tor-browser

The Tor Browser
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DOMArena.h (2281B)

      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 "mozilla/mozalloc_oom.h"  // for mozalloc_handle_oom
     10 #include "mozmemory.h"
     11 #include "nsISupportsImpl.h"
     12 #include "nsString.h"
     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  explicit DOMArena(const nsACString& aLabel) {
     38    nsCString label = PromiseFlatCString("DOMArena "_ns + aLabel);
     39 
     40    arena_params_t params;
     41    params.mMaxDirtyIncreaseOverride = 7;
     42    params.mFlags = ARENA_FLAG_THREAD_MAIN_THREAD_ONLY;
     43    params.mLabel = label.get();
     44    mArenaId = moz_create_arena_with_params(&params);
     45  }
     46 
     47  NS_INLINE_DECL_REFCOUNTING(DOMArena)
     48 
     49  void* Allocate(size_t aSize) {
     50    void* ret = moz_arena_malloc(mArenaId, aSize);
     51    if (!ret) {
     52      mozalloc_handle_oom(aSize);
     53    }
     54    return ret;
     55  }
     56 
     57 private:
     58  ~DOMArena() { moz_dispose_arena(mArenaId); }
     59  arena_id_t mArenaId;
     60 };
     61 }  // namespace mozilla::dom
     62 #endif