dom/base/DOMArena.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: set ts=2 sw=2 et tw=78:
   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 #ifndef DOM_Arena_h___
   8 #define DOM_Arena_h___
   9 #include "nsISupportsImpl.h"
  10 #include "mozmemory.h"
  11
  12 #include "mozilla/mozalloc_oom.h"  // for mozalloc_handle_oom
  13
  14 #define NS_DECL_DOMARENA_DESTROY void Destroy(void);
  15
  16 #define NS_IMPL_DOMARENA_DESTROY(class)                              \
  17   void class ::Destroy(void) {                                       \
  18     if (StaticPrefs::dom_arena_allocator_enabled_AtStartup()) {      \
  19       RefPtr<nsNodeInfoManager> nim = OwnerDoc()->NodeInfoManager(); \
  20       RefPtr<DOMArena> arena =                                       \
  21           HasFlag(NODE_KEEPS_DOMARENA)                               \
  22               ? nsContentUtils::TakeEntryFromDOMArenaTable(this)     \
  23               : nullptr;                                             \
  24       this->~class();                                                \
  25       MOZ_ASSERT(nim, "nsNodeInfoManager needs to be initialized");  \
  26       nim->Free(this);                                               \
  27     } else {                                                         \
  28       delete this;                                                   \
  29     }                                                                \
  30   }
  31
  32 namespace mozilla::dom {
  33
  34 class DOMArena {
  35  public:
  36   friend class DocGroup;
  37   DOMArena() {
  38     arena_params_t params;
  39     params.mMaxDirtyIncreaseOverride = 7;
  40     params.mFlags = ARENA_FLAG_THREAD_MAIN_THREAD_ONLY;
  41     mArenaId = moz_create_arena_with_params(&params);
  42   }
  43
  44   NS_INLINE_DECL_REFCOUNTING(DOMArena)
  45
  46   void* Allocate(size_t aSize) {
  47     void* ret = moz_arena_malloc(mArenaId, aSize);
  48     if (!ret) {
  49       mozalloc_handle_oom(aSize);
  50     }
  51     return ret;
  52   }
  53
  54  private:
  55   ~DOMArena() { moz_dispose_arena(mArenaId); }
  56   arena_id_t mArenaId;
  57 };
  58 }  // namespace mozilla::dom
  59 #endif