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 "nsHashKeys.h"
  21 #include "nsTArray.h"
  22 #include "nsTHashtable.h"
  23
  24 class nsWindowSizes;
  25
  26 template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
  27 class nsPresArena {
  28  public:
  29   nsPresArena() = default;
  30   ~nsPresArena();
  31
  32   /**
  33    * Pool allocation with recycler lists indexed by object-type ID (see above).
  34    * Every aID must always be used with the same object size, aSize.
  35    */
  36   void* Allocate(ObjectId aCode, size_t aSize);
  37   void Free(ObjectId aCode, void* aPtr);
  38
  39   enum class ArenaKind { PresShell, DisplayList };
  40   /**
  41    * Increment nsWindowSizes with sizes of interesting objects allocated in this
  42    * arena, and put the general unclassified size in the relevant field
  43    * depending on the arena size.
  44    */
  45   void AddSizeOfExcludingThis(nsWindowSizes&, ArenaKind) const;
  46
  47   void Check() { mPool.Check(); }
  48
  49  private:
  50   class FreeList {
  51    public:
  52     nsTArray<void*> mEntries;
  53     size_t mEntrySize;
  54     size_t mEntriesEverAllocated;
  55
  56     FreeList() : mEntrySize(0), mEntriesEverAllocated(0) {}
  57
  58     size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
  59       return mEntries.ShallowSizeOfExcludingThis(aMallocSizeOf);
  60     }
  61   };
  62
  63   FreeList mFreeLists[ObjectIdCount];
  64   mozilla::ArenaAllocator<ArenaSize, 8> mPool;
  65 };
  66
  67 #endif