layout/base/nsPresArena.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
   8 /* arena allocation for the frame tree and closely-related objects */
   9
  10 #ifndef nsPresArena_h___
  11 #define nsPresArena_h___
  12
  13 #include "mozilla/ArenaAllocator.h"
  14 #include "mozilla/ArenaObjectID.h"
  15 #include "mozilla/Assertions.h"
  16 #include "mozilla/MemoryChecking.h"  // Note: Do not remove this, needed for MOZ_HAVE_MEM_CHECKS below
  17 #include "mozilla/MemoryReporting.h"
  18 #include <stdint.h>
  19 #include "nscore.h"
  20 #include "nsDataHashtable.h"
  21 #include "nsHashKeys.h"
  22 #include "nsTArray.h"
  23 #include "nsTHashtable.h"
  24
  25 class nsWindowSizes;
  26
  27 template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
  28 class nsPresArena {
  29  public:
  30   nsPresArena() = default;
  31   ~nsPresArena();
  32
  33   /**
  34    * Pool allocation with recycler lists indexed by object-type ID (see above).
  35    * Every aID must always be used with the same object size, aSize.
  36    */
  37   void* Allocate(ObjectId aCode, size_t aSize);
  38   void Free(ObjectId aCode, void* aPtr);
  39
  40   enum class ArenaKind { PresShell, DisplayList };
  41   /**
  42    * Increment nsWindowSizes with sizes of interesting objects allocated in this
  43    * arena, and put the general unclassified size in the relevant field
  44    * depending on the arena size.
  45    */
  46   void AddSizeOfExcludingThis(nsWindowSizes&, ArenaKind) const;
  47
  48   void Check() { mPool.Check(); }
  49
  50  private:
  51   class FreeList {
  52    public:
  53     nsTArray<void*> mEntries;
  54     size_t mEntrySize;
  55     size_t mEntriesEverAllocated;
  56
  57     FreeList() : mEntrySize(0), mEntriesEverAllocated(0) {}
  58
  59     size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
  60       return mEntries.ShallowSizeOfExcludingThis(aMallocSizeOf);
  61     }
  62   };
  63
  64   FreeList mFreeLists[ObjectIdCount];
  65   mozilla::ArenaAllocator<ArenaSize, 8> mPool;
  66 };
  67
  68 #endif