1 files changed, 73 insertions, 0 deletions
diff --git a/layout/painting/nsDisplayItemTypes.h b/layout/painting/nsDisplayItemTypes.h
new file mode 100644
index 0000000000..f0c7c333e0
--- /dev/null
+++ b/layout/painting/nsDisplayItemTypes.h
@@ -0,0 +1,73 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// IWYU pragma: private, include "nsDisplayList.h"
+
+/**
+ * It's useful to be able to dynamically check the type of certain items.
+ * Every subclass of nsDisplayItem must have a new type added here for the
+ * purposes of easy comparison and matching of items in different display lists.
+ */
+
+#ifndef NSDISPLAYITEMTYPES_H_
+#define NSDISPLAYITEMTYPES_H_
+
+enum class DisplayItemType : uint8_t {
+  TYPE_ZERO = 0, /** Spacer so that the first item starts at 1 */
+
+#define DECLARE_DISPLAY_ITEM_TYPE(name, flags) TYPE_##name,
+#include "nsDisplayItemTypesList.h"
+#undef DECLARE_DISPLAY_ITEM_TYPE
+
+  TYPE_MAX
+};
+
+enum {
+  // Number of bits needed to represent all types
+  TYPE_BITS = 8
+};
+
+enum DisplayItemFlags {
+  TYPE_RENDERS_NO_IMAGES = 1 << 0,
+  TYPE_IS_CONTENTFUL = 1 << 1,
+  TYPE_IS_CONTAINER = 1 << 2
+};
+
+inline const char* DisplayItemTypeName(DisplayItemType aType) {
+  switch (aType) {
+#define DECLARE_DISPLAY_ITEM_TYPE(name, flags) \
+  case DisplayItemType::TYPE_##name:           \
+    return #name;
+#include "nsDisplayItemTypesList.h"
+#undef DECLARE_DISPLAY_ITEM_TYPE
+
+    default:
+      return "TYPE_UNKNOWN";
+  }
+}
+
+inline uint8_t GetDisplayItemFlagsForType(DisplayItemType aType) {
+  static const uint8_t flags[static_cast<uint32_t>(DisplayItemType::TYPE_MAX)] =
+      {0
+#define DECLARE_DISPLAY_ITEM_TYPE(name, flags) , flags
+#include "nsDisplayItemTypesList.h"
+#undef DECLARE_DISPLAY_ITEM_TYPE
+      };
+
+  return flags[static_cast<uint32_t>(aType)];
+}
+
+inline DisplayItemType GetDisplayItemTypeFromKey(uint32_t aDisplayItemKey) {
+  static const uint32_t typeMask = (1 << TYPE_BITS) - 1;
+  DisplayItemType type =
+      static_cast<DisplayItemType>(aDisplayItemKey & typeMask);
+  NS_ASSERTION(
+      type >= DisplayItemType::TYPE_ZERO && type < DisplayItemType::TYPE_MAX,
+      "Invalid display item type!");
+  return type;
+}
+
+#endif /*NSDISPLAYITEMTYPES_H_*/