From 1b703629548950882063495679b9307519271b92 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Tue, 20 Aug 2024 18:44:22 -0400
Subject: [PATCH] LibWeb: Implement the DataTransfer items attribute

---
 Userland/Libraries/LibWeb/HTML/DataTransfer.cpp  | 16 ++++++++++++++++
 Userland/Libraries/LibWeb/HTML/DataTransfer.h    |  6 ++++++
 Userland/Libraries/LibWeb/HTML/DataTransfer.idl  |  3 ++-
 .../LibWeb/HTML/DataTransferItemList.cpp         | 15 ++++++++++++++-
 .../Libraries/LibWeb/HTML/DataTransferItemList.h |  6 +++++-
 5 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/Userland/Libraries/LibWeb/HTML/DataTransfer.cpp b/Userland/Libraries/LibWeb/HTML/DataTransfer.cpp
index b109537dc58..8cd25b62284 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransfer.cpp
+++ b/Userland/Libraries/LibWeb/HTML/DataTransfer.cpp
@@ -12,6 +12,7 @@
 #include <LibWeb/FileAPI/File.h>
 #include <LibWeb/FileAPI/FileList.h>
 #include <LibWeb/HTML/DataTransfer.h>
+#include <LibWeb/HTML/DataTransferItemList.h>
 #include <LibWeb/Infra/Strings.h>
 
 namespace Web::HTML {
@@ -44,6 +45,12 @@ void DataTransfer::initialize(JS::Realm& realm)
     WEB_SET_PROTOTYPE_FOR_INTERFACE(DataTransfer);
 }
 
+void DataTransfer::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_items);
+}
+
 void DataTransfer::set_drop_effect(String const& drop_effect)
 {
     set_drop_effect(FlyString { drop_effect });
@@ -82,6 +89,15 @@ void DataTransfer::set_effect_allowed_internal(FlyString effect_allowed)
         m_effect_allowed = AK::move(effect_allowed);
 }
 
+// https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransfer-items
+JS::NonnullGCPtr<DataTransferItemList> DataTransfer::items()
+{
+    // The items attribute must return a DataTransferItemList object associated with the DataTransfer object.
+    if (!m_items)
+        m_items = DataTransferItemList::create(realm(), *this);
+    return *m_items;
+}
+
 // https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransfer-types
 ReadonlySpan<String> DataTransfer::types() const
 {
diff --git a/Userland/Libraries/LibWeb/HTML/DataTransfer.h b/Userland/Libraries/LibWeb/HTML/DataTransfer.h
index cc71f3b2f1b..0bdeacb2cb7 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransfer.h
+++ b/Userland/Libraries/LibWeb/HTML/DataTransfer.h
@@ -49,6 +49,8 @@ public:
     void set_effect_allowed(FlyString);
     void set_effect_allowed_internal(FlyString);
 
+    JS::NonnullGCPtr<DataTransferItemList> items();
+
     ReadonlySpan<String> types() const;
     String get_data(String const& format) const;
     JS::NonnullGCPtr<FileAPI::FileList> files() const;
@@ -60,6 +62,7 @@ private:
     DataTransfer(JS::Realm&);
 
     virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(JS::Cell::Visitor&) override;
 
     void update_data_transfer_types_list();
 
@@ -69,6 +72,9 @@ private:
     // https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransfer-effectallowed
     FlyString m_effect_allowed { DataTransferEffect::none };
 
+    // https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransfer-items
+    JS::GCPtr<DataTransferItemList> m_items;
+
     // https://html.spec.whatwg.org/multipage/dnd.html#concept-datatransfer-types
     Vector<String> m_types;
 
diff --git a/Userland/Libraries/LibWeb/HTML/DataTransfer.idl b/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
index bb96818413b..460be573368 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
+++ b/Userland/Libraries/LibWeb/HTML/DataTransfer.idl
@@ -1,4 +1,5 @@
 #import <FileAPI/FileList.idl>
+#import <HTML/DataTransferItemList.idl>
 
 // https://html.spec.whatwg.org/multipage/dnd.html#datatransfer
 [Exposed=Window]
@@ -8,7 +9,7 @@ interface DataTransfer {
     attribute DOMString dropEffect;
     attribute DOMString effectAllowed;
 
-    [FIXME, SameObject] readonly attribute DataTransferItemList items;
+    [SameObject] readonly attribute DataTransferItemList items;
 
     [FIXME] undefined setDragImage(Element image, long x, long y);
 
diff --git a/Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp b/Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp
index fb14dfef8a8..1b10c6eecbd 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp
+++ b/Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp
@@ -7,14 +7,21 @@
 #include <LibJS/Runtime/Realm.h>
 #include <LibWeb/Bindings/DataTransferItemListPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/HTML/DataTransfer.h>
 #include <LibWeb/HTML/DataTransferItemList.h>
 
 namespace Web::HTML {
 
 JS_DEFINE_ALLOCATOR(DataTransferItemList);
 
-DataTransferItemList::DataTransferItemList(JS::Realm& realm)
+JS::NonnullGCPtr<DataTransferItemList> DataTransferItemList::create(JS::Realm& realm, JS::NonnullGCPtr<DataTransfer> data_transfer)
+{
+    return realm.heap().allocate<DataTransferItemList>(realm, realm, data_transfer);
+}
+
+DataTransferItemList::DataTransferItemList(JS::Realm& realm, JS::NonnullGCPtr<DataTransfer> data_transfer)
     : PlatformObject(realm)
+    , m_data_transfer(data_transfer)
 {
 }
 
@@ -26,4 +33,10 @@ void DataTransferItemList::initialize(JS::Realm& realm)
     WEB_SET_PROTOTYPE_FOR_INTERFACE(DataTransferItemList);
 }
 
+void DataTransferItemList::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_data_transfer);
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/HTML/DataTransferItemList.h b/Userland/Libraries/LibWeb/HTML/DataTransferItemList.h
index 50e4d1ce13c..5f773de66bc 100644
--- a/Userland/Libraries/LibWeb/HTML/DataTransferItemList.h
+++ b/Userland/Libraries/LibWeb/HTML/DataTransferItemList.h
@@ -17,12 +17,16 @@ class DataTransferItemList : public Bindings::PlatformObject {
     JS_DECLARE_ALLOCATOR(DataTransferItemList);
 
 public:
+    static JS::NonnullGCPtr<DataTransferItemList> create(JS::Realm&, JS::NonnullGCPtr<DataTransfer>);
     virtual ~DataTransferItemList() override;
 
 private:
-    DataTransferItemList(JS::Realm&);
+    DataTransferItemList(JS::Realm&, JS::NonnullGCPtr<DataTransfer>);
 
     virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(JS::Cell::Visitor&) override;
+
+    JS::NonnullGCPtr<DataTransfer> m_data_transfer;
 };
 
 }