LibWeb: Implement DataTransferItemList.prototype.add()

Author: https://github.com/trflynn89
Commit: 74d9cfbf2a
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1158
Reviewed-by: https://github.com/shannonbooth

Userland/Libraries/LibWeb/HTML/DataTransferItemList.cpp

@@ -7,8 +7,10 @@
 #include <LibJS/Runtime/Realm.h>
 #include <LibWeb/Bindings/DataTransferItemListPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/FileAPI/File.h>
 #include <LibWeb/HTML/DataTransfer.h>
 #include <LibWeb/HTML/DataTransferItemList.h>
+#include <LibWeb/Infra/Strings.h>
 
 namespace Web::HTML {
 
@@ -39,4 +41,63 @@ void DataTransferItemList::visit_edges(JS::Cell::Visitor& visitor)
     visitor.visit(m_data_transfer);
 }
 
+// https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransferitemlist-add
+WebIDL::ExceptionOr<JS::GCPtr<DataTransferItem>> DataTransferItemList::add(String const& data, String const& type)
+{
+    auto& realm = this->realm();
+
+    // 1. If the DataTransferItemList object is not in the read/write mode, return null.
+    if (m_data_transfer->mode() != DragDataStore::Mode::ReadWrite)
+        return nullptr;
+
+    // 2. Jump to the appropriate set of steps from the following list:
+    //    -> If the first argument to the method is a string
+
+    // If there is already an item in the drag data store item list whose kind is text and whose type string is equal
+    // to the value of the method's second argument, converted to ASCII lowercase, then throw a "NotSupportedError"
+    // DOMException.
+    if (m_data_transfer->contains_item_with_type(DragDataStoreItem::Kind::Text, type)) {
+        auto error = MUST(String::formatted("There is already a DataTransferItem with type {}", type));
+        return WebIDL::NotSupportedError::create(realm, error);
+    }
+
+    // Otherwise, add an item to the drag data store item list whose kind is text, whose type string is equal to the
+    // value of the method's second argument, converted to ASCII lowercase, and whose data is the string given by the
+    // method's first argument.
+    auto item = m_data_transfer->add_item({
+        .kind = HTML::DragDataStoreItem::Kind::Text,
+        .type_string = MUST(Infra::to_ascii_lowercase(type)),
+        .data = MUST(ByteBuffer::copy(data.bytes())),
+        .file_name = {},
+    });
+
+    // 3. Determine the value of the indexed property corresponding to the newly added item, and return that value (a
+    //    newly created DataTransferItem object).
+    return item;
+}
+
+// https://html.spec.whatwg.org/multipage/dnd.html#dom-datatransferitemlist-add
+JS::GCPtr<DataTransferItem> DataTransferItemList::add(JS::NonnullGCPtr<FileAPI::File> file)
+{
+    // 1. If the DataTransferItemList object is not in the read/write mode, return null.
+    if (m_data_transfer->mode() != DragDataStore::Mode::ReadWrite)
+        return nullptr;
+
+    // 2. Jump to the appropriate set of steps from the following list:
+    //     -> If the first argument to the method is a File
+
+    // Add an item to the drag data store item list whose kind is File, whose type string is the type of the File,
+    // converted to ASCII lowercase, and whose data is the same as the File's data.
+    auto item = m_data_transfer->add_item({
+        .kind = HTML::DragDataStoreItem::Kind::File,
+        .type_string = MUST(Infra::to_ascii_lowercase(file->type())),
+        .data = MUST(ByteBuffer::copy(file->raw_bytes())),
+        .file_name = file->name().to_byte_string(),
+    });
+
+    // 3. Determine the value of the indexed property corresponding to the newly added item, and return that value (a
+    //    newly created DataTransferItem object).
+    return item;
+}
+
 }