has_value()) {
         // then when the user changes the element's value
         m_value = value_sanitization_algorithm(picked_color.value().to_string_without_alpha());
@@ -497,6 +505,8 @@ void HTMLInputElement::did_pick_color(Optional<Color> picked_color, ColorPickerU
 
 void HTMLInputElement::did_select_files(Span<SelectedFile> selected_files, MultipleHandling multiple_handling)
 {
+    set_is_open(false);
+
     // https://html.spec.whatwg.org/multipage/input.html#show-the-picker,-if-applicable
     // 4. If the user dismissed the prompt without changing their selection, then queue an element task on the user
     //    interaction task source given element to fire an event named cancel at element, with the bubbles attribute
@@ -2949,4 +2959,22 @@ bool HTMLInputElement::suffering_from_bad_input() const
     return false;
 }
 
+// https://html.spec.whatwg.org/multipage/input.html#input-support-picker
+bool HTMLInputElement::supports_a_picker() const
+{
+    // The input element can support a picker. A picker is a user interface element that allows the end user to choose a value.
+    // Whether an input element supports a picker depends on the type attribute state and implementation-defined behavior.
+    // An input element must support a picker when its type attribute is in the File Upload state.
+    return first_is_one_of(type_state(), TypeAttributeState::FileUpload, TypeAttributeState::Color);
+}
+
+void HTMLInputElement::set_is_open(bool is_open)
+{
+    if (is_open == m_is_open)
+        return;
+
+    m_is_open = is_open;
+    invalidate_style(DOM::StyleInvalidationReason::HTMLInputElementSetIsOpen);
+}
+
 }
diff --git a/Libraries/LibWeb/HTML/HTMLInputElement.h b/Libraries/LibWeb/HTML/HTMLInputElement.h
index 36df2fa706c..494cc556f17 100644
--- a/Libraries/LibWeb/HTML/HTMLInputElement.h
+++ b/Libraries/LibWeb/HTML/HTMLInputElement.h
@@ -216,6 +216,10 @@ public:
     bool selection_direction_applies() const;
     bool has_selectable_text() const;
 
+    bool supports_a_picker() const;
+    bool is_open() const { return m_is_open; }
+    void set_is_open(bool);
+
     static bool selection_or_range_applies_for_type_state(TypeAttributeState);
 
     Optional<String> selection_direction_binding() { return selection_direction(); }
@@ -368,6 +372,8 @@ private:
     String m_last_src_value;
 
     bool m_has_uncommitted_changes { false };
+
+    bool m_is_open { false };
 };
 
 }