xpcom/ds/nsGkAtoms.cpp

   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 #include "nsGkAtoms.h"
   8
   9 namespace mozilla {
  10 namespace detail {
  11
  12 // Because this is `constexpr` it ends up in read-only memory where it can be
  13 // shared between processes.
  14 extern constexpr GkAtoms gGkAtoms = {
  15 // The initialization of each atom's string.
  16 //
  17 // Expansion of the example GK_ATOM entries in nsGkAtoms.h:
  18 //
  19 //   u"a",
  20 //   u"bb",
  21 //   u"Ccc",
  22 //
  23 #define GK_ATOM(name_, value_, hash_, is_ascii_lower_, type_, atom_type_) \
  24   u"" value_,
  25 #include "nsGkAtomList.h"
  26 #undef GK_ATOM
  27     {
  28 // The initialization of the atoms themselves.
  29 //
  30 // Note that |value_| is an 8-bit string, and so |sizeof(value_)| is equal
  31 // to the number of chars (including the terminating '\0'). The |u""| prefix
  32 // converts |value_| to a 16-bit string.
  33 //
  34 // Expansion of the example GK_ATOM entries in nsGkAtoms.h:
  35 //
  36 //   nsStaticAtom(
  37 //     1,
  38 //     0x01234567,
  39 //     offsetof(GkAtoms, mAtoms[static_cast<size_t>(GkAtoms::Atoms::a)]) -
  40 //       offsetof(GkAtoms, a_string),
  41 //     true),
  42 //
  43 //   nsStaticAtom(
  44 //     2,
  45 //     0x12345678,
  46 //     offsetof(GkAtoms, mAtoms[static_cast<size_t>(GkAtoms::Atoms::bb)]) -
  47 //       offsetof(GkAtoms, bb_string),
  48 //     false),
  49 //
  50 //   nsStaticAtom(
  51 //     3,
  52 //     0x23456789,
  53 //     offsetof(GkAtoms, mAtoms[static_cast<size_t>(GkAtoms::Atoms::Ccc)]) -
  54 //       offsetof(GkAtoms, Ccc_string),
  55 //     false),
  56 //
  57 #define GK_ATOM(name_, value_, hash_, is_ascii_lower_, type_, atom_type_)     \
  58   nsStaticAtom(                                                               \
  59       sizeof(value_) - 1, hash_,                                              \
  60       offsetof(GkAtoms, mAtoms[static_cast<size_t>(GkAtoms::Atoms::name_)]) - \
  61           offsetof(GkAtoms, name_##_string),                                  \
  62       is_ascii_lower_),
  63 #include "nsGkAtomList.h"
  64 #undef GK_ATOM
  65     }};
  66
  67 }  // namespace detail
  68 }  // namespace mozilla
  69
  70 const nsStaticAtom* const nsGkAtoms::sAtoms = mozilla::detail::gGkAtoms.mAtoms;