dom/bindings/PinnedStringId.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 file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOM_BINDINGS_PINNEDSTRINGID_H_
   8 #define DOM_BINDINGS_PINNEDSTRINGID_H_
   9
  10 #include "js/GCAnnotations.h"
  11 #include "js/Id.h"
  12 #include "js/RootingAPI.h"
  13 #include "jsapi.h"
  14
  15 class JSString;
  16 struct JSContext;
  17
  18 namespace mozilla::dom {
  19 /*
  20  * Holds a jsid that is initialized to a pinned string, with automatic
  21  * conversion to Handle<jsid>, as it is held live forever by pinning.
  22  */
  23 class PinnedStringId {
  24   jsid id;
  25
  26  public:
  27   constexpr PinnedStringId() : id(JSID_VOID) {}
  28
  29   bool init(JSContext* cx, const char* string) {
  30     JSString* str = JS_AtomizeAndPinString(cx, string);
  31     if (!str) {
  32       return false;
  33     }
  34     id = JS::PropertyKey::fromPinnedString(str);
  35     return true;
  36   }
  37
  38   operator const jsid&() const { return id; }
  39
  40   operator JS::Handle<jsid>() const {
  41     /* This is safe because we have pinned the string. */
  42     return JS::Handle<jsid>::fromMarkedLocation(&id);
  43   }
  44 } JS_HAZ_ROOTED;
  45 }  // namespace mozilla::dom
  46
  47 #endif