LibWeb: Begin implementing the drag data store

Author: https://github.com/trflynn89
Commit: https://github.com/LadybirdBrowser/ladybird/commit/9e98e63559e
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1111

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -284,6 +284,7 @@ set(SOURCES
     HTML/DOMParser.cpp
     HTML/DOMStringList.cpp
     HTML/DOMStringMap.cpp
+    HTML/DragDataStore.cpp
     HTML/DragEvent.cpp
     HTML/ElementInternals.cpp
     HTML/EmbedderPolicy.cpp

Userland/Libraries/LibWeb/Forward.h

@@ -360,6 +360,7 @@ class DocumentState;
 class DOMParser;
 class DOMStringList;
 class DOMStringMap;
+class DragDataStore;
 class DragEvent;
 class ElementInternals;
 struct EmbedderPolicy;

Userland/Libraries/LibWeb/HTML/DragDataStore.cpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/HTML/DataTransfer.h>
+#include <LibWeb/HTML/DragDataStore.h>
+
+namespace Web::HTML {
+
+DragDataStore::DragDataStore()
+    : m_allowed_effects_state(DataTransferEffect::uninitialized)
+{
+}
+
+DragDataStore::~DragDataStore() = default;
+
+bool DragDataStore::has_text_item() const
+{
+    for (auto const& item : m_item_list) {
+        if (item.kind == DragDataStoreItem::Kind::Text && item.type_string == "text/plain"sv)
+            return true;
+    }
+
+    return false;
+}
+
+}

Userland/Libraries/LibWeb/HTML/DragDataStore.h

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2024, Tim Flynn <trflynn89@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/ByteBuffer.h>
+#include <AK/ByteString.h>
+#include <AK/FlyString.h>
+#include <AK/String.h>
+#include <AK/Vector.h>
+#include <LibGfx/Bitmap.h>
+#include <LibGfx/Point.h>
+
+namespace Web::HTML {
+
+struct DragDataStoreItem {
+    enum class Kind {
+        Text,
+        File,
+    };
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#the-drag-data-item-kind
+    Kind kind { Kind::Text };
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#the-drag-data-item-type-string
+    String type_string;
+
+    ByteBuffer data;
+    ByteString file_name;
+};
+
+// https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store
+class DragDataStore {
+public:
+    enum class Mode {
+        ReadWrite,
+        ReadOnly,
+        Protected,
+    };
+
+    DragDataStore();
+    ~DragDataStore();
+
+    void add_item(DragDataStoreItem item) { m_item_list.append(move(item)); }
+    ReadonlySpan<DragDataStoreItem> item_list() const { return m_item_list; }
+    bool has_text_item() const;
+
+    Mode mode() const { return m_mode; }
+    void set_mode(Mode mode) { m_mode = mode; }
+
+    FlyString allowed_effects_state() const { return m_allowed_effects_state; }
+    void set_allowed_effects_state(FlyString allowed_effects_state) { m_allowed_effects_state = move(allowed_effects_state); }
+
+private:
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-item-list
+    Vector<DragDataStoreItem> m_item_list;
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-default-feedback
+    String m_default_feedback;
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-bitmap
+    RefPtr<Gfx::Bitmap> m_bitmap;
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-hot-spot-coordinate
+    Gfx::IntPoint m_hot_spot_coordinate;
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-mode
+    Mode m_mode { Mode::Protected };
+
+    // https://html.spec.whatwg.org/multipage/dnd.html#drag-data-store-allowed-effects-state
+    FlyString m_allowed_effects_state;
+};
+
+}