layout/painting/nsDisplayItemTypes.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   6  */
   7 // IWYU pragma: private, include "nsDisplayList.h"
   8
   9 /**
  10  * It's useful to be able to dynamically check the type of certain items.
  11  * Every subclass of nsDisplayItem must have a new type added here for the
  12  * purposes of easy comparison and matching of items in different display lists.
  13  */
  14
  15 #ifndef NSDISPLAYITEMTYPES_H_
  16 #define NSDISPLAYITEMTYPES_H_
  17
  18 enum class DisplayItemType : uint8_t {
  19   TYPE_ZERO = 0, /** Spacer so that the first item starts at 1 */
  20
  21 #define DECLARE_DISPLAY_ITEM_TYPE(name, flags) TYPE_##name,
  22 #include "nsDisplayItemTypesList.h"
  23 #undef DECLARE_DISPLAY_ITEM_TYPE
  24
  25   TYPE_MAX
  26 };
  27
  28 enum {
  29   // Number of bits needed to represent all types
  30   TYPE_BITS = 8
  31 };
  32
  33 enum DisplayItemFlags {
  34   TYPE_RENDERS_NO_IMAGES = 1 << 0,
  35   TYPE_IS_CONTENTFUL = 1 << 1,
  36   TYPE_IS_CONTAINER = 1 << 2
  37 };
  38
  39 inline const char* DisplayItemTypeName(DisplayItemType aType) {
  40   switch (aType) {
  41 #define DECLARE_DISPLAY_ITEM_TYPE(name, flags) \
  42   case DisplayItemType::TYPE_##name:           \
  43     return #name;
  44 #include "nsDisplayItemTypesList.h"
  45 #undef DECLARE_DISPLAY_ITEM_TYPE
  46
  47     default:
  48       return "TYPE_UNKNOWN";
  49   }
  50 }
  51
  52 inline uint8_t GetDisplayItemFlagsForType(DisplayItemType aType) {
  53   static const uint8_t flags[static_cast<uint32_t>(DisplayItemType::TYPE_MAX)] =
  54       {0
  55 #define DECLARE_DISPLAY_ITEM_TYPE(name, flags) , flags
  56 #include "nsDisplayItemTypesList.h"
  57 #undef DECLARE_DISPLAY_ITEM_TYPE
  58       };
  59
  60   return flags[static_cast<uint32_t>(aType)];
  61 }
  62
  63 inline DisplayItemType GetDisplayItemTypeFromKey(uint32_t aDisplayItemKey) {
  64   static const uint32_t typeMask = (1 << TYPE_BITS) - 1;
  65   DisplayItemType type =
  66       static_cast<DisplayItemType>(aDisplayItemKey & typeMask);
  67   NS_ASSERTION(
  68       type >= DisplayItemType::TYPE_ZERO && type < DisplayItemType::TYPE_MAX,
  69       "Invalid display item type!");
  70   return type;
  71 }
  72
  73 #endif /*NSDISPLAYITEMTYPES_H_*/